Wildguzzi.com
General Category => Bike Builds, Rebuilds And Restorations Only => Topic started by: SED on March 25, 2015, 10:42:18 PM
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The Monza tires were very slippery in the wet. Dot markings indicated 20 years old :o Ordered new Road Riders.
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_5553crop_zpsc5272b40.jpg)
New tires means removing the wheels, and wheels were looking a little shabby, so took them to the powder coater. Made an executive decision to eliminate the black. They will be all silver like the LMIII (and the cooking V50). Color is called "Silverstone".
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1330crop_zpsbabemzpf.jpg)
The forks were leaking a bit of fork oil and seemed to lack some rebound damping so better rebuild those. I've rebuilt girders and mtn bike forks - how hard can this be? :BEER: Pulled the fairing and loosened everything up:
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1339_zpsfre5taky.jpg)
Darn fork tubes were stuck in the triple clamps so used a rubber hammer to drive them out and got a little careless: (ugh! this is the type of thing I hate doing and it's the second time on this bike :'( )
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1351_zpswr2zehao.jpg)
Removed the instrument panel so I don't bash the speedo too:
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1353_zps6bc53ocd.jpg)
Actually a good trick is to just put the axle through the lower fork leg and use the rubber mallet on the axle. If only I'd thought of it earlier...
edit 3/29/2015
:+=copcar Stop!!! A better method was just posted by JRT on another topic. Take the pinch bolts out of the lower yoke and thread them in from the back then drop a washer or thin plate into the slot in the yoke and tighten the bolt against it. It will spread the slot and loosen the clamp on the stanchions. Nicer than either a wedge or a hammer.
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Ahh , the famous 30 minute repair job :D
Dusty
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Ordered seals, dust seals and FAC dampers from MotoInternational. ;-T
To pull the fork lowers off the stanchions a hex bolt has to be removed from the bottom of the lowers. It's accessible after the axle pinch bolt is removed.
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1346_zpstjxuon3j.jpg)
Then the cartridge and spring assembly can be unscrewed from the stanchions.
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1348_zpsl0icoftz.jpg)
Then the snapring at the bottom of the spring becomes accessible so that the spring can be removed from the cartridge assembly:
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1356_zpsxre4apoh.jpg)
There is a little plastic spacer between the cartridge and the top of the spring:
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1355_zpsmbqhzksi.jpg)
Seals arrived from MotoInt, chrome on the stanchions looks good, just waiting on the FAC dampers.
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Ahh , the famous 30 minute repair job :D
Dusty
Yes, there a bit of mission creep going on.
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While waiting for the powder coater and the dampers, I check out the speedo drive. Reportedly the small block speedo drives are very fragile and have a tendency to seize and break the drive tang off which renders them useless.
The brass receptacle for the speedo cable had slipped a cm or so out of the housing so I just pulled on it and the worm gear came out with it.
There was a retainer ring on the back so pulled it too to release the drive tang. Haven't figured out how to pull the rest of it apart, but may not need to. Will clean it and pack it with grease and hopefully it will last another 34 years.
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1378_zpspd5opmup.jpg)
Also had time to go to the friendly glass cutter and they cut a new lens for the tach: (the rim is only a little bashed :-[)
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1389_zpsko1w1td5.jpg)
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The steering head bearings have a bad reputation so the triple tree yokes had to be pulled to check. Until the late 1980s (I think!) small blocks ran loose ball bearings rather than tapered roller bearings like modern bikes. These bearings have a reputation for early failure but these were not terrible. Lower race in the head tube looks OK:
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1370_zpszjavfqus.jpg)
Strangely the upper race is in the worst condition because the track for the balls was chromed! This picture shows chrome flaking from the bearing surface. Why would they chrome plate a bearing surface?! :P
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1374_zpsm7yetnv4.jpg)
Polished the inner races and bought 44 new balls. I measured the balls at 0.1875" (3/16"). I expected them to be metric!
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1375_zpsssdo7hbp.jpg)
With the triple clamps out I decided to remove the steering lock because I didn't have a key for it. Pry the brass rivet out using a strong knife blade as a wedge, pull the cover, then use a large punch the diameter of the lock cylinder to drive the lock cylinder in about 3/8". The pin that holds the lock cylinder will be sheared and the lock removed by pushing it out - not in (good info here: http://w6rec.com/duane/bmw/lock/)
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1341crop_zpskezyub5g.jpg)
After the lock cylinder was removed I used a dremel to cut a slot in the sheared pin and removed it. It was easy to replace with a short length of 3mm bolt. I also pulled the cover off the lock pins (tumblers?) - they are tiny! Much smaller than household lock pins. And the springs are tiny and fly everywhere. There are 5 pins (the BMW site says 4) and I removed one, filed one and made another and was able to rekey the lock so that it uses the same key as my LMIII but with 4 instead of 5 pins. I now have a key! ;-T
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SED,
Removing my fork tubes is accomplished by driving wedges into the gaps in the triple tree. The gaps are closed with pinch bolts to hold the tubes securely. With the gaps spread, twisting the tubes one way, then the other, liberates the tube quickly. That's my bike anyway.
With your bike being 34 yo however, that might be asking a bit much if there was a chemical(?) reaction between the different metals in the tube and triple tree. glad you did not have to hammer the axle :o ;D
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Removed the instrument panel so I don't bash the speedo too:
;D ;D
And yeah the balls are 3/16". Surprised me, too.
Nice tutorial.. ;-T
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SED,
Removing my fork tubes is accomplished by driving wedges into the gaps in the triple tree. The gaps are closed with pinch bolts to hold the tubes securely. With the gaps spread, twisting the tubes one way, then the other, liberates the tube quickly. That's my bike anyway.
With your bike being 34 yo however, that might be asking a bit much if there was a chemical(?) reaction between the different metals in the tube and triple tree. glad you did not have to hammer the axle :o ;D
:+1
The condition is called Shipwright's disease. Can't put a new part on a grungy old part.
Bashing the axle would be a good way to possibly damage the fork slider or the damper cartridges. Brute force should be reserved for Caterpillar D9 maintenance. Nice write up though. I miss my Monza.
;-T
Tobit
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Thanks for posting the steps on rebuilding the forks. It all makes sense now!
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Great post. These sort of DIY posts are priceless. Thanks. ;-T
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If the fork tubes don't come out willingly, I just leave them in the triple clamps. Sliders come off the bottom, damper spring units out the top. Less aggravation and achieves the same result.
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:+1
The condition is called Shipwright's disease. Can't put a new part on a grungy old part.
Bashing the axle would be a good way to possibly damage the fork slider or the damper cartridges. Brute force should be reserved for Caterpillar D9 maintenance. Nice write up though. I miss my Monza.
;-T
Tobit
(edit 3/29/2015)
:+=copcar Stop the presses!!! Tobit's right. A better method was just posted by JRT on another topic. Take the pinch bolts out of the lower yoke and thread them in from the back then drop a washer or thin plate into the slot in the yoke and tighten the bolt against it. It will spread the slot and loosen the clamp on the stanchions. Nicer than either a wedge or a hammer. Wish I'd read it a week ago. (end edit)
Apparently I did all the bashing on the tacho :'(. The stanchions were moving, but very tight so using a rubber mallet on the axle wasn't too bad - not trying to break anything loose and the axle fits well in its bore. But Charlie's, right I could have left them in the triple clamps but I've never had motorcycle tele forks all the way apart before so I figured I better try to do it by the book. :P
Removing my fork tubes is accomplished by driving wedges into the gaps in the triple tree. The gaps are closed with pinch bolts to hold the tubes securely. With the gaps spread, twisting the tubes one way, then the other, liberates the tube quickly. That's my bike anyway.
Balvene, I did however use a wedge to open the bore once the stanchions were out. But the clamps in the Monza yokes are not split to the outside like some forks so couldn't get a wedge in with the yokes on the bike. I knew I'd never be able to install the stanchions back in them without spreading them so used a cold chisel. (More brute force and ignorance but it worked. :BEER:)
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1376_zpsiopizbrq.jpg)
Thanks for all the kind words all! More soon!
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Great photo in front of Mt Shuksan, added to my screensaver. What road were you on?
Matt.
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Great photo in front of Mt Shuksan, added to my screensaver. What road were you on?
Matt.
Good eye Matt!
It's the road to Artist's Point above the Mt Baker ski area just one turn below the top. Most years they try to get it open by the end of July, but this year it'll probably melt out by the end of May. Going to be a dry summer...
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If the fork tubes don't come out willingly, I just leave them in the triple clamps. Sliders come off the bottom, damper spring units out the top. Less aggravation and achieves the same result.
[/quote
Kinda hard to get at the neck bearings that way Charlie :D
Dusty
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Need to clean up the fork lowers so pulled the top seal with a bent screw driver:
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1354_zpsn0nbmuat.jpg)
and made sure the "lower element" (brimstone? ;))came out of the bottom of the slider:
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1350_zpslveen7ig.jpg)
Soaked the sliders in hot water and powdered laundry detergent and scrubbed them all over. Was wondering how to clean all the way down the inside of the slider. Finally figured out that a threaded a loop of wire through a 12" tube would trap a rag and I could swab out the slider with it. Worked great:
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1377_zpsrtvn4yxg.jpg)
The bore of the slider after cleaning:
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1360_zps5vdpodh0.jpg)
The "lower element" has a locating pin and the workshop manual says there is a detent to receive it and that you must make sure it is located correctly. Dave Richardson suggests putting in in 180 out from the detent then rotating it with a long screwdrive so that you can feel the pin drop into place. As the only detent is formed by the drain hole you can also mark the top of the lower element with a marker so you can look down and confirm that it is lined up with the fork drain plug:
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1366_zpsbamwwtoi.jpg)
Still need to paint the lowers.
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Kinda hard to get at the neck bearings that way Charlie :D
Dusty
;-T
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If the fork tubes don't come out willingly, I just leave them in the triple clamps. Sliders come off the bottom, damper spring units out the top. Less aggravation and achieves the same result.
When I FACed my V50II I discovered that's how you have to assemble it. The integrated top nut of the FAC damper will not fit through the triple clamps; no pre-assembling the fork legs.
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When I FACed my V50II I discovered that's how you have to assemble it. The integrated top nut of the FAC damper will not fit through the triple clamps; no pre-assembling the fork legs.
Thanks for the tip JPL. Looks like the FACs are still a week away.
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This started with wanting to put new tires on the Monza. But first I had to get the wheels powder coated.
Picked them up Friday:
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1400_zpsdllvwcej.jpg)
Tires on today:
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1407_zpsagbsxpxo.jpg)
The rear shocks were leaking so looked for a rebuild kit. Marzocchi Stradas. Got the rebuild kit here (for 12mm shafts only):
http://marzocchimoto.blogspot.com/p/ag-strada-kit-buy-it-now.html
Don't like having so many components in pieces. Ugh! It now looks like this:
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1437_zpskrtskuew.jpg)
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Coming along nicely. ;-T Once done you can rest assured things have been addressed. Looking forward to hearing about your suspension upgrade.
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If the fork tubes don't come out willingly, I just leave them in the triple clamps. Sliders come off the bottom, damper spring units out the top. Less aggravation and achieves the same result.
Kinda hard to get at the neck bearings that way Charlie :D
Dusty
So, leave the tubes in the lower triple and just remove the top clamp. That usually comes off quite easily compared to removing the tubes completely.
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Progress! Rebuilt the 'zocchs today and installed the rear wheel and tire.
Marzocchi Strada rebuild kit from http://marzocchimoto.blogspot.com/p/ag-strada-kit-buy-it-now.html
You can also find a Strada manual several places on line, but there's some things it doesn't have.
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1425_zpsvxlwvycc.jpg)
Got the spring off by compressing it all the way with the adjuster, tying it with wire loops and then loosening the adjuster. The last 1/8" or so of clearance I got by prying with a screwdriver in the slot of the spring retainer.
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1417_zpsp6hwwxmc.jpg)
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1458_zpsy7ta0r3g.jpg)
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1415_zpsiheofxjc.jpg)
Release air pressure through Schrader valve and then release hydraulic pressure through screw on air chamber.
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1419_zpsa074txsa.jpg)
Clamp in vice and remove large (32mm) "plug".
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1421_zps0gkqi2js.jpg)
Once the plug is out, rock the piston back and forth to work the O-ring seal out of the shock body. It's easier if pull toward you rather than up, but it will spill smelly oil all over. ::)
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1423_zps6tqlvkrw.jpg)
The piston rides in a steel tube with a small hole at the bottom. This tube ("sleeve" in the 'zocchi manual) will probably come out with the piston. When it does the hole will leak smelly oil all over the workshop. :P
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1422_zpsy6wlftlj.jpg)
Next disassemble the air chamber. You will need a 30mm pin-wrench to do it. Fortunately I have an old Sugino chainwheel pin-wrench.
The holes to insert the pins are under the sticker. (Apparently you can buy sticker kits, but I don't need no stinking stickers!)
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1430_zpsooehhqww.jpg)
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1426_zpsq9gwtzdx.jpg)
The cap has an O-ring, followed by a steel shim and the rubber air bladder. Used a dental pick to pluck out the edge of the bladder.
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1428_zpsy9stes0n.jpg)
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1429_zpsrixbmdrf.jpg)
At this point the shock bodies are bare except for the rubber in the lower mount. I soaked them, springs and spring adjusters in hot water and powdered laundry detergent.
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The Laverda forum has a good thread on rebuilding these shocks with lots of pictures and info - very helpful. ;-T
Clean the parts and reassemble the air chamber with new air bladder and new o-rings on cap and bleed screw. I used some light synthetic grease on the o-rings and soaked or slathered other pieces with shock oil as assembly lube.
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1438_zps6jtsp0ru.jpg)
There isn't much info on the piston assembly in the Strada rebuild manual. BTW, apparently the upper mounting eye is cast over the top the piston rod - it can't be unscrewed to be re-chromed or replaced (info from Laverda forum).
The picture shows from left to right - nut, aluminum piston with plastic ring and o-ring below it (this seals to the inside of the sleeve), 3 thin shims on the top of the piston, piston valve piece with another thin shim (looks like a wave washer) below it, spring and aluminum plug that has o-ring to seal top of sleeve and seal for piston rod (this entire piece comes with the kit), dust seal (fits into plug), threaded plug and rubber cushion. There are at least 4 thin shims between the aluminum piston and the spring and the lower two are very similar and easy to mix up.
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1434_zpsehot3uvb.jpg)
Picture of the piston shims:
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1442_zpswajm8fuk.jpg)
A neat trick to removing o-rings is to stretch them by pinching around the outside so that it puckers out:
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1448_zpskbm8r9y3.jpg)
The piston has a plastic (teflon?) seal over an o-ring. The o-ring is easy to install but the plastic ring isn't. One guy on the Laverda forum just cut them at a 45 degree angle - and it looks like the originals were cut too:
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1443_zpsfsjb1wpj.jpg)
At the risk of breaking or stretching the ring and ruining it, I decided to press it on with a block of wood in the vice. It stretched over the wide part of the piston.
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1450_zpsh2fbdtu7.jpg)
Then I pushed the rest of the way over the o-ring with a screwdriver, but should have used something softer. Photo shows that it sits tight enough over the o-ring to make contact, and it slid into the sleeve easily so apparently not stretched too much.
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1446_zps3teolzdg.jpg)
Installing the pieces on the piston rod. Both rubber cushion and dust seal for the plug flare out toward the bottom.
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1441_zpsrhvrw0mb.jpg)
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I used solvent and compressed air to clean the valve at the bottom of the sleeve, then flushed with shock oil. Some on the Laverda forum found that these valves would stick open so check that yours are OK. The Marzocchi manual describes how to take them apart and change the shim order to change the compression damping.
Clamp the shock body in the vice at an angle so that the air chamber is up and the bleed screw upper-most. Insert clean sleeve.
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1455_zpsiywonrz1.jpg)
Fill with shock oil until it dribbles out the bleeder hole. Install the bleeder screw with its o-ring.
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1451_zpstbftohdy.jpg)
Tip the shock up in the vice so that it sits vertical. The shock oil should be within 2-3 cm of the top of the threads. Wrap a soon to be oily rag around the shock and vice and insert the piston in the sleeve, then slide the aluminum seal holder ("pilot boss" in the manual) and spring into the sleeve until the seal holder seats in the sleeve and the sleeve seated in the shock body. The top of the seal holder should be just below the top of the shock body. Leave the piston at its max extension and thread in the plug with its dust seal. Marzocchi warns to watch that the dust seal doesn't push up too far - its top surface should be level with the top of the plug. When I did this oil squeezed out when I put the plug indicating that there is no trapped air.
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1453_zps3mdgtfks.jpg)
After everything was sealed up I cycled the shocks several times. Compression damping was very light and rebound damping significant. Felt smooth throughout the stroke after a couple of cycles. Install the springs. Air up with a bicycle suspension pump. The air volume is so small that normal air pumps or compressors won't give you an accurate reading.
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1460_zpsvt4lsgxv.jpg)
Install the shocks, then the new tire on the powder coated rim!
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1463_zpsnl6ug6hu.jpg)
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1462_zpsaexuobrf.jpg)
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Great looking V50! and I can sure relate to where you are heading with this little bit of work :BEER: Nice work and keep at it, soon it will be brand new ;-T
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Thanks Canuck. It sure is a fun little bike. Hope to do many nice rides this summer. ;D
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SED, thank you for taking the time to document the Marzocchi Strada rebuild. ;-T I've seen Marzocchi's document but was a little cloudy on a few points. I've have them on mine too; they're not leaking and still damping okay but probably overdue for a change of the smelly oil. What weight oil did you use?
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Nice! ;-T I have a set of those.. didn't even know you could get parts for them..
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Excellent pics and procedural write up. Dang, I miss my Monza.
Btw, our dishwasher died and my wife knows that if I replace it, the cost will be about $25,000 for new disposal, sink, cabinets, lighting, wall removal, appliance relocation and flooring. Can't just replace the DW...
Just get me started....
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SED, thank you for taking the time to document the Marzocchi Strada rebuild. ;-T I've seen Marzocchi's document but was a little cloudy on a few points. I've have them on mine too; they're not leaking and still damping okay but probably overdue for a change of the smelly oil. What weight oil did you use?
I had some Golden Spectro 125/150 for mtn bike forks and checked the viscosity rating and it appears to overlap the 5wt oil (http://bmwmotorcycletech.info/ShockOilComparo.pdf) that was recommended on the Laverda site so I went with it. The Marz manual says Engler 1.8, Art. 52.46 and SAE 5 so hope I'm close.
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Excellent pics and procedural write up. Dang, I miss my Monza.
Btw, our dishwasher died and my wife knows that if I replace it, the cost will be about $25,000 for new disposal, sink, cabinets, lighting, wall removal, appliance relocation and flooring. Can't just replace the DW...
Just get me started....
HaHa! We just moved and the new house has a DW - do I have to worry??!
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I'm loving this thread, thanks for making it. I have a few questions... If I just want to remove the lower front legs to get them powdercoated for example and replaced the seals and dust covers, is this the only step required in my case to remove them (while the rest is all still on the bike)? Will oil come gushing out, or is the oil contained within the dampers?
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1346_zpstjxuon3j.jpg)
Also, what size Avon RoadRider did you use. Tubed or Tubeless Conversion done?, and what color powdercoat did you use? Looks close to the factory color...
Great job on all!
Thanks!
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I'm loving this thread, thanks for making it. I have a few questions... If I just want to remove the lower front legs to get them powdercoated for example and replaced the seals and dust covers, is this the only step required in my case to remove them (while the rest is all still on the bike)? Will oil come gushing out, or is the oil contained within the dampers?
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1346_zpstjxuon3j.jpg)
Yes, removing that bolt allows the slider to come off without disturbing anything else. Unless you've drained the oil first, it will come flowing out as the bolt is removed. There are two separate areas with oil in those forks: the oil (atf) that lubricates the slider and tube (this is what will come out) and the oil contained inside the sealed damper cartridge (should not come out).
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Thanks, then I will do this soon! To refill the ATF fluid/oil, I'm assuming that done from the top of the forks (the large aluminum caps)?
EDIT: Found it in the manual! Thanks again!!
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I'm loving this thread, thanks for making it.
Also, what size Avon RoadRider did you use. Tubed or Tubeless Conversion done?, and what color powdercoat did you use? Looks close to the factory color...
Great job on all!
Thanks!
Hey Groover,
Thanks for the nice comments. Charlie's got you set with removing the lowers. You just need to have your powdercoater mask and plug the lowers so no blasting grit or powder gets inside.
The powder color is "Silverstone" - probably this: http://www.prismaticpowders.com/colors/PMB-847/SILVERSTONE/
It is bluer and darker than the LMIII wheels I was trying to match. The LMIII wheel color looks lighter and yellower. But it is a nice color and not glittery with metal flake.
Guzzi left all paint off the outer lip of the LMIII wheels. It would've been good to mask that lip on the Monza rims too because it is easy (very easy! :() to chip the coating with the tire irons.
The RoadRiders are 90/90-18 and 100/90-18 (original size) with tubes. They are a tight fit on the rims and impossible to seat the bead with normal air pressure so it would be good not to add powdercoating to the inside of the rim - so mask that too.
Cheers,
Shawn
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Great information, thank you. I made a note of it all!
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FAC dampers on back order. Word is a month away. Ugh! :(
So how 'bout them Guzzi dampers? Might as well have a look. :BEER:
Unscrew cap...
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1515_zpsquevcjwt.jpg)
Cap fits nicely into rubber boot...
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1516_zpsshfmmdub.jpg)
Pry out rubber boot with dental pick then pull with needle nose pliers...
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1517_zpstx651vnt.jpg)
Then pull out with needle nose pliers... (looking a little cut up)
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1518_zpstzyijmoq.jpg)
All the reachable parts...
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1519_zpshc9cnrjk.jpg)
Note that the rubber boot is deformed - especially at the "receptacle tip". I think the way it is supposed to work is that the tip of the boot blocks the holes in the top of the damper (compression), but the deformation makes a poor seal.
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1521_zpsy7n8ghwo.jpg)
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I cleaned the dampers out with light weight fork oil and decided they needed more damping so got 20w fork oil.
I did a lot of pumping up and down on the piston and thinking more about how the Guzzi dampers are supposed to work... (always dangerous! :beat_horse)
and noticed that oil and air bubbles seemed to come up the center hole and returning oil went down the small outer holes.
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1521_zpsy7n8ghwo.jpg)
The way the air bladder boot is made it probably only blocks the center hole increasing compression damping. A benefit for suspension is that increasing air pressure in the boot during compression would increase resistance to compression - a (very small) increasing rate air spring. The purpose of the boot is probably the same as the air bladder in the Marzocchi shocks - prevent air and oil from mixing and ruining the damping.
The boots were so deformed that they would not make a good seal at the holes and one was leaking oil and air. Rationalizing :pop that heavier fork oil would mimic air pressure in the boot, and that a leaking boot just takes up space for oil... I cut the boots just below the top cap leaving a sealing ring for the top cap, filled the dampers with 20wt and cycled them 'til all the air was out, then filled the top reservoir about 1/2 full with the piston all the way down. Pushing the piston all the way up increased the level in the reservoir to near the top but leaves a little air space. Presumably (ahem!) air over the oil will be at 1atm full extension and pressurized about 4x at full compression. Hopefully this will be OK.
So this brings up the question: what is so great about cartridge forks? Why not use the whole fork as the cartridge with a large reservoir of oil and air in the stanchion (or slider in upside down forks) so it will build up little air pressure at full compression and put less load on the seals. (or is 4x atm not a big deal?) It also has fewer parts because the cartridge duplicates a piston, seal and reservoir.
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I take it you want to know how a cartridge works differently from damping rod? Short answer is the cartridge accounts for slow and fast internal pressures through a valve so you get an even feel for slow and fast damping. The older rod type which you have is an oil displacement type where the given holes in the system displace fluid (oil) while damping. Problem is that while going fast they are quite ineffective and you get a very stiff ride. At slow speeds there is time for the displacement to happen (think slow motion) and they sometimes feel rather mushy. It's a one size fits all to compensate for slow and fast and does neither end much service. A cartridge mitigates this with its efficiency.
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I take it you want to know how a cartridge works differently from damping rod? Short answer is the cartridge accounts for slow and fast internal pressures through a valve so you get an even feel for slow and fast damping. The older rod type which you have is an oil displacement type where the given holes in the system displace fluid (oil) while damping. Problem is that while going fast they are quite ineffective and you get a very stiff ride. At slow speeds there is time for the displacement to happen (think slow motion) and they sometimes feel rather mushy. It's a one size fits all to compensate for slow and fast and does neither end much service. A cartridge mitigates this with its efficiency.
Thanks Kev, ;-T Don't know much about them so was thinking that the cartridge worked like the damping rod. It must be possible to engineer the fork with a cartridge-like valve and reduce the duplication of parts - probably only for racers and weight weenies. ;D
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A few more updates while waiting for parts.
Paint stripper results:
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1470_zpsfeuwsxdn.jpg)
Sanded, masked and 1st coat with self etching primer:
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1473_zpssumhgzfc.jpg)
Final results:
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1528_zpszfmj1pzi.jpg)
Also cleaned the speedo drive parts and found that the worm threads (top center) were quite worn. This may have been caused insufficient lube and because its retainer - the brass bushing top right - had slipped out several mm.
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1378_zpspd5opmup.jpg)
The worm wheel is held into the casting by a pressed in stamping so just cleaned with solvent and packed it with moly grease.
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1410_zpseyrf6gsy.jpg)
There is a rubber seal (not an O-ring) between the drive tang and the rest of the drive:
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1411_zpsy1gtk9fg.jpg)
Had to crimp the mouth of the casting to hold the bushing, but the drive turns smoothly:
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1465_zpsxf3vqbk0.jpg)
Hopefully this helps someone!
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;-T
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Thanks Kev, ;-T Don't know much about them so was thinking that the cartridge worked like the damping rod. It must be possible to engineer the fork with a cartridge-like valve and reduce the duplication of parts - probably only for racers and weight weenies. ;D
I can't help you there, but I would say those forks aren't worth messing with as they are pretty low quality parts Guzzi used. They flex like toothpicks and that's their biggest downfall, not the dampening IMO. Put your front brake on and push on them back and forth (not up and down) and you'll see what I mean about why things wallow in turns. An upgrade to better quality forks is the best thing you can do. I did and it's HUGE how stable these little guys can feel. It's the single best upgrade for rideability I found.
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An upgrade to better quality forks is the best thing you can do. I did and it's HUGE how stable these little guys can feel. It's the single best upgrade for rideability I found.
I hear you Kev,
The stanchions on my mtn bike forks are the SAME diameter! :o And it's a light weight cross country bike - about 350lbs less than the Monza! If it were a downhill bike the stanchions would be bigger.
I do have hopes of finding a V65 and doing an engine/transmission/fork transplant into the Monza - someday! :)
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. An upgrade to better quality forks is the best thing you can do. I did and it's HUGE how stable these little guys can feel. It's the single best upgrade for rideability I found.
What forks did you use Kev?
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Not sure if anyone cares about trying to make the original forks work on the V50III & Monza, but with the FAC dampers at least a month away I thought it was worth a try.
As you recall from our last episode the air bladder was removed from the original dampers, then purged and refilled them with 20wt fork oil.
Stanchions were cleaned out by pulling a rag through them.
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1532_zpsclcenwjc.jpg)
Per Guzziology, the lower spring seat was dropped into the sliders with the its locating pin 180 degrees from the notch to receive it, then turned with a long screwdriver. You can feel it drop into place. If you have marked a line on the top you can also confirm that it points toward the notch which corresponds to the drain screw.
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1531_zpsl5iq9qjf.jpg)
Then time to drive in the new seal:
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1529_zpsdapvq3qm.jpg)
Slather everything with assembly lube - use a long finger to wipe it on the aluminum bearing surfaces down in the in the slider:
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1533_zpsnsgs7ps3.jpg)
Smear a thin layer of lube over the surface of the stanchion and insert. Wear marks indicated the bleed hole had been at the front so turn it 180 degrees so it bears on a fresher surface. (maybe just superstitious ::))
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1534_zpsudw56rcu.jpg)
Smear a little lube around and slide the dust seals over:
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1539_zpspuplspfq.jpg)
Assemble the spring on the damper rod. Notches at the bottom retainer engage the notches in the lower spring seat to keep it from turning while tightening the lower retaining bolt:
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1536_zps6jw8bkw3.jpg)
Slather the spring and damper with assembly lube (more superstition) and lower it into the slider, then insert and tighten the bottom retaining bolt with its aluminum gasket:
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1537_zpsvdplztdv.jpg)
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1538_zpswlg557l6.jpg)
Check that the lower bolt is tight and the drain plug installed and then fill the fork lowers. There is very little room between the damper cartridge and the stanchion. A large syringe (feed store item) makes it relatively easy to fill with the correct amount. The oil goes in slow and needs time to drain down past the cartridge. If you give a good squeeze on the syringe it will quickly overflow and drip on your shoes (ask me how I know! :P). Pumping the stanchion up and down encourages the oil to drain into the slider.
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1540_zpsmxenrhqb.jpg)
Pull the stanchion up out of the slider and screw the damper top into it - after lubing the threads and o-ring of course!
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Now time to install the triple clamps with their new ball bearings. Tighten the bearings correctly, but don't tighten the pinch bolt in the upper triple clamp.
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1541_zpsjbualkzb.jpg)
It's worth doing a test fit of the fork legs in the triple clamps. Friction holds the stanchions in the clamps so nothing has to be tightened yet:
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1542_zpsopp151dw.jpg)
By far the most tedious part is inserting the stanchions through the headlight bracket and clip-ons while routing the cables correctly. It is worth marking every cable and wire bundle with tape to know whether it goes above or below the headlight bracket, and around or behind the stanchions. I failed to do this and had to disassemble the twist grip/switch assembly to reroute the throttle cables. Opening the grip/switch pod broke a wire off one of the incredibly fragile switches so now looking for a replacement. Any suggestions?
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1544mod_zpszajmph7a.jpg)
I found there was plenty of room between the upper and lower triple clamps if I loosened the pinch bolt that clamps the bearing lock nut and raise the upper clamp as far as it would go (see arrow above).
The twist grip is impossible to assemble with two hands. My solution is to clamp a vice grip over it to provide some tension while one hand puts some tension on the cables and the other two install the screws. Works every time :BEER:
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1550_zps8munashp.jpg)
Eventually everything goes together. Install the axle and gently tighten the pinch bolts in the fork lowers to align them vertically, then tighten the rest of the pinch bolts and it's almost done!
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1547_zpsofq9yglh.jpg)
Ready for a test ride!
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1552_zpshajldnau.jpg)
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I would say those forks aren't worth messing with as they are pretty low quality parts Guzzi used. They flex like toothpicks and that's their biggest downfall, not the dampening IMO. Put your front brake on and push on them back and forth (not up and down) and you'll see what I mean about why things wallow in turns.
Kev, Here's photographic evidence of the size of 375lb Guzzi forks compared to 28lb mtn bike forks - Yikes!
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1543_zpsbsgnsmqi.jpg)
Better clean up the mtn bike... ::)
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FAC dampers finally arrived and have been installed - WOW! :thumb:
The whole bike feels more "planted" on the road and is much more confidence inspiring on old uneven concrete. There was a big improvement after the rear shocks were rebuilt, but the new dampers are great - what fun!
Compared to the original dampers the FACs have much better rebound damping and very little compression damping (no air). Divots no longer jar the bike, and the uneven road surfaces in corners are not very noticeable.
I used Antietam Charlie's method for replacing the dampers and it took about 1.5 hours.
Block up sump and pull dampers from the stanchions.
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1729_zpsja3toqwi.jpg)
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1728_zpsjpxahxu8.jpg)
Pull pinch bolts and axle, drain oil from one side then pull the lower fork bolt on that side:
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1731_zpsp5fofhfi.jpg)
Pull the damper and spring assembly out and swap dampers: (FAC top)
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1732_zps1ijz8yyw.jpg)
Insert new damper spring assembly into fork leg, rotate until notch in spring retainer seats in the bottom of the fork leg and re-install lower fork bolt. At this point the manual suggests you dribble fork oil down into the leg between the damper and stanchion - this is tedious and messy and time consuming. Instead use a syringe with a fat o-ring or piece of vacuum hose (see pic) over the nipple and inject the oil into the drain hole. Finish filling from top if necessary.
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1735_zps5roquez2.jpg)
Back from test ride:
(http://i305.photobucket.com/albums/nn233/shawnsci/IMG_1739_zps5gges8vc.jpg)