Author Topic: 1980 CX100(Tonti) 35 mm front fork question att Charlie,Pete,Steve, Waynes etc  (Read 4643 times)

Offline 80CX100

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     I'm hoping that someone that is familiar with the old Tonti 35 mm front forks, and has some experience with this bodge, will read this, and chime in,,, either reassuring me,,, or letting me know if I'm courting disaster,lol.

     I'm still waiting for my taillight bracket to come in from Harpers for my CalVin,, in the mean time, I've started doing a bunch of work on my CX100,,,, hopefully I'll get riding it again this summer.

     I'm removing the clip on bars and installing a set of PowerMadd riser clamps and Rizoma Standard (but higher) 22mm handlebars, to help with my neck issues, and among the various jobs I'm doing on the bike, I'm also putting Ikon shocks on the back, and FAC dampers/Wirth progressive springs in the front forks.

      The left front fork rebuild went fine and is back on the bike,,, but as I was assembling the right fronk fork, I noticed that the dog earred tab? on the lower spring cap had previously been bent and folded over,,, item 27 part no 14 52 76 01 in the enclosed diagram. I tried to bend the tab back out, without breaking it off,,, it moved a little, but not a lot.
     
      I was able get the lower spring cap item 27 on the bottom of the damper/spring assembly slid into proper position in the recess inside the bottom of the fork slider, engaging enough of the corresponding female notch on the inside of the bottom of the fork slider, that I was able to torque to spec, the screw holding the bottom of the damper rod/lower cap in place,,, and thanks to a recent post, I used an O ring crush washer & Yamalube on the bottom screw, so I'm not too worried about it leaking out the bottom.(fingers crossed) 90 ml of ATF is in place.

      Once I get the rebuilt fork back into the triple clamps and clamped into place, I'll be able to torque the top fork tube caps on the FAC dampers up to spec in the stanchion tubes, but I wanted to check with some of the learned folks here, BEFORE I do that.

       My question is this,,, how crucial is that dog ear tab on the lower cap item 27 that engages into the female notch cast in the bottom of the inside of the fork slider?

       I can see that with that dog earred tab deformed and flattened out,,, the lower spring cap, could in theory rotate a little inside,,, is that a real bad thing? or not that big a deal  if I'll have spec torque holding the lower cap damper/spring into place in the recess in the bottom of the slider,,,,, and I'll have spec torque in the top caps holding the damper/spring down in position in the fork tube from the top.

       If it's a real big issue, I could start searching for a replacement lower cap, item 27, but if torque spec top and bottom holding the lower cap/damper/spring in place is sufficient, I'll continue on, and finish that part of the job tomorrow.

       TIA

       Kelly
« Last Edit: July 06, 2017, 11:47:45 PM by 80CX100 »
2008 California Vintage
2003 V11 Lemans
2007 Griso 1100
1979 G5 & 1980 Lemans CX100
2010 Suzuki DR650 & 1978 SR500

In a time of universal deceit, telling the truth becomes a revolutionary act. George Orwell

pete roper

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As long as the tab has engaged enough to allow the cap a damper rod to drop right down into the bottom of the slider you should be find as long as you can tighten the bolt sufficiently without the rod and cap spinning.

The problems occur if full engagement hasn't occurred as when the forks start moving the cap will deform further allowing it and the damper rod to drop lower in the slider and therefore removing the preload torque from the bolt. It will loosen, oil will leak out and, if ignored for long enough,the bolt may drop out meaning that the fork leg will be undamaged and the slider unsecured. Chaos ensues.

Pete

Offline 80CX100

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As long as the tab has engaged enough to allow the cap a damper rod to drop right down into the bottom of the slider you should be find as long as you can tighten the bolt sufficiently without the rod and cap spinning.

The problems occur if full engagement hasn't occurred as when the forks start moving the cap will deform further allowing it and the damper rod to drop lower in the slider and therefore removing the preload torque from the bolt. It will loosen, oil will leak out and, if ignored for long enough,the bolt may drop out meaning that the fork leg will be undamaged and the slider unsecured. Chaos ensues.

Pete

Hey Pete,    I'm confident that I could feel the deformed tab and cap drop into place in the recess in the slider, and held it tight there, while I installed the screw and snugged it tight,,, the cap and rod didn't move from there as I tightened it.

                    Thanks very much for the reply

                     Kelly
2008 California Vintage
2003 V11 Lemans
2007 Griso 1100
1979 G5 & 1980 Lemans CX100
2010 Suzuki DR650 & 1978 SR500

In a time of universal deceit, telling the truth becomes a revolutionary act. George Orwell

Offline Arizona Wayne

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Even though my `81 CX100 has over 100K miles on it, I have yet found it necessary to replace the fork cartridges or springs, even though with me owning it I have ridden it 2up & loaded more than otherwise.  When I got this CX it had 6k miles on it 30+ years ago.  I have had to replace fork seals as where I used to live small insects (rice fields) got into them.  But at that point 25? years ago I installed rubber gaitors to stop that happening.  :thumb:

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Offline Guzzistajohn

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Even though my `81 CX100 has over 100K miles on it, I have yet found it necessary to replace the fork cartridges or springs, even though with me owning it I have ridden it 2up & loaded more than otherwise.  When I got this CX it had 6k miles on it 30+ years ago.  I have had to replace fork seals as where I used to live small insects (rice fields) got into them.  But at that point 25? years ago I installed rubber gaitors to stop that happening.  :thumb:

How many of those 25 years have been spent in the barn?
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Offline 80CX100

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Even though my `81 CX100 has over 100K miles on it, I have yet found it necessary to replace the fork cartridges or springs, even though with me owning it I have ridden it 2up & loaded more than otherwise.  When I got this CX it had 6k miles on it 30+ years ago.  I have had to replace fork seals as where I used to live small insects (rice fields) got into them.  But at that point 25? years ago I installed rubber gaitors to stop that happening.  :thumb:

     Hey Wayne,     I had picked up the Ikon shocks, FAC Dampers,Wirth springs quite a while ago,,, and debated putting them in the CX100 or into the G5 when I get around to working on it.

     My CX100 (30K+ miles) stock front suspension, didn't feel as vague/rubbery as the stock rear shocks,,,but the stock front end would dive quite a bit rolling off the throttle and definitely drop a LOT under hard braking,,, hopefully I'll notice an improvement in the front end tracking/response.

     The stock dampers on my CX100 still had pressure and decent movement, but there was one spot where the cartridge body was worn and rusted quite bad, and a bunch of the rubber gasket sealing/packing material had broken down and worked it's way loose, out and away from around the damper rods themselves,,, so imminent failure was on it's way.
 
     I've got new fork seals in there and rubber gaitors,,, I agree with you, the fork gaitors are almost a necessity in my riding area with the heavy black flies/mosquitos.

     The CX100 is definitely a lifer bike for me,,, parked in the garage collecting dust, wasn't fair to her, and it was heartbreaking for me not to be riding her,,, I'm hoping that with the higher bars, I'll be able to enjoy riding her again,,, the new suspension, should add a little bit more composure/confidence putting her through her paces, riding the twisties in the back hills of the Ottawa Valley.

     Tks

      Kelly
2008 California Vintage
2003 V11 Lemans
2007 Griso 1100
1979 G5 & 1980 Lemans CX100
2010 Suzuki DR650 & 1978 SR500

In a time of universal deceit, telling the truth becomes a revolutionary act. George Orwell

canuck750

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Did you get the snap ring to seat into position?



This picture is of my 77 Lemans but it looks to be the same set up on T3's etc. that I have rebuilt and probably the same as your CX100.

This hommade made spring compressor makes getting the snap ring and cap into place easy.


Online Antietam Classic Cycle

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Did you get the snap ring to seat into position?



This picture is of my 77 Lemans but it looks to be the same set up on T3's etc. that I have rebuilt and probably the same as your CX100.



That's not where the #26 circlip is supposed to go. It goes on after and sits inside #22, the lower spring seat. The #27 cup is not secured by the circlip - at least not from the factory. Look at the drawing in the first post.
« Last Edit: July 07, 2017, 11:54:57 AM by Antietam Classic Cycle »
Charlie

canuck750

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That's interesting, I am probably wrong in where I put the circlip but hat's the way it was installed on the Lemans and 750 S3 when I dissembled the forks.

It holds the cap in the right position to engage the dogs into the rods, do you think compressing the cap and circlip to the lower fork leg casting is going to cause any problems other than preloading the springs by the thickness of the circlip?

Offline 80CX100

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Did you get the snap ring to seat into position?



This picture is of my 77 Lemans but it looks to be the same set up on T3's etc. that I have rebuilt and probably the same as your CX100.

This hommade made spring compressor makes getting the snap ring and cap into place easy.



     Hey Jim,    My set up differs just slightly from yours,,, as you can see in the diagram, the end of the damper rod is secured and centered in the spring by the lower cap item 22,,, then held in place by the circlip item 26,,, lower cap 27 slides over these pieces and 2 internal tabs in item 27 are located in place by the slot cut across the end of the damper rod.

     This whole assembly is placed into a recessed hole cast into the bottom of the fork slider,,, I found this easiest to accomplish holding it upside down and letting gravity do the work,,, much easier to feel it drop properly into place.

     At first I really struggled getting the springs compressed and into position,,, but there was a very convenient hole(oil or damping port?) drilled through the damping rod near the top of the spring,,, I simply placed a thin screw driver into this hole,,, using that as leverage it was a simple matter to just wind the sping into position, giving me enough slack to fasten lower cap 22 with the circlip,,, then unwound the spring, back into proper position,,, worked like a charm.

     Tks

      Kelly
2008 California Vintage
2003 V11 Lemans
2007 Griso 1100
1979 G5 & 1980 Lemans CX100
2010 Suzuki DR650 & 1978 SR500

In a time of universal deceit, telling the truth becomes a revolutionary act. George Orwell

Offline 80CX100

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     I didn't realize Charlie had posted already,,, but mine is definitely like the stock drawing.

     Now back out to the garage to see if I can get the tube back into the triple clamps,,,, the left tube was easy,,, the right tube has been a proper b*tch,,, I cleaned up the top of the right stanchion tube and the inside of the triple clamp, with my dremel and a fabric abrasive buffing wheel,,, hopefully it slides in easier, than the fight to get it out! lol

     Thanks to all for taking the time to reply.

      Kelly
« Last Edit: July 07, 2017, 12:29:15 PM by 80CX100 »
2008 California Vintage
2003 V11 Lemans
2007 Griso 1100
1979 G5 & 1980 Lemans CX100
2010 Suzuki DR650 & 1978 SR500

In a time of universal deceit, telling the truth becomes a revolutionary act. George Orwell

Online Antietam Classic Cycle

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     Hey Jim,    My set up differs just slightly from yours,,, as you can see in the diagram, the end of the damper rod is secured and centered in the spring by the lower cap item 22,,, then held in place by the circlip item 26,,, lower cap 27 slides over these pieces and 2 internal tabs in item 27 are located in place by the slot cut across the end of the damper rod.

     This whole assembly is placed into a recessed hole cast into the bottom of the fork slider,,, I found this easiest to accomplish holding it upside down and letting gravity do the work,,, much easier to feel it drop properly into place.

     At first I really struggled getting the springs compressed and into position,,, but there was a very convenient hole(oil or damping port?) drilled through the damping rod near the top of the spring,,, I simply placed a thin screw driver into this hole,,, using that as leverage it was a simple matter to just wind the sping into position, giving me enough slack to fasten lower cap 22 with the circlip,,, then unwound the spring, back into proper position,,, worked like a charm.

     Tks

      Kelly

^^ This.  :thumb:
Charlie

canuck750

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My bad, I will swap the cirlcip to the other side of the cap, 10 minute job :violent1:

Offline Arizona Wayne

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     Hey Wayne,     I had picked up the Ikon shocks, FAC Dampers,Wirth springs quite a while ago,,, and debated putting them in the CX100 or into the G5 when I get around to working on it.

     My CX100 (30K+ miles) stock front suspension, didn't feel as vague/rubbery as the stock rear shocks,,,but the stock front end would dive quite a bit rolling off the throttle and definitely drop a LOT under hard braking,,, hopefully I'll notice an improvement in the front end tracking/response.

     The stock dampers on my CX100 still had pressure and decent movement, but there was one spot where the cartridge body was worn and rusted quite bad, and a bunch of the rubber gasket sealing/packing material had broken down and worked it's way loose, out and away from around the damper rods themselves,,, so imminent failure was on it's way.
 
     I've got new fork seals in there and rubber gaitors,,, I agree with you, the fork gaitors are almost a necessity in my riding area with the heavy black flies/mosquitos.

     The CX100 is definitely a lifer bike for me,,, parked in the garage collecting dust, wasn't fair to her, and it was heartbreaking for me not to be riding her,,, I'm hoping that with the higher bars, I'll be able to enjoy riding her again,,, the new suspension, should add a little bit more composure/confidence putting her through her paces, riding the twisties in the back hills of the Ottawa Valley.

     Tks

      Kelly


The CX is a lot lighter than the other T-3 type Tonti bikes, so I figure the CX has softer springs.  I've had my CX 30+ years since it only had 6K miles on the odo.  I've ridden it 2up & loaded + pulling a Unigo 1 wheel trailer.  Mine has the original integrated braking system and yes, the front end dives some, but not much if you use the integrated foot lever brake (left front, rear brake).  My front forks rarely bottom out (maybe in a pothole) and I added a fork brace that helps firm up the front forks.  If I thought the front cartridges were shot, believe me, I'd have already replaced them.  :wink:  Years ago I got Progressive econo. rear shocks with HD springs to handle all the weight I've pulled on this bike and they're still good.  :cool:  Unfortunately my CX has been off the road for years now as I have too many other rigs to ride instead.
« Last Edit: July 07, 2017, 01:44:00 PM by Arizona Wayne »

Offline Mark W

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Related to this topic - How do you ensure that the fork tubes etc are properly aligned?
Is the a sequence to follow or measurements?

Offline 80CX100

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Related to this topic - How do you ensure that the fork tubes etc are properly aligned?
Is the a sequence to follow or measurements?

Hey Mark,     I'm definitely not the expert, and I'm sure many can find fault with my process or a better way of doing it,,, but here's what I did.

As best as I was able to, I followed Dave Richardson's instructions in Guzziology,,, The bike was (and still is,lol) up on the work table with no handlebars, so I was somewhat limited,,, hopefully it works fine.

I tightened the lower triple clamp, then the top triple clamp, to hold things in place then installed front wheel with the axle and tightened the axle and pinch bolts,,, that is supposed to align the bottom perfectly,,,, I then loosened the bottom and top triple clamps,,, cycled the forks from the bottom as square as I could with a lever against the tie down straps,,, (not much movement),,,, then beat around the triple clamps with a big wooden mallet to remove any set that might have taken place,,, tightened the lower triple clamps first,,, beat on the upper triple clamps again and then tightened them up.

It would have been nice to cycle the front suspension a few times to help align it better,,, but with the bike up on the table with no bars,,, that wasn't happening.

Dave recommends in a perfect world to unscrew the top cap and loosen off the spring pressure and cycle the fork tubes up when you tighten the axle to get a finer alignment,,, before you tighten the triple clamps,,, I wasn't going to tempt fate by doing that and fighting to screw the caps back in,,, those stanchion tubes are easily stripped,,, especially after I ran into trouble with the bottom spring cap tab,,, I was just glad to get the whole works assembled, tight and in place securely,,,, they look square and aligned,,, I guess riding will be the final test,,, subject to further adjustment if there is an apparent need,lol.

fwiw ymmv

Kelly

« Last Edit: July 31, 2017, 07:18:02 PM by 80CX100 »
2008 California Vintage
2003 V11 Lemans
2007 Griso 1100
1979 G5 & 1980 Lemans CX100
2010 Suzuki DR650 & 1978 SR500

In a time of universal deceit, telling the truth becomes a revolutionary act. George Orwell

Offline rodekyll

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Just a thought on running the fork tub up a tight tree:  Tap a wedge (screwdriver, flat punch, etc) SLIGHTLY SNUG in to the pinching slot to gain a mil of clearance.  Don't get crazy with the wedging.  You want to deflect, but not deform.  It takes very little.

Offline 80CX100

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Just a thought on running the fork tub up a tight tree:  Tap a wedge (screwdriver, flat punch, etc) SLIGHTLY SNUG in to the pinching slot to gain a mil of clearance.  Don't get crazy with the wedging.  You want to deflect, but not deform.  It takes very little.

Hey RK,    My left tube was easy in and out,,, the right one was horrible,,, wooden wedges did nothing,,, I sharpened up a big brass chisel,,, that did nothing as well. I forget where I read it, but the author mentioned that the stiction was usually quite bad from the rubber grommets on the tubes of the headlight bracket, not the triple clamps themselves,,, that seemed to be my biggest obstacle as well..

     Normally to loosen seized things up, I lube everything with aceton/atf, but I was afraid the acetone would attack the rubber grommets on the headlight bracket tubes,,, so I used Armorall,,, my favorite tool on the hole job was a huge hardwood mallet that I picked up in a tool deal,,, tap and twist the tube and add Armorall etc etc,,, bit by bit,  it finally came out.

     Once I cleaned everything thing up,,, it went back in much easier,,, good twists, upward pressure and gentle taps from the bottom with the wooden mallet got it in with no drama.

      My final height adjustment(much better than original) of the tubes was simplified greatly, again using the wooden mallet,,, I never thought I'd be using the big old beast on a bike, but she earned her keep on that job,lol.

       Kelly
2008 California Vintage
2003 V11 Lemans
2007 Griso 1100
1979 G5 & 1980 Lemans CX100
2010 Suzuki DR650 & 1978 SR500

In a time of universal deceit, telling the truth becomes a revolutionary act. George Orwell

Offline rodekyll

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 :thumb:

Yeah, those rubbers can be a bear.  Mine are usually so hard that they couldn't stick to themselves.   :grin:

Offline Arizona Wayne

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The best thing I did to my CX100 for getting it to handle better in corners was to put a Tarozzi fork brace on it and a 16" front rim w/a 110/90 front tire to duplicate what I had put on my `87 LM IV.  As stock the 18" 100/90 front tire w/clip ons or even w/o steers too slow for changing directions compared to what I did.  :thumb:

Offline 80CX100

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The best thing I did to my CX100 for getting it to handle better in corners was to put a Tarozzi fork brace on it and a 16" front rim w/a 110/90 front tire to duplicate what I had put on my `87 LM IV.  As stock the 18" 100/90 front tire w/clip ons or even w/o steers too slow for changing directions compared to what I did.  :thumb:

     Hey Wayne,     Thanks for the feedback and your opinion of the Tarozzi fork brace. I'll definitely keep it in mind.

     When I ordered my suspension parts, from Laverda specialist and Ikon distributor Wolgang Haerter at Columbia Car & Cycle in British Columbia, I tried to get a fork brace from him as well.

     Wolfgang is in semi retirement mode,,, and is trying to focus on his first love, which is Laverdas,,, he was having a hard time sourcing me a brace, and I had read about some owners, having a problem with some of the brace's poor design causing misalignment of the forks,,,, so I didn't pursue it further.

      I feel very lucky that I was able to get what I did through him in Canada,,, I've tried to repeat the order since for my G5, and he's refused, his main thing is Ikon shocks & Laverda parts.

       My CX is slowly coming together,,, but I'm finding it tough to dedicate time to work on her with all my other jobs on the list and still trying to get some riding in,lol.

       Kelly
2008 California Vintage
2003 V11 Lemans
2007 Griso 1100
1979 G5 & 1980 Lemans CX100
2010 Suzuki DR650 & 1978 SR500

In a time of universal deceit, telling the truth becomes a revolutionary act. George Orwell

 

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