‘75 850T Newb Restoration Project

[shiskowd]

I took another look at the front bearing carriers to see if the 2nd circlip would present any issue. I had previously lightly torqued the bolts that fasten the two bearing carriers (without the brake disc) as to spin the wheel on my truing stand and noticed that the bearings were jammed such that they would not freely spin.  I backed off the bolts and both bearings were free to spin.  The 2nd circlip had moved the bearing too far into the carrier and against the spacer between the bearings.  When the bolts were tightened this effectively squeezed the bearings so they were binding in the races.  I took out the 2nd circlip, tightened the bolts and the bearing moved a slight distance out of the carrier, far enough that circlip would not fit into the groove.  The manuals and Charlie are correct - you shouldn't install the 2nd circlip.  The previous owner and/or mechanic of my bike had this wrong.

On the single front disk brake bikes the circlip needs to be on the bearing carrier supporting the brake disk, keeping the brake disk a consistent distance from the fork, aligning the brake caliper.  When the axle nut is tightened the 'floating' bearing will tighten against the spacer.

[shiskowd]

Finally, engine assembly!  Been reading through many threads pulling tips and trick from the many posts on the topic and can finally apply want I learned.

I purchased the HMB billet front and back bearings since I was already shipping the con rod bolts from HMB in Gemany (seems these are in scarce supply).  The billet front bearing is the later style for the later big twins with oil filters so I needed to modify to suit my non-oil filter engine.  Guzziology covers how to but it's pretty straight forward with a couple of sharp drill bits and a drill press to make the oil passage from the oil pump and the extra hole on the bearing flange.



The machined rear billet bearing is a thing of beauty...



Front bearing was a tight fit but position it just right and it seated without any effort.  I elected to use M8 wave washers rather than the retaining tabs.  Use a light coating of blue thread locker.



Installed the timing chain tensioner with the 3 & 4 o'clock bolts.  Schnoor locking washers under the bolts on the steel tensioner backet.



Red thread locker on the aluminum plug for the sludge trap.  Crank was thorough cleaned prior to get any of the remaining sludge.



Put a light coat of Permetex Aviation gasket goop on both sides of the gasket. Crank bearings lightly coated with assembly lube.



Double checked the alignment of the oil passages in the bearing - get that wrong and, well, don't want to think about that.  The rear bearing is a tight fit and needed gentle taps from a rubber mallet.  Used longer M8 bolts threaded into the engine case to align the bearing as it slips down.  Followed  Guzziology Dave's suggestion for seating the bearing in the case.  Suggests taping gently with a mallet rather than using the bolts to seat the bearing flange against the engine case - his theory is it may be less prone to leaking done this way.



Cam all lubed up prior to inserting into the engine case.



New cam retainer thrust flange from HMB.  You can see there is some slight wear in the old one were the timing chain sprocket wears against the flange.





Question for the experts ...

The new flange is is 0.1mm thicker than the old flange (not factoring the wear on the old one).  I haven't torqued down the sprocket nut yet but it would seem there's not going to be much if any clearance for the flange between the shoulder on the camshaft and the sprocket.  I have seen other posts from LesP (https://wildguzzi.com/forum/index.php?topic=93655.msg1628200#msg1628200) and Jim (https://wildguzzi.com/forum/index.php?topic=89764.msg1436835#msg1436835) where modifications were made to ensure good oiling to either side of the thrust flange.  Should I modify similarly?  Has this been an issue that some have experienced?  The service manuals make no reference to the clearances surrounding the thrust flange.

[LesP]

The shoulder on the rear of the cam and the cam front face/rear of the sprocket face makes the clearance go, no go and it was fine on my HMB flange.
I did fairly extensive machining on all those parts, will it get a better oil firm is unknown and probably won't check, the only reason I did half channels was so oil would not just flow through and there was not increased pressure bleed off (clearance between the flange faces)
Hopefully the best of both worlds.
The wear I saw on the old parts including the rear of the camshaft sprocket thrust face suggested it could do with more oil one way or another.
I seem to recall the flange from MGCycle already has some channels/grooves in the face .

I have to laugh (at myself) , I saw the front oil filter bearing and thought how will it get filtered oil then after rereading realised you don't have a filter and did not modify the engine case to suit one.
Nice job, keep up the good work.

[shiskowd]

I don't have the machining tools nor none of the skills LesP has to modify the thrust flange as he did so I simple used a mini dye grinder on a rotary tool to groove the surface faces the camshaft sprocket.



Flange installed with Schnoor locking washers with a centering trick from LesP.



Lubed up the inside of the rear seal and applied a thin coat of Permetex Aviation on the outside of the seal per Charlie's suggestion I read somewhere.



Seal installation tool makes quick work of setting the seal into the bearing at the right depth.



Moving on to the connecting rods, installed the new bearing shells and bolts and nuts.  The shells I purchased from MGCycle are all the same (two holes on each shell so they work for either half).



Shop manual suggests the rod assemblies be weighed in an effort reduce any imbalance.  Snuck these into the kitchen when my wife wasn't looking. Close enough as the manual states 3 grams is the maximum allowable difference but I doubt that kitchen scale is that repeatable.



Question - does it matter which way you install each connecting rod?  I know the machine surfaces on the side of both housings need to be on the same side and the pairing of the two pieces need to be maintained.  With two lubrication holes on each shell half there is no up/down?  The old single hole shells had the hole on the machined side of the con rod assembly.  Is that the orientation I need to maintain?

[Antietam Classic Cycle]

Is there an oil hole in the rod? One of the holes in the shell will line up with it. If there are oil holes, then the left - up and right - down in the instructions applies.

[shiskowd]

Yes, there are holes in the rod - just noticed that now.  The oil hole is on the same side as the machined side of the big end bearing holder, just like the drawing.  I found I picture I had taken of the rod bolts before I removed them, they are installed as you and the manual suggest.  Thanks 

[shiskowd]

So, funny story.  This morning I'm sitting on the throne (privy, latrine, head, amenity - understanding this is an international audience) thumbing through Hayes Owners Workshop Manual that I have at the ready and come across this picture concerning engine assembly.



Bugger!! I forgot to install the locking pin or push fit pipe as the manual calls it.  But... does this billet bearing assembly need the locking in to keep the inner bearing from rotating in the housing?  Email to HMB went unanswered although HMB sells the pin as a related part to their billet bearings.  LesP replied to a PM and said he did install the pin in the same billet bearing but also questioned why it was needed.  Better safe than sorry, I pulled out the bearing before the sealant, thread locker and gasket goop set any further.  Messy task but accomplished.  Can't imagine the angst if I had the engine back in the bike when I came across that!   

[canuck750]

Coming along real nice!

I forget something in most every engine I put together and end up pulling it apart at least once, I think its called learning, at the very least its a bonding experience with the engine

[shiskowd]

Installed the connecting rods today.  As the crank journals were in spec and I purchased new bearing shells I didn't bother plasti-gauging the clearance.  With the shells lubed up and the rod bolts torqued the rods were snug on the journals but still moved freely albeit well dampened due to the thick assembly lube.





New oil pump, milled from solid billet.  Gear/impellers have are larger diameter over stock for improved oil capacity.



With the pump and oil pickup in place I test fit the sprocket on the new oil pump. 



ARRGGGG   ... The new key I purchased from MGC with the pump is too large to fit the shaft of the new oil pump.  Why would they sell a key that is specifically for this pump (it's the straight type, not the half moon style of the original pump) yet has no chance of fitting?  The slot in the new pump is too narrow and not deep enough for the straight key.  The key fit perfectly in the sprocket slot which is quite shallow.  Do these sprockets have differing depth of slots such that the key would fit the deepest sprocket/pump shaft slot??

Had to pull the pump off and use a cut off wheel in a Dremel to widen the slot and make it deeper to accommodate the key - ridiculous...



I installed the oil pan temporarily with a few or the old bolts as the bolts in my Stainless Cycle kit for the pan were too short.  I'm sure I specified I had the stock 850T oil pan when I ordered. Oh well..., I'll pick up some stainless cap screws locally.



Next I wanted to install the flywheel so I could use the flywheel holding tool to torque the crank and cam sprocket nuts.  Installed the breather and oil return tubes with the suggested gasket and sealant goop respectively.

Before I install the flywheel I want to clean up the timing marks as they are difficult to see and the markings are confusing.

This is the left "S" side timing mark.  The alignment of the arrow on the flywheel to the TDC case indicator (see http://www.thisoldtractor.com/projects_roy_smith_2013-03-19_install_the_flywheel_and_clutch.html) aligns with the faint scratch just above the "S" stamped on the flywheel edge (red line in the picture).

The specs state the idle timing advance is 8 degrees.  I don't have a degree wheel but I did a bit of trigonometry to determine that an angle of 8 degrees extended along the radius of the edge of the flywheel (115mm) would equate to a distance of 16mm from the TDC mark (formula for similar eng geeks as I is (115^2+115^2-2x115x115xCos(8))^0.5 =16.0).

There are multiple punch marks at the 16mm measurement (blue line below) that suggests the previous owner/mechanic likely marked those as a timing target.  Also note another scratch highlighted in blue 2/3's of the distance to the 16mm mark, unsure of that purpose.  I also applied the same trig math to the 34 degrees advance timing for the engine running at 4,500 RPM to get a value of 67mm from the TDC mark.  There is another faint scratch on the flywheel that measures 67mm exactly from TDC that would be used for the timing mark - seems my math works...



Below is the picture of for the right cylinder with TDC marked "D".  There is a similar faint scratch just above the "D" and a faint scratch at 8 degrees (16mm) but the punch marks (with red highlighting) is only 5mm or 2.5 degrees from TDC.  Had that been used for timing the cylinder the ignition would have been retarded way too much.



The best way to determine TDC is with a piston stop and degree wheel when the heads are installed.  There is a degree or two of play with the M8 bolts that fasten the flywheel to the crankshaft that can be used to align the existing timing marks if needed. I'll need to come back to this later when my heads are on and then mark the flywheel accordingly. 

[wirespokes]

Instead of that trig formula, why not calculate the diameter, divide by 360, then multiply by 8?

One of these days I should make an adapter for a dial indicator using an old spark plug, and check my timing marks.

[canuck750]

A piston stop made from an old spark plug with the porcelain punched out and a 6 mm nut and bolt will work fine, that with a degree wheel will do the trick.

Nice work on the engine assembly. I have had a similar experience with the key for the newer style oil pumps, PITA!

Merry X-Mas

Jim

[shiskowd]

Instead of that trig formula, why not calculate the diameter, divide by 360, then multiply by 8?

Yes, there's more than one way to figure this!  That works as long as you measure that distance along the diameter (curve) vs a straight line distance measured with a caliper.  Not a big difference for the 16mm but the 34 degree advance timing mark is 67mm (tangent) and a bit more than 68.2mm along the diameter.  Nerd stuff...

[BikeMike]

Nice work!  I have my 850T stripped down and waiting for me to find the time and $ to start rebuilding.  In the meantime I am enjoying your posts and will definitely use them as a reference.

Cheers,

BikeMike

[wirespokes]

Yes, there's more than one way to figure this!  That works as long as you measure that distance along the diameter (curve) vs a straight line distance measured with a caliper.  Not a big difference for the 16mm but the 34 degree advance timing mark is 67mm (tangent) and a bit more than 68.2mm along the diameter.  Nerd stuff...

I haven't used Trig since high school, so don't remember how to do those calculations. That's pretty cool you've got a good understanding of those tools.

Of course, I wouldn't have thought of taking a straight line measurement from point A to point B rather than arcing the diameter. In roughly 2.5" you'd be .05" off.

[shiskowd]

Is this too much wear on the flywheel splines?

[Antietam Classic Cycle]

In my opinion, yes.

[shiskowd]

In my opinion, yes.

  Thanks Charlie..  Do you have a suggestion for a new flywheel?  MGC sells a 17067050 ~9.5 lb model that I believe will fit the 850T.  Should I consider one of the lighter versions (5.5 lbs)?

[Peter949]

Last winter I replaced only the clutch plate on my 1984 California II, since the splines on the flywheel showed only very light wear marks. The splines on your flywheel clearly show too much wear, and I would definitely replace the flywheel at this stage in your rebuild.

[Antietam Classic Cycle]

Thanks Charlie..  Do you have a suggestion for a new flywheel?  MGC sells a 17067050 ~9.5 lb model that I believe will fit the 850T.  Should I consider one of the lighter versions (5.5 lbs)?

You'll get a lot of different opinions on this, but I would stick with a flywheel of the original weight (9.5 lbs.).

[canuck750]

I spent today cleaning out my garage attic and buried in a container is a flywheel, pressure plate etc... stop by next time you are up in Edmonton and take it away, I need the space!

[shiskowd]

I spent today cleaning out my garage attic and buried in a container is a flywheel, pressure plate etc... stop by next time you are up in Edmonton and take it away, I need the space!

Jim - I'll take you up on that offer!  I'll PM you when I'm headed that way, thanks!  Happy new year!

[shiskowd]

I've gone as far as I can with the engine assembly as I'm waiting for the head work to be completed at Universal Cycle in Calgary.  I'm also trying to source locally the 2 bearings (large 2 row input and output) before I can assemble the transmission.  So, moving on to the rear drive...

I hadn't taken too close a look at the drive shaft when I took the swing arm and rear drive apart but I did note that the remaining grease was very thin and had a rusty look.  I cleaned up the pieces in solvent today and removed the corrosion with a brass wire brush.  Following picture is the drive shaft splines and rear pinion splines that fit into the coupling.  Noticeable pitting where rust was removed with a wire brush.



Next is the opposite end of the drive shaft that fits into the U-joint.  The splines on the opposite end of the drive shaft are in much better condition and only exhibit a very slight axial play when inserted into the U-joint.  The picture does contrast what the splines should look like on the pinion gear.



The U-joint itself is very tight, but I can feel a very slight amount of play when I twist the opposite ends of the U-joint.

All put together, the following video shows the lash in the entire drive shaft from the U-joint to the read drive.  The splines on the output shaft of the transmission are in good shape, the mating end of the U-joint has no discern-able play/movement.

https://youtu.be/hS1es3Cpoz4

Unless someone has a different suggestion, I'll be needing a new drive shaft, coupler sleeve and ring & pinion gear set.  The latter is regrettable due to the cost and complexity taking apart the pinion bearing assembly and the required shimming on the ring gear to make it all run smooth  .

[Antietam Classic Cycle]

I've gone as far as I can with the engine assembly as I'm waiting for the head work to be completed at Universal Cycle in Calgary.  I'm also trying to source locally the 2 bearings (large 2 row input and output) before I can assemble the transmission.  So, moving on to the rear drive...

I hadn't taken too close a look at the drive shaft when I took the swing arm and rear drive apart but I did note that the remaining grease was very thin and had a rusty look.  I cleaned up the pieces in solvent today and removed the corrosion with a brass wire brush.  Following picture is the drive shaft splines and rear pinion splines that fit into the coupling.  Noticeable pitting where rust was removed with a wire brush.



Next is the opposite end of the drive shaft that fits into the U-joint.  The splines on the opposite end of the drive shaft are in much better condition and only exhibit a very slight axial play when inserted into the U-joint.  The picture does contrast what the splines should look like on the pinion gear.



The U-joint itself is very tight, but I can feel a very slight amount of play when I twist the opposite ends of the U-joint.

All put together, the following video shows the lash in the entire drive shaft from the U-joint to the read drive.  The splines on the output shaft of the transmission are in good shape, the mating end of the U-joint has no discern-able play/movement.

https://youtu.be/hS1es3Cpoz4

Unless someone has a different suggestion, I'll be needing a new drive shaft, coupler sleeve and ring & pinion gear set.  The latter is regrettable due to the cost and complexity taking apart the pinion bearing assembly and the required shimming on the ring gear to make it all run smooth  .

I'd replace the driveshaft and coupler, but not the ring & pinion (unless there's more damage, like chipped gear teeth or something). If kept greased, those input splines will most likely run a long time.

[shiskowd]

I'd replace the driveshaft and coupler, but not the ring & pinion (unless there's more damage, like chipped gear teeth or something). If kept greased, those input splines will most likely run a long time.

Thanks Charlie... I was hoping for that response!  I'll replace the driveshaft components and ensure it's lubed up well.

[shiskowd]

I picked up the output bearing from a local bearing supply shop.  There are many variants of the 3205 two row bearing, this one had plastic sealing shields that were easily removed to make it an open style and has a plastic bearing holder.  The application specialist insisted these would work fine in the relatively low transmission temperatures with the shields removed for open lubrication. Old bearing is on the right.



Seals installed in the output and input sides.





Cleaned up the output shaft.  There was a sealant of sorts that had clogged up & hardened around the old o-ring.


New 4mm spline hub with the tricky peg nut and locking tab washer.


Laying in the shafts is a bit tricky. John Noble's 'Inside the Lemon Box' is a great resource on 5-speed transmission rebuilds - highly recommended for newbies like me.


Positioned the selector mechanism to ensure that I had the drum positioned to 'neutral' so the pawls would slip over the drum cut outs.  It's all well explained in the Lemon Box.


Backside of the case cap with the selector mechanism fitted.  Note the new output bearing.


Tightened it all down to precisely 115 ft-lbs with the two proper hand wrenches (feels like 115 ft-lbs...)


Stake the thin edge of the nut into the splines in a few places.


Transmission completed!  Just need to source that tiny washer at the end of the speedo drive gear which was missing when I disassembled the transmission.  Never been this deep into a transmission before and I had anticipated putting it together to be more of a chore than it was.  Again, John's guide provides step by step for those unfamiliar.

One tip not mentioned in the Lemon Box guide.  Test the neutral switch with a ohm meter prior to sealing up the gasket.  I had to bend the copper tongue up slightly to get it to ground to whatever it is that it bumps up against when the box is in neutral.

[SED]

Beautiful work!  Astonished you describe yourself as a newbie.  I'll be referencing this thread when I have to get deep into the LeMonIII.

[canuck750]

Great work

Check Home Depot in the hardware section, plastic revolving parts bins in Edmonton they have a selection of small hard steel shims, you may luck out and find one that fits the speedo drive shaft.

[shiskowd]

Beautiful work!  Astonished you describe yourself as a newbie.  I'll be referencing this thread when I have to get deep into the LeMonIII.

When I bought the 850T I had no idea of the resources that are out there for these older Guzzi's.  If you take the time to poke around this site and others you should be able to find any answer you're looking for.  The 'regular re-builders' who lurk on these threads are invaluable to fill in any gaps, be sure to abuse them!

[shiskowd]

Great work

Check Home Depot in the hardware section, plastic revolving parts bins in Edmonton they have a selection of small hard steel shims, you may luck out and find one that fits the speedo drive shaft.

Home Depot?  No kidding - I'll give that a try today!

I did find a thread that pointed to Fastenal (https://www.fastenal.com/products/details/11511041), minimum order is 20 pieces at $7.50 each ($150 for the order!).

[Antietam Classic Cycle]

Home Depot?  No kidding - I'll give that a try today!

I did find a thread that pointed to Fastenal (https://www.fastenal.com/products/details/11511041), minimum order is 20 pieces at $7.50 each ($150 for the order!).

I have a baggie full of those washers. I can send you one (or more) if necessary.