1978 850 T3 Restoration

[texasmoto]

Appreciate the confirmation. The transmission is buttoned up and sitting pretty. Where to from here....

[n3303j]

Appreciate the confirmation. The transmission is buttoned up and sitting pretty. Where to from here....

Ride it like you stole it!

[texasmoto]

"If it's aint broke, DON'T BREAK IT!"

With the transmission buttoned up, I'm digging into the engine: the one part that I know had some problems. The bike's been sitting for about 20 years and I could see some corrosion on the left cylinder. With most of the engine disassembled, the right cylinder doesn't actually look to be damaged. The pistons seem alright. Not that it matters I have the Gilardoni kit ready to reinstall and I'll be replacing the valves, valve springs and guides.

Inside the engine, there is a spot of corrosion (see photo A)



And there also seems to be some kind of corrosion on the right connecting rod. I wrote the "R". (see


photo up load
photo B) .

Is it necessary to replace these two components in the photos?


For everything else, I came across a thread wherein the poster had replaced the following as part of a standard engine rebuild:

- rocker cover gaskets, thick (2)               
- timing cover gasket                       
- head gaskets (2)                     
- base gaskets (2)                       
- oil pan gasket, thick                       
- breather pipe gasket                       
- rear main bearing flange gasket                 
- exhaust gaskets (2)                       
- intake manifold gaskets (4)                 
- distributor gasket                         
- oil pick-up gasket                       
- oil pipe gaskets (2)                     
- cylinder stud o-rings (12)                     
- front crankshaft seal                     
- rear crank seal                     
- flywheel bolt kit                       
- 8mm crush washers (6)                     
- 12mm crush washers (2)                         
- 20mm crush washers (3)                   
- Gilardoni cylinder kits (2)                                 
- rod bearing shells, 1st under (4)           
- front main bearing, 1st under                     
- rear main bearing, 1st under                       
- oil pump                             
- oil pump key                         
- intake valves (2)                     
- exhaust valves (2)                     
- valve guides (4)                     
- valve guide circlips (4)                     
- refaced lifters (4)                     
- timing chain                     
- timing chain tensioner                 
- rocker arm pins (4)                     
- sludge trap plug                     
- oil pressure sender                                                                       
- NGK BP6ES (2)                     
- distributor advance springs, pr.               
- distributor rotor                     
- condenser

Gaskets, I can understand, but the whole list seems a little like overkill to me.

The timing chain? The bearings? Seals? There was no evidence of any leak before. The rocker arm pins? They came out fine! I think I went overkill in replacing the bearings on the transmission. A supplier asked me, when trying to source a bearing, "Well how bad is it?" and it wasn't actually bad at all.

This engine came with 30k miles on it.

I'm not counting pennies, it's just that, if it ain't broke don't break it!

[Antietam Classic Cycle]

Your "spots of corrosion" are actually paint splotches that Guzzi applied to denote the "grade" of the crank and rods.

I'm guessing that's a list I posted at some point. Pretty common to need everything on that list for an Eldorado engine rebuild. Without an oil filter and with chrome bores, the crankshaft almost always needs to be ground and undersize bearings fitted.

You won't have these, since you're engine has an oil filter:
- oil pick-up gasket
- oil pipe gaskets (2)

Make sure you get the appropriate head gaskets for the Gilardonis. If they have oval pushrod holes, get the gaskets with the same.

You'd only need to replace bearings, rocker pins and oil pump if they're worn or damaged. The original timing chain has likely stretched, the original tensioner... didn't (unless one removed the timing cover and slid it over periodically). A new chain is better quality and the new bow-type tensioner actually tensions the chain. Seals? Definitely replace. It's false economy not to IMO.   

[n3303j]

Timing chain & gears good for at least 100K miles.
Stock tensioner is junk, replace now.
Replace all seals as long as you are in there.
At 30K miles the valves probably are fine. Check for leaks.
Bottom end should be solid unless it spent time under water.
A joy with this bike is you can replace everything from rod bearings outward without removing the engine. And it's quick access.
So run the bike and address top end issues if they show up.

[texasmoto]

Got it! This is welcome news. Appreciate the input. Will update at the next step.

[texasmoto]

Howdy,

I'm almost on the last step of disassembling the engine. Trying to remove this bearing housing but it is really glued on there. In the manual, and elsewhere, it seems to come off really easy. It doesn't seem like anyone has been here before, so maybe I've overlooked something. Is this supposed to be that difficult to remove?

[n3303j]

Two of the holes are threaded for a puller. I'd run a bar across the housing to pull against rather then pressing on the crankshaft.

Freeze it solid when you go for a reinstall and it should just drop in. Put a couple of bolts with the heads cut off in the mounting holes to guide the carrier into place. It makes lineup much easier.

[Don G]

Set engine with the rear bearing facing down towards bench, give the crank snout a firm twap with a dead blow hammer, use a 3 or 4 pounder. Place a piece of wood between bench and rear of crank so as to catch the assembly when it exits the case. Works every time stress free.  DonG

[Guzler]

https://www.rockauto.com/en/moreinfo.php?pk=33315&jsn=271

[texasmoto]

Two of the holes are threaded for a puller. I'd run a bar across the housing to pull against rather then pressing on the crankshaft.

Freeze it solid when you go for a reinstall and it should just drop in. Put a couple of bolts with the heads cut off in the mounting holes to guide the carrier into place. It makes lineup much easier.

Aaah! I didn't realize that only two of the holes were threaded. I missed those! Thank you

[Scout63]

+1 on a dead blow hammer to knock the rear main bearing out if you don’t have a puller. Just go slow.  Make sure you install the rear main bearing absolutely straight or you will wedge it and never get it in. You can use longer bolts to line it up. Also install a new bow timing chain tensioner like Charlie said.  New rod bolts and nuts are a must and sometimes a pain to source. Check front main bearing oil dowel placement carefully and seal the bottom front main bearing bolt where the hole goes all the way through.  I used Yamabond.  Also a good idea to seal the rear cam plug with JBWeld. After trying to time the points a few times I went with a Dyna III ignition.

[texasmoto]

I'm ready to start rebuilding the engine. It is all upwards from here, putting parts on instead of taking them off!

The rear main bearing gasket is a right pain-in-the-ass. I would literally rather order a new main bearing from Europe than deal with getting this gasket off and consequently having to take it to a machine shop because I know the machined surface will be wrecked.

How do I know what size bearing to get? It seems there is the normal one and then an undersized one.

[Antietam Classic Cycle]

Use chemical gasket remover, which should help. "Aircraft Remover" (paint remover) also works. I find that heating the gasket (propane torch) softens it and makes it easier to remove as well.

If you're still determined to just buy a new bearing, you'll need to measure the crankshaft's o.d. and compare that to the specs. in the factory manual to see if your crank is standard or undersize.

[n3303j]

Just went through the gasket removal on my T3. Aircraft Remover dropped the magic ingredient (as did all others). No more Methylene Chloride. Patience and a single edge Razor will work. Especially since you can do the job sitting at your workbench instead of lying on your back in the driveway. Patience grasshopper.

[texasmoto]

Just went through the gasket removal on my T3. Aircraft Remover dropped the magic ingredient (as did all others). No more Methylene Chloride. Patience and a single edge Razor will work. Especially since you can do the job sitting at your workbench instead of lying on your back in the driveway. Patience grasshopper.

Yeah I heard too many people were killing themselves trying to strip their bathtubs or something. I used aircraft remover recently on the frame and it was absolute garbage.

This could be a good excuse to get a propane torch to heat it up!

[Antietam Classic Cycle]

Worth a try: https://www.crcindustries.com/products/gasket-remover-12-wt-oz.html

Even without the "good stuff", Aircraft Remover still works for me (on gaskets).

[texasmoto]

For anyone in the future trying to figure out what size main bearing to get, I found this chart in an old workshop manual.

[Antietam Classic Cycle]

Um, yeah. Usually the first place to look. 

[texasmoto]

Happy new year suckers! Let's hope I'll be riding this motorcycle by summer!


I biffed the gasket removal on the rear main bearing. I have NEVER been good at removing gaskets.

The replacement arrives from Europe today. And with that, I am at the bottom of the disassembly process and ready to put her back together.

In my infinite wisdom, I did not make any timing marks on the way out. How screwed am I?

Having never rebuilt an engine, is it simply the same as the disassembly process backwards?

[Antietam Classic Cycle]

Happy new year suckers! Let's hope I'll be riding this motorcycle by summer!


I biffed the gasket removal on the rear main bearing. I have NEVER been good at removing gaskets.

The replacement arrives from Europe today. And with that, I am at the bottom of the disassembly process and ready to put her back together.

In my infinite wisdom, I did not make any timing marks on the way out. How screwed am I?

Having never rebuilt an engine, is it simply the same as the disassembly process backwards?

There are timing marks stamped into both the crank and cam sprockets. The flywheel should have a painted mark that lines up with the same on the crank. If not, turn the left cylinder to TDC and line up the stamped arrow on the flywheel with the "nub" pointer on the crankcase.

This may help in your reassembly.
https://www.thisoldtractor.com/projects_roy_smith.html

[texasmoto]

Well, that's a relief. Thanks for the reference!

Stay tuned for updates 

[texasmoto]

I am struggling to better understand this post from thisoldtractor





Where is the oil feed dowel in this photo? It says that it's at 12 o clock but I don't see anything there, so is 12'oclock the blue circle or the red circle?

I never took the front bearing out so maybe that's why I'm confused at this instruction. This is the current state of the engine

[Antietam Classic Cycle]

You need to remove the bearing in order to see the dowel. It fits into a hole at the top (12 o'clock) and keeps the bearing insert from rotating in the flange.

[texasmoto]

Alright, just wanted to make sure. 'preciate it

[Antietam Classic Cycle]

Alright, just wanted to make sure. 'preciate it

If you haven't already done it, you'll need to remove the oil dowel from your old rear main bearing and fit it to the new one. They don't come with the dowel.

[texasmoto]

I'm really struggling with the oil pump key!

Fortunately, I haven't biffed it or tried to force it. And it came out easily enough. But even when things are lined up EXACTLY, it still doesn't want to go in. It seems like it doesn't sit deep enough on the extruding bolt/screw. I'm tempted to shave a few thou off the key itself, but knowing that it's hardened steel makes me think that isn't possible with a simple wire wheel.

[n3303j]

A few thousandths comes off a hardened key by running it back and forth on a sheet of emery cloth laid on a very flat surface.

[texasmoto]

I took off a tiny bit, but it still didn't fit. It eventually went in with a little bit of the ol' tappy tap tap. Once the head was in it was smooth sailing from there. Cue innuendo here 

[texasmoto]

I am so close to finally rebuilding the top end (the whole purpose of the rebuild in the first place!)

But, I'm worried that I may have done something wrong in the reassembly, I am on the following step in the reassembly (see attachment). Bottom end is all but back together, excluding the oil sump.

However, in one of the two guides on thisoldtractor, he says,

"the best way to check if things are right are to set the case on its sump and the lift the rod to its highest possible point. With a decent assembly lube in the bearing, when released, the rod should slowly drop to the other side of the crankcase mouth under it's own weight. If it goes 'Clonk!' or doesn't want to move without force then there is something wrong."

I don't have that on my rebuild and so I'm pausing where I am for now. The crank does not move under it's own weight. It isn't binding anywhere, but it does need to be pushed. Not pushed too hard, it just doesn't move freely. I am using a brand new rear main bearing and rear seal. As well as new timing chain and timing chain tensioner.

I'm using this assembly lube, perhaps that is the culprit? https://www.autozone.com/greases-and-gear-oil/assembly-lubricant/p/lucas-oil-products-assembly-lube-4oz/692400_0_0

Is this common or have I done something wrong somewhere? I've been following instructions and torque specs to the letter, but it is likely that the guide wasn't thorough and I may have missed something due to inexperience.