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Quota rear main seal

jetpoweredmonkey

Just got it firing!
Joined
Nov 10, 2015
Messages
18
Location
Sacramento, CA
Hi Quota fans - I have my low mile Quota 1100 back on the road after an extensive refresh. It sat around for years in the previous owner's care. She is running very well but unfortunately the rear main seal has packed up. I confirmed it is the main seal by looking in through the timing inspection port, that's a handy feature!

So, it looks like I will be extracting the drivetrain - to my eyes it appears easiest to remove the exhaust system and drop the engine and trans out still attached to the lower frame.

My question for you all is what I ought to do while I'm in there. I have not taken a Guzzi apart before. Obviously I will need the rear main seal and might as well do the trans input seal while I'm in there. Also appears that there are some o-rings on the input shaft. There is also a paper gasket between the rear main bearing holder (?) and crankcase. It would seem silly not to change that, but I don't know what's involved. Workshop manuals and internet info are thin on the ground for this bike.

What else should I be looking for and what special tools will I need?
 
I haven't seen a Quota in some time, but if a two piece frame as you say, try crabbing the frame like we do with Tonti bikes. You should find posts on that procedure here. Some special tools are needed for the clutch components and gearbox input hub. If the rear main carrier is not leaking at the gasket, you can remove the seal by drilling two small holes in the metal part of the seal and use two small sheet metal screws inserted in the holes. You pull the seal out by those sheet metal screws. You do have to be very careful not to nick the area where the seal rides on the crankshaft. Your call on how you want to remove the seal.
 
Thanks, John...I found the attached photo, it looks like the transmission can stay in situ and the lower frame rails can be removed to let the engine loose. A front or rear wheel chock is needed since the main stand comes off with the frame rails, but that's no problem.

Seal extraction is easy enough but I still wonder about replacing that paper gasket. I don't know if it's just a cover/seal holder or if the bearing actually rides on the plate. If so, I would think that the crankshaft needs to be supported somehow when removing the plate.

Anyway, I guess will just have to get in there and take a look. I appreciate the input.
 

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Where the rear main resides is also the rear main bearing. The crank won't go anywhere if you remove the bearing. If you do remove it, mark its orientation before removal. It contains oil passages that must align on re-assembly or you toast the rear main and camshaft.
 
Good to know - I will get some photos of this thing when I have it apart and post them up for future reference.
Careful to use the right bolts if replacing the paper seal. Sounds like a no-brainer, but the low mileage Q that I bought had what I assumed was a rear main seal leak. When the trans was removed however, we found that the leak was the bearing carrier paper gasket. On further examination/removal, it was shown that the seal was pretty much blown right out, due to a PO reinstalling the carrier with bolts jut a fraction longer than the correct bolts, making a proper seal impossible. I have attached a rather blurry picture showing the remains of the gasket.
JD
 

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Thanks for sharing a useful tip. I'm still having trouble with the idea of the rear of the crank hanging in space like that. No problems up front leaving it unsupported while changing that gasket?

Maybe I'm just being paranoid because of the BMW crankshaft blocking necessity.
 
I've worked on many BMW airheads, never needed to support the crank when working on the rear main.
John, I was speaking of blocking the front of the airhead crank to prevent the thrust washer falling off the back when the flywheel is removed. Off-topic, but...just wondering out loud if there are any such pitfalls with the Guzzi.
 
John, I was speaking of blocking the front of the airhead crank to prevent the thrust washer falling off the back when the flywheel is removed. Off-topic, but...just wondering out loud if there are any such pitfalls with the Guzzi.


No there aren't. Crank position is set by the front main. There are no thrust washers in a Guzzi crankshaft system.
 
Got this job done over the weekend. I ended up using a front wheel chock to secure the bike, then removed the lower frame and dropped the engine out, leaving the trans where it belongs. All looked good inside and I determined the source of the leak straight away, oil was migrating up the threads of at least one of the two lower bolts on the rear main bearing plate. Upon removal, it looked as though the factory had applied sealant to those bolts. Those two were the only ones that had threads cut all the way through into the crankcase. The rear main seal was bone dry. I went ahead and put in a new seal and gasket while I was at it, bolts were sealed with Elring sealant, and the trans got a new seal and o-rings though no leaks were evident.

Too late for this job, I noticed after extraction that the rear bearing plate has two of its holes threaded for pushing it out with a larger bolt. Now that's a handy feature.

All in all a rather easy job, with the exception of a grade 8 bolt that twisted off the pressure plate upon removal. I replaced all of those bolts. And, trying to align the transmission hub with the clutch plate centers was a real bear despite using a clutch pilot tool. It just would not go, until finally it went! Perhaps there is a trick to that. It's probably much easier to mate the trans to the engine when both are out of the frame.

While I was in there, I had obtained a very lightly used flywheel from a California and installed that as well. The original was 6.5lbs, the new one is 9.3lbs. Since the bike is no rocket anyway, I'm hopeful this will help it out at low speeds where it tends to be a bit abrupt. The fuel injection probably plays a part there as well, but it felt like too light a flywheel on top of that. As an owner of a /5 and a Ural, I could care less how fast she revs. :)
 

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And a final note...after working on airheads and now this Guzzi, I sure feel like the MG design is the better one. The transmission hub "splines" look a lot more substantial and are easily replaceable without a teardown, the clutch is no more difficult to work on and appears to have a larger surface area, even the main seal holder can be replaced so any ham-fisted mechanics don't wreck the whole crankcase.
 
And a final note...after working on airheads and now this Guzzi, I sure feel like the MG design is the better one. The transmission hub "splines" look a lot more substantial and are easily replaceable without a teardown, the clutch is no more difficult to work on and appears to have a larger surface area, even the main seal holder can be replaced so any ham-fisted mechanics don't wreck the whole crankcase.


I agree on the Guzzi design. Unfortunately on the new 8V bikes, they have the single clutch plate and no replaceable hub gear like the BMW. A step backwards in my opinion.
 
I'm just doing a similar job myself. I've also got hold of a heavier flywheel.
What was the upshot of the heavier wheel, did you notice a better lower end power delivery?
 
The heavy flywheel didn't make a huge difference, but it does help noticeably getting the bike moving from a stop. I also feel like it smoothed out shifting a bit, the RPMs drop a little slower between gears, which is a good thing in my opinion, since the transmission doesn't like to be hurried. Clutch...wait...shift, like butter. I'm happier with the heavy flywheel though would not spend a whole bunch of money on one, I got mine cheap.

Incidentally I had a problem with this job, the torque spec in whatever manual I used (factory reprint I think) was wrong for the rear main bearing carrier, and my gasket leaked. I had to pull the engine out again and fix that. Easy to avoid, just torque those to about 20ft/lb and you'll be fine.
 
Did you check the bottom two bolt holes for the bearing carrier? During some production years these were through holes instead of blind holes and oil would travel there. When I come across these I clean the thread well plus the bolts and insert the bolts with blue thread locking compound to seal the threads.
 
Those holes on my bike were through holes and were the source of the original leak. They had some kind of sealant or thread lock on them from the factory but it had failed to stanch the drips. Good reminder to have a look at these when putting her back together. The rest of the bearing carrier holes are blind holes.
 
The factory sealer doesn't work as well as blue loctite. Key is to get got the threaded holes completely free of oil and dry before using the loctite.
 
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