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Griso 1100 Crankshaft Clearance

cse

cse

Tuned and Synch'ed
Joined
Oct 11, 2010
Messages
34
Location
Portugal
Hello,

During a front crankshaft seal change procedure I noticed some endplay on the crankshaft. That clearance is only noticed on 45º angle, horizontally and vertically it has practicaly no clearance but on a 45º angle it moves enough to stretch the chain and see the tensioner moving.
Is that normal? The engine has only 40K Km,
 
Front main should have 0.001 to 0.002 inch (0.0254 to 0.0508 mm) clearance. Movement should be imperceptible. This may require further investigation. With luck it is only the front main that is worn and not the crankshaft. It can be replaced after you remove the timing chain. Timing chain removal and install is easier with a second person to hold the tensioner out of the way.
 
Ok, thank you for fast reply, John.

I have a few questions.

How do I measure it to see if it is worn? do I need to remove the crankshaft? Is it normal to be worn in 40.000Km? What causes it? All maintenace intervals were respected (with 8000 Km´s interval) loaded with 5W40 oil in the 2 first changes then with 10W60 Motorex and the last 2 with 10W60 Eni i-ride, and good oil filters.

That clearance is getting me worried..:(:(:(:swear::mad:
 
Mostly I've seen the front main bearing in the carrier wear, but the crank shaft did not. Once the front main is out, you can use a telescoping device (T shaped that fits in then you lock to hold the dimension) and good caliper on micrometer to measure. Compare the measurement to what the specification is in the service manual. If lucky, it may only need replacement of the front carrier. With such low mileage, I'm a bit surprised, but on assembly at the factory the fitment may have been a little out of spec, or at the outer limit of the specification. That is the from main may have been bored out a little too much.
 
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cse said:
Ok, will take the front main out and measure it.

Thank you.
Click to expand...


Are you familiar with setting up the timing marks on re-assembly? Also once the timing chain is off, see how much deflection you can get at the front of the crankshaft.
 
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Ok, I turned the crank and the clearace is in the same direction, so it must be the main.
 
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The tensioner looks to be fine, and after I removed the main bearing I found out the cause of the clearance.
IMG 2286 IMG 2287 IMG 2288
Don't know how that happens.. Asked opinion to a couple of mechanics and their opinion were that It had bad lubrication, or because of the wear marks in the front and rear maybe the cranckshaft has to much front/back clearance..

I ask your opinion about if I should just put a new main, or disassemble more to see if it has any more damage, The crankshaft looks fine, has no wear or score marks where the main seats...
 
cse said:
Don't know how that happens.. Asked opinion to a couple of mechanics and their opinion were that It had bad lubrication, or because of the wear marks in the front and rear maybe the cranckshaft has to much front/back clearance.. I ask your opinion about if I should just put a new main, or disassemble more to see if it has any more damage, The crankshaft looks fine, has no wear or score marks where the main seats...
Click to expand...
I have done eleven rear main seal replacements on the 8V motors to date, and all of them require you to remove the main bearing support plate similar to the front plate as you show. All of them, even brand new, have some type of tiny marking such as this as this is where (IMO) the bearing material starts/ends, as in a seam of sorts. It usually is only in the area where there is the dropped groove in the middle, however with wear they tend to surface. I would replace just the front, and dig into the clutch side if/when the clutch needs looking at or if the rear main seal leaks.
 
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Ok, thank you for the advice, I will replace the main and the seal.

I still wonder what causes the bearing to crack like that in only 40.000Km's, could overheating or faulty lubrication been the cause?
It looks like it has been like that for some time and the fact that the seal has been leaking for a few years tells me that the problem was not a damaged seal but the main bearing being cracked for that time now.
Didin't notice any strange vibrations or behaviour from the engine, wich I probably should have.

Is there any upgrade or better bearing to fit?
Is there any way to tell if the rear main is cracked without removing the engine or the gearbox?

Thanks for the help GuzziTech has been one of the best tools a Guzzista can have for many years now..
 
The bearing material is poured into the carrier. Then it is bored to standard or undersized. It is possible there was a problem with the temperature control of the pour. I have seen this type of failure in poured bearing surfaces in old cars (pre 1950 engines). As far as I know, the mains are only available from Guzzi. As Todd said, I wouldn't worry about the rear main unless you see a problem. First sign would be a rear main leak from the crank moving excessively. Since you don't have one, it is probably OK.
 
IMG 2258
The part have arrived today from SD germany and I have a little problem with a seal.
I ordered the seals from a local part dealer and He couldn't find the small seal (camshaft) in viton.
My question is if it is safe to install a std seal in the camshaft ?
What is the purpose of that seal, I can't quite understand how that engine breathing system works. It vents well when the engine is working..
 
One other thing. Todd wrote that the plates all "have some type of tiny marking such as this". But as you can see by this better photo it isn't that tiny.
You may call me stubborn, but I still wonder what may have caused it...


IMG 2294

Just want to know so I can prevent other identical situations ...

Any ideas or opinions are welcome.
 
cse said:
The part have arrived today from SD germany and I have a little problem with a seal.
I ordered the seals from a local part dealer and He couldn't find the small seal (camshaft) in viton.
My question is if it is safe to install a std seal in the camshaft ?
What is the purpose of that seal, I can't quite understand how that engine breathing system works. It vents well when the engine is working..
Click to expand...


So long as the seal is oil resistant you should be fine.
 
cse said:
One other thing. Todd wrote that the plates all "have some type of tiny marking such as this". But as you can see by this better photo it isn't that tiny.
You may call me stubborn, but I still wonder what may have caused it...
Just want to know so I can prevent other identical situations ...

Any ideas or opinions are welcome.
Click to expand...

I replaced a front main on a 72 Eldorado not long ago. There were no imperfections in the bearing surface of the new main. As to what may have caused it, I don't think it was anything in the running of the bike, just a glitch in manufacture.
 
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