v50 crankshaft end float

[Tony Lyons-Lewis]

We are fixing up a 1980 V50 nag, when the clutch lever is pulled in, we get a horrible grating noise that transmits up to the hand lever. Gearbox off and clutch all looks in good condition, but there is about 1/4" end float in the crank. Is this excessive and, f so, how much should it be and how is it fixed? With thrust bearings on the crank flanges?

 

[john zibell]

I believe end float on a Guzzi small block crank is determined by the front main. It probably requires replacement. Locate a service manual for the bike and it should give the front main and crank specifications/dimensions. Hopefully with that much end float the crankcase halves haven't been damaged, but with that much play it is possible. I'd also carefully inspect the rods to see what is going on there as well. That much end play could cause a problem.

 

[Tony Lyons-Lewis]

Thanks very much for the help. We are now busy stripping the motor to see what has gone wrong! There are small bits of metal apparent on the sump gauze filter. Battling to undo the Allen cap screws holding the timing chain guide - why Allen cap when hex bolts would do, so much easier to apply some force on seized fixings with a socket!!!!

 

[Tony Lyons-Lewis]

All stripped down and the half collar thrust bearing, I think that is the term for it, is lying lose in the housing, severely ground and damaged. Question: what holds it in place normally? I have worked on old MGs quite a lot and the thrust bearings have always been in two semi-circular bits, located by a small tag on the outer circumference. I have never seen one like this with it only being half circular!
Next question: Is a replacement just one standard thickness or are there oversizes available. Also, is it sold on it's own or only as part of a full set of replacement main bearings?
Lastly: is there a sludge trap in the crank shaft?
We need to clean everything very carefully to get rid of the metallic bits left behind from the failed thrust bearing!

 

[Tony Lyons-Lewis]

Nobody got any helpful comments on the questions asked??!!

 

[GuzziV65TT]

its quite a common problem with small blocks, My old monza engine got scrapped as the rear of the crank was damaged but thrust bearing failure. My V65TT is just starting to have odd noise when red hot and clutch pulled in. Far as im aware the bearings just sit in the rear of the block and are pressurised with oil... Guzzoligy talks a lot about later lario spec bearings being used and factory mod for adding a oil hole to the bearing

Bearings are sold alone an i have only ever seen one size.

There is a sludge trap according to the workshop manuals

 

[Tony Lyons-Lewis]

its quite a common problem with small blocks, My old monza engine got scrapped as the rear of the crank was damaged but thrust bearing failure. My V65TT is just starting to have odd noise when red hot and clutch pulled in. Far as im aware the bearings just sit in the rear of the block and are pressurised with oil... Guzzoligy talks a lot about later lario spec bearings being used and factory mod for adding a oil hole to the bearing

Bearings are sold alone an i have only ever seen one size.

There is a sludge trap according to the workshop manuals

its quite a common problem with small blocks, My old monza engine got scrapped as the rear of the crank was damaged but thrust bearing failure. My V65TT is just starting to have odd noise when red hot and clutch pulled in. Far as im aware the bearings just sit in the rear of the block and are pressurised with oil... Guzzoligy talks a lot about later lario spec bearings being used and factory mod for adding a oil hole to the bearing

Bearings are sold alone an i have only ever seen one size.

There is a sludge trap according to the workshop manuals

Thanks for the info. We have machined the face of the crank where the outer thrust fits and are making up an oversize item, then white-metalling it. Hope this all works as locally no bearings are available