Left Pipe blue smoke/Crankshaft issues too

[stoneage_godzilla]

1981 GS650 , 47,000 miles , recent barn find bike/recsue

We took godzilla out again today for its second time.

When I start it it sounds like im banging a 3/8 drive ratchet on the crankcase quickly.

It goes away once its in gear and going down the road.

and is gone pretty much if it is warmed up and not on its kickstand. So it can be in nutral and be fairly quiet

at any speed above 35 its burning oil and blowing out of the left pipe , i belive there is something wrong on cyl no 2. I think this becuse when it was started for the first time a ton of oil was burning off the exaust gasket area for cyl 2.

Oil and filter have been changed , I still need to do new o rings for the carb boots (high idle no matter what i do with the throttle cable so i belive i have an intake vaccum leak)

anyone have advise ? i see these arent prone to crank failures becuse of the roller bearings , so any other ideas? It sounds terminal to me ...too bad becuse it runs VERY well

[Steve]

i see these arent prone to crank failures becuse of the roller bearings ,

Sorry to burst your bubble, but the shaft-drive 650s have plain bearings and high-pressure oil systems. It's the chain-drive 650E that has the roller bearings.

.

[stoneage_godzilla]

uh oh , so it is possible to have a burnt up main bearing , becuse it really sounds like it is ..

[reddirtrider]

You've gotta' find the source of the noise first. Pull the clutch cover and check the housing nut to see if it's tight. I wouldn't ride it until I discovered that particular problem.

As for the burning oil, it's either coming past the valve guides or the rings. If you want to keep the bike you may need to pull the motor and break it down and rebuild. If not sell it or part it out.

[mike_of_bbg]

Banging that goes away when warming sounds a lot like piston slap to me. Could also be a timing chain getting thrown around, maybe? Did you have to un-seize the motor? Was it frozen? How long did it sit? Done a compression test (wet/dry)? Does the banging change speed with just the engine? Does it vary in different gears?

[TheCafeKid]

Banging and piston slap are also symptoms of a blown or a couple blown conrod bearings. There are a couple tricks you can try to see if youve got a blown conrod bearing, but the BEST way is just to pull the head and jugs off and grab a piston and wiggle it. If it has alot of up and down play, its shot. Ive personally seen the high pressure motors blow them, a replaced a motor in a 550ES that had done just that. Not saying thats your problem for sure, id know if i heard it, but it definately is a possibility.

[Nessism]

Banging noise at idle could be the clutch hub nut coming loose as well. Lots of things to check.

[stoneage_godzilla]

Banging that goes away when warming sounds a lot like piston slap to me. Could also be a timing chain getting thrown around, maybe? Did you have to un-seize the motor? Was it frozen? How long did it sit? Done a compression test (wet/dry)? Does the banging change speed with just the engine? Does it vary in different gears?

1)Motor wasnt siezed at all when we got it ...
2)It sat for what we can tell based on registrations was 6 years...
3)no compression test yet (recently moved cant find it)
4)the banging does change noise based on rpm with no load on the engine , if its in gear and moving the noise goes away

My old caddy had a bad no 1 main bearing it acted very much like this , being a car engine tho it was much deeper , i can tell a bottom end issue in a car but these bikes its hard to tell for sure , but it really sounds like a 3/8 drive ratchet is tied to the crankshaft and is hitting the crankcase as it runs ...

were keeping godzilla for sure , if it needs rebuilt we will do it ....but i do wonder if a fuel injected GSX-R motor will fit LOL ....the 4 mukinis were a nightmare to clean up and get right ....

[TheCafeKid]

1)Motor wasnt siezed at all when we got it ...
2)It sat for what we can tell based on registrations was 6 years...
3)no compression test yet (recently moved cant find it)
4)the banging does change noise based on rpm with no load on the engine , if its in gear and moving the noise goes away

My old caddy had a bad no 1 main bearing it acted very much like this , being a car engine tho it was much deeper , i can tell a bottom end issue in a car but these bikes its hard to tell for sure , but it really sounds like a 3/8 drive ratchet is tied to the crankshaft and is hitting the crankcase as it runs ...

were keeping godzilla for sure , if it needs rebuilt we will do it ....but i do wonder if a fuel injected GSX-R motor will fit LOL ....the 4 mukinis were a nightmare to clean up and get right ....

In gear it goes away? Id look elsewhere other than the crank. I am with Nessism on the clutch hub nut. Sounds pretty possible with more explaination from you..

[stoneage_godzilla]

sorry its been a few days...Been away working on my harley and her dads harley ...

Took the zuki out today to get more of and idea on whats going on with it. The case around the clutch area gets hotter then the damned heads so i have some sort of clutch issue , and the clutch is slipping (which i think is the cause of all the heat) so im gonna tear that side down to see what i can find , i think you guys are right as im having clutch issues.
The lever has been very hard to pull in since we got it but i lubed the cable and all and figured that was the nature of it. Im going to re route the cable too , she cant ride it far becuse of the effort needed to use the clutch , im not much better lol.