Replacing 1978 GS1000 crank shaft

[liloaty]

I am thinking about picking up a project bike with a buddy of mine. Its a 1978 GS1000 that suffers from a vibration due to what I believe is a bent/twisted/warped crankshaft. I am very mechanically inclined (mechanical engineer), but I am curious as to the actual difficulty of this project. I just need an estimate of time (ie 4 hours, weekend, evenings during the week)

Thanks guys

[Billyboy]

Me too. I've got a spare motor that is said to vidrate because of a spun crank. Balancer spun.

Can I swap it from the bottom without tearing up the top end?

[t3rmin]

I guess I don't see why you couldn't do it from the bottom. I just helped a friend replace a motor<->secondary drive seal from the bottom and the crankshaft is right there for the pickin'.

[Suzuki mad]

It would be easy to do from the bottom in theory. The sumbling block comes as the conrods are solid and pressed into the crank, so to get it apart you would have to split it at the pistons (gudion pins.) [Cam chain would be easy with a camshaft out.]

Its easier to strip the whole motor.

Best way I can suggest is to half strip it in the frame then lift the engine out. It saves a lot of backs.

If the crank needs repairing then time frame to do the job, I'd give it a full day to get it apart and another to get it back together again.

Suzuki mad

[weazzor]

I'ts not a hard job, if you take your time and be careful, I'd say 8 to 10 hours. That's what it took me the first time. Definitely remove the top end in the frame and then remove and split the cases out of the frame. Get a Haynes or Clymer manual and you'll have no problems. Good luck, and have fun!

[SqDancerLynn1]

They have it right You need to completely dissemble the motor. The big end of the connecting rods are one piece. It would be possible with a plain bearing crank, not the roller