GS1150 Crankshaft replacement ?'s

[youbloph]

So I bought a project GS1150 pretty cheap not to long ago, I've fixed some of the other problems and figured i'd move onto the starter clutch (the bolts to the flywheel ended up being sheered off). Once I got the flywheel off I decided to check the crank to see if it was straight coming out of the case, it has just under .010 at the end of the tapered surface for the flywheel and .004 at the edge of the surface next to the bearing, the bearing is tight though. I figured I should start looking for a crank, i'm looking for the cheapest way to get the bike running, and the gs1150 cranks seem to be going for around 300 post shipping, but I've read that the gs1100 cranks could potentially drop in, and they go for around 100-200. I'm just wondering if the two are compatible (as far as balance dimensions and gearing) and what it might take to swap in an 1100 crank.

 

[posplayr]

First off all 1100 cranks are not created equal; the 83 are welded and command much more than a pre 82.

Next is even a bigger problem. the cranks are all pressed which means you cant get the rods off. The 1150 uses 20mm piston pins so you would have to put 18mm piston on your 1100 crank . Now you looking for +2mm 1100 piston to fit your 74mm bores of the 1150.

If you were going to go that way, do a straight swap for the 1150 engine "as is" for a running 1100 83 Black engine.

The real value is if you get the 1150 crank and fix the 1150 motor is that is what is really wrong. Not sure why you think to use a straightedge on the end? There is probably nothing wrong with it unless it was laid down.

 

[rapidray]

Hey newbie!, call me at 714--356-784 five. I build & race these & can answer any questions you have. Welcome to the site!!
Ray.

 

[youbloph]

sounds like if I where going from 1100 to 1150 i'd be able to get bushings for the pistons but not the other way around. I used a dial indicator on the exposed portion of the crank under the flywheel (as the flywheel had around .02 and I was testing to see if it where just the flywheel that was screwed up or the if the crank was bent, it ended up being a combo of both). I'll probably just go ahead and get a crank from an 1150.

 

[rapidray]

I have 1150 cranks also.
Ray.

 

[blowerbike]

hey newbie where are you at on this planet?

 

[brufnus]

Hey newbie!, call me at 714--356-784 five. I build & race these & can answer any questions you have. Welcome to the site!!
Ray.

Hi Ray, perhaps you can help me with a problem. I've tried like mad getting a stuck flywheel off one of my 1150 engines - puller, banging with a hammer, heating the flywheel/cooling the crank, but it's stuck. Do you have any suggestions?