gs850 into gs650 frame

[kokopelli]

i have a chopped 1982 gs650g and am wondering about dropping in a gs850 motor
will this work and how much should i have to change out? if not, is it possible just to swap the heads?

[Nessism]

The 550 and 650 share some similarities but the 850 is completely different. For one thing the engine is much larger and heavier; very few parts would interchange.

[kokopelli]

deff dont wanna drop any 550 parts in lol
like i said tho, the bike is chopped so slight mods to the mounts and all for fitting purposes wouldn't be too bad a problem (i dont think), mainly would the drive shaft and things of that nature still work?

the 650 motor in it is in fairly good condition so it's just more of a thought i've been toyin with to get a little more power out of the my chop

[TheCafeKid]

Not positive here, but I do know the 650 uses a smaller final drive than the 850/1000/1100s did, so methinks perhaps the propeller shaft and swinger would be entirely different too, which would mean the mounts in the frame would be different as well....

[kokopelli]

appreciate the input, guess im just have to do what i can to the 650

[Nessism]

Last thing you need for a "chop" project bike is to have more weight and power. Removing the rear suspension is bad enough without adding a bunch of extra engine weight on top of it.

[kokopelli]

still has the rear suspension, did a good bit to the frame and still got plans to rake out the front end just a few degrees but didn't do struts or a hard tail

[SqDancerLynn1]

Depending on your mechanical skills anything is possible. Not easy.. I would start by looking into mod/adapting an 850 swingarm assembly

[kokopelli]

def be the place to start. could probably do somethin for the motor mounts. i'ld already been thinkin the big problem would come in if the drive shaft and swing arm were too different
it'll be somethin good to kill some free time lookin into

[themess]

For all of its extra displacement and weight, the 850 doesn't put out a lot more power or tortque than the 650. The 650 has a newer head and valve design, and higher compression. You might be able to increase the 650's power easier than you can adapt the frame and drive to the 850 engine.