Heads

[gsridekc]

I have an 81 GS850 that has just begun to make some valve noise. I have read that the 850 motor is really just a bored out 750. If that's true, then would it be practical for one to put the four valve 750 heads on it? (Are the mating surfaces the same shape? Would the timing components need to be changed?) I wouldn't likely do this myself; would it be beneficial performance v. costwise? I'm a rank amateur; if anyone could enlighten me....

 

[speedy400]

if you wanted, you could do a search, I'm sure theres plenty of info on this site, what I can inform you of though is.- for one, the valve noise is most likly just in need of a valve adjustment, aka the shims in the cam buckets need to be replaced shims that maintain the correct lash(also lots of info on the site via search). I have heard the 4v head is a little better for performance, but for the work involved, not quite worth it. I thought about it on my 850, but then someone reminded me of the valve indentations on the pistons, and ours only have 2, you'd need 4.-darren

 

[odl777]

not all 850's are 16 valve and i remember reading that when someone put a 850 kit on a 750 they had to grind the casing with a dremal tool. So 750 jugs on a 850 might be too small for the casing.

 

[gsridekc]

Thanks for all the info. I think the new heads idea was more of a solution looking for a problem. I didn't come up with a similar thread when I searched the site. That should have been a good enough answer.

 

[Dink]

750 16v head will NOT fit, it is an entriely different motor.
Dink
"850" kits were only bore jobs.