So I know that basically the lower ends are the same.
My question is specially about the clutch and trans.
I was wondering what the difference is between them beside the primary?
Also is there any difference in a 73 RD250 vs later bikes as far as those parts?
I want to use the parts in my other R5 buildup.
Thanks.
just primary and clutch gear. maybe the idler gear & oil pump gear.. and oil pump as well. but thats it.
since I've been dealing so much with oil pumps lately...I can confirm that the plastic drive gear and the worm are different on a 250.
RD250
"280" pump drive gear (22 teeth)
"275" worm shaft, coarse-7 thread (or "522" fine 9-thread for late-1975 models)
RD350
"274" pump drive gear (21 teeth)
"278" worm shaft, coarse-6 thread (or "214" fine 9-thread for late-1975 models)
yes. when i referred to oil pump, i meant all of it. Russ is, of course, correct.
Is there any benefit to using a RD250 trans vs vs a RD350 trans in the 6 speed swap for a R5?
Also does the FZR discs swap into a RD250 clutch like a RD350 clutch?
Pretty sure the trans parts are identical between RD250 & RD350
Clutch parts are the same and interchangeable with the FZR/YZ upgrade.
The only parts I see different are:
Primary gear, 21T on the 250 and 23T on the 350
Primary driven gear (clutch basket), 68T on the 250 and 66T on the 350
Tach gear, primary
Thanks guys.
I have 2 RD 250 motors so now with your help I've got plenty of hard parts to work with.
the 250 primary/clutch will help reduce windage in the clutch. TBH, one of my favorite motors was a 250 bottom i did a 350 lc top on, it was quick as stink. you up the front sprocket 1 tooth and it puts the gearing about where a stock rd was, but the transmission effectively spins slower. EVERYTHING will work fine, including the 250 oil pump, drive, tach, etc.
It is not likely an issue on a street RD, the TZs have the same difference between the 250 and 350 as far as primary ratios. If you run a 350 top end on an engine with a 250 primary you will very likely break gears. (transmissions are the same).