how close to lining up do the sprockets need to be?

[3leggeddog]

i'm doing a motor swap to my 86 r.the problem i have is the sprockets are not lined up.they are off about a 1/4 inch.do you guys think it will throw the chain?or is this close enough?

[kando]

If thats the best you can do, All that is left is to try it out.

[hotroddal]

what is the engine that you are swaping in there????

[Red Rider]

The importance of sprocket alignment is inversely proportional to your frustration level from derailed chains. In other words, if you want to save a lot of time & work on getting the sprockets aligned properly, then plan on spending a lot of time & work on putting the chain back on after it derails every 5 minutes. That of course doesn't include the additional time & expense caused by the chain going through your side case.

These are only estimates, and actual results may vary. Should chain derailment occur & persist for more than 3 days, engine swappers should contact a certified motorcycle mechanic shop.

[hrc85250r]

Dude, Get Them Perfect.....it Takes A While To Do The First Couple Motor Swaps, But It Is Totally Worth It!i Have Never Thrown A Chain And I Take At Least 2-3 Hrs Lining Them Up, Jigging It In Them Frame Is The Hard Part....

[1984kxtTECATE]

Take the extra time too do it right, like Red Rider said, it is possible to bust the case from throwing the chain off, then you are out more money and you will look back and wonder why you didnt line them up. 1/4" off is a pretty big margin and it would be very risky.

[3leggeddog]

of course i plan on doing it right,i was just curious if they had to be dead nuts on,or if 1/4 inch would be ok.looks like i will have to shim the rear sprocket or something.the motor is set and all the mounts are made.it's impossible to move the motor in the frame any more due to the exhaust port location.i set the motor as far left as possible.
the pipe fits with no problems,and everything seems to be alright but the sprockets.

do you think it's ok to shim the front sprocket out 1/4 inch? or will that put excessive
load on the output shaft?what about shiming the rear sprokect in?any suggestions would be great.thanks 3leg

[RideRed250R]

wat motor is this a 500??? or wat?
adam

[3leggeddog]

its a 92 cr 250 motor.

[Billy Golightly]

of course i plan on doing it right,i was just curious if they had to be dead nuts on,or if 1/4 inch would be ok.looks like i will have to shim the rear sprocket or something.the motor is set and all the mounts are made.it's impossible to move the motor in the frame any more due to the exhaust port location.i set the motor as far left as possible.
the pipe fits with no problems,and everything seems to be alright but the sprockets.

do you think it's ok to shim the front sprocket out 1/4 inch? or will that put excessive
load on the output shaft?what about shiming the rear sprokect in?any suggestions would be great.thanks 3leg

I had to do this on the rear of the 500X. since the sprocket bolts on it were not countersunk and did not go in flush with the sprocket I got some new allen head bolts and ground the heads down where they were pretty short, then we counter sunk it on the lathe. Next thing we did is made some spacers that fit on the sprocket hub and it moved the sprocket over a fair amount. I can't move mine anymore though or I'll be into the swingarm and the bearing carrier. If you look at it you'll probably see what I'm talking about. If the 250R has the flush mounted sprocket bolts (And I think it does) You should be able to move it over quite a bit.

If you need to move the opposite direction...pull the axle out and take the sprocket hub off if your want, and just work on that area where the sprocket sets. See if you can thin it up a little bit.