Chain grinding on case!

Joined
Nov 18, 2003
Messages
128
Likes
0
#1
I have checked out bearings, chain alignment/tension, c-shaft play, c-shaft sprocket torque...
Just bought this '93 RM250, and the chain is DEFINITELY worn out, but how could the chain be mounted on the c-shaft sprocket and yet be able to rub on the case? The chain is no way wide enuff to do this, but yet I see the damage!
Any ideas!?
 
Joined
Jan 27, 2000
Messages
6,959
Likes
42
#2
Originally posted by txkawboy

Just bought this '93 RM250, and the chain is DEFINITELY worn out,
Any ideas!?
txkawboy.

You may have answered your own question. :confused:

If the chain and sprockets are worn, the chain can climb up on the teeth of the sprocket and rub the case. Be sure the case saver is in place and not worn. It is the little flat plate that rides just in front of the countershaft sprocket and prevents the chain from damaging the case.

Just my $ .02
 
Joined
Nov 18, 2003
Messages
128
Likes
0
#3
Nawp Ol89r, the case saver is fine, but the case is damaged behind the c-shaft sprocket, which is why it is such a mystery. I cannot figure it out. Yet. 8>]
 

los36

Subscriber
Joined
Feb 7, 2002
Messages
410
Likes
0
#4
the cs sprockets on RM's are offset. It's possible that the sprocket is installed facing the wrong way.
 
Joined
Nov 18, 2003
Messages
128
Likes
0
#5
thanks but that was not it either...my guess is now that apparently the poor spode I bought it from had allowed the worn chain to jump off and wedge in between the c-shaft sprocket and the case (??), even tho' the grooves look too fresh for that... 8(
 
Joined
Mar 25, 2001
Messages
481
Likes
0
#6
The only other explination is that the bike was not orginally equiped with an o ring chain, someone put one on there, which was just a hair too wide and it rubbed on the case. I had this happen to me before. so i just use regular chains now.
 
Joined
Nov 18, 2003
Messages
128
Likes
0
#7
Forgot to answer this one...turned out that upon v-close inspection, that 5 links had been replaced with some type of s-bike 520 chain, (ie, 2mm wider). (This 'trick' will work on older bikes, but not modern ones such as this, with such tight clearances...) But anyway I got tired of trying to fix all the things/flaws that were 'built into' the RM strait from the factory, rat bike or not, and dumped it. Got a '96 CR250 for a second bike, instead. ---Even tho I bleed lime green when cut, I must admit that Hondas are SO engineered...sigh.