hello
you can install a 52 tooth SX sprocket on a rt125 in place of its
49 tooth
you must cut the center out of the old 49 tooth sprocket
just above the mounting holes so it can be used as a spacer
it will cut very easy with a hacksaw then have a machine
shop trim the edges so its round on a lathe with a three jaw chuck
this spacer is used to get the offset so the front and rear sprockets
line up as the SX sprocket has no offset but has the same bolt pattern
longer bolts will be required
also it is required so the original snap ring will work to hold the whole
unit together
this will make the bike perform better at speeds up to about 70mph
and give you better pulling power on hills at 55 and 60
it steals some top end but this bike is only 300 LB and much too
light to be going over 65mph any way
IF YOU ARE A ALL THUMBS PERSON GET PROFESSIONAL HELP DONT SCREW SOME THING UP
AR Dave RT125 in WV USA plus 95 Saxon Tour (rotax motor)
update this mod does cut top speed a bunch
the rev limiter cut out at 10500 rpm = 70 mph
wide open so 65 mph is about top speed
but it does ok for me as 99 % of my roads are 55 mph or less
and boy does it pull hills good now
july24 04
after a few months use it also gets less gas miles i get 62 65 mpg
stock i was 72 74 mpg most of the time
but i can put up with that for the better hill climbing
EDIT ON GAS may 22 2014
most of the run problem here in the usa is from the ethanol
in the fuel ..i changed to mower gas 90 octane and no ethanol and
it starts and runs better...ethanol in the fuel is a BIG joke
A NOTE FOR 125SM OWNERS
above may apply if you have alloy wheels
if you have spoke wheels then it may be direct bolt up
as the alloy wheel has an offset sprocket that will not fit an SX
(march2007)
