Yamaha TRX850 Enthusiasts Forum

greatings all,

just to inform, i dropped a tooth from the front sprocket on my trx. it has obviously improved acccel.....but..... with original sproket bike would criuse comfortably in 2nd at 60kph. since dropping the tooth, 2nd revs too high and 3rd revs too low. was thinking of dropping an extra tooth still but was informed that this would cause excessive chain wear. just thought i would give the heads up

cheers

Should be ok... so you've got 16 tooth front and you sure you've got a standard 39 tooth rear: might be worth checking the rear is standard: number of teeth will be stamped on it. Another alternative is keep front standard and go for 41 rear which is a little less low-geared than a 16 front/standard back I think.

i was considering going up on the back sprok. does increasing the teeth on the back sprock still sacrifice top end speed??? also, i have a friend that tells me that some speedos run off the front sprocket, hence changing the sproket would cause the speedo to be inconsistant. do you know if this is true of trx's or do they run off the front wheel???

matttp wrote:i was considering going up on the back sprok. does increasing the teeth on the back sprock still sacrifice top end speed??? also, i have a friend that tells me that some speedos run off the front sprocket, hence changing the sproket would cause the speedo to be inconsistant. do you know if this is true of trx's or do they run off the front wheel???

yes it will decrease the topend
speedo drive is on the front wheel on TRXs

matttp wrote:i was considering going up on the back sprok. does increasing the teeth on the back sprock still sacrifice top end speed??? also, i have a friend that tells me that some speedos run off the front sprocket, hence changing the sproket would cause the speedo to be inconsistant. do you know if this is true of trx's or do they run off the front wheel???

The difference of going up 3 at the back (or down 1 at the front as this is pretty much the same) is about 10mph. With standard gearing you might just see 145mph (with a tail wind and going downhill). With a 42 t rear you will be much more likley to see 135 and you'll get there quicker. No brainer for me

Interesting stuff.
Just for the european guys
145 mph = 232 km/h
135 mph = 216 km/h

According to the dyno, mine will pull just shy of 150mph at 9,300 rpm

I went down one tooth on the front, and use a standard rear sprocket.

The bike still pulls with ease to 135 mph on the clocks, not that I really want to go that fast TBH.

I personally find the bike responsive enough in the lower gears like this, I can't see a great deal of advantage in lowering the gearing any more.

the best i found was 17 front and 42 rear, this is probably the best compromise and i still use the 110 link chain

what he said ^^^

anyone got a 42 rear kicking about to try ?

I got a rear sprocket - not sure how many teeath. Will check tomorrow.

so does the 17/42 fit on the standard chain/standard length

When I went to 42 rear it did but right to the front of the swinging arm (and I presume the chain had streched a bit)

I'd guess at 112 links if the chain is new