Sprocket size change - FXR 150

[Hermit]

Hi all,
I've got FXR 150 that I do a lot of long trips on and hope to be able to make it travel at 100kph more comfortably. The speedo over-reads by about 14% but at speedo speed of 100kph (actual speed around 88kph) the revs are at 8 grand of its 12.5-14 redline. I guess the revs would be at about 9.5 at 100kph actual speed. Could I change sprocket size, say one tooth on the front to make it travel better at higher speeds or would the load become too much, and is a 150cc not really suitable to maintaining higher speeds?

[Sketchy_Racer]

FXR will go all day at 100.

But i doubt changing the gearing will solve your problem.

Always give it a shot though.

And welcome to Kiwibiker!!

[Hermit]

I don't care about the speedo being off I just thought 9.5-10 grand might be a bit high a revs over long distance

[Tints]

FXR will go all day at 100.

But i doubt changing the gearing will solve your problem.

Always give it a shot though.

And welcome to Kiwibiker!!

i have an FXR that i have done the coro loop on twice with absolutly no problem, the bike didin't complain at all (my parents have a place up there, and the bike is my only transport). i would agree with RG100 and say that it is not worth changing the gearing if you can even get it.

[et al]

I put sprocket with one extra tooth on gearbox end of my son's FXR150 - made a noticeable difference in that you could go further in first gear before having to change and it didn't cause issues at the other end ie no struggling in top gear. That was a few years ago so the details of how many teeth etc escape me however I will have noted it in my little book at home if you need more info. I do remember though that I ordered it through MotoMail, and it was just one tooth more than standard - also I think the sprocket is same as used on the RG/RGV150 so you should not have trouble getting one.

[GB500nz]

Go for it. I've often changed gearing to make a smallish bike better for highway work. Your bike is optimised for city riding and will last longer if it's geared up. I just re-geared my Yamaha Serow and it makes a world of difference.

[et al]

Found my notes on this - good thing I keep meticulous records because actually went 2 teeth bigger. Standard gearing is 14T Front, 48T Rear. I had put a 16 tooth front sprocket on. Part number E425-16, got it from MotoMail for $16 (this was 2001 so price probably will have changed since then). I am sure your local bike shop could order the spocket for you if you don't want to use MotoMail (I havn't got anything from them for a couple of years so no idea how their stock/service is these days). This would also be a good time to review the condition of your chain and rear sprocket and replace them as well if chain and Rear sprocket are not in good condition.

[skidMark]

of course it's worth it rg100

if you change two teeth you will be running a hell of alot less revs which is alot more loving to the poor lil 150

yes it will take a little longer to get there but will still be fine and if hes doing constant long trips etc it's not practical to have standard gearing ratios.

i used to have an fxr as a race bike standard gearing i would not want to sit on 100 kph especially not at those kind of revs.

[kickingzebra]

i used to have an fxr as a race bike standard gearing i would not want to sit on 100 kph especially not at those kind of revs.

I agree the change could be worthwhile, but bollocks to the quote above. They will sit there all day every day.
How many FXRs that have been blown up under street use have you heard of?
Gear it down to make it gentler on you, and maybe slightly better fuel efficiancy, but I wouldn't bother if you are only worried about the engine. Mine did a year of 100 km a day, 5 days a week open road, full throttle. Ran better at the end of said year it ran better than when I bought it brand spankers.

They are tough little brutes.

[skidMark]

I agree the change could be worthwhile, but bollocks to the quote above. They will sit there all day every day.
How many FXRs that have been blown up under street use have you heard of?
Gear it down to make it gentler on you, and maybe slightly better fuel efficiancy, but I wouldn't bother if you are only worried about the engine. Mine did a year of 100 km a day, 5 days a week open road, full throttle. Ran better at the end of said year it ran better than when I bought it brand spankers.

They are tough little brutes.


it's not gunna harm it but they arn't designed for it

changig the gearing is going to put so much less top end strain on it

[kickingzebra]

If it ain't gonna harm it, then the top end strain will be well within acceptable limits.
The only real question is do you want to trade off your rather leisurely 8 second 0-100 time for a little less buzz and a little more top speed?!

[skidMark]

If it ain't gonna harm it, then the top end strain will be well within acceptable limits.
The only real question is do you want to trade off your rather leisurely 8 second 0-100 time for a little less buzz and a little more top speed?!


don't need to i'm not the one with the fxr :scooter:

[Pathos]

bah I've done 6 hours non stop of redlining on the fxr multiple times, and thats after I trashed the fairing :)

I think increasing the gear may help the 0-100 as it will be reached easier in 4th and less short shifting required.

[Hermit]

Cheers for the help people.
Might try one tooth bigger on the front. Might actually replace the rear as well as the chain because they're all reasonably worn I think. Is this a job I could possibly do myself as a relative novice or best I get it all done at a shop?

[merv]

I've done a lot of gearing changes on trail bikes and usually if you change by no more than 2 teeth on the front sprocket or about 5 on the back (not upwards or downwards together) you can get away with leaving the chain the same length and just take up the change with the chain adjusters.

Going one tooth up on the front of the FXR I'm expecting you'll find quite a difference provided it really is reaching full revs in top gear now. If not you may find you'll end up changing down gears in head winds anyway. So just don't overgear it so top gear becomes unusable (which one tooth shouldn't do).

Is your chain fitted with a clip link or a rivetted link? If its a clip link then its very easy to do all the changes yourself.