ride like its your last
ok i would like to get a bit more speed on the pull away so was thinking of trying to get different sprockets can any one tell me what i should look for i know i will lose some top end but this bike is for offroad and i have to say im happy with the way she rides just slugish on pull away
Red Blooded Biker
For better acceleration you could go down one tooth on the gearbox sprocket (cheapest option) or go up about 2 teeth on the rear sprocket, which is not so extreme. The bigger rear would mean that the chain might not be long enough.
A modification that I did to my wifes 125, which was restricted to 12 bhp, was to lift the needles in the carbs by one notch. This made the engine give better throttle response in the mid range. I also turned the small airscrews at the front of the float bowl out another half a turn...this improved the fuelling from tickover.
ride like its your last
ok thanks for reply which of the 2 would be better and do you think it will make much differance
Senior Member
Go 1 tooth less on the front, then try it on the trails. . . . if you still want more take off, go up 3 on rear. as said you may need longer chain.
ride like its your last
how much speed would i lose top end not to bothered but would be nice to know
Red Blooded Biker
If your top speed was say 100mph it might go down to 85mph by dropping one tooth on the front sprocket.
Your fuel consumption will be affected as well.
Fine, upstanding member
...and as your top whack is about 60, it'll become a chronically slow 50 and it's going to be revving its nuts off at 30 unless you are in top gear.Originally Posted by 416cc
The XR125 is a fine bike which will last forever but there's not much scope for making it do anything it's not designed for. It is only a tiddly engine.
If you are talking about quicker pull-away off road then you could drop a tooth on the front sprocket but you'll get the benefit occasionally and you'll pay for it all the time.
If you mean on-road, forget about it as it'll just be too much of a fag.
Happy riding.
Last edited by pdsquire; 04-03-10 at 11:05 AM. Reason: inadvertent insult
1997 Jag 3.2 Exec (jangly jangly!); two bicycles; 2001 XL 650 V-1 which is ready for anything, cuts through traffic like a hot knife through butter and just gets better and betterand a low mileage Pan European ST1100
ride like its your last
hi and thanks for reply im not a young rider well 32 yrs old the bike is only for off road as this is my 1st bike for off roading didnt want to start with something to big i find it a great bike just wanted abit more poke in the lower gears thanks again dazz
Fine, upstanding member
Well if it is for UK offroading only then the front sprocket has got to be the better choice because you can keep the same chain and you can change it back in 15 minutes if you don't like it. There's an XLV rider who rides to a trail, pops a smaller front sprocket on and adjusts the chain, goes trailing, swaps them back and rides home!
1997 Jag 3.2 Exec (jangly jangly!); two bicycles; 2001 XL 650 V-1 which is ready for anything, cuts through traffic like a hot knife through butter and just gets better and better
Snotty lane fan!
Yes the front sprocket is the simplest and cheapest option I change mine on the XR400 for ON/OFF road and is simple to do without changing the chain length.
I spent 3 Yrs off roading on a 125, a heavy pig at that (an MZ125SX) and loved it. I now use a XL200R for the easy stuff and the XR400 for the tricky stuff. The 125's are nice and light and perfect for easy lanin'.
Don'e expect too much from a 125 4 stroke, I say really a 200 is the minimum for lanin' and I'd make sure it's got chunky forks too as the rocks bash the front end all over the place. I always come back way more tired on the 200 than the 400!
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