well lads i got another fzr 250 for parts to save me some money chain and sprockets are good on it but they,re different than the one on my bike back sprocket on my own bike has 44 teeth and this other one has 57 the front sprocket on my own has 14 teeth and this other one i have has 18 what difference is this goin to make ? so im, going from 14 front 44 back to 18 front 57 on the back.
Its all about gearing ..... changing the teeth number on front and/or back increases acceleration but lowers top speed and vice versa. The other vital thing to check is chain pitch .......... the FZR takes a 428/130 link chain as standard but u never know what the POs have done..... chain has to match the sprockets. You need to make sure the front sprocket is large enough to stop the chain rubbing on anything .... my spares bike had ,I think, a 13 upfront and the chain had chewed into the swingarm and guard. Take a look here .... http://www.gearingcommander.com/ http://www.mrspecialties.com/_howto/_drive/gearingCalc.htm#gearing Factory specs... Yamaha FZR250 EXUP 3LN Japan 1989 onwards Front Sprocket: JTF1263 Teeth: 17 Rear Sprocket: JTR1847 Teeth: 56 Chain Pitch: 428 Length: 130 You can of course buy a chain thats longer and cut it with a chain cutter ...or very carefully with a grinder. Make sure the rear wheel is pushed as far as possible forward to allow for later adjustment. Recommended chain freeplay is 20-30mm.
Rule of thumb is for every extra or lesser teeth on the front sprocket is equivalent to 4 on the rear. Given these figures you might not see a great difference, apart from the area to fit them. Can't figure why the gross variance.
