sprocket gearing

[Mulisha_troop]

not sure where to post this so il do it here ...im currently rebuilding/repairing my 04 cr125 and want to change the gearing im currently running a 51tR and a 12tF .i guess im going for more top end .has anyone done those power adventures scrambles? if so what sort of gearing would you recommend? any help would be great

[pete376403]

will the motor pull redline in top gear? If it hasn't got the power to pull that, then overgearing isn't going to make it faster - possibly even slower. if yhou can go faster in 4th than in 5th, it's overgeared already.

[Mulisha_troop]

will the motor pull redline in top gear? If it hasn't got the power to pull that, then overgearing isn't going to make it faster - possibly even slower. if yhou can go faster in 4th than in 5th, it's overgeared already.

naa faster in 5th then 4th just not fast enough

[pete376403]

Your current ratio is 51/12 = 4.25:1. Going down one tooth on the back (50/12) would raise it to 4.16:1. 49/12 is 4.08:1. Leaving the back at 51 and going up one at the front would raise it to 3.9:1 - way too high. Other than that get you calculator out and work out the combinations of sprockets that are available for the engine and rear wheel.
Ideally you should have a selection of both front and rear sprockets so you can alter the gearing to suit the event.
When I was racing on the speedway I carried 3 engine and 4 back wheel sprockets and I had a chart of all the possible ratios.

[Mulisha_troop]

thanks man