KR-1S.co.uk Forum

Hi I raced a kr1s at mablehorpe sandracing club last season. Is the balance shaft worth taking out to make it rev up faster .
Also lightening the flywheel any major differences thanks bezisbird..

the balance shaft is in it for a reason, leave it in

there was talk about this in the early 90's, I believe Stan Stephens done it a few times, but he later said that it isn't worth it as it can seriously affect reliability, but skimming the flywheel was also a common mod

Don't do it, you're better off getting a KX125 flywheel machined to fit and add a second pickup to do away with the wasted spark.

don't do it
when you hold the steering feels like 1000 volts passing through your hands

Lightening the flywheel gives you better response / acceleration but at the cost of less torque.

Don't forget to check the balance after lightening