Called in at a local track and was watching some guys go around on 4/ mx bikes, doing a few practice starts and generally having a good time. This may cross over to another thread on repair costs. but i will continue, Hold the engine on the limiter and dump the clutch these blokes could get around the track fast but you know that the rev limiter is there just like a red line operate the engine on or above this and you will damage something. Before 2/ we used to all ride the old 4 stroker hell we even had an sl100 bombed to eyebrows its just what you did, i f you over reved it exploded new 4/ over rev that and it will explode just the same. Road race bikes at four stroke had a tacho you learnt where they would operate reliably and set the red line for the engine at that and set the gearing for max speed at max revs get it wrong and rev into the red and bang bent valve or ventilated cases.You see people young and old abusing engines every day.just a thought i had so thought i would share it, i dont have a lot of these.