Any Ideas on Why I Have a Loss of Power After Start Up?

by Rob
(Tuscaloosa, AL, USA)

The scooter is a Honda Helix and the top end has just been rebuilt with new pistons, rings, and gaskets, cylinder bored .5mm. The scooter runs fine when cold... power is there like normal, but after about 15min or so of riding, the scooter starts to lose power until it will only go about 35 miles an hour.

It doesn't make any weird noises... it's just like someone turned off a switch. If you ride the bike till it doesn't have any power, let it sit for awhile than try it again, it will run fine again until the motor is warmed back up again. Any help with this issue will be very much appreciated.

Thanks... Rob

Comments for Any Ideas on Why I Have a Loss of Power After Start Up?

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Oct 29, 2009
Power Loss
by: Ron Goldwyn, Milford CT

Check that all head bolts are tight and gaskets are not leaking. Sounds like the problem may be coming from expansion when hot. But I'm no mechanic, just an old physics major 50 years ago.

Oct 29, 2009
Valve Adjustment
by: Jim Zeiser

That sounds like a classic case of valves out of adjustment. Long story why but I would check the clearances and see if they are to spec. They might have have changed when the head was re-torqued during the rebuild.

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