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Backfire past 3/4 throttle
Posted: Thu Jul 19, 2018 12:10 pm
by Davidsquaredson
Hey,
A GP200, 22mm jetex, 125 main, scootrs pipe. Plug chops after a long ride is okay, light tea, could be a bit darker but I did not think alarming. At 3/4 throttle it back fires. Is this electrical? If so why? I can change the CDI and see if that helps, but I'd like to learn what the underlying issue is.
Tx
David
Re: Backfire past 3/4 throttle
Posted: Fri Jul 20, 2018 7:46 am
by Daggs
The only time I had a CDi fail. It began with backfiring as the revs went up.
Re: Backfire past 3/4 throttle
Posted: Fri Jul 20, 2018 7:40 pm
by Davidsquaredson
Just as I suspected. Many thanks
Re: Backfire past 3/4 throttle
Posted: Fri Jul 20, 2018 9:01 pm
by Mrnice71
Light tea plug colour is a bit close to the edge for my liking but the main jet sounds about right if its a standard top end , l like to see more of a milk chocolate colour lol
Re: Backfire past 3/4 throttle
Posted: Sun Jul 22, 2018 9:24 am
by johnny650
what was the outcome David ? I'm curious .
If it were me and I wanted to try and narrow down whether it was an ignition or fuel related problem I'd probably ride the scoot steady at 3/4 throttle and then apply a little choke and see what happened.
If it was an electrical /ignition issue, the additional fuel shouldn't have any effect on the backfiring but saying that I believe a exhaust manifold/silencer leak can cause backfiring too .