High performance carb issue


New Member
Aug 15, 2018
I wanted better performance out of my 68cc motorized bike, so I went and bought delorto clone from Amazon. I also bought some jets for tuning. I put it on the bike with a 60 jet and now I have great top end performance. It goes WAY faster than the stock carb ever got me going. But now the low end performance and idle are terrible. It will keep a high idle for about 6-7 seconds but then the rpm's start going down until it dies. If you give it throttle when it's at low rpm's or when they are dropping, it severally bogs and dies. So you have to feather the throttle just to keep it from dieing. I also tried some bigger jet sizes but they just made it worse at any rpm. I need to sell it so any help is much appreciated. Thanks


Well-Known Member
Sep 23, 2013
Are you suggesting that the OP needs to advance the timing, or retard it? I used that offset magnet key to retard ignition timing at all RPM as a cheap "blunt instrument" to retard the timing at high RPM where it needs it. I did this to help with the high RPM vibrations that are supposedly due to the lack of proper ignition timing curve (ignition needs to retard at high RPM), but this was a trade-off as the timing did not need to be retarded at all RPM.
I don't know how this relates to the OP's problem. Am I missing something?

I would advise that he puts the stock carb back on with a good air filter. The bike may be slower then but at least it will chug along reliably.