Re: T500 Knocking its head off
Posted: Wed Jul 03, 2019 11:49 am
It is easy to tune for just WOT (main Jet). The issue is after you done a pull at WOT up to a high RPM, then suddenly back off throttle it may go ping! cling! ping! cling! The carb switched from main jet circuit to one of the other circuit(s). If you backed all the way off you would be solely on pilot jet and can fix it easy (not nature to back that far off though ). If you instead backed off to "almost" closed throttle (more normally what we do) harder to make that AFR correct there and also cover a wide rpm range.
Here it involves slide cut and needle jet,etc. You can test those circuits by riding on flat, open throttle and hold to that pos. and let it climb up RPM range either it won't climb up and/or start to ping or be Perrrrfect. If it starts to Ping at mid-higher RPM too lean possibly. Not easy to tune a non linear function of AFR for such a carb design and cover a wide range of RPMs but you can get close
. Then go back and check main jet
You would be better served with stock air box me thinks for stock porting (up to 8K RPM) you would see little loss on top end. But would see a great improvement at other throttle positions.
Here it involves slide cut and needle jet,etc. You can test those circuits by riding on flat, open throttle and hold to that pos. and let it climb up RPM range either it won't climb up and/or start to ping or be Perrrrfect. If it starts to Ping at mid-higher RPM too lean possibly. Not easy to tune a non linear function of AFR for such a carb design and cover a wide range of RPMs but you can get close
. Then go back and check main jet You would be better served with stock air box me thinks for stock porting (up to 8K RPM) you would see little loss on top end. But would see a great improvement at other throttle positions.