This 30 second video shows how the the bike acts in neutral when slowly given increased throttle and how it acts when suddenly given wide open throttle. This is of course an issue when riding as well. Just demonstrating in neutral.
Notice that when given full throttle at about 16 seconds the RPMs are all over the place and hesitating/bogging down. And then when given wide open throttle from idle at 24 seconds the motor instantly quits. It will instantly die every time when given wide open throttle from idle.
The engine has been rebuilt with new rings, new cam chain, all new gaskets, valves lapped and new valve seals. Carburetors are cleaned and fully rebuilt with new floats and stock #88 and #38 jets. Float height is properly set at 21mm. The main jet needles are set on the leanest (highest clip) setting - this is how it seems to run the best. The mixture screws are set 1 1/4 turns out as called for in the service manual. The air filters are stock air boxes and appear pretty nicely clean.
Other new parts include: ignition coil, condenser, throttle cable, fuel petcock + filtering screen.
The bike is rideable as long as you don't open up wide open throttle at low speeds. Once you're in 4th or 5th gear and going 40mph+ you can then hold open full throttle without apparent issue. I've had the bike up to 70 mph in this state. It is of course a problem though and I'm dying to fix it but I'm completely stumped as to what is causing this. Any thoughts?
Notice that when given full throttle at about 16 seconds the RPMs are all over the place and hesitating/bogging down. And then when given wide open throttle from idle at 24 seconds the motor instantly quits. It will instantly die every time when given wide open throttle from idle.
The engine has been rebuilt with new rings, new cam chain, all new gaskets, valves lapped and new valve seals. Carburetors are cleaned and fully rebuilt with new floats and stock #88 and #38 jets. Float height is properly set at 21mm. The main jet needles are set on the leanest (highest clip) setting - this is how it seems to run the best. The mixture screws are set 1 1/4 turns out as called for in the service manual. The air filters are stock air boxes and appear pretty nicely clean.
Other new parts include: ignition coil, condenser, throttle cable, fuel petcock + filtering screen.
The bike is rideable as long as you don't open up wide open throttle at low speeds. Once you're in 4th or 5th gear and going 40mph+ you can then hold open full throttle without apparent issue. I've had the bike up to 70 mph in this state. It is of course a problem though and I'm dying to fix it but I'm completely stumped as to what is causing this. Any thoughts?