on going problem... 6 month old carb, float set right, ran great ... then ran like the rev limiter was kicking in (no topend in power)push the over ride button (going forward) no change.... new plug,coil & wire ran great (for about 200 miles) then cutting out again... another new plug and air filter, run great (but cut out a little around 50 mph, but not bad i normaly ride around 5 to 25 mph). then started cutting out again ... another new plug still cutting out ... hit override button, no change still cuting out... i shifted to reverse backed up override kicked in, pushed over ride button speed up then cut out again but at a higher rpm its got me stumped checked new plug wire its conected tight both ends... clean fuel filter (can blow through it easly) fuel flow is great ( pumps a nice consistent stream) new ngk brk5 plug and then a new bosch 4202 then a 4201 (one size hotter) plug. no change, problem seems to be getting worse but it can set for a week and starts excellent on the first half crank with no choke

 

Unplug the black wire from the rev limiter and see what happens.If it still messes up I would bet you the cam is bad.

 

Is the plug getting fuel fouled or oil fouled? Have you done a compression check? And what about valve lash? Is it using engine oil? A rev limiter can cause weird stuff also,as ftwflh says.
Good luck and keep us updated.

 

thie bike starts and runs super, dosent use oil. i dont see compression being the problem, it can set for a week i can turn on the fuel and key and pull the rope and it starts on the first pull always (ive bragged to friends doing this) if the cam were bad i would think it would have lifter noise, and it doesnt. when i nail the throttle it spins the back wheels before it starts to cut out( lota torque)... is there any way i can run a wire from the mag to the coil and get it to run just to see if it is the mag or between the mag and coil????

 

I would try the unplug thing before anything.But if you havent had the secondary clutch apart for awhile clutch buttons could do what you say it is doing too.Along with the cam lobe wearing down the 425s and early 500s had a problem with that you know.

 

rev limiter was it thanks...

 

guess what ... cutting out again