99 RMK 600 help? engine performance issue

[powderchaser]

i recently purchased a 99 rmk 600, on the first ride out it was dieing out and losing power but only on intial acceleration from a stop and wide open throttle.
i cleaned the carbs and replaced the jets as well as tuning the carbs(they were way out of adjustment) checked both clutches even had a shop look at them. replaced plugs as they were fouled from overfueling. after all that the low rpm seems to be back as long as you dont go right to the bars with the throttle then it seems like its killing the engine(as if hit the kill switch) then backfires imedietly after releasing throttle. checked compression both holes at 120psi i know thats a bit low but normal for an older engine. pulled out the reeds they look in good shape nice and clean no cracks but could they still be weak causing my high rpm trouble. i suspect the safety switches in the throttle may be toast. has anybody had similar problems that could share any wisdom? tried bypassing them as the circuit only needs one to be grounded at a time, with both switches grounded so it would still run but still acting up when i go to the bars with the gas. could swapping the carbs to mikunis fix my issue? it has kehin carbs on it ive been told they suck and could be part of my problem also? any help would be gratefully apreciated need to get this thing fixed asap

 

[CatMan16]

Sounds like a loss of ignition at full throttle. Which would explain the back fire when the throttle is released. If you have a friend with a similar sled you could try swapping Cdi boxes and coils.

 

[retiredpop]

Is the ACCS still hooked up?
Keihin carbs are harder to work on than Mikunis but I doubt they are your problem. As mentioned above it could be the CDI box. Also have a good look at your spark plug caps. They may not be fitting snugly on the spark plugs in which case you get all sorts of problems.