JJ Joseph wrote: 2-strokers arguing that the oil pump is irrelevant are ignoring developments in 2-stroke technology. The oil pump was developed by Yamaha to overcome a major defect in 2-strokes: premix 2-strokes are dirty and unreliable. With premix methods, your engine will be either over-oiled or under-oiled with the same mix. When your engine is under-oiled during closed throttle ops (high-speed, downhill) you will cook the moving parts. If you are over-oiling during acceleration, your engine will accumulate excessive carbon deposits. Accumulated carbon increases wear in the engine and decreases performance. Many racers don't worry about carbon because they run at continuous wide-open throttle & don't mind rebuilding their engines. The people on this forum aren't racers. They're low-budget performance enthusiasts who mostly don't know how to do a 2-stroke rebuild. The oil pumps were added by clever Yamaha & Honda engineers for one reason: increased engine life & reliability. The difference in reliability was so huge that most "premix" bikes like Bultaco & Montesa went out of business after Yamaha (and Honda) introduced oil injection. If you figure you know more than Honda, Yamaha, Suzuki, Hirth, Rotax, BRP, and the aircraft engine builders that insist on oil pumps for reliable engine operation, there's not a lot the rest of us can do to save you from self-destruction. As has been said before, you must have more "dollars than sense".
The oil pump was added for convenience only, and it works well at 50cc.
anything over 70cc needs more oil than the stock pump can provide.
When the throttle is closed, oil gas mix still flows through the bigger aftermarket pilot jet.
JJ has the stock carb on his "90cc" setup.
Is the stock carb the best for BBK's too ?
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