Quote:
Originally Posted by qwertydude
There reason you don't want to run too big a pilot is it masks the symptoms of a lean top end. This is a dangerous situation because your plug may look well and good on a plug chop but you're in reality running lean on the top end. That's why a plug chop isn't the only tool to use when determining correct jetting. The top speed method works especially well for scooters especially well because on most bikes you won't be able to reach top speed in order to determine correct jetting.
It's a simple fact that the correct jetting gives you the most power so hence the jetting which gives you the highest top speed is the correct jetting. From there you work your way down, and experiment with needle height and then finally mixture screw. I don't know why it keeps getting posted over and over again if you're lean on the top end just turn the mixture screw. That's absolutely 100% bad advice as it doesn't solve your problem and only makes you foul spark plugs and again on a plug chop hides the true reading.
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That makes a lot of sense querty, thanks for all the help. I'm aware that the a/f screw only effects up to something like 1/8 throttle thus the a/f screw advice from others is a bit wonky.
I'll order me up a #95 from Absolutely Scooters and see how it works.
Thanks again!
Quote:
Originally Posted by blueboy5000
On my three 139 bikes, all of them are properly upjetted, and NONE of them have had a thing done to the idle jets (which are all #34 stock jets). I agree that there should be no reason to switch to a bigger idle jet. Properly adjusting the needle and switching to a larger main jet should solve your mixture problems.
That said, I run a 95in a 83cc BBK, and I probably could get away with a 88 to 90 mainjet. My current 95 and tape-restricted air-filter proves that the 95 is too big.
I am going to suggest you adjust the needle to a richer position.
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Alright, alright I'll get a smaller idle jet. haha. It's just weird to me that it solved all my a/f adjusting problems, I can only assume my stock jet had something wrong with it.
If I'm getting no popping, backfiring, or vrapping and I'm almost hitting 60mph downhill, should I really mess with the needle? My plug chops were only WOT and I thought the needle stops effecting throttle at 3/4? Am I incorrect? My full range of throttle is the best it has ever been right now.
