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Post by photowiz on Dec 14, 2012 13:26:43 GMT -5
My scooter makes popping sounds at WOT. I have a new carb, high flow air filter with 1 1/2" hose to the carb. I have a 108 jet. I'm not sure if it's running rich or lean. The old carb worked fine. Any thoughts on this would be welcome,
thanks
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Post by skuttadawg on Dec 14, 2012 13:28:35 GMT -5
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Post by skuttadawg on Dec 14, 2012 13:57:46 GMT -5
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Post by photowiz on Dec 14, 2012 13:58:35 GMT -5
The engine is a 150 and a stock carb 24mm
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Post by jazzman on Dec 14, 2012 14:14:27 GMT -5
If it pops on exceleration it is to RICH, try a 105 main jet.
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Post by skuttadawg on Dec 14, 2012 14:27:30 GMT -5
The air filter lets in more air than the air box and you will need a larger jet to compensate with more fuel . H3nry may still have some Gy6 jet kits for cheap
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Post by scootercapecod on Dec 14, 2012 15:01:35 GMT -5
Backfiring at WOT usually means lean, go up to a 110 main jet, that should help.
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Post by scootnwinn on Dec 15, 2012 1:13:41 GMT -5
Check the plug like the link above says before you do anything. Why guess when you can know for sure?
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Post by jazzman on Dec 15, 2012 1:22:17 GMT -5
He said POPPING NOT BACKFIREING TWO DIFFERENT things, A backfire is like a shotgun went off a POP is just that POP POP. They will POP getting to high rpms when rich and if they POP just about getting to IDLE it is LEAN, which in that situation you can just richen the mixture up.
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Post by Blueboy5000 on Dec 16, 2012 8:04:54 GMT -5
Yep you are probably slightly rich, a pop is not a severe problem (unlike a backfire) Turn your mixture screw COUNTER CLOCKWISE 1/4 turn and see if that fixes it.
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Deleted Member
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Post by Deleted on Dec 17, 2012 12:24:38 GMT -5
Before you go diving into tearing things apart and spending money on parts I would check... Well... You do need a torque wrench for this, I found out, it is best when working on these half cheap steel half aluminum the rest is plastic scoots to do most of it with a 3/8" torque wrench as this helps greatly in preventing unwanted damage in ways of stripped threads due to over- tightening and believe me you will think you don't need such a torque wrench until you are writing this article. The good news is there exist about two torque settings to remember, 8-9 ft.lbs. and 17-18 ft.lbs, those two torque settings fix pretty much everything, having such a torque wrench greatly extends the longevity of my scooter and helps with having to do repairs only once. The reason I mention the above is because if you over-tighten one of the below and you strip the bolt inside the casing you're looking into replacing the cylinder head itself and it's not terribly expensive but it turns a 5 minute repair into an entire afternoon! And they sell the torque wrench at Harbor Freight for about the same cost as the cylinder head. So after you have acquired such a torque wrench I would check... The two exhaust stud nuts that hold the exhaust pipe onto the cylinder head, these like to work themselves loose causing an exhaust air leak... Air leaks which in that scenario allow air to infiltrate the exhaust pipe which allows the unburnt fuel exiting the engine to form a volatile mix that combined with the heat of the exhaust results in short backfires, likely what you're hearing as popping. These two exhaust stud bolts need to be tightened to 8-9 ft. lbs. I also found it wise to replace the cheapo gasket there that likes to pretty much melt away thus causing air leaks at the exhaust manifold... With a $5 150cc GY6 NCY racing performance exhaust gasket such as: www.ebay.com/itm/SCOOTER-150cc-GY6-NCY-RACING-PERFORMANCE-EXHAUST-GASKET-/160932957145 |
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