Carb jetting questions
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Joined: Mar 2015
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From: Fredericksburg, VA
Carb jetting questions
I usually just figure this kind of thing out by trial and error but like to see if any of you have any input. My bike is a 97 Superglide. The only mods that I know of are a K&N type air filter and Python3 2 into 2 pipes. It currently has a 45 low and a 180 high jet with a NOKK needle. It runs fine except that when you close the throttle (think compression braking) I get some very light exhaust backfiring and if I roll back on the throttle it will backfire out of the throttle. Otherwise it runs fine, pulls hard, and doesn't backfire.
When trying to set the idle mixture I can get it to stumble when turning it in but I can back it way too far out with no affect.
I assume that I need to put a larger low jet in it. Do you think a 48 will be too big? How about shimming or changing the needle?
When trying to set the idle mixture I can get it to stumble when turning it in but I can back it way too far out with no affect.
I assume that I need to put a larger low jet in it. Do you think a 48 will be too big? How about shimming or changing the needle?
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Joined: Mar 2015
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From: Fredericksburg, VA
I suspected an intake leak so I replaced the seals and the carb boot. I used the paper trick on the exhaust gasket area and didn't find any leaks.
I have a kit coming with both of those and some shims. I'm not sure about the 190 because it runs fine on the top end now but I guess I'll see,
I have a kit coming with both of those and some shims. I'm not sure about the 190 because it runs fine on the top end now but I guess I'll see,
Road Captain
Joined: Jun 2010
Posts: 533
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From: Fredericksburg, VA
It can still run fine, if a little lean. I've always believed it's better to start a little fat. And, it does sound like your low jet is a bit small, at least.
Fredericksburg? I live in Falmouth..... And should be riding again soon.
Fredericksburg? I live in Falmouth..... And should be riding again soon.
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Joined: Jul 2014
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From: Cental, MI
2 into 1?
I have always experienced Backfires with a 2-1 exhaust...Certainly when accompanied by a Dual Fire Ignition. Betting a set of staggered duals would Make the Backfire go away...Probably Not be a Performance gain tho.
I have always experienced Backfires with a 2-1 exhaust...Certainly when accompanied by a Dual Fire Ignition. Betting a set of staggered duals would Make the Backfire go away...Probably Not be a Performance gain tho.
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From: Upstate New York
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Joined: Mar 2015
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From: Fredericksburg, VA
Thanks for the replies. I'm going to start with a bigger idle jet and then shim the needle if it needs it.
Axis,
Let me know when you're riding again. We can check out some of the roads. I know a few and am always looking for new ones.
Axis,
Let me know when you're riding again. We can check out some of the roads. I know a few and am always looking for new ones.
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I usually just figure this kind of thing out by trial and error but like to see if any of you have any input. My bike is a 97 Superglide. The only mods that I know of are a K&N type air filter and Python3 2 into 2 pipes. It currently has a 45 low and a 180 high jet with a NOKK needle. It runs fine except that when you close the throttle (think compression braking) I get some very light exhaust backfiring and if I roll back on the throttle it will backfire out of the throttle. Otherwise it runs fine, pulls hard, and doesn't backfire.
When trying to set the idle mixture I can get it to stumble when turning it in but I can back it way too far out with no affect.
I assume that I need to put a larger low jet in it. Do you think a 48 will be too big? How about shimming or changing the needle?
When trying to set the idle mixture I can get it to stumble when turning it in but I can back it way too far out with no affect.
I assume that I need to put a larger low jet in it. Do you think a 48 will be too big? How about shimming or changing the needle?
Woods W6 uild yielded 93/85
W8 yielded 95/93
And they sound real good. Old school....