Jetted "fat" and still pops and spits, will this fix it? : V-Twin Forum: Harley Davidson Forums

rel3rd · 06-01-2009, 10:04 PM

97 Softail Custom with Screaming Eagle (barely baffled) slip-ons and Forcewinder air cleaner setup. It's coughed, sneezed, and popped on deceleration and under low rpm/high load acceleration since I bought it a month ago.

Just for kicks, I tried swapping on stock mufflers and air cleaner and there was no change, so I swapped back to the SE slip-ons and Forcewinder.

I bought a Dynojet kit for it, as well as an EZ-just mixture screw, and installed these this past weekend. I went with 185 main jet and installed needle as instructed. The bike's mid and upper rpm feels a lot more powerful by seat of the pants, but coughing/sneezing at low rpm (and decel popping through exhaust) is no better, even with mixture screw turned so far counter-clockwise so far it is ready to fall out.

I ordered a 45 and a 48 slow jet for it, hoping this will finally "cure" the problem...am I on the right track?

car_guy · 06-01-2009, 11:13 PM

Have you checked for any intake leaks?

rel3rd · 06-02-2009, 04:38 PM

Quote:

Originally Posted by car_guy

Have you checked for any intake leaks?

Yes I have. None detected. I used "Gum Cutter" which has always worked well in the past on automotive vacuum leak detection.

nmaineron · 06-06-2009, 09:39 AM

That's a condition of "jetted fat",specially your decel issues.Turn your screw in to about 2 1/4 out and work around from there.I would start by going further into the 2 turns direction.You should have a 42 or 45 no larger.

I run a 94 FX set up with drags that have glass packed baffles 42,165 and a .030 shim under the needle.

TheNowhereman · 06-06-2009, 11:03 AM

Quote:

Originally Posted by rel3rd

97 Softail Custom with Screaming Eagle (barely baffled) slip-ons and Forcewinder air cleaner setup. It's coughed, sneezed, and popped on deceleration and under low rpm/high load acceleration since I bought it a month ago.

Just for kicks, I tried swapping on stock mufflers and air cleaner and there was no change, so I swapped back to the SE slip-ons and Forcewinder.

I bought a Dynojet kit for it, as well as an EZ-just mixture screw, and installed these this past weekend. I went with 185 main jet and installed needle as instructed. The bike's mid and upper rpm feels a lot more powerful by seat of the pants, but coughing/sneezing at low rpm (and decel popping through exhaust) is no better, even with mixture screw turned so far counter-clockwise so far it is ready to fall out.

I ordered a 45 and a 48 slow jet for it, hoping this will finally "cure" the problem...am I on the right track?

I believe that you need to turn the mixture screw "in" not out to richen the low speed mix.

rel3rd · 06-06-2009, 09:33 PM

Quote:

Originally Posted by nmaineron

That's a condition of "jetted fat",specially your decel issues.Turn your screw in to about 2 1/4 out and work around from there.I would start by going further into the 2 turns direction.You should have a 42 or 45 no larger.

I run a 94 FX set up with drags that have glass packed baffles 42,165 and a .030 shim under the needle.

42 was what mine had stock. I got my "tuner kit" from CV Performance yesterday and was able to swap the pilot jet today. The kit included a 45 and a 46 pilot jet and they recommended a 46 with my aftermarket air cleaner and better breathing exhaust. The sneezing/coughing is a good bit better, as is the decel popping through exhaust, but definitely not cured. Is this an issue I'll have to just live with? A few people have recommended removing the DynoJet parts (needle, main jet, and emulsion tube) and using the CV Performance parts instead? This is really starting to irritate me since it seems to be not responding to any of the "fixes" I've tried so far.

BTW, bike has ZERO popping, coughing, sneezing (at any rpm or load) with "Choke" knob pulled out about 1/4", so that tells me it's definitely still lean. I can't help but wonder if the carb is just junk.

Quote:

Originally Posted by TheNowhereman

I believe that you need to turn the mixture screw "in" not out to richen the low speed mix.

Everything I have read about the KeiHin CV carb says turning screw in is lean and out is rich?

claydbal · 06-07-2009, 10:05 AM

get rid of the jet kit stuff and install a keihen 45 or 46 pilot, 2-3 turns on mix screw, and the early sporty needle.. if no air leaks, no hiccups.(of course this is after running 10 miles to reach operating temp.

rel3rd · 06-07-2009, 09:50 PM

Quote:

Originally Posted by claydbal

get rid of the jet kit stuff and install a keihen 45 or 46 pilot, 2-3 turns on mix screw, and the early sporty needle.. if no air leaks, no hiccups.(of course this is after running 10 miles to reach operating temp.

This is what I did today...

Removed the DynoJet kit's emulsion tube, main jet, lighter spring and adjustable height needle.

In it's place went the stock emulsion tube, a 185 main jet (stock was 175), the stock diaphragm spring, the CV Performance needle, and also removed the very loose fitting CV Performance EZ Just mixture screw and replaced it with the stock one. At a base setting of 2 turns from seated, the bike is 90% better than it ever has been. On a 1.5 hour ride this afternoon, it coughed "maybe" 4 times total, as opposed to 4 times every 5 or 10 minutes.

At this point I think some tweaking of the mixture screw will get the bike as close to perfect as I can get it.

Thanks for the replies everyone.