richer or leaner?

[bigtwinpower]

Okay when I put my slip on mufflers on awhile back with the baffles in my bike ran fine. Well after awhile I took the baffles out and it popped like crazy. Well I went to my dealer and they told me to change the main jet. Well I had a 190 jet in it so I took it out and put a 195 in. Alot of the poppin went away, but it still pops when you rev the bike up in the higher rpms. I'm assuming I need a size bigger jet like a 200, but when you rev the bike up to almost the max. rpms a blue flame shoots out one of the pipes along with popping. A friend of mine seen it do that and he claims its too rich, but with the 190 jet in it pops all the time so I still think it need a 200 jet, what do you guys think?

[Markster6828]

Bigtwin, the main jet basically doesn't get used till you're almost wide open. For instance if you were running 120 thru the quarter and wanted to go a little faster , then you'd richen up the main. Most street bikes (TC88's) when rejetting go from a stock 45 PILOT jet to a 46 ,with a 48 as the max. Leave the stock 190 main in, shim up the needle with two #4 brass washers, and adjust the idle mixture screw for the smoothest low speed idle. Some replace the stock for the 88 Sporty needle and don't use the washers. This is the shade tree method. Without baffles in there is nothing stopping the reversion wave from going back up into the exhaust system on decel. This is one reason for the popping. My experience has been richen it up enough and the popping gets better , just do it with the pilot/slow jet.

Lotta guys go with the Dyno-jet kit but D.J. can explain it better than I can cause I've never had one.

[springer]

This may sound stupid but did you drill out the plug on the lean and enrichner adjustment screw and adjust. A 48 and a 195 should be fine. tune your carb....cut two rungs off the slide spring....drill a 1/8 hole in the piston vent hole and shim with the brass washers. Also use a K&N air filter. I hope this helps. If you neede more info on the carb enhancement, I can send you some pretty detailed info. Okay when I put my slip on mufflers on awhile back with the baffles in my bike ran fine. Well after awhile I took the baffles out and it popped like crazy. Well I went to my dealer and they told me to change the main jet. Well I had a 190 jet in it so I took it out and put a 195 in. Alot of the poppin went away, but it still pops when you rev the bike up in the higher rpms. I'm assuming I need a size bigger jet like a 200, but when you rev the bike up to almost the max. rpms a blue flame shoots out one of the pipes along with popping. A friend of mine seen it do that and he claims its too rich, but with the 190 jet in it pops all the time so I still think it need a 200 jet, what do you guys think?

[bigtwinpower]

No I didn't drill out the plug, but I do have a book that shows doing that. I don't think the kid who sold me the jets at the dealer knew much about harleys because he didn't really explain to me what I should do he just said "here's our two most popular jet sizes we sell". I do have a diagram of a cv carb and I just rebuilt two kehin carbs on my dad's 73 Honda so I do know a little bit about the carbs. So I guess I need to change my pilot jet, shim the needle, and drill out that plug and do some tunning. I have been planning on getting a K&N filter also. I guess I could just put the baffles back in but I really hate to do that and besides I'm thinking of going to straight pipes anyway.

[bigtwinpower]

Well I did a little research on the dyno-jet kit the other day and I decided to get one. So I installed it today the way the instructions said to. I drilled the slide lift hole bigger, put in their slide spring, put in their needle. Then I put in their jet holder (emulsion tube) with a 180 jet. They said to use a 175 for stock bike and a 180 for one with a aftermarket exhaust or air filter. I also drilled away the plug that covers the idle mixture screw and the instructions said to turn it clockwise until it seats then counterclockwise 3-1/2 turns. Well I thought my problems were over, but I still got 'em. It does start alot quicker and has a little more power, but it still backfires when you rev it up. Now it don't backfire when you give it pretty decent revs but when you rev it to about as far as the throttle will turn then let off that's when it backfires and a blue flame shoots out the pipes. As long as I'm cruising I have no backfires but when I really lay into the throttle then let off thats when it backfires, kinda sounds like a firecracker going off. I messed with the mixture screw some more but it didn't help. I guess I'm not going to worry about it since it don't really do it when I'm cruising anyway. It's just that I'd like to rev my bike up real loud once in a while without it backfiring. I do have a assorment of main jets, they go from 175 to 200. I know you guys said to change pilot jet but the kit didn't come with any.

[Markster6828]

Bigtwinpower, with the dyno-jet, you don't have to change out the low jet. I believe the emulsion tube takes care of that. For the popping try cutting the baffles down to keep it loud. I've run the lollipops (washer welded to a bolt) inserted on the inside of the muffler thru one of the baffle mounting holes, secured with a nut. You can turn the washer crossways for more torque without hurting the sound. I have run cut down baffles, just the end caps ect. You don't need much back there to prevent the exhaust reversion waves from traveling back up into the pipe on decell.

As it is now when you decell, all that fresh air is rushing back into the pipe, and the pop is the explosion of raw unburned fuel in the system , when the air gets to it.