pilot jet and popping on decel

[rosco15]

I have a set of 36 flat slides on my gs1166 motor. When you let off the gas it has a wicked popping sound. I could try changing the pilot jet. but dont know if I need a larger pilot jet or smaller pilot jet to cure this problem. I have a set of 38 mikuni't that I could pilfer the jet from. I've got an older star pro pipe and I know it leaks where the down tubes go into the collector. I can see the black exhaust on the pipe. I'm thinking about trying a vance and hines pipe. The one-piece kind that I know won?t leak. I'd like to try the carb jetting first to get rid of the popping. Cheaper than buying a new eshaust that might do the same thing. So what do you guys think.

Thanks for the input,
Ryan

[daveo]

The leaky exhaust can cause the popping also, I'd check or repair that first before going to larger pilot air jet

[RacingJake]

Re: pilot jet and popping on decel

I have a set of 36 flat slides on my gs1166 motor. When you let off the gas it has a wicked popping sound. I could try changing the pilot jet. but dont know if I need a larger pilot jet or smaller pilot jet to cure this problem. I have a set of 38 mikuni't that I could pilfer the jet from. I've got an older star pro pipe and I know it leaks where the down tubes go into the collector. I can see the black exhaust on the pipe. I'm thinking about trying a vance and hines pipe. The one-piece kind that I know won?t leak. I'd like to try the carb jetting first to get rid of the popping. Cheaper than buying a new eshaust that might do the same thing. So what do you guys think.

Thanks for the input,
Ryan

Good Morning

I'am planning to install the 13.5-1 1166 piston kit this winter on my 82 1100e drag bike. Did you have any problems with your kit and are you running stock cams. Oh by the way how does it run now ?

Thanks,
Jake

[KEITH KRAUSE]

Do your carbs have mixture screws? You can try adjusting them a little "richer", as long as that does'nt cause other idle/low speed problems.
You can always just put them back to where they were if you don't like the results.

[rosco15]

This is an 1166 low compression kit. Bike went 10.17 @ 126 with stock head and cams. With stock pistons it went 10.52 @ 121. When you bore the block bigger you lose the chamfer at the bottom and its a pain to get the rings compressed and into the bore. It took 2 of us almost an hour.

I have the mixture screws at 1/4 turn out. I went to half and it seemed to get worse. What does the mixture screw on the Mikuni's do. Does it regulate air or exhaust. And what does turning the mixture screw further out do to the mixture. My dad is going to stop over on monday and weld the down tubes to the collector to fix the leaking problem. Since the pipe has no baffle in it I dont think it will fix the problem, but you never know.

I posted a video of the 10.17 pass. You can hear the bike popping at the end as I let the motor slow the bike down. Its under the video section on my web page. I put it in the THompson Dragraceway video folder and then called it gs1100 new 1166 kit. http://www.angelfire.com/pro/rccracing0/

Ryan

[Jeff Tate]

The popping you describe is fairly common with a 4-1 pipe and the more unrestrictive it is the louder the popping and banging is. I went to a one size larger pilot jet and it helped some. I also intalled a restrictor in my collector that V&H makes and that also helped with the added bonus of moving the power curve down to where it's more useable for everyday riding.