I posted this question in the tech forum & didn't get any answeres, so I thought I would try here.

I have a 2000, sporty. It's had the buell 1200cc Buell upgrade, (installed before I bought it). It has 10.5 to 1 pistons, Thunderstorm heads (ported & flowed), 42 mm flatback Mikuni carb, & V & H 2 into 1 tunable header.This bike produced right at 85.3 HP on the dyno. The problem I've noticed is that when I run it up to about 4300 RPM,(in any gear),it starts popping & cutting out. After Irun it hard up through the gears a coupleof times, it seems to quit, and runs fine. I will tell you that alot of my riding is in town, & the motor tends to get lugged quite a bit. I try to get it out and "blow the cobs " out of it when I can, & that seems to be when it runs the best., & when I say it runs, I mean this thing screams.Is this just a product of carbon build up on the plugs & pistons from the intown driving since it's had such a H.P. upgrade? Thanks.

 

I guess the first thing I'd do is pop the plugs out and see what they look like; then go from there. Of course I'm prejudiced... I switched mine out to NGKs and they'd be the last thing I'd suspect. But they would tell me if I was running too rich. Usually I can see that in the exhaust pipe soot.

 

I have an883 converted to 1200 with drag pipes and no baffles. Mine pops aliitle to like back pressure when it is cold. I was told it was because no baffles. Dont know if its true or not. Hope this helps.

 

When I bought the bike, I was told to run no less than 96 octane because of the high compression. The only way I can get to 96 is to add octane booster. I was also told to not lug it too much, but like I said, I do alot of in town riding. The tail pipe does look a little sooty. It runs great at lower rpms, but when I run it up to "blow out the cobs", it pops a bit in each gear when I get right at 4300 rpms. After I do it a couple of times, it will go to 5000 & up with no problem, butI don't like having to dothat, & that's why I'm asking. I'll pull the plugs & take a look at them.

 

Lugging any engine is hard on the bearings.Use a lower gear instead of lugging the engine.You are probably loading up the engine from not running it hard enough and that will cause the popping you are getting.If you keep lugging the engine you will have to rebuild it at some point and decarbon the heads.An engine that has not been hopped up will do the same thing.Keep your rpms up a little and your problem should be solved.

 

Thanks diablo. That's what I figured was happening. I try not to lug it, but the things got such a quick throttle response, (I'm not saying this to brag either), I have a tendency to up shift sooner than I probably need to. Maybe at my age, I need more of a geezer bike, as I'm not the speed freak that I used to be. It sucks to get old.

 

I don't think your problem is from lugging the bike. You said up to 4300 rpm. Anything after 2.5K rpm is not lugging the bike. Also, lugging will sound different than popping and cutting out.

It can be from the jetting. You can have missfires from both mixtures that are too lean and too rich. Do you need the enricher to start the bike?

It can also be a component such as the ignition, spark plugs, spark plug cables, etc.

Any other information you can provide?

 

I agree also I dont think you should have to run 96 octane with the set up you have , every thing 1200c says is true, also a fix may be to shim the needle since you could be leaning out in the mid range.

 

I would recommend a Dyno tune... That should tell you if it is running lean at 4.3k.

 

I very seldom ever have to use the enricher **** to start it, unless it sets for a couple of weeks & it's cold out, then I can push it (the enricher ****), back in after10-20 seconds.I'm usually in the 2000- 3000rpm range around town, & the only time I run it up to 4300 is when I get a chance to get it on the highway. Like I said before, once I clean it out a couple of times, I can run it up above 4300 with no popping at all.I did check the plugs, & they looked good,(a nice light brown color). Thanks guys for the help.