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Exhaust popping?


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Here's the scoop I put in fresh plugs runs sweat after a couple hours if that then it starts popping out the right pipe when giving er. If I change the plugs everything is fine again I changed the seals in the pipe thinking it was leak in the pipe plugs look fine when I pull them might be to the rich side as you can see in the pic. jetting is 380main 27.5 pilot 300ft bike specs in the sig.

 

Thanks.

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Generally speaking, a popping would tell me to look for a lean condition. If your running super rich that plug should be really wet all the way around.

 

What's your compression and what fuel are you running?

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I'm not much of a Mikuni guy when it comes to knowledge and experience, and top that off with a 38mm single carb. So, I'm not sure where exactly you should be at. Just from your plug, I'd say try one size richer main, but 380 is fairly rich. Have you looked for an airleak? I'm not saying that is your problem, but I'd just say do a quick check for air leaks around the intake. If you find nothing, maybe try a 390 or 400 just to see what shee does and feels like.

 

BTW, overall, how do you like the 38mm with your porting? I've always thought about running a 38 if I get some porting and/or a stroker kit, but I was worried about losing the midrange pull. Any opinions on running that carb?

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Actually I should mention that I'm running the stockers the 38mm was killer on the mid and top but I lost to much on the bottom with it.

as for the air leak I don't think so but will check tomorrow whats weird is that if I throw in a new set of plugs it's fine for a half day or so then it starts up again.

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im thinking u are way fat.. i would honestly go up one size on the pilot and start around 300 i still think u will be fat if u dont think so. start at 320 then go leaner as the plug looks better.. seems to me that u are so fat its fouling plugs and that the popping u are hearing is the cylinder loading up with fuel ..

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that's very likely why the popping is occuring. 380s are pretty fat. the only unsure thing you have is the port and polish. that could require a lot more fuel, or not much at all.

 

Like reas said, throw in a 320 and run a plug check and see if the popping subsides.

 

Let us know what you get.

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I just got done having this problem, is it a poping though or a misfire?

 

I'd have to change my plugs every hour to get my banshee to run WOT. I tried 5 different jet sizes 340's 350' 360's 370's 380's and went from lean to super rich and had the exact same problem every time...every time I thought I had fixed it because i also changed the plugs...then sure enough it came back....Had this problem ever since Jim did my motor and I stuck with the stock carbs. I only had the problem at WOT after running the plugs through a little less than 1/2 a tank.

 

Ended up buying new reeds, manifold, and carbs and now I'm happy. No more problems... Just went out last weekend and it just went from having your problem to a real screamer after I finaly got the recomended parts. Not a very good solution for you I guess..

 

I have a feeling it may have been the TORS unit, Try disconnecting ALL TORS plugs first. I think it was either that or my reeds were shot or I messed them up when porting them.

 

Edit, just was your not running any TORS...my Guess is your reeds then.

Edited by Justintoxicated
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Thats what I had in it originally but she was falling on er face when I hit 6th would loose power would rev fine but had no power in last gear when I went up it pulls like a mother :)

then it was lean try going up from there.. and do plug chops . by any chance did u check the reeds? make sure they are seated right and there are no cracks ..

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Check your sync. That was my problem today. I have a few threads with a similar problem. I checked my air screws. they were fine.

CHecked my sync, it looked fine. This morning, it was "popping" like crazy and even backfiring out of my left exhaust pipe. After I re Calibrated my sync, the problem went away. No more popping.

The thing is, my sync looked good, but I re did it anyway and that seemed to fix everything. Now I am a happy camper. Hope that fixes your problem. :)

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