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Exhaust backfire

4K views 3 replies 2 participants last post by  bgkid2966 
#1 ·
I have a 77 Exciter with a 540 fan from an 80 XLV in it. When the engine was in the XLV it ran like a top with a ton of power.
It backfires through the exhaust when I try to accelerate from an idle. I have replaced the plugs, reeds, and cleaned and reset the carb. It has the exhaust from the 340 Exciter in it. It does not have an airbox on it yet. I was hoping to get it running before modding an airbox to fit.

I was told if the exhaust was not the right size it would create an issue with the performance. It sounds like I am going to have to modify the XLV exhaust. It is going to be a major job, so any help would be appreciated. The XLV pipe is a monster in comparison to the Exciter pipe and chassis.

This project has been one challenge after another. This is a custom I would never attempt again. I just want the mechanics right so I can get the hood done and painted over the summer. I hope to have everything done for next winter as my daily rider.

We affectionately call this Frankensled. It has parts from Yamaha, Polaris and A/C.

HELP PLEASE!!!
 
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#4 ·
The exhaust has been merged and works well. The engine backfires through the exhaust after hard rev or acceleration. Flames shoot through the pulse line for the fuel pump. I have cleaned the carb at least 5 times. Changed the plugs. Fresh fuel and filters. Pulled the plugs and the right plug is black and the left plug is tan. The black plug is on the same side as the pulse line.
This thing is driving me crazy!!:wallbash:

Any help would be appreciated.

Thanks, Geno
 
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