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Post by borjawil on May 28, 2011 15:26:41 GMT -5
Ok so ive heard of homemade glass pack or mufflers or pipe inserts whatever ya call em ya make em at home and put them in your pipes and they help out haha. I have open headers on my bike and ive rejetted it a bit, but it still back fires a bit. just wondering what i can do- as in make an insert and how to help out. Also pod filters. And please no comments about reverting to stock exhaust and all that.
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Post by Tom Graham on May 29, 2011 8:30:37 GMT -5
Use a smaller diameter thin wall tube as long as will fit in the end of your existing pipe. This should be a much smaller diameter. The stock pipes are 1 1/4" diameter so thats a good start or smaller. Flare teh ends of teh small tube so it just fits inside the larger pipe. A muffler shop can help. Buy a box of 1/8" drill bits and drill thousands of holes through the small pipe. Get some fiberglass cloth or grab some insulation. wrap the fiberglass around the small pipe and compress it by wrapping tape around the fiberglass. Force this insert into the larger pipe and secure it with a sheet metal screw at teh end through the outer pipe.
Tom
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Post by 650leo on May 29, 2011 23:20:22 GMT -5
Why is every one so afraid of a good head pipe and muffler. Short baffled pipes suck, look like nuts, run like nuts.
Leo
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Post by headcase on May 30, 2011 8:35:25 GMT -5
Just about anything with a carburetor is going to let some fuel and air past it even when it's not needed...like during decel at higher rpm. A backfire out the exhaust is just unburned fuel collected in the pipe lighting off when the fire out the exhaust port catches it. The richer the mix, the worse it gets usually. Or if the ignition misses a cycle, you have a blast of unburned fuel/air mix into the pipe just waiting for something to set it off. It still happens on fine-tuned setups, but most times it goes unnoticed because the mufflers silence it. After I put electronic ignition on mine, and tuned the carbs better, the pop-n-snap out the backside went wayyy down but it still happens. Open tubes just amplify it.
Electronic fuel injection would take care of this for good, but I'll shuddup right here.
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kopcicle
Full Member
"don't crush that dwarf , hand me the pliers "
Posts: 150
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Post by kopcicle on May 30, 2011 12:26:45 GMT -5
but I'll shuddup right here. I doubt it  takes one to know one ;D ~kop |
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Post by grizld1 on May 31, 2011 9:18:32 GMT -5
Borjawil, you know exactly what you want, so my advice to you is to learn how to tune for what you want, since you don't want to use stock components. There's plenty of stuff out there for you to read. If you want to mod your exhaust, do the reading and the work and don't ask to have your hand held. I'll give you this for free: if the "open headers" you're using are OEM primaries, you have two problems. One: they're too short for effective tuned length, and too short to allow the exhaust to cool sufficiently to prevent fresh oxygen sucked in on the back pulse from exploding unburned hydrocarbons in the pipe. Two: they're too small to use with any kind of internal baffle.
In future, you might consider researching things before you decide what changes you want to make, rather than after the fact.
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Post by Tom Graham on May 31, 2011 12:07:49 GMT -5
Are you sure one of the carbs doesn't have a plugged idle jet? Even a partially plugged jet will poppity-pop-pop on a backed off throttle.
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