"backfire" from carb??

[400eXr1d3rZ]

I just got my sparks pipe on (finally), i had to wait forever because i had bent studs. anyway, i rode it around for a little while to see the power gains of the pipe (they were GREAT!) and i turned it off, when i turned it off, i heard air rush out the front of the carb(actually right behind the motor, where that rubber peice, forgot the name, bolts to the head) and i took a look at it, i didn't see anything wrong, i started it back up and turned it off again and it didn't happen again. Anyone know what could cause this? It's very annoying, could it do damage to my motor?

[Franky G]

the boot might be cracked. and check if the carb fits tight betwen the air box and the boot

[hornetgod13]

The part you're describing is called a "insulator" It connects the carburetor to the cylinder head. You may have a leak there that would cause a lean condition which causes popping or back firing. There could be a bad O-Ring on the cylinder side where the insulator attaches or the clamp that attaches the carburetor to it could be loose. Check to ensure everything is tight and leak free.
What sized jets do you have in the quad (Pilot and Main)? If you have a stock pilot installed after all the mods you've done it's time to bump the pilot to a 40K or 42K.
www.servicehonda.com carries the insulator $25.12 and the o-ring $2.61 if you find that you need them.
The popping or back firing is an indication of a lean condition. Do a plug check and see what you got. Running your engine with an excessive lean condition will cause the motor to run at a very high temperature and will lead to motor failure. You're getting too much air either from a leak or the jets that are installed are too small.

[400eXr1d3rZ]

I think i found the problem, the bolts that held the "insulator" to the cylinder head was loose, i could turn the with my fingers! I got them tighten now, started the bike up and it didn't happen again.