Backfire "Pop" When Engine Shuts Off - Normal?

[Dirt_McGert]

It doesn't exactly "over run" (or "diesel") when the motor shuts off.... when I turn the key to off, the motor stops cranking like normal, then at the end lets out a whisp of air (possibly the exhaust valve opening and letting out the compressed air? - sounds like "pshhhh"), and then a half-second or less later, the muffler lets out a nice little pop.

[Dupo]

Well, thats odd lol. Hopefully the sea foam might clear it up. Let us know!

You sure you didnt buy it off Uncle Buck? :lol: Remember his car... dieseling, pssshhh then BOOM!! haha.

[Dirt_McGert]

Hahahaha I love that movie.

But no, it doesn't diesel. It shuts off normally, then a quick little "pshh" and then "pop".

I took her for a spin about an hour ago. I started it with a cold engine (about 70 degrees out) and it started right up after the first or second "whine" of the starting motor (took about a second to start.) I shut it off, then I put about 2/3 of a can of SeaFoam in the gas tank, gave it a little extra for good measure. Took the bike for a spin to get the SeaFoam throughout the fuel system.

It says on the back that I can pour SeaFoam directly into the crankcase.... is this recommended for this bike??? This might be good to clear away some of the gunk in the engine, since the bike sat quite a while.

[Dupo]

Yea you can put it in the crankcase if you want, but i doubt it would be necessary. Pull the dipstick, if its clear yet, then dont bother. They really dont get sludged up in there anyways.

Be careful, dont wanna put too much sea foam in there

Let us know how it turns out.

[Dirt_McGert]

Starts right up just fine now (don't think I fully opened the choke lever all the way haha.)

Still lets out a little pop when it shuts off though, not a big deal personally.

[Dirt_McGert]

I asked one of my teachers about it, and he said something like the backfire sensor regulator controller thing (not exactly what he said) could be broke...... to my knowledge, I'm pretty sure these bikes don't have any type of backfire sensors haha.

[Dupo]

Yea they do, bystanders that say 'hey, your bike is backfiring' :lol:

[Dirt_McGert]

Haha, yeah today shut it off and it didn't backfire, so who knows. I'll do the shim mod in about a week or so once I get time. Is this recommended since my bike only has 850 miles on it? I read in the manual that it isn't fully broken in till about 1000 miles, so maybe I'll wait till then...

[Dupo]

Doesnt matter when you do it. All it does is make it run a little more rich than factory. Wont make a difference in the break in period.

[Dirt_McGert]

actually he said a backfire solenoid, but then he checked it out and said it looked like it didn't have one :roll: