backfire

[dvjoiner]

The saga continues I have a 1987 gl1200 that backfire thru the exhaust hare ALL of the things I do to it,
1st had a water pump go bad and burn a head gasket,replace both along with new timing belts and cleaned carbs using spray carbs cleaner
2nd had a bad power wire to the coils and cdi ,No spark, Did a coil mod.se attachment still no spark, Thought it was a bad pulse generator,replace them no luck so replace cdi with a used one still no luck then found bad wire, replace it and it runs
3rd now that it runs I have a bad backfire could it be that the carbs are out of synced

[Frank]

That carb cleaner probably melted your air cutoff valve and your idle jets could still be plugged also

[bs175dths]

I must caution you and all other, about the use of todays chemicals on a 30 year-old design.
Todays chemicals can have a detrimental effect on rubber parts used throughout our carburetors.
SEAFOAM is one of todays chemicals which is known NOT to have negative effects on these parts, but you must follow the directions. More is not better! Follow the directions.

Chemicals are by no means a substitute for a good, thorough carburetor cleaning.

Since you failed to mention when you get a backfire, I would suggest, as was already suggested, check the anti-backfire device located under the carburetor assembly.
There are two devices under there along with the reed valve chamber.
One is a slow air cutoff valve and the other is the anti-afterburn valve.

For s and g's, check the synch. of the carburetors, at idle, at normal operating temperature BEFORE removing the carburetors to inspect the anti-backfire devices.
Since you have the carburetors off the bike, if you have the time, clean the carburetors. Do a complete and thorough job, be meticulous, but use caution, be gentle, double check your work on assembling.
Resynchronize the carburetors after and compare what you find to what you found before taking them apart.

The anti-backfire device comes into play when getting off the throttle.
A backfire may still occur if there is a hole in the exhaust, allowing cold air to be sucked in, so inspect your exhaust system for leaks.

Good Luck

-Ride On

[bagelboy]

I had a backfire that was driving me crazy for some time. I tried several things and then I put it on a lift and found a few small rusted holes in the bottom that I couldn't find. After changing the exhaust, no more backfires! Hope yours is less costly, but it is nice with no more backfiring!

[dvjoiner]

Update pulled carbs off and the air cutoff valve was bad could see light trough it order Randakk's Cycle Shakk Honda GL1200 Carb Overhaul Master Kit http://randakks.com/products/randakks-ow...erhaul-kit

[bs175dths]

You do realize, once you get the carburetors sorted out and the bike stops back-firing, you will be able to hear all those voices in your head!

(at least, that is what happened to me.)

-Ride On

[dvjoiner]

You do realize, once you get the carburetors sorted out and the bike stops back-firing, you will be able to hear all those voices in your head!

(at least, that is what happened to me.)

-Ride On

you mean I TOLD YOU SO, I TOLD YOU SO