Musky, Doc, BB, Curt, Gram....somebody lol

In my previous thread on the backfire and flames on my bike I forgot to mention something. Can an intake leak cause backfire with flames? I put two and two together. I been getting a little intake backfiring for 10 months now. This was about the time I messed with the air filter. I took it out and cleaned it. I remembered what I did now though. I couldnt get the thing apart. I took the screw out of the center and it wouldnt come apart. Then I realized that it had a couple of long green screws in the back. When I put it back together I realized those screws were still laying there. I think about 3? Anyways I figured well, next time it will be easier to get to the filter if I leave these out and the outer screw will hold the cover and filter on. Could those 3 screws be causing an air leak on the intake. I am going to investigate this further. I have the screws in my tool pouch. I guess I should put them back in and see what happens. Just thought I would get some opinions.

LE,you need to put them back in as they help seal up the breather.

And make sure to get the intake boot tight on the carb. My .02 cents anyway.

My bad,didn't notice you did stage 3. If you did the pipes while still on the bike you could have caused an air leak at where the pipes attach to the heads or any of the joints. You might also need to tweak the pms alittle. And like Flash said what about your plugs.

They do need to be in to seal up the air breather like GS said but I am not sure that is what is causing you backfiring and flames. What all have you done to the bike up to this point(mods)?

Did the same thing as LE. One screw holding the chrome cover on the air filter because the 3 screws were a pain to put in. So far no problems even in cooler weather. For now it seems to work.

Greyphart

Looking at your profile, your stock except for drilling the pipes..have you pulled the plugs yet..? how do they look?
wish you would have used the previous thread....

Yeah I really should have flashback. That way it would be all together. Bike is totally stock besides the pipe mod. I removed the pipes when I did the mod. Havent pulled the plugs yet. Just havent had the time to take it apart but I plan on it. I might just put a new set in while I have them out. That way I dont have to take the tank off again anytime soon. When I get the plugs out I will take a pic of each one of them. The backfire only happens on a real hard decel in a low gear. You know, really wound out. I can also make it do it blipping the throttle just right at idle but its alot harder. When it does backfire theres about a 2-3 foot flame for a half second. I think my best bets gonna be to get a look at those plugs and check again for leaks. Maybe when i put the pipes back on I damaged a gasket or didnt tighten a clamp enough. Also that boot to the carb could be loose a little as I have had it off the bike before. I'll get some pics of those plugs and I'll make sure to post em back in this thread. Thanks guys for the reply.

I did not see your post earlier, but i have exhaust flames too and a thread about it, at first i thought it was a jetting problem swapped plugs but they were ok...no air leaks in intake and didnt notice any leak at exhaust, however i reinstalled my pipes with new fel pro gaskets(same brand i used the first time) and like last time it didnt pop at all in the beginning and then after about 30 miles it started popping and flaming on decel
what gaskets do you have on your exhaust? make sure the bolts are tight, and if you have fel pro gaskets consider changing to yamaha ones...just my two cents

Mine was doing this, It was in intake leak at the Bolts, They used felt washers on the bolts to seal it up. Then it ran perfect but going so long with intake leak cause rear cylinder to run 10 times as rich as front...... it was all carbon ed up like someone tossed 3 hunks of charcoal into the cylinder. It's in shop now waiting on new valves as it ruined them beyond grinding. The way you can easily tell is it acts SORTA like SVS. Throttle is not crisp, has an "Airy" type idle and exhaust sounds "Fluffy" Take pipes off and look at the valve stems from there, On mine one was kind white and clean and one was Carbon Junk Black! It was really ugly!

Another indication is that a gasoline type lubricant such as Sea-foam, Lucas,Marvel Mystery oil and the like will make it run better, but no cigar. It's just making the valves stick less, not fixing it.

This was just my experience. It may be same thing happening to yours. I chased the problem from new! 12K miles, 4 Intakes! 16 Plugs several new jets, many adjustments. I get it back this week. MC

might want to try doubling up the exhaust gaskets, I have heard that it works...

Backfiring flames and backfiring through carb are symptoms of different conditions.

Backfiring with flames on a stock bike is usually a symptom of the exhaust valves not funcitoning properly.

Backfiring throught the carb could be an intake valve but usually it points to a lean carb condition.

Doc