Backfiring/Popping on deceleration??

[SeaingDouble]

Well I had it out yesterday after adding seafoam. Bike ran fine for 30 mins no backfire or popping. After the first 30 mins started doing it again, not real bad but it is persistent while slowing/downshifting. Decided to take a look in the tank and there is definitely signs of rust. I can't believe a respected shop would go through the trouble to clean/rebuild carbs, change all fluids/filters, etc. and not clean the tank. Not sure how much is tolerable (if any) but it wouldn't surprise me if this has something to do with it. I guess I should take a look at the fuel filter to see if it has rust in it. If it doesn't does that mean its not bad enough to flow through fuel line yet? I know the tank will need to be cleaned, but I'm not 100% convinced carbs are plugged up with rust because the bike runs very nice on the throttle.

 

[jfeagins]

I guess I have a little troubleshooting to do...As stated the bike runs awesome and passes all those tests found in the sticky regarding the WOT in 2nd/3rd gear, cold starting rpm, and the 5th gear WOT from 4k. Just some popping on decel is only problem. And its not real bad but there nonetheless. Will check boots, try seafoam, etc. and if no luck I guess i'll have to take the next step. Hoping it wont come to that this early in my Vmax ownership:bang head:

Each carb has a small diaphram device bolted up to it called a coasting enrichener valve. (or something like that) I think the purpose of it is to add a bit of air to the bike as you let off the throttle and control the a/f mix upon deceleration.

It is possible to get "stuff" in the small ports inside those coasting enrichener assy's. (don't ask me how I know this.) Among other possibilities, is that the small coasting enrichener diaphrams themselves are deteriorated enough to cause blockage (as was the case when mine gave trouble). If the bike runs good otherwise, and coasting is your only problem, you might give that area of the carbs a look see.

The only way I know of to check them is visually, and to do that, the carbs gotta come off. Seems like new diaphrams for that are a bit pricey too, if memory serves me. :ummm:

 

[SeaingDouble]

Well if I have to pull carbs, it will be a learning experience that seems almost mandatory owning one these.
So, now that I know the tank shoulod be cleaned, whats the easiest/most effective way to get it out?

 

[adamax]

This forum is a diamond mine full of helpful threads and very helpful people willing to help. If you are mechanically inclined see the carb forum for a complete procedure. It is not very easy simple 1/2 hour stand but it is not rocket science either. It is your call anyway
Good luck

 

[jfeagins]

See HOW TO REMOVE FUEL TANK, by Buster Hymen

http://www.vmaxforum.net/showthread.php?t=9885&highlight=tank+removal

 

[davidon]

Guys removing/cleaning pilots..why not just spray jets with carb cleaner through straw to get deposits out??

 

[2fear]

Well if I have to pull carbs, it will be a learning experience that seems almost mandatory owning one these.
So, now that I know the tank shoulod be cleaned, whats the easiest/most effective way to get it out?

Personally I would not pull the carbs for a decel pop, give the seafoam a chance to work. Add a little extra and go through a couple tanks of gas first, as far as the fuel filter goes if in doubt change it out, cheap and easy.

 

[marecki]

Guys, I have the same problem, I have done the a/f mixture screw fix, that seemed to reseolve the issue for a little bit of time, but then it came back... carbs were just cleaned... I thought maybe this was because the bike was from FL and I'm in IL, our weather is just a tiny bit ... cooler...

 

[SpecOps13]

I'm in Florida and when it gets cold like it has been for the past week all of my bikes run great with the denser air. These carbs are sensative to any crap that may get past the fuel filter. I am running some cleaner in my gas often to keep the problems to a minimum. Ethanol gas can be a problem too. It goes bad quickly and even when it's fresh acts to break anything in the system loose and feed it to the carbs. I use only Non Ethanol in my bikes. Ethanol absorbs water and can cause serious rust problems to fuel systems too.

 

[marecki]

That's understandable... I was considering trying to mess with the a/f screw some more after the bike is back together to see maybe I can resolve the issue that way... I have a feeling that's what it is... sounds like a lean pop to me, but I'm not certain.

 

[SpecOps13]

Strange if it just popped up. Colder whether makes the air and fuel denser. try a 1/4 turn difference on the AF Screws. Shouldn't take much... Good Luck...