Just added VH Monster Ovals to my Ultra. I can not afford to do the rest of the stage one right now so the air system is still stock. I am getting some popping on decel

• What causes this?
• Is it bad?
• Any problem waiting until the end of the year to finish the stage one and put a FuelMoto tuner on?

Thanks

 

How much riding do you plan on doing between now and then? You can run it as-is, but with these motorcycles leaned out already, adding a better flowing muffler can make it slightly worse. You won't cause irreversible harm to you bike by leaving them on.

I had a similar situation as you - I put brand new CFRs on my stock RK, then I road out to Myrtle Beach and back with the wife. I noticed the right side pipe started to turn gold at the header/muffler joint (lean condition). Since then I went ahead with the FuelMoto PCV and air cleaner. The bike does run noticeably cooler as indicated by it not going into EITMS nearly as much, even in stop and go traffic.

 

Decel pop will not in itself harm your engine, and even HD states you can change your pipes with the stock air filter and leave the stock lean tune in place.

if your ride didn't decel pop before the new pipes, I would look for an air leak in the first instance.
If the decel pop is ~2000 to ~2400 revs it can be a sign of an air leak sucking back into the system somewhere.
On the exhaust side, check the pipe joints with smoke, just slightly snug up the head outlet flange nuts-- do this carefully and not too tight -- if they turn just take them up a bit and leave alone-- they could be a teensy bit loose. If you have a service manual find the correct torque application and better yet use a torque wrench on them. You can do it without one though. Did I suggest to be careful?

From the intake side it's not likely that you have an intake but it is plausible. Sometimes the intake rubber seals can develop a leak.
I'd try the exhaust side first as the intake seals are harder to get to.

 

V2 - g'day mate - thanks for the response. Not sure what you mean by "smoke". Please explain. The popping was not there on the stock pipes.

 

By smoke he means use a smoke source such as a cigar, cigarette or burning incense and while you bike is running in a draft free environment, such as your garage, with the door open of course, you put the smoke source all along the exhaust system and see where the smoke trail leads. That will be your source of leak.

Also, I agree with checking on the torque of the headpipes. With care so as not to overtighten. I had the same issue when I recently had my Indy put a new set of headpipes on. Too loose and was causing severe popping with the occasional very loud "backfire". The torque specs say 110-120 in. lbs. I just re-torqued until very snug but not too tight. Three of the 4 nuts were only lightly snug. Anyway I haven't had any popping since.

 

Thanks Danzio--much appreciated.
I've just got back to this thread after a couple of day away. I've never used it but I suppose a spray can of 'smoke detector testing smoke' would work as well.

Two Blue you may need to check any welded joint on the header system as well, as it is possible for a header pipe to crack at a weld. This will suck air as well and cause popping. The smoke test will work for that as well.

Hope you get it sorted and do let us know if you find anything.

 

Probably just leaking where they slipon, it doesnt take much.

 

There are a few possible reasons. (1) Leak in the system - exhaust gasket, cross over gasket (assuming you have one), muffler to pipe leak (out of round or deformed clamp). (2) Insufficient back pressure with the current mufflers (3) incorrect map with this muffler/pipe combo.

I wanted to say what I thought about hearing a decel pop but I'll keep that comment to myself. Bad or do you mean harmful? Depends on the cause and severity.

See second question.

Humor me...if you're doing a stage 1 which normally includes a download, why are you going with a tuner?

Sorry to hear that you're having problems but this is extremely common for those that just had to change out the exhaust systems before they understood what else changes. They begin to chase their tails trying to addressing little issues (like popping) when most if not every problem could have been avoided by going to a good tuner first.

Good luck!

 

On a carb bike it means the idle circuit (fuel delivery) is too lean and giving it more gas smooths it right out. On my PCV I added 5% more fuel from 750-1250 RPM and my decel popping disappeared. If your getting decel popping on a stock bike after putting on slip's, what's your guess is happening? Exactly, your running leaner in the idle ranges and it needs more fuel. Is it bad, these bikes are running lean right outta the crate and I say yes its bad which is why I did something about it. The choice is yours.

 

Pine Tree - I know what you are talking about with the popping - drove me crazy this weekend.

From my reading here I think I have learned the following

• ECM download from the dealer may still leave the bike a bit lean
• Basic FuelMoto system will come pre-programmed, but can still be tweaked if needed. Nothing fancy here as I do not really care to get involved with figuring out my own data.
• When I sell the bike I can take all of the stage one hardware with me and the bike will not need to be remapped back to standard.

Sound right?