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[porkypig]

With this new engine, 2 days ago, riding home from work (100 degrees) in the afternoon, I began to take notice that when shifting from 1st gear to 2nd, there was a distinct "pop" noise coming from the muffler just as soon as I switched gears.  Not discernible from 2nd to 3rd, etc. but definitely from 1st to 2nd.  Just one "bang" and nothing else.  Seems to have ample power otherwise.  Anybody got a clue?  Wonder if I have some bad gas from the last fillup?   Pork.

[Jasray]

Pork,  has that new engine been dyno tuned?

JB

[05Train]

Exhaust leaks do that. 


Sent from my iPad, probably while I'm pooping.

[porkypig]

Jas, no it hasn't.  You think I ought to invest in that?  Nothing going to void the warranty, etc?  are you thinking that will find the culprit?

[grc]

Jas, no it hasn't.  You think I ought to invest in that?  Nothing going to void the warranty, etc?  are you thinking that will find the culprit?

If I remember correctly you never did have the old engine tuned, right?  Did you have this same pop on upshifts with that one? 

I'd be more inclined to believe it has to do with the exhaust system being removed and reinstalled when they did the engine swap.  An air leak in the exhaust system will cause that problem, as 05train mentioned.  Before you decide on tuning versus not tuning, do the basics first.  Check the exhaust for leaks, and if you have leaks have the dealer correct their work. 

Jerry

[Jasray]

I would have to agree with GRC that you should check the exhaust first (kiss principle), but if its OK, then yes I would have it dyno tuned.  I was having popping on deceleration and now it runs fantastic.

[porkypig]

ok, taking it in tomorrow.  For the last couple weeks I thought it just went away on its own but yesterday it started rearing its ugly head a few times again.  it's sort of a double pop.  Sounds not too disimilar to a black powder rifle going off (flintlock).  so, it sounds like some sort of pre-detonation thing going on.  Jasray, if I have it dyna tuned, are there adjustments that can be made at the time?  I'm used to them saying, "ah, there isn't anything we can do to it from the factory like that.  You'll have to buy a tuner, etc."  is that right?   Pork.

[Jasray]

Pork, yes you will need either a Harley or third party programmable tuner.  There are other threads on those choices, I stayed with Harley and am very happy with it.  The factory tune is very lean in order to comply with emission requirements but it makes the engines pre-detonate in many circumstances and also make them run even hotter than they would otherwise.  The tuner will allow them to adjust the air/fuel mix and ignition timing for the current air flow in and out of the engine which is why you should also consider a high flow air filter and less restrictive exhaust and have them put on before the dyno tuning.  You will also see significant increases in torque and horsepower.  Good luck, let us know the results.