backfir, misfire blues, please help

[rhino]

Hi guys,

New to posting but have been cruising the forums for a bit now trying to trouble shoot simliar sypmtoms on my bike

My mentality has reached a breaking point recently trying to find a way to alieviate the back/misfire problem ive been experiencing.

05 xb12r
20k miles
race ecm, air filter, exhaust
ecmspy capable
no breather mod, i didnt feel it was neccesary when the bike ran well

The problem is most apparent after 5 mins/5miles of casual riding and gets worse and worse as i go, backfiring in the box during acceleration, poping in the muffler when decelerating. All this seems to happen the at its worst around 3k rpm and will work its way into lower rpm untill it stalls out, the back/misfire causes the bike to surge when missing a beat and jolt as it picks back up, not a good feeling for such a torquey bike.

The only thing i have found that will help the situation, and by "help" i mean "extreme limping home", is to clutch in, rev the throttle, and endure the the constant barrage of backfire, getting the rpms up to 4.5/5k, and that allows me about anothr 10-20 secs of clean acceleration till the back/misfire begin to build back up, slowly at first then progressively more and more, till a stall out, or another clutch in rev trick.

I've recently replaced the stator, the bike was on the stand for 3 weeks-ish total. After i was done tracking down and repairing the stator problem is when the back/misfiring started. I felt i was pretty thorough and competent in mechanics enough as a machinist to do the repair myself since i had more time than money as most do. Also note the bike ran fine prior to this which has got me second guessing a procedure that i was confident about when i completed the work.

I found a bad ignition coil (faulty rear post) and plug wire (also rear), replaced both, and both spark plugs (ngk iridium), cleaned and recharged the k&n filter with the red stuff, reset the tps; all things that i thought would lead to a solution in the back/misfiring problem, ...nothing

Im asking for any advise to get me back to buelling, i love how this bike feels and want to keep it on the road as i know we're only gonna see fewer of them

Please help, i will read this daily and keep yall updated, any course of action, or questions to find a solution ar appreciated, no question to small.

thank you

 

[Loki]

Which exhaust?

 

[07Bolt]

ur clutch rev trick works b/c ur adjusting the rpms without a load i.e; the rear wheel.

u replaced the stator, which means u removed the clutch. could be a simple clutch adjustment

ive seen a faulty cam sensor make a bike run bad too

if ur clutch is dragging; it could interfere with the timing of the engine

misfire/backfiring is a result at the plugs.

check for codes; and make sure ur ecm and regulator are good too and battery!

 

[jimijeans]

Yes Bolt covered it darn good.What was your TPS reading once done with it? Have the Battery Load Checked at your auto parts store.Also do a Voltage read out for piece of mind. When in Neutral does the Bike run[rev] good & [idle)good? ONLY with a load on the Engine does it Pop/through the Throttle body?I would start with a New(TPS)reset & check the grounds all over the bike.Small things first.I've done Hundreds of Stators over the years here in the Shop.Never had this come up before.So when you find out maybe you could share that piece of Knowledge for others to benefit.Maybe a pinched wire.Maybe a plug wire, OR where the stator plug is,along with the Regulator plug harness.There are upgrades for the regulators wire plug.It may have melted Inside the wire terminals, and got pulled around some,during your work.I know You will get it.Welcome to the Forum.*Jimi

 

[rhino]

Thanks for the input guys,

@ loki

I assume it was the race exhaust you get from the HD package, since the guy that had it before me bought it as a set. Silver in color with one exhaust port on each side of the bike, near the rear.

@ 07bolt

I felt pretty confident with the clutch, to double check im going to redo the clutch proccess tonight and make sure i didnt miss anything.

Is there any simple way to check the timing, i've heard something about a static timing "peep hole" of sorts cruising the forums, would that suffice for a check?

I'll tear into the big blue book and find out how to test the cam position sensor, im sure they have a test for good/replace proccess.

Absolutely 0 codes have shown themselves, historic or current, on either of the two ecms that i have had in the bike( one stock on race, thought one may had been faulty)

Battery tested good on voltage and load, the charging system seems to be charging fine and producing the desired numbers on an ohm, plugs replaced 1 week ago with proper gap. I have not checked voltage reg, ill put that on the list for tonight as well.

@ jimijeans

not sure what ya mean by voltage readout, sounds informative.
Tps reset seemed to come out fine except for the fact that i cant keep the bike at a constant 3-3.5k for the ecm to learn with all the nonsence going on. I will also redo that as wll tonight just to make sure

I felt good about the stator swap and im starting to believe this may be a fuel related issue; pump or filter, or breathing related issue, since it seems like its choking and the revving helps to get the snot out of the sys for a little bit.

I did notice today that the tank seems warmer than ussualy, but chalking that up to being paranoid with the back/misfire situation and that its summer in texas. I dont suppose anyone can shed light on how warm a bike should be, theoretically at the outside of tank, near leg, (warm enough to feel like its burning when wearing jeans)

Thanks agian for your time guys, any help is greatly appreciated

 

[Iamarchangel]

Forgot all that.

You're riding in too low a rev range. The bike is set to run in the 4000 - 4500 range.

Around 4100 is the transition point, below that it will pop, etc. Above that, it'll sing.

Go for a good, hour long ride keeping it around 5000+, see what happens then.

 

[misfit2023]

Rhino, I know this is an old thread, but I am having the same exact problem with my 08 xb12 ss, and I was hoping you have fixed your bike by now and could shed a little light on the solution for me.

 

[octopusenvy]

Hey misfit2023,

It may not make a lick of difference to your bike running better yet, but several of us have had the same symptoms for different issues. There is also a few posts that pop up on badweatherbikers.com, like the one i started here. My bike seems to be better, as the new EBR ECM seems to be correcting whatever issue I HAD. Plus my bike is running more tricky mods (breather reroute, open airbox, rare micron with custom mapping), so can be more tricky. I've seen people spend $$$$s on trying to chase the gremlin, so listen to the simple things you can do first, and see if that sorts it. Here's a link to the other post i started, and there are a few more on that site as well.

http://www.badweatherbikers.com/buell/messages/142838/747866.html?1409895407

Hopefully between the two you can find a solution and get back on the horse.badweb