missing when hitting the gas from idle.

[black_xb12r]

hey my 04 buell XB12R misses and almost sounds liek its backfiring when i hit the gas from idle. and once in a while it will miss going down the road. i took off the airbox cover and there is a servo on top of the airbox lid is that the exhaust servo because it only opens once in a while and i can hear the exhaust note change when the servo moves...
any help or advice would be greatly appreciated!
thanks much
casey

 

[2Evil4U]

Sounds pretty normal. The sneeze off idle is common with every HD motor ever built. The mid-range cough is pretty common with these bikes too. Have you had the TPS reset recently? I'd have that done and then ride it fairly agressively 3500+Rpm for a while to see if that helps.

Strangely, mine runs much better if I keep the RPMs up more often. I think the FI system learns some bad lean habits when you baby the bike.

 

[black_xb12r]

yea mine seems to run great from 3000rpm and up but she chugs and shit down low i think it is just the harley twin i just ordered a pipe and race ecu for it so i will have the tps reset when i put the pipe on and race ecu in

thanks much for the help!

 

[tbramich]

"i took off the airbox cover and there is a servo on top of the airbox lid is that the exhaust servo because it only opens once in a while and i can hear the exhaust note change when the servo moves"
yes and if you put an after market pipe on it you will need to disconnect the cable. its debatable if the race ecu will let you remove the box completely, some say yes & some say no.

whats your idle rpm?

 

[White03 9R]

check the o2 sensor! i had the same problem, replaced said sensor, runs like a friggin champ now![up]

 

[flicky]

Sounds pretty normal. The sneeze off idle is common with every HD motor ever built. The mid-range cough is pretty common with these bikes too. Have you had the TPS reset recently? I'd have that done and then ride it fairly agressively 3500+Rpm for a while to see if that helps.

Strangely, mine runs much better if I keep the RPMs up more often. I think the FI system learns some bad lean habits when you baby the bike.

I have riddin many HD's and never felt that.
My 08 XB12R is new with only 85 miles on it.. The off idle sneeze/hiccup is bad. It's great above 1500 rpm.

 

[roadsrfr]

harleys dont do that just the buells you have to roll on the throttle untill 1500-2000 rpm its something with the ddfi

 

[LeFox]

i don't understand what some of you consider as normal...[confused]

when i roll on the throttle the bike does what it is supposed to do without hesitation.
smooth as silk!

Have you had the TPS reset recently? I'd have that done and then ride it fairly agressively 3500+Rpm for a while to see if that helps.

i would ride at a steady 3000/3500rpm for about 10/15minutes and give your ecm time to learn after the reset.

 

[mrdozer2you]

I think hes saying that if you crack the throtthe fast at low RPM's it will miss. Mine does that too but not very often.

 

[LeFox]

you shouldn't...atleast not when the engine is warm.
when cold, you shouldn't be cracking the throttle fast [smirk]

 

[mrdozer2you]

when cold, you shouldn't be cracking the throttle fast

Never

you shouldn't...atleast not when the engine is warm

It does, once in a blue moon...but it will. Next time it happens I'll make a point to remember the conditions when it happened. I.e. how long i've been riding ( how warm the bike is ) outdoor temperature and relative humidity. I bet all that will play a part in the cause [up]

 

[mezap]

blackxb12r:
Owners manual (as well as the shop manual) calls for a TPS reset at 1000 miles. Give the bike a little time for break in, then take her in for the first service, and stress that you want the TPS reset.
Buells tend to behave oddly at slow speeds with low RPMs. I think its the mapping they have coupled with the
under square engine. Most of these guys could tell you more about it. Anyone? Anyone? Bueller?

 

[justice720]

You're complaining about a throttle blip you're making the bike do when not in motion..? does it happen when you chop the throttle while in gear rolling down the street? It's normal for that kinda stuff to happen when sitting still since the engine has no strain on it... there's nothing to compete with the vacum of the engine. so it's gonna fart and burp..

Newton's law: for every reaction there is an equal or opposite reaction..

Also make sure you're all warmed up before you open it up and chop the throttle.. you might want to disconnect the battery for 30 mins to reset the ecm.. let her idle for 5 then take her for a leisurely stroll.. don't pin the throttle or chop it for at least 30 miles... just to get the ecm set for "normal" use again.

 

[justice720]

Also, while the battery's disconnected spend the 30 mins checking the throttle body/ manifold makeing sure it's all clean and not sticking.. it couldn't hurt to pour some of that cheap injector cleaner through it either..






nm I just realized how old this post is.. lol.. but still

 

[MrOrange]

One thing that I noticed was that the ignition timing will go advanced when your at idle and cracking the throttle. I was watching what the timing in deg was doing a couple of TPS resets ago. Maybe just a lag in the software, but there was something going on with the timing when the engine was at idle to 2000 or so and back to idle again. By the way I really never really looked into the issue more than that since then.