Hesitation under 2k rpm

[rsm688]

Okay well I have noticed with my 03 XB9S that when I am accelerating from a stop or cruising out of parking lot below 2k rpm the bike sort of hesitates/stumbles, after that it's just fine but it almost feels kind of like there is a point to when I am below it the bike hestitates/stumbles a little and after that no problems at all, it of course doesn't do it when decelling only when I slow down to almost a stop and start going again (like at roundabouts and in parking lots), does anyone know what could cause this or is this just an XB thing (I know they like higher RPMs).

Thanks,
Spencer

 

[user_deleted]

spencer: what i call nature of the beast. these are big displacement air-cooled 45 degree V-twins with fairly aggressive camshaft profiles and compression ratios. within reason they like to be revved and not loaded hard at low rpms. add in virtually 0 driveline lash, a light compact bike with minimal rolling inertia and you tend to feel most everything the motor is doing or not doing. and for what it's worth i'm on my 5th XB to date being a mixture of 9's and 12's and all of them have been what i would call "grumpy" or "tempermental" at low speeds.

 

[rsm688]

Okay great thanks lunaticfringe, I knew my 99 M2 did the same thing but since these bikes were more refined and fuel injected and typically much smoother in general I just wanted to make sure that it was normal with them and not leaking intake seals or something like that.

Thanks,
Spencer

 

[JustinMT]

Downshift?

 

[rsm688]

Lol, usually in first gear is when I notice it like when I slow down to make turns in a parking lot and then pull back on the throttle to speed up once I get on an aisle or when I get to roundabouts and whatnot

 

[06xbss]

Breather re-route helped my bike with the low rpm stumble. Although, like lunaticfringe said, a lot of it is just the "nature of the beast"

 

[rsm688]

06xbss, how exactly does the breather re-route help with the rpm stumble (just curious, doesn't seem like it would make much difference mechanically in my head, but I'm no expert). Where did you re-route it to?

 

[06xbss]

Factory breather routing is for emissions..... Low rpm creates the most vacuum, therefore you are sucking the most crap from the engine into the intake.

The re-route lets any condensation and oil vapor from the engine drain, either on the ground or into a catch can. Mine is routed to a small air filter and catch can on the left side of my bike........

 

[rsm688]

Thanks 06xbss, I will see if I can find a good thread on the re-route and give that a try. On my M2 it came (guess previous owner did) already routed to an air filter with no catch can. Any advantage to running it to an air filter/catch can versus running a hose to the bottom of the bike and just letting it drain out?

 

[06xbss]

Where you route your re-breather system really depends on a lot of things......... Climate, temp, altitude, riding style, bike......

With my bike, I get a fair amount of condensation out of the re-route. When I just had it draining to the bottom of the bike, my swing arm/rear tire/rim were covered in a oily residue[sad] I use a catch can because covering my rear tire in an oily residue is not a very safe option.

 

[rsm688]

Gotcha, thanks. Did you purchase a catch can from one of the vendors like ASB or did you use something from a local auto parts store for it?

 

[06xbss]

Here is a pic of my re-breather..... Not the best looking set-up, but it works.

Red arrow: 3/8th hose from where the factory breather tubes are hooked together with a "T" under the air box base plate.
Blue arrow: plastic 3/8th "T"
Green arrow: ~15in of clear tubing I use for a catch can. You can see the milky/oily residue it fills up with, need to drain it
White arrow: small, cheap air filter I found at the auto parts store.

 

[JustinMT]

Breather reroute/ catch-can write up I did.

 

[rsm688]

Thanks a ton 06xbrss for the info/pics and Justin for the link, that's exactly what I needed, I will be adding this to my list of things to do to my 03 XB9S this weekend:

Race Maps/TPS reset
New Intake Seals
Adjust Primary Chain
Adjust Clutch
Change Primary Fluid
Breather Re-route
Iridium spark plugs
Extra ground wire from coil
Install Ride Side Scoop
Swap on new plastics
Plasti-Dip centers of wheels black
Install crossroads bars


Any other good mods I should do while I'm at it? I'm a vet student and busy as hell 24/7 but have a 5 day weekend with nothing to do that is going to be devoted to the Buell.


Thanks,
Spencer

 

[JustinMT]

If you're changing your primary fluid you might as well do your oil too. Royal Purple 20W-50 both holes ever 3K miles is what I do.

 

[rsm688]

Oil was changed about 1k miles ago by the previous owner but I will probably end up changing it as well (I checked it's still clear but I like to know exactly what is in my bike and how long it's been in there). Air filter looks pretty clean, I'll probably blow it out with some compressed air as well.


Also going to remove my snorkle in the frame that goes into the air box to get more air flow

 

[ich]

Also going to remove my snorkle in the frame that goes into the air box to get more air flow

http://www.ukbeg.com/forum/viewtopic.php?f=8&t=15469

 

[rsm688]

Very interesting read, thanks ICH. Guess I will leave the snorkle in place then

 

[roxxx]

My Old 2005 12 hated 1 2 3 gear at low RPM it had the race only ecm which was even worst If you were turning at low rpm you had to be very careful on the hesitation or you could easily fall over

I also had a low mile 12 that was bone stock and it wasn't as bad but it still had the hesitation