| Author | Message | ||
     Barker |
Just scored a used 06 12X. All stock. 16k miles. I have have rode buells for a while and this is a new one on me. I have had tubers an XB9 and a Blast, but this is my first 12XB motor, and the first time I have experienced this. I am noticing a intermittent stumble (for a lack of better words) when riding @ less than 3500 rpm. I notice it alot when running constant throttle from 2000 to 3200. Runs great running over 3500, and it seems to be OK when starting off <2000 rpms. Normal? Any ideas? Exhaust Valve issues? Thanx, Barker | ||
| Ft_bstrd |
If it's at 3,000RPM, it's normal. There is a weird fueling hunt at 3,000RPM that gives it a "weak impulse". You might want to give it a fresh TPS reset if you haven't already. I can tell when I hit 3,000 RPM because of the "stumble". I can tell when I hit 4,000RPM because of the slight vibration. | ||
| Barker |
Now that I think about it, 3000ish sounds about right. Time to fire-up ECM SPY for a TPS reset. | ||
| Ft_bstrd |
The TPS reset will help only a little bit, but it couldn't hurt. Play with the RPM range, and I think you'll find that the stumble is almost exactly at 3,000RPM. Occasionally I'll cruise there and notice it. I also notice it is more severe when it rains. I'd be interested to see if you notice the same thing. | ||
| Maximum |
Barker: All Stock??? What's the fun in that? Unless you just wanted to do the farkling yourself! Can't wait to see some knee draggin on that beast.  | ||
| Pso |
Had a bad TPS reset by dealer at first service. I got the hardware and software and did my own reset. Made a great big difference, but still very minor stumble at that range. | ||
| Teeps |
1st mod, cheap & easy, replace the clutch cable wire form with the updated part (DIY Cost: $14.) 2nd mod, move crankcase breather out of the air box. (DIY Cost: $25 and up, depending on which way it's done.) This may lessen the 3000rpm stumble... | ||
| Wolfridgerider |
It goes away after my bike is warmed up. So, every morning I fire it up while I put my gear on. I don't notice it as much now, but I'm still afraid to demo a '08 model. It could get costly..... | ||
| Etennuly |
Mine will only stumble once at 3000. The only time it ever does it is if I don't let it warm up before riding. Once warmed up it never does it. But then.....my bike is better than your bike!  | ||
| Bobr |
I wonder if what you are experiencing is what I have heard called "low speed surge". It seems to be common to Sportster and Sportster derived engines and is related to lean running conditions I'm told. It seems more pronounced on 1200cc engines on the Buell's I've ridden. It also seems worse when the engine is cold to me. On my XB9 the surge was less pronounced as the bike aged. On my new 08 XT when I leave my neighborhood and observe the 25 mph speed limit I keep it in 1st to stay in a higher rpm range and reduce surge. By the time I get back the bike is really warmed up and I can maintain the same speed in 2nd with minimal surge. Primary chain maladjustment can really exacerbate this effect. | ||
| Gotj |
Barker, Another idea for you to consider: get an 07 air cleaner cover or modify yours by drilling it out to approximate the 07 cover. The cover is about $35. It cleaned up my low-end running completely. There are a myriad of threads on this on BadWeb if you are into doing the drilling. Otherwise, it is a simple R&R job. | ||
| Towjam |
On my new 08 XT when I leave my neighborhood and observe the 25 mph speed limit I keep it in 1st to stay in a higher rpm range and reduce surge +1 | ||
| Barker |
Just put on a 07 XB12 Airbox cover off of my NineR. I'll give that a try tomorrow. | ||
| Froggy |
That should help.  I got the American Sport Bike open airbox kit, no low speed issues here. But also got race ecm, and a few other tweaks. |
