| Author | Message | ||
     Hoovdawg |
From reading here and elsewhere I know this is a very common issue, especially with xb12's. I've modded my pipe and started tuning with ECMSpy. The idle is much better, and moderate to hard acceleration seems good. But there is a persistent stumble during light to medium loads at around 2750-3250 RPM. I've seen this mentioned on the rather exhaustive 130 page thread about ECMSpy over on the Buelletinboard. Its was stated that its a common issue, but can be tuned out; yet they don't say how. I've logged 6 times. Each ride I start out by heading down to the freeway from my house before I start the log to get the bike up to temp. Then I'll stop and get the laptop out and start logging. Then I ride 5 miles at 70mph/3200rpm on the slab to allow the AFV to learn using the new map, then I put on around 10-12miles with varied acceleration through the gears and roll-ons, riding through town. Then, I'll get back on the slab and return the way I came. Everywhere else seems to have improved, and the stumble has improved a bit I guess, but not to a large extent. All I have messed with so far is fuel. Is this problem tied to timing maybe? Also, I have not adjusted any of the target AFV values in the afrbins2 table. The table doesn't really resemble the figure laid out in the tuning guide. (Figure 19, the one they show you when they are stating all the goals; fuel econ., pop-free decel, etc.) Is that something I need to mess with? I am only using the stock O2 sensor. Also, when using the VEAnalyzer, if it wants to lean out(red number) a cell by a more than a few, I have been manually altering the change to -2 or -3. Trying to be careful and not let it lean out any cells too much. (some of the suggested changes have been fairly large, mainly in the WOT cells) Is this a good idea? Thanks for any help y'all can offer. | ||
| Adrenaline0210 |
My bike stumbles around that RPM as well. I have the race ecm with open airbox and jardine exhaust. If I know correctly the only proven way to get solid power throughout the RPMS is to really have it dyno tuned professionally. Anyone I know that has tuned there hearts out end up finally going to a dyno and getting a custom map done. Just my 2cents. | ||
| Hoovdawg |
Hey,I am drawing close to that decision also. Problem I have is that I don't know of any dyno tuners in my area. I'm in Spokane, WA. Anybody know of any around the Pacific Northwest? I'm not against taking it to another town if I know I'm taking it to a reputable tuner. I've even thought of taking the 800 mile trip to have it tuned at JT&S down at Infineon cuz I know they know these bikes inside and out. I have made a little headway. The stumble is better, but not gone. In addition to adding fuel, I have now retarded the timing just a bit in the problem area. I think I may buy another NB sensor and add a bung to the front header pipe and tune both cylinders individually. Not a huge cost involved there. Thanks for any info ya'll can pass along. Hoov | ||
| Bryn1203 |
I have the 3K stumble but its only when under light load roll on. And oddly not when the air is colder - at night. I have the Erik Buell Racing ECM & they will retune it with no guarantee - for a price - or you can play with the exhaust set up. Kevin from 'Drummer' gave me some good advice on this topic = "3000 [rpm] is where the cams are starting to overcome engine airfuel consumption and the packpressure is real critical in that area. [my exhaust is] probably too open for the bike...it needs progressive backpressure....alot of messing around is how you find the magic....keep trying..." If I had the money I'd get a Drummer can (muffler) and probably a good dyno job done. Goes like stink when right though - third gear power wheelie (1" air  ) - with standard gearing & stage 1 tune. (Message edited by bryn1203 on September 18, 2010) (Message edited by bryn1203 on September 18, 2010) |
