| Author | Message | ||
     Kowpow225 |
I had the ecm of the race kit installed today and the tps reset done by dealership. I've had the chance to run the bike at 3500-4000 rpm for a constant 10 minutes each way. After that, I went to some of my favorite backroads for a sample. Heres what I found. The bike runs really well, but only at times. It feels a little sluggish when holding it at wide open throttle (WOT). And its especially noticable all the way up to around 5000 rpm. However, if I let off of the gas just a smidge, to around 5/6 throttle, it accelerates nice and snappy. Also as another note, if I ease into the gas gradually before reaching WOT it seems to negate what I just said. Not completely but somewhat improved. To me there are a few possibilities. One, the tps adjustment is incorrect. Two, the new ecm has not had sufficient time to readjust itself. Or Three, there is a possibility I haven't yet considered. All ideas are welcome.  | ||
| Gentleman_jon |
Something doesn't sound right. I have the same bicycle,( including the color), and she ran perfectly once the race kit was installed and tps was reset. If I were you, I would have the tps set again. Also I might refit the stock intake trumpet, just to make sure that isn't the problem, and not leave your dealer any wiggle room. You also might want to try a replacement ecm. Bottom line: there just aren't any problems with the race kit if it is working, the tps is properly calibrated, and there isn't some other problem with the motor. Of course you will want to be picking up a 12 airbox on your next trip to your Harley dealer, and don't forget to remove your snorkle. | ||
| Kowpow225 |
I agree. The tps is the likely suspect. Do you think more time for ecm to "learn" would be a good idea? My snorkel has been out for some time now. | ||
| Slaughter |
If your engine isn't "seeing" the WOT settings when you PIN the throttle, the TPS probably does need to be re-set. If you can roll-on through a given RPM range but at the same RPM you just PIN it and it doesn't respond, then it DOES sound like TPS re-set I don't know anything else that sounds like what you're describing. | ||
| Kowpow225 |
Thats a very good point slaughter. I'll pay more attention on this next ride. I wonder if what I'm feeling is referred to as the 'hole' in the race kit setup. I'll go check out some dyno sheets in the meantime. | ||
| Slaughter |
You might try a 3rd gear slow roll-on from 4500 through 5500 rpm... then roll-off back below 4500 and then just BANG open the throttle HARD at about 4200 and let it come up through 5500. If you get no response, that may well mean that the TPS is off a little. It'll also give you a couple data points you can feed your mechanic. Keep in mind, I'd advise against trying the above stunt in the quiet comfort of your residential area! If you have the room to do it safely, you could do it over a wider RPM range - maybe 4500 to wherever your comfort level is and do the same thing at WOT for the same range. Not exactly certain how the race ECM picks up WOT. As long as you're slamming it open in the upper third of throttle positions, you should get a consistent throttle response. (Message edited by slaughter on September 11, 2004) | ||
| Kowpow225 |
It's only sluggish in the 'hole'. Dang! Did Englishman119 post any dyno sheets on his test of the, sorry to say these words, ahem, BRION-JAMES SVVS, kit? I only found the final results. | ||
| Darthane |
No dynos. The FAST system was the winner in terms o fpeak numbers, and I cannot stress this enough - DO NOT GIVE ANY MONEY TO COREY JAMES. PERIOD. The man is a thief and a liar. | ||
| Glitch |
Corey has disappeared. Upset one too many people? | ||
| Fed |
i like the F.A.S.T. system. i bought it from iron machine ,it's the U.S. distributor for hillbilly motors. it's expensive but when it comes to toys sometimes you just gotta have it I'm not sorry about the purchase, and it looks baaaaaaaad | ||
| Kowpow225 |
Yeah, I'm aware of Corey James and his little charades game. Thanks for looking out. I'd like to find some sort of dyno sheet which shows how much of the 'hole' a 12 airbox top gets rid of. Been looking all over. | ||
| Glitch |
It just smooths it out a bit. You got to mod the air box to get it best. Don't think you'll ever get rid of it all, unless you change from the Buell pipe. | ||
| Ingemar |
As far as I know the relearning of the ecm has to do with open loop functioning of the ecm. That's everything from idle upto WOT or something like that. At idle and WOT the ecm functions in closed loop operation and then it ignores input from the sensors (except tps) and simply injects fuel based on a fixed map (whereas open loop uses the sensors' input to correct the FI ). I'd say have the tps reset again. Wouldn't be the first time a so called 'harley engineer' screws this up. Mods are unlikely to fix this issue, since it's got nothing to do with the intake system. The bike should run fine as it is. | ||
| Tikiman1 |
If what you're suggesting is correct about the ecm, then there is something else you could try. Adjust your throttle cables after the TPS Reset. That would, in a sense fool the ecm. You might loose a few rpm up top, but then again, you ride a BUELL, who cares. | ||
| Ingemar |
I guess it depends. If the throttle valve is wide open (physically at its end), but miscalibration of the sensor makes the ecm believe its not wide open, there's nothing to adjust with a cable. In the reverse situation, the sensor would think its wide open while in reality the valve is moving past the point of wide open. Not sure how the ecm reacts in these situations. Personally I wouldn't try to solve it that way. Dealer needs to calibrate the tps correctly. Period. | ||
| Kowpow225 |
I've been messing with this a lot the past few days and have narrowed it down a bit more. 1. The higher gear I'm in the more noticeable the 'sluggishness' becomes. 2. Almost 90% of this activity is 3700-4500 rpm. 3. I'm looking at the dyno sheet from the buell website, and this 'hole' is exactly where I'm describing. RATS!!! 4. I've narrowed it down to the TPS was indeed reset correctly. (as far as I know). Essentially, the TPS acts as a device for smoothing out throttle response, correct? And once at WOT, all sensor data is thrown out other than that particular one. So if this TPS is wrong, it is in essence telling my bike that it is either above or below at WOT, and therefore is only delivering the specified amount of fuel, timing, coil dwell, etc. that it believes it is being ran at since this is programmed from the factory. Are these assumptions correct?  | ||
| Ingemar |
The tps does exactly what it says it does: it tells the ecm the position of the throttle valve. It does this by sending out a certain voltage to the ecm. The higher the voltage, the wider open the throttle is. The tps reset creates a correction factor that the ecm applies to the values returned by the sensor. Iaw, if, when the throttle is fully closed, and the sensor sends out 1v, the correction factor could be minus .5v if the ecm expects .5v for a closed throttle (example numbers for simplicity's sake). I do not know if this correction factor is linear or not. Things get much more complicated if its not, and somehow I believe its not... Would you mind describing your sluggishness a little more in detail? I own a xb9. I broke the bike in while it was stock. I noticed it would start to pull, than hold back and pull again till red line. While holding back, the motor itself ran smooth. No misses or roughness. Simply a lack of power. I think the gearing thing you explain is logic since the dip is mainly in the torque curve. At a higher gearing you will notice it more than in a lower gearing. Whatever the cause, the bike should run smooth till red line. | ||
| Kaese |
Just saw this post. Mine has the same symptoms as Kow. WOT just falls flat. 95% throttle and everything is fine. That extra 5% is just flat. I have the Drummer and Race ECM. I have about 16K mileage on a XB9R since the install. I was so happy with the TPS reset that I have just lived with this minor problem. I tried to explain this to the Drummer Folks for some possible fixes, but maybe they didn't understand. No Dynos on my end. | ||
| M1combat |
Maybe the slight closed state of the throttle butterfly helps with intake velocity. I noticed this on my old Honda. It revved out to about 11.5K and if I just went WOT from 5000 it would feel "sluggish" until it reached an RPM that took good advantage of the intake velocity at WOT (10K and up). RPM's lower than that point seemed to suffer. I learned with that bike that it was much better to roll on the throttle and basically try to tune the proper intake tract with the throttle as the revs rose... In fifth gear on that bike at around 135 I could notice differences proper vs. improper throttle positioning. I was originally clued into this when I slowly rolled off the throttle in the upper RPM range and the bike got a surge of power from about 92-96% throttle. I started playing around with it by rolling off slowly at lower RPM's and found it to be true down there as well. I then started playing with how much "ahead of the RPM's" I would twist the throttle and found out how to tune my throttle hand for maximum power... This seems to still be true with the XB12R but to a smaller extent due I think to the fact that it doesn't rev out to 11500 RPMs. That and trying to adjust just right for the exhaust valve opening is almost futile... It seems to work at higher RPM's in third through fourth gear though. First and second seem to go by too fast to be able to make use of it. | ||
| Ingemar |
My car does the same. Put the pedal all the way down and it takes 5 minutes for it to reach top speed. Let it come up a few millimeters and it will jump ahead and reaches its incredible topspeed of a whopping 100mph in less than a minute ... *yawn* | ||
| Opto |
My Sportster used to do that until I drilled out the main jet. It was running lean at WOT (main jet). | ||
| Slowby |
running w/ less air better(closing the throttle) means a rich condition. if you have the dealer check the tp have them also look at the afv to see that it has changed. |
