| Author | Message | ||
     Vonsliek |
searched knowledge vault but came up epty on actual experiments done &/or resultant behaviour of bike. while i am aware there are other *fixes* for more top speed & acceleration, i am still wondering abt getting an extra 1000-1200 revs in all gears. i have read in articles by top buell racers/builders (well, at least one article that went indepth) that bikes will sfely rev to 8500. i'd be happy for now w/ 8000 & or no limit & keeping my eye on tach. any assistance greatly appreciated. i will be reboring my bike next winter anyway, so i am eventually gonna open her up .. if it shortens engine life a little, i am not too concerned, as i take it on track & rev the crap out of it anyway. i know i am not the only one interested. | ||
| Olinxb12r |
Don't do it! There is a rev limiter for a reason. The track guys probably have a different bore and stroke that allows the bikes to rev higher in the same way that the 9 revs higher than the 12. Top speed doesn't matter! If you are riding on the street I'm sure that 140ish is plenty fast enough, and if you need more than that on the track maybe you should be racing metric. If you need more than that on the street maybe you should also be riding metric on the street. The Buell is what it is, and if you try to make it something it is not it will blow up! Especially if you are wanting to have metric V-Twin revs. | ||
| Diablobrian |
You need to be a licensed racer to get the ecm that has the adjustable rev limiter. | ||
| Slaughter |
Besides, back when we were going to try to run the 6-hour in Fontana, we set our rev limiter DOWN to 7500 in order to make the engine last. Hitting the rev limiter at 8300+ will destroy a bottom end in about 2-3 seconds. You're really flexing the C-rods pretty dramatically when you hit it and that impact load BASHES the crank bearings. The only reason I've set my rev limiter to 8000 is that Bartels does the engine rebuilding. If I lose that sponsorship, it goes back down to 7800 when I have to work on it. What Brian said is totally correct. IF there were a way to raise the rev limit without buying another ECM, I haven't heard of it. ALL the other aftermarket fuel injection systems operate in series with the original ECM and only change fuel mixture and don't even touch ignition - the original ECM still sets the redline. Also, I'm only talking about my XB-9 motor which is overbored to 3.8125 in. The XB-12 would be even worse at the high revs. I haven't heard of anybody else making an ECM replacement. It just doesn't make a whole lot of sense since there are still so few of the XB-types out there compared to the (fill in the blank) Japanese sportbikes. | ||
| Cyclonecharlie |
AHHHH, Now is when a carb. version of an XB would solve your problem. Just get a programmable Ignition (Dyna 2000i or others) And in little time you could set your own rev. limit. Then hit the track and spray oil all over the end of the back straight. And you will have satisfied that itch you had to turn them big rev.numbers......Charlie | ||
| Slaughter |
Charlie has a point about the carb and ignition... but taint gonna be cheap that way either. Oiling your rear tire is usually a poor way to limit your revs  | ||
| Diablobrian |
Well, maybe the reason they limit access to the real race ECMs is because they figure that there will be at least one mechanic on the team that will know the mechanical limits of the motor design. Or they figure the teams will know you have to finish to win. Either way Slaughter is correct. what a race team considers "safe" has to last 5-15 laps in most cases. Your street bike needs to last a little longer than 60 miles*, or people will be on here upset about how Buell didn't build a strong enough motor. *most tracks are shorter than 4 miles. | ||
| Glitch |
What about the DirectLink? I think you can change just about everything in the ECM with it. | ||
| Diablobrian |
Terry said that DL does not change the rev limit, but that was a while back. Maybe a software change since then? | ||
| Glitch |
Not sure. I do know however you can quickly kill an engine with it, so the outcome may just be the same?  | ||
| M1combat |
You don't want ANY more than about 7200 or so out of the 12 stroke... I hear with a nine stroke and fairly stock parts you can make 7800, 8100-8200 with good parts, maybe 83-8350 with a good builder and good parts. I've heard that the "RR" engine has gone higher .} | ||
| Skyguy |
I have my suspension set up pretty darn well. At 130+ the XB gets a bit twitchy when the surface gets rough. Saw 142 indicated on the XB9 today. I doubt it was more that 132. I was nose to tush with a Ninja 636 and he started to slowly (very) pull away.............. Then we ran out of road. | ||
| Slaughter |
The RR has the same 3.125 stroke that the XB9 has. Therefore the piston speeds are the same for the same RPM. They just have that DINNERPLATE - sized big bore. For my own preferences, I had set the redline to 7500 but found that when drafting, I could be pulled up into the rev limit so I set it up to 7800. Bartels now has it set at 8200 while Dixon is racing it for me - but they can afford to rebuild the motor every couple months. ...and Hal's usually shows up to the races with an A bike, a B bike AND enough spares to probably drop in another motor on top of all that. (Message edited by slaughter on June 21, 2006) | ||
| Fullpower |
limiting factor is nowhere close to piston speed. inertial and centrifugal forces on crank pin will pose very serious limitations on the lifespan of the engine at higher rpm. for reference i use my 1458cc sportster engine with a 4.312 stroke which has lived over 5000 rpm for a great number of hours, and has been twisted to 7000 rpm more than a few times. even zorched an oil pump drive gear once at6000 rpm and the motor is still running just fine. (new oil pump and drive gear) so the relatively short stroke of the XB12 will easily live at 7000 rpm, at least with some good quality con rods, i have some forged S&S rods in the sportster. | ||
| Diablobrian |
Fullpower, You're correct in that,but a stock motor can't be pushed that hard. It will not survive for long trying to chase down r1s and gsxrs at 7.8k rpms. How often is a street rider happy rebuilding his motor? (Message edited by diablobrian on June 21, 2006) | ||
| Vonsliek |
well . jst back from tracknite .. easily past a gsx-r600 (2003) on the straight & found a full race ninja zx-6r (636)(2003) getting in the way thru the chicane. intermediate group. we had MAJOR hail storm interfere & that screwed up any further i4 scalpelling. i rev the crap out of bike tho .. 5000-6500 to keep in on the boil. yep .. i need an i4 for the track. too often i am frustrated w/ scaredy cat riders around all corners (but we can't overtake on any bends bar 5, for *insurance* reasons) but i can't get by them on the straights .. this is getting old hat, so i'll quit my whining. nothing wrong w/ the buell tho .. afterall, it got me ON the track! | ||
| Lenb |
Yeah, I have the same problem at trackdays (well, it's not really a problem - but for want of a better word...). I find that when I gun it to overtake a slower rider on an I4 on the straight I haven't got the revs to do it. One minute it's pulling hard, then "poof" - its hit the rev limiter. Frustrating. XBs pull hard but just can't sustain the acceleration in any given gear. | ||
| Trojan |
We run our XB12 race bike with the stock rev limiter and really don't have a problem with it. In fact we are still playing with final drive gearing options because we aren't hitting the limit on the straights yet in top gear. Our primary drive is (slightly) higher geared than stock but we were still pulling a true (datalog confirmed) 142mph at 6200rpm at Bruntingthorpe recently. This was with a chain drive fitted using a 21T front and 48T rear. We changed to a 51T rear for Snetterton and that was good for drafting the quicker bikes on the straight but still wasn't hitting the limiter. There is always a big compromise with changing final drive gearing because you inevitably hit the limiter too quickly in the lower gears once you lower the gearing too much. We still use the stock gears on our bikes but there is a close ratio set available from Andrews. Personally I would rather keep the lower rev ceiling and a longer lasting motor  There are lots of other options to explore for more speed first before messing with the rev limit. Suspension and braking upgrades will get you onto the straights faster without putting any extra strain on the motor | ||
| Dago |
Vonsliek, What you're talking about is exactly what the XB did to me. I believe it made me a better rider do to the fact it's like riding a bull around the track. They're twitchy and ...oops... I mean to say they're full of character. I got a new 600cc in March and have now done 4 track days on it. It's worlds apart from the XB; better in every way. I'll spare you with stories of personal improvement that'll surely bore you to death. But I will say that the new bike has filled me with confidence and clarity. Remember: "Inspired by the track. Built for the street." (unless you're Trojan with oodles of resources) | ||
| Trojan |
(unless you're Trojan with oodles of resources) Alas if only it were true.....  I think the biggest resource we have is a dogged determination to make the XB work on the track. We speak to so many people who race Jap IL4's and SV650's that just fill them with fuel and race. They don't even change the oil between meetings! No midnight oil burning, head scratching, no having to commission special parts, no bits vibrating off....They even have time to relax between races... Where is the pleasure in that | ||
| Dago |
I commend your efforts fighting the good fight, Trojan! Me? I'm that lazy guy you speak of with his feet propped up laying under his awning, napping between sessions. And I take absolutely no pleasure in it.  | ||
| Cyclonecharlie |
Sad to say, the pleasure is they are becoming better racers/ riders without the headaches. And were just becoming better mechanics and fabricators. I love my Buells so don't start flaming me, but it's true until something major changes it........Charlie | ||
| Trojan |
When Buell introduce the model with the reliability and tuning potential of a Honda CBR600RR and the character of an XB I'll be first in line Until then we'll soldier on (cue the violins...) | ||
| Josh_cox |
This is the reason why the RR can rev high without grenading. Notice the extremely lightened flywheel and the "holy cow that is big" crank pin:  Whatever they come out with, I'll get it:P Even if it is the same XB with minor tweaks! | ||
| Firemanjim |
Might want to ask Al and Terry if they can access rev-limit with the new software they are playing with--???? | ||
| Slaughter |
Well - except in the desert heat at the last race weekend - where the Buells did better than the liquid cooled racers (103 degrees in the shade) From the Willow Springs board: Their bike did better than my 996. the 996 did one session Saturday and when I parked it in the pits it immediately blew a hole in the coolant resivoir and peed out coolant for 10minutes. I am honestly happy for them. 2 other 996s in the pits did the same thing as mine... My GSXR1k came in from F40 and dropped or had dropped about 6oz of coolant in the catch pan...it was hot out there...they deserve to celebrate...just not sure what it was about. note: our applause and the celebration was for ALL the Buell riders pitting together - we would ALWAYS applaud for EVERY racer. It's a social thing more than anything else. There was a Buell in second (Dixon on my bike) and one in DFL and a half dozen in between - they ALL got the same applause when they returned. And another from the same thread: My R6 did that on Saturday. Blew the cap off the coolant reservoir when I was about to put it on the stand and scalded my neck and chest. | ||
| Diablobrian |
That's definitely how I remember Willow.... It's like being on a huge griddle. Slaughter: Good show of solidarity! Other people do notice. (even if they are confused about our family atmosphere) |
