rev limit on CBR900

roland5color · 11-07-2009, 2:19 PM

I usually shift my 97 cbr900 around 11,000 rpm when I am blowing the cobwebs out of her but today I hit 12,500 indicated on the tac and there was no signs of a rev limiter. Suprized the hell out of me. I know the tac isn't exact but is it that far off. At what rpm on the tac does the rev limiter actually kick in?

bladeracer · 11-07-2009, 2:57 PM

Quote:

Originally Posted by roland5color

I usually shift my 97 cbr900 around 11,000 rpm when I am blowing the cobwebs out of her but today I hit 12,500 indicated on the tac and there was no signs of a rev limiter. Suprized the hell out of me. I know the tac isn't exact but is it that far off. At what rpm on the tac does the rev limiter actually kick in?

Tried searching for some dyno charts and it looks like it's around 11,500RPM on the dyno's tach but that doesn't tell us what the bike's tach might be indicating.
CBR900RR Fireblade Performance Modifications

roland5color · 11-08-2009, 5:34 AM

Quote:

Originally Posted by bladeracer

Tried searching for some dyno charts and it looks like it's around 11,500RPM on the dyno's tach but that doesn't tell us what the bike's tach might be indicating.
CBR900RR Fireblade Performance Modifications

Thanks for the help blade. That would put my tack off by at least a 1000 rpm or so. Which is easily believable. Well at least now I know that I can wring her neck a little more without bumping the limiter. I will have to get a more accurate device to measure the rpms I to find out how far my tack is off.

bladeracer · 11-08-2009, 6:45 AM

Quote:

Originally Posted by roland5color

Thanks for the help blade. That would put my tack off by at least a 1000 rpm or so. Which is easily believable. Well at least now I know that I can wring her neck a little more without bumping the limiter. I will have to get a more accurate device to measure the rpms I to find out how far my tack is off.

If it's in neutral the tach will go well above the limiter but I'm assuming you mean that you revved a gear out to 12,500TPM?

roland5color · 11-08-2009, 7:17 AM

Quote:

Originally Posted by bladeracer

If it's in neutral the tach will go well above the limiter but I'm assuming you mean that you revved a gear out to 12,500TPM?

You would be assuming correctly. I would never rev a bike to the limiter in neutral.

To me that is motorcycle abuse. Normally I don't rev the bike to the limiter at all. I try to shift about 500 rpm before it kicks in. I have only had the 900 for a few months and I always assumed that the rev limit was about 500-1000 rpm past the 11,000 mark on the tach so I would just shift at 11,000 but this time I held the throttle a little longer than usual. Now this was in third gear so I was moving pretty good and only caught a glimpse of the tach but I know it was past 12,000. May have only been 12,200 or 12,300 but it was sure past 11,500. Is there any chance someone could have removed the limiter or raised it.

bladeracer · 11-08-2009, 7:23 AM

Quote:

Originally Posted by roland5color

You would be assuming correctly. I would never rev a bike to the limiter in neutral.

To me that is motorcycle abuse. Normally I don't rev the bike to the limiter at all. I try to shift about 500 rpm before it kicks in. I have only had the 900 for a few months and I always assumed that the rev limit was about 500-1000 rpm past the 11,000 mark on the tach so I would just shift at 11,000 but this time I held the throttle a little longer than usual. Now this was in third gear so I was moving pretty good and only caught a glimpse of the tach but I know it was past 12,000. May have only been 12,200 or 12,300 but it was sure past 11,500. Is there any chance someone could have removed the limiter or raised it.

I don't know about raising it but I'm sure it's possible to remove it entirely.

unfetteredmight · 11-08-2009, 1:24 PM

Quote:

Originally Posted by bladeracer

I don't know about raising it but I'm sure it's possible to remove it entirely.

Either is possible with custom programming in the ECU, no way to do it otherwise.

roland5color · 11-08-2009, 1:35 PM

Quote:

Originally Posted by unfetteredmight

Either is possible with custom programming in the ECU, no way to do it otherwise.

I knew you could program newer fuel injected bikes but I wasn't sure about 97 CBR900. I know the previous owner had the bike dyno tuned. Maybe he had the limiter raised. Hopefully I will have a shift lift soon and I won't have to worry about it so much. Thanks for your reply

unfetteredmight · 11-08-2009, 1:46 PM

Quote:

Originally Posted by roland5color

I knew you could program newer fuel injected bikes but I wasn't sure about 97 CBR900. I know the previous owner had the bike dyno tuned. Maybe he had the limiter raised. Hopefully I will have a shift lift soon and I won't have to worry about it so much. Thanks for your reply

It's possible to reprogram anything that uses programming to operate.

It's unlikely he had the limiter raised, chances are your tach is just off. Just because you rev a bike to a higher RPM doesn't automatically mean it's producing more power, or any engine for that matter. It has an optimal point, which isn't necessarily the rev limit and then power will fall beyond that.

cbr900racer77 · 11-10-2009, 12:12 AM

You can definitely reprogram the limiter but it's very expensive to have someone do it. Back when they had 600 supersport class in AMA dragracing, Schnitz would reprogram your brain but they charged like 1500 bucks for it. I'd just find an old Vance & Hines powerpak if I wanted more rpm's. Btw...if you rev that thing hard often, definitely consider a set of good springs. I have PM's in mine and have ran it up to 13.5 a few times on dyno. Money well spent for peace of mind.

submaniac · 11-10-2009, 12:42 AM

OK, not to thread jack but...is hitting the rev limiter that bad? Like I never do anyways, but I always assumed that it was OK as that was the purpose of the rev limiter, and there is a safety margin set by the factory (i.e. it could go a bit higher than the rev limiter). And yes, I know that the max hp/torque is below the rev limiter, and that when you go past the sweet spot it is diminishing returns.

bladeracer · 11-10-2009, 1:15 AM

Quote:

Originally Posted by submaniac

OK, not to thread jack but...is hitting the rev limiter that bad? Like I never do anyways, but I always assumed that it was OK as that was the purpose of the rev limiter, and there is a safety margin set by the factory (i.e. it could go a bit higher than the rev limiter). And yes, I know that the max hp/torque is below the rev limiter, and that when you go past the sweet spot it is diminishing returns.

I wouldn't expect a problem in a good strong engine but running at redline or the limiter a lot is over-stressing a lot of engine parts. The more you do it, the more likely something will let go eventually.