Don't trust the rev counter...

Started by Coffeebaron, April 12, 2012, 02:37:08 PM

Previous topic - Next topic

Buckethead

Well, as long as it's got rods, it's got rod bolts.  :P
Quote from: Jester on April 11, 2013, 07:29:35 AM
I can't wait until Marquez gets on his level and makes Jorge trip on his tampon string. 

Slide Panda

Quote from: bdub on April 16, 2012, 12:29:29 PM
I was under the impression everything has a rev limiter.

Well, yes - but those are also call critical points of mechanical stress failure. All the EFI ducs to have an ignition cut-out limiter.

But older carbie bikes with no brain could be pushed past the recommended RMP ceiling. OF course that's at your own peril as too much of that and bits stop being connected like the should.

Also, many times peak power is achieved before the limiter  so anything past peak power and you're losing out and and the next gear will be better.

Look at some dyno graphs and you'll see it go up-up-up and right before the lines stop it goes over the hump and heads down again.
-Throttle's on the right, so are the brakes.  Good luck.
- '00 M900S with all the farkles
- '08 KTM 690 StupidMoto
- '07 Triumph 675 Track bike.

bdub

but since the OP was talking 796, I assumed fuel injection. I realize everything will eventually spin out of control. It's happening now with me (slowly)
2005 900ie
now with mivv s'

Y2K  M900 ie  totaled  10/09/08

duc996

I would just listen and feel for the bike, and not look at the tach.
"All we ask is to be let alone"
       "Monster S4r"
       "KTM SMC 690"

Privateer

i'm curious, have you previously ridden mostly i4's?
My fast lap is your sighting lap.

bdub

If you are asking me, then no. I've only had mine 900. Not counting the 125 I had 35 years ago. I really don't pay any attention to my tach unless I'm trying to figure out speed at a particular rpm.
I just shift when it sounds right.
2005 900ie
now with mivv s'

Y2K  M900 ie  totaled  10/09/08

monsterjoe

ive hit about 8000 rpm, can i hit it till 11000? rpm? i ride a 620 dark 2005

Slide Panda

Quote from: monsterjoe on June 19, 2012, 11:21:41 AM
ive hit about 8000 rpm, can i hit it till 11000? rpm? i ride a 620 dark 2005

Nope - you've missed the fundamentals of the discussion perhaps.
1) Your bike has an electronic limiter that kicks in some place just beyond 8000.
2) More Revs /= more better, especially going that high.
   - After a point the engine will produce less power. Generally the Rev limit and engine tune are set to work together. The limit being set at a point just beyond the point where power starts to drop off.
   - Too high an RPM in and engine not designed for it is a good way to destroy it. I'd wager that if you managed to run a 620 engine up to 11,000 RPMs via messing with the electronics, it would be a lesson on critical mechanical failure.
-Throttle's on the right, so are the brakes.  Good luck.
- '00 M900S with all the farkles
- '08 KTM 690 StupidMoto
- '07 Triumph 675 Track bike.

herm

everyone should seek out the rev limiter (in a safe and controlled situation.) this will achieve two things.
1- you will know what it feels like, and not panic when/if you hit it by mistake
2- you will know where it is, which is pretty important because you don't want to bang up against it when you still need to be accelerating
 
Never wrestle with pigs. You both get dirty, and the pigs like it...

Privateer

Quote from: bdub on April 25, 2012, 05:09:58 AM
If you are asking me, then no. I've only had mine 900. Not counting the 125 I had 35 years ago. I really don't pay any attention to my tach unless I'm trying to figure out speed at a particular rpm.
I just shift when it sounds right.

no, i was addressing the OP.
My unscientific research has shown me I4 riders have trouble riding twins because they want to wring the thing's neck out.  No amount of me trying to explain it helped, they only learned that docs are 'junk' because of an 8k rev limiter.
My fast lap is your sighting lap.

The Bacon Junkie

Quote from: herm on June 20, 2012, 07:58:36 PM
everyone should seek out the rev limiter (in a safe and controlled situation.) this will achieve two things.
1- you will know what it feels like, and not panic when/if you hit it by mistake
2- you will know where it is, which is pretty important because you don't want to bang up against it when you still need to be accelerating
 

+1

I hit the limiter on my 999 in first gear by accident... 

I was pulling out onto a two lane highway, across traffic.  The speed limit there is 55, but people routinely do 70ish...  Luckily for me, the Triple-9 has a TALL first gear!  ;)

It was almost as if I head a BANG in my head when it cut out...  But I think that was just my chest, then my chin, hitting the tank!  I didn't panic, but it certainly got my attention!!!  :o

Find your limiter when you're expecting it... not in a real world situation...  [thumbsup]




[bacon]
Quote from: bobspapa on December 19, 2011, 03:11:09 PM
I only see jesus having a sauna with a teletubbie.
Quote from: El Matador on December 19, 2011, 03:19:02 PM
I find it disturbing that you're imagining me in a sauna, never mind the teletubbie aspect of it

Save the Brass...

bdub

Is it hard on stuff if you hit the limiter to often ? I dont't hit mine often, usually shift around 6 - 7800 ish.
2005 900ie
now with mivv s'

Y2K  M900 ie  totaled  10/09/08

Slide Panda

Nah. that's the purpose of it. As long as you're not riding the limiter for extended periods, hitting it shouldn't make no nevermind
-Throttle's on the right, so are the brakes.  Good luck.
- '00 M900S with all the farkles
- '08 KTM 690 StupidMoto
- '07 Triumph 675 Track bike.

Triple J

Quote from: bdub on July 04, 2012, 10:19:38 AM
Is it hard on stuff if you hit the limiter to often ? I dont't hit mine often, usually shift around 6 - 7800 ish.

Depends on who you ask, and how often you hit it I think. It's a fairly violent affair in Ducs compared to I-4s.

My 749 racebike has a broken crankshaft, and it previously had a spun crank bearing (crank itself was OK after that...although it may have been damaged internally and we couldn't tell). It has been suggested that hitting the rev limiter too often may have contributed to the problem. When I get it back I will be putting a big piece of red tape on the tach. at 10,500 rpm to help keep me from doing it again. It may not have caused the failure, but it surely didn't help.

herm

the other important take away here is that there is NO REASON to be regularly bouncing of the rev limiter on a duc! but the time you hit it, you are way past the top of the power curve... = less power.

once you learn where it is, shift accordingly and stay away from it.
Never wrestle with pigs. You both get dirty, and the pigs like it...