Hello Guest

F4I Rev Limiter Gone ?

  • 13 Replies
  • 2553 Views

0 Members and 1 Guest are viewing this topic.

*

Mongoose

F4I Rev Limiter Gone ?
« on: December 04, 2006, 07:33:07 pm »
Howdy,

New Guy Here. I raced Homestead Yesterday On My F4i Bike ran Great, But I ran my Loudon gearing And was doing a lot of shifting. And not being used to Long  Staights(again Loudon), I wound it up pretty good and Hit the rev limiter ALOT, Even Hit a false neutral going in to turn 1 Full throttle. Also Downshifting Violently during hard braking.

Well anyway The Middleweight gp Comes around my last race of the year I notice, When i start the bike the tach needle sort of moved funny like it was getting hung up and noticed when I over rev'ed  the bke no rev limiter Kicked the tach would go all the way past the red line. The bike seened fine Maybe a little down on power ( I cant be sure I had Burned about 20 Gallons at the track this weekend All practices and Four Races and The penguin advanced school, So I was so beat i was almost halucinating.

Any ideas what this could be, I could take it to the dyno Guy, Or to the Motor guy for a leak down/ Compression  check up.

Also I was Running 108 Leaded sunoco (race gas)

Any Ideas Please, I am kinda Worried


Daniel P 441
Like
0
Dislike
0
Agree
0
Disagree
0
No reactions
No reactions
No reactions
No reactions

*

Super Dave

  • I hate salad...
  • ******
  • 11415
    +1261/-454
  • I'm the ghost with the most...
Re: F4I Rev Limiter Gone ?
« Reply #1 on: December 05, 2006, 06:40:46 pm »
When you say you started and idled it, then whacked it and it over reved...it can do that because it's not under any kind of load...just spinning motor mass.

No extra gearing?
Like
0
Dislike
0
Agree
0
Disagree
0
No reactions
No reactions
No reactions
No reactions
Super Dave

*

Mongoose

Re: F4I Rev Limiter Gone ?
« Reply #2 on: December 06, 2006, 12:01:51 am »
When I first started the bike, before the race it idled fine Then I gave the throttle a little whack the tack seemed to sort of get stuck at Like 4k and then at 7 K

I did not notice the over rev without rev limiter until i was racing

DC
Like
0
Dislike
0
Agree
0
Disagree
0
No reactions
No reactions
No reactions
No reactions

*

Super Dave

  • I hate salad...
  • ******
  • 11415
    +1261/-454
  • I'm the ghost with the most...
Re: F4I Rev Limiter Gone ?
« Reply #3 on: December 06, 2006, 12:13:40 am »
Might be a vacuum leak for the high idle.

Rev limiter shouldn't go away, if it's stock.
Like
0
Dislike
0
Agree
0
Disagree
0
No reactions
No reactions
No reactions
No reactions
Super Dave

*

K3 Chris Onwiler

  • They were good gerbils, and they gave me much pleasure.
  • *
  • 4193
    +207/-141
  • Hours to build, seconds to destroy...
    • HIGHSIDE!
Re: F4I Rev Limiter Gone ?
« Reply #4 on: December 06, 2006, 07:10:19 am »
Find a reputable shop with a leakdown tester, a compression gauge, and a dyno.  The leakdown and compression tests will let you know if you've hurt the motor.
As Dave said, the rev limiter SHOULDN'T  stop working, but that doesn't mean it didn't.   Your tach is acting up, and I've seen some bikes that use the tach to put the rev limiter into effect, although I don't know if your Honda is one of them.  In any case, the dyno has it's own tach.  It shouldn't take more than one run to determine if the rev limiter has quit like you think it has.
Word to the wise, buddy.  Hitting the rev limiter on upshifts it hard on your engine.  Hitting it on downshifts is motor murder.  All a rev limiter does is pull pulses from your ignition to hold the RPM from passing the point where the rod bolts might stretch, or the valve springs lose their ablity to close valves before they hit pistons.  On a downshift, the rev limiter cannot control rpm.  Turn the bloody key off if you want, but if you "downshift violently" the rear wheel will mechanically overspeed the engine, and no rev limiter can prevent that.
Not a slam of any kind, just trying to teach you something that might save you some money.  Don't ask me how I know this....
Like
0
Dislike
0
Agree
0
Disagree
0
No reactions
No reactions
No reactions
No reactions
The frame was snapped, the #3 rod was dangling from a hole in the cases, and what was left had been consumed by fire.  I said, "Hey, we've got all night!"
Read HIGHSIDE! @ http://www.chrisonwiler.com

*

Mongoose

Re: F4I Rev Limiter Gone ?
« Reply #5 on: December 06, 2006, 08:04:49 am »
K3, No offense taken,

 I never came close to the limiter on down shifts(thank God), However I am guilty of downshifting hard enough to break the rear loose.

Leak down and compression Test is today, Then dyno next week

Thanks for the help
Like
0
Dislike
0
Agree
0
Disagree
0
No reactions
No reactions
No reactions
No reactions

*

K3 Chris Onwiler

  • They were good gerbils, and they gave me much pleasure.
  • *
  • 4193
    +207/-141
  • Hours to build, seconds to destroy...
    • HIGHSIDE!
Re: F4I Rev Limiter Gone ?
« Reply #6 on: December 06, 2006, 07:50:57 pm »
Good luck.  I hope your solutions are inexpensive!
Like
0
Dislike
0
Agree
0
Disagree
0
No reactions
No reactions
No reactions
No reactions
The frame was snapped, the #3 rod was dangling from a hole in the cases, and what was left had been consumed by fire.  I said, "Hey, we've got all night!"
Read HIGHSIDE! @ http://www.chrisonwiler.com

*

catman

Re: F4I Rev Limiter Gone ?
« Reply #7 on: December 06, 2006, 09:55:31 pm »
K3 and Dave (some of our local MC Phd.'s) might mention the calming effects of a slipper clutch for future peace of mind 8)during downshifts ?Good luck !----------John in Victory Gardens NJ
« Last Edit: December 06, 2006, 09:57:56 pm by catman »
Like
0
Dislike
0
Agree
0
Disagree
0
No reactions
No reactions
No reactions
No reactions

*

K3 Chris Onwiler

  • They were good gerbils, and they gave me much pleasure.
  • *
  • 4193
    +207/-141
  • Hours to build, seconds to destroy...
    • HIGHSIDE!
Re: F4I Rev Limiter Gone ?
« Reply #8 on: December 07, 2006, 05:52:24 am »
Can't personally comment on a slipper clutch.  Never rode a bike that had one....   :wah:
Like
0
Dislike
0
Agree
0
Disagree
0
No reactions
No reactions
No reactions
No reactions
The frame was snapped, the #3 rod was dangling from a hole in the cases, and what was left had been consumed by fire.  I said, "Hey, we've got all night!"
Read HIGHSIDE! @ http://www.chrisonwiler.com

*

Super Dave

  • I hate salad...
  • ******
  • 11415
    +1261/-454
  • I'm the ghost with the most...
Re: F4I Rev Limiter Gone ?
« Reply #9 on: December 07, 2006, 08:21:12 am »
A little self control with a blip of the throttle always helps. 

A slipper clutch has a cost.  Some can't afford that.  Learning proper technique, though, is invaluable.  Even with a slipper clutch, some modulation can be necessary or an adjustment of the system.
Like
0
Dislike
0
Agree
0
Disagree
0
No reactions
No reactions
No reactions
No reactions
Super Dave

*

Mongoose

Re: F4I Rev Limiter Gone ?
« Reply #10 on: December 07, 2006, 08:44:52 am »
I have thought of a Slpipper Clutch, But I dont think the Downshifting Has caused me any Problems, I have spent About 22 Years on Dirtbikes and still ride them, So I am not really upset by  to much a Bouncing or sliding Rear.

You guys have been very helpful :boink:
Like
0
Dislike
0
Agree
0
Disagree
0
No reactions
No reactions
No reactions
No reactions

*

Super Dave

  • I hate salad...
  • ******
  • 11415
    +1261/-454
  • I'm the ghost with the most...
Re: F4I Rev Limiter Gone ?
« Reply #11 on: December 07, 2006, 09:01:28 am »
Understood.  You're just getting a reaction from  what you said, "Also Downshifting Violently during hard braking," "However I am guilty of downshifting hard enough to break the rear loose. "

A down shift is a down shift.  You push, or pull, on the lever, and the mechanism does the work.  What you do, or don't do,  with the clutch and throttle is affecting the chassis.

Bouncing around more than likely is affecting your entries into corners.  There's a whole lot of load that is placed on the engine also.  Dirt has more give as there is less traction, less weight, and less speed.  That back torque is trasmitted into the chassis and contorts the geometry.
Like
0
Dislike
0
Agree
0
Disagree
0
No reactions
No reactions
No reactions
No reactions
Super Dave