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
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?
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
Might be a vacuum leak for the high idle.
Rev limiter shouldn't go away, if it's stock.
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....
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
Good luck. I hope your solutions are inexpensive!
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
Can't personally comment on a slipper clutch. Never rode a bike that had one.... :wah:
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.
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:
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.
So Dave, since I have no experience here, are you saying that throttle blipping and prudent downshifting are still required with a slipper clutch? Somehow I had the idea that a slipper clutch was either transmitting acceleration or letting the bike freewheel. Is there still engine braking with a slipper clutch?
(This summer I'm gonna try me one-O-them newfanglt bikes with sus-PEN-shun an' rubber tahrs fur shur....)
Well, it does still have some back torque.
I've watched Spies at Mid-Ohio going into the left hander after the long back straight still manipulating the throttle and the clutch. Seems like every pick of MotoGP of guys on the brakes starting to lean in has all the riders with their hand still working the clutch too.
It's cool technology, but there are variations in their function. Rode a Ducati with it, and it was great. Dump it and go. Stock R6, well, it's different.