10k rev limit

[cannondale27]

I also have never had a failure but my decompresion came close to falling off.On the other hand I have seen what happens when a valve breaks and I want to do whatever it takes to prevent that.Replacing high wear parts is the only way to do that.

[Derno24]

So are we all in agreement that the stock 11,600 rpm maps are fine?

Next do we all agree that if we want to bulletproof our valvetrain better parts are needed?

Also for casual riders and weekend warriors the stock set-up is fine?

Last but not least that we can all agree to stop comparing valvetrains in Streetbikes and quads? This one is because I have spent way to much time thinking to myself that this should not be compared as these motors aren't even sloce to being similar. Also to make a well informed blanket statement you would need all the motor information as bikes are different from each brand.

[bombsquad54]

i hit the rev limiter alot when clutching through corners. it scares me. but i will tell you that when my decompression mech. broke i i was slamming around a corner in 3rd. should have been in 4th. it was tapped out. lol we need beefier decomp. mech. and better valves and springs

[Derno24]

One thing to clear up for everyone the Decompression mech would fail at any rpm due to a cheap build.

[MX Quad Dad]

QUOTE

Originally posted by cannondale27
Also why do the valvetrains on streetbikes often take a dive after a light crash..

Sorry to bring up the street bike but this just triggered a thought. If you have a hard landing and were close to the rev limit would the G-force actualy help the valve float? Not that we could do anything about it short of landing correctly.

[theJeStEr1340]

27 hit the nail on the head on what I was trying to say, a street bike riddin by a weekend warrior will not be abused liek we abuse our bikes. And Derno, yes. Here, have a beer :drink:

[Derno24]

No before I put the street bike thing to rest I want everyone to know that I gave you all a chance to let it go.

I have been riding street bikes for over 14 yrs. I spent the last 3 down at the drag strip. I know the torture that can be placed on a street bike and I have seen the same torture that can be placed on an atv. I placed several calls to local street bike engine builders (friends) and asked our question all of them responded with a huge laugh. All replied with the same thing sound like you need tougher components. I asked who do you think is harder on a valve train. All answered the same depends on the motor. Stock vs stock they wouldn't say without seeing numbers, but they mentioned they doubt the stress levels for the atv's could match it. I mentioned after market on a stock head and they said are you spraying a quad motor? And all replied not a chance. A hayabusa motor, a yamaha r1 and suzuki gsxr1000 are all capable of spraying with no head work being done. The head componenets are better not that it takes less stress as the spray put all 3 machines into the upper 200's in hp. Almost tripling the stress on the motor. Now can we get back to what we should be talking about which is our own valve train.


USAMOTO I knew that about the bikes, but watch one of their races even with these clutches they are locking the bike up even in down shifting. :wow

[USAMoto00]

c27-are you trying to suggest that your atv's are harder on valvetrains than a streetbike? I seriously hope not! I have been a hooligan street rider for years with bikes such as GSXR 750's and 1000's. I can gurantee that I will bash the **** out of those bikes at the drag strip or on a side street with minimal damage to anything but the chain and/or sprockets. I must AGREE with Derno that the 2 can't be compared, but if you must, I have to say that street bikes are engineered with much higher expectations than our valvetrains were. I can't speak for all manufacturer's, but Suzuki does more homework on those bikes than most. I think our quads were aiming in that direction, but money fell short as did the time on these motors. They CAN be made to handle anything that we could dish out. But we might want to study the street bike motors for answers. By the way, the Star Boyz had most of their problems with the CBR900 motors rather than the Suzuki 750's. Their tranny's would give out from smashing down a few gears at highway speeds to bring up the front end and then shifting into the "false neutrals" while on the throttle hard. Whenever we make improvements though, we will expose the next weakest link on our quad. It will be a never-ending process as with ALL race machines.

[Happyboy]

QUOTE

Originally posted by Derno24
So are we all in agreement that the stock 11,600 rpm maps are fine?

No, ya beer guzzleing hippee! I don't think that the higher rpms are the absolute reason for our failures but at the same time I do think it contributes to our problems. I am shooting for a high 10,800-11k rpm limiter. Look at it this way, the faster you rev the more wear you will give to the crank bearing, the valves, valve springs,etc.... When the springs do fatigue you are more apt to valve float especially at high rpms. Normally when we talk about high rpms the community (not us) jokes about 10k rpms. Now we add almost 2k rpms to that. Man, our motors are freaking monsters. That is just one way I am going to tame mine. And you know what, I won't miss 500 rpms.

[Cdale_racer_669]

how about set it at 11200 to make everyone happy:confused: