10k rev limit

[Derno24]

It could be a lack of sleep or just the simple fact that there is a new wave going on of people parading around the 10 k rev limit like it is the new fix for these quads, but what is the big whoopie.

I understand for breaking the motor in and getting things to seat before opening up torture, but how many people ride in the rev limit anyway that this would be a fix of any kind? Also if you do ride in the rev limiter why? The motor keeps increasing power till right around 10,000 anyway. Why cut yourself short? If it is for the valves then instead of shortening the rev limit get better valves or valve components (springs and such). It isn't due to the cranks. They have been balanced and such and I have never heard someone say that there crank went due to a high rev limit.

I am trying to sort out for people alot of goop we Cannondale supporters put out there. There are a ton of updates that have surfaced even after Cannondale closed it's doors and I really think that we have done ourselves more harm by listing things that aren't a true problem. Alot more people visit this site and look and read about a phonebook list of updates they have to do to just ride the quad.

Post away I don't care as I know several machines out there that have over 200 hrs on stock set-ups and are running fine with the higher rev limit. And they also have no updates done to them at all. So even factory updates weren't completely necessary.

[Psychosis]

Good post. Makes a lot of sense to me atleast. I myself usually hit the rev limiter 1, maybe 2 times a race if that and rarely ever do when just riding. I'd say I probably shift around 10k or less usually b/c I like to lug it around. i'd like to see people's responses to this.

[bknight]

ok i ride most of the time on the sand dunes. most of the time your at the rev limit. sand riding is not like riding in the woods or on a track. most of this is long hills runs so a high rev limit is bad im at 10.6 or 10.8 limit

[Derno24]

But the question is have you lost your motor with stock maps with the higher rev limit. Also riding in the limiter isn't helping you with power!

[cannondale27]

Decompressions break because of a poor design or not being assembled correctly not from valve float.Timing is to maximum advance at 10,944 rpm in all the maps it goes no higher no matter what RPM the rev limiter is at.All the Jap 4st motors are supposed to get new valves and springs at or before 50hours if the parts in your valvetrain last longer than that which sometimes they will or sometimes they wont consider yourself just plain old LUCKY!We need to get used to the facts that your valvesprings will wear out BEFORE your piston.Timing chain and valves follow shortly thereafter.Lowering the rev limit will slow the process down.I have decided to leave the higher rev limit and replace parts hopefully before they break at 50 hrs.Now if you run XC or Harescrambles where you rarely get into the rev limiter you could go longer maybe.For anyone with any doubts about these statements read Dirt Rider the last two issues have had in depth articles on valvetrains and everything they said can be found elsewhere.The new 250 4st motors the replacement interval is cut in half 20 hrs.They run at 13,500 rpm vs the 11,500 rpm of most of the 450's.Valvetrains are the same so 2000 rpm extra doubles the wear.Now go the other direction and 10,000 rpm should just about get you double the time.Not worth the power loss for me though.

[bknight]

Decompressions break because of a poor design or not being assembled correctly your right on that one 27
will still i going to keep it low just on the safe side intill we can get good vavle and valvesprings.

[cannondale27]

It sounds like Kibblewhite may be coming up with valves for us.I think Haydug had to workem over for those!Keep your fingers crossed.Just need better springs and the decompression.Even with the best parts they still recommend replacing parts way more than we do though.

[banzairx7]

I hate to admit it but my motor hits the rev limiter at least a dozen times every ride. Not really on purpose on my part. I think my cam timing is screwed up- my low end is terrible and the top end just rips. In 1st thru 3rd it revs into the limiter almost instantly. I've ridden other cdales and the motors don't rev like mine does. I actually didn't even hit the rev limiter at all riding those.

I've put about 30hrs on this motor like that. Don't know what it had before I got it. I have to rebuild my motor now too. Not for any of the usual reasons. My crank has some crazy sideplay I've got to fix. Still runs great though.

[cannondale27]

You know what else?Our motors dont lose hardly any power until they hit the rev limiter whether that is 10,000 or 11,8000.Higher gearing helps to keep you off the rev limiter but man those high rpms sure are sweet.

[haydug]

I think 27 hit it on the head perfectly. I have raced dales since spring of 2002. I have lost one decompression in that time, and that was on a moto that had lots of hard time on it. The weekend it broke, 2 of us rode it at the High Point national, it was on the track all day on Friday in practice, and ran 4 motos a day. It also finished out the weekend.
I have put lots of thought into this, and I will not lower my rev limiter. I feel safe running factory maps, and using the timing set by cannondale for reliability.
Once you have ridden with a Falicon, or truly "balanced" crank, I think you will notice a huge improvement on your motor, which will improve the engine life 10-fold.
I know when Cannondale was in business, they would put a machine on the dyno, lock it full throttle, and walk away for hours. They also did this to the yz426 and also crf450. They had a goal to last longer than the Jap bikes, so I'm sure if lowering the rev limiter 500rpm was a fix, they "should" have caught it. I say "should" loosely because they did miss some stuff, but I think it was more the higher up people saving money, not the guys on the floor who could change a map FREE and never look back.
As for Jeff running his blaze, I'm pretty sure he has not lowered his rev limiter, but for woods riding you are no where close to the rev limiter, so it shouldn't matter in that circumstance. What alot of people should realize is Jeff takes excellent care of his quad, oil changed constantly, clean air filter, constantly going over the whole bike to find problems before they happen. The key word here is Maintenence, not rev limiter.
I have been into several motors, which lots of different maps, and I have seen 200 hour motors with nothing wrong. However, throw an unbalanced crank into the mix, and watch it vibrate apart. I also honestly believe the unbalanced crank to be the problem with the cracked cases. Case in point: go put a car tire on your car, and have it balanced, and go drive around awhile, then go back, take off all the weights, add alot to just one side to throw it way out of balance, and go drive around again. Now picture this at 10,000 rpm and you will see the point.