Rev Kit Help

[ill_lil_romey]

I have a 416 kit on my 01 ex and I race mx and tt. AT times I notice that I do hit the rev limiter and it aggravates me. Ive heard that the rev kits are useless, and it makes the quad a biyatch to start. Is this true?

Originally posted by ill_lil_romey
Ive heard that the rev kits are useless, and it makes the quad a biyatch to start. Is this true?

yes it's a fact,,your battery has to be fully charged all the time to avoid the problem. Putting something on your quad that cost $100 and makes it not want to start is kinda goofy,. Spend the money on something else..there not all there cracked up to be. Sounds like ya need ta shift more to fix your problem.. or change your gearing around..

[smith]

no, rev kits are not worth the material that they are made of! They do help pep up a stock motor, but make it near imposible to start a cold motor with it! built motors have no effect on it seams! Swaping CDI's every time that you ride is not a fun thing!! Also, fyi, 400ex's lose power near the rev limiter, the only way that you should be hitting it is if you are tapped out in the highest gear possible!! (if not, shift up!) Changing gearing for TT'ing will best suit the problem. MX'ing, just go thru the gear box.

[RAPTORAZ]

I havn't noticed any difference in starting between my stock CDI and my White Brothers. I think most peoples hard starting issues are due to improper pilot jetting. As for a performance difference, I didn't notice any. Other than the fact that I don't bang the limiter anymore at the dunes. It's easier to rev it out on a dune than it is to constantly upshift and downshift. Probably easier on the clutch and trans as well.

Originally posted by RAPTORAZ
I think most peoples hard starting issues are due to improper pilot jetting.

Actually WB is advertising that when you buy their CDI box your battery must be fully charged,,they are aware of the issue but still selling the POS's.

I know my jetting is spot on,,no problems starting it this weekend at a race when it was 18 degrees outside. I garauntee it would't start with a WB cdi in there.

When I noticed mine having problems starting,,I could crank away for 10 minutes tryijng to get it started,,put the stock CDI in and it turned right over first try. In all honesty the CDI box is the problem for hard starting,,I've been down that road and it will cause problems.

[RiPPiNiTuP7]

I tried a WB Rev Limiter on my 400ex...it started fine (keep in mind my battery is new), but I didn't notice any difference from the stock one..not worth it to me :(

[ill_lil_romey]

I guess in that case I should just leave that alone and gear up a little. That does'nt suit my riding style though. I'm one of those that likes to ride my ex like an R;) But I guess thats gonna have to change:(

Originally posted by ill_lil_romey
I'm one of those that likes to ride my ex like an R;)

Spend the money on getting your flywheel lightened, it will make your thumper rev like a 2 stroke,,but you will have to use the clutch more often which is sounds like you like to do. I have my flywheel lightened that's why I say this..:D

Also,,dyno printouts show that the WB CDI add NO power gains at all..the extra 1000 RPM's are just tearing up your motor..:eek:

[smith]

I fully agree with Rico. White Bros had sent me 2 new ones and every one did the same thing. At first I began to think that it was my bike, but after trying it on multiple other bikes, stock and built up, they all had the same result. However, on the same note, I know someone that had a WB rev box and rarly had problems starting his, plugged mine in (each one they sent me) and guess what? NONE of them fired! so, it is possible to get one out of a hundred to have no starting problems, but don't go to Vegas betting on that one!

for Raptoraz....ya, it's a lot easier to rev it out as opposed to shifting, but it is a LOT harder on the piston/rings, valves, transmission and many other of the moving parts in a four-stroke. Is it worth it to rev out as opposed to shifting, NO WAY, not to mention that the only four-stroke atv in production that doesn't fall off on power in the high RPM's is the Cannondale. If you don't want to shift, get a Polaris or the new V-force!

[ill_lil_romey]

Rico feathring the clutch is not a problem for me, it seems like the kit would be a waste of money that could go elsewheres though. How much does it cost to get the flywheel lightened, and if it does rev like that 2 stroke will I still have the notorious EX torque and pull? Doesn't it feel good to lug out of that corner a gear to high and still pull in the comp???:D

[smith]

Another option for getting a quicker reving motor and still having gobs of torque is a Thumper Racing 440 piston. Thumper has a piston made that is significantly lighter than other 440 pistons. It is a night and day difference when you ride with it!

[ill_lil_romey]

That would be a great option, but I don't want anything over 426 bore. I have the 416 with a xr cam right now, but I'm going to a 12:5:1 compression with a HRC cam!

[smith]

just be carefull going to that compression. at that point, reliability becomes a concern also. It is more reliable to have the 440. High compression like that begins to stretch studs, pull the studs out of the cases (when the aluminum begins getting brittle from the heat) and is really hard on the rod (they are VERY weak), and not to mention blown gaskets.
If you don't mind a lot of maintainance, and keeping after your ride and going thru it after each ride, the high compression isn't that bad of a thing, but if you like to ride it a couple of times between prep schedules, keep the compression down! (or the parts bill will go up!)

[ATVer14]

I just bought a used 440ex that has a totally built motor. High compression piston, TC national cam, ported head, bored out carb, X-6 exhaust, and it came with a WB rev box. I've been reading about the rev boxes doing nothing, but I've also heard that on built engines where the power is higher in the rev's, the box is a good idea, like on my engine. So my question is: should I get rid of the WB limiter and go back to a stock one even though I've got a modded engine? If so, where can I pick up a stock CDI, and for how much? Thanks
Kenny

[RAPTORAZ]

Originally posted by smith
for Raptoraz....ya, it's a lot easier to rev it out as opposed to shifting, but it is a LOT harder on the piston/rings, valves, transmission and many other of the moving parts in a four-stroke. Is it worth it to rev out as opposed to shifting, NO WAY, not to mention that the only four-stroke atv in production that doesn't fall off on power in the high RPM's is the Cannondale. If you don't want to shift, get a Polaris or the new V-force!

I doubt the 1000 or so extra RPM does any harm to the motor. OHC engines are built to rev. And I'm not saying the motor is constantly on the rev limiter. I just like having that little extra RPM when I'm shooting up a dune. Sometimes the loss in momentum from shifting is enough to cause you to not make it to the top. Albeit the dune has to be really steep for any perceptible loss in momentum. As for me not wanting a manual transmission, look in my signature and you'll notice that two of my Hot Rod's are manual transmissions. There's just something about 5500 RPM launches and 7500 RPM powershifts that makes me want a manual transmission. :D