Looking to do a rev box on an 06 yfz 450. But I was wondering if it was worth the money or not. So please let me know how they are working. Thanks in advance.

not sure.. but I'd check here

yfzcentral.com

or

yfztech.com

Have you had any work done on the engine?

Okay i will check there too. Thanks for the info.

Keep the stocker

No motor work, just a pipe and a K&N.

A rev box will do nothing besides raise our rev limiter. So unless the mods you have done are making you hit the rev limiter like crazy, it wont do anything for your bike. I have done more than pipe and filter to my YFZ and still dont hit the limiter. Every bike is different

Now the programable box will actually change your curves, but with your mods you wont see the difference. I see alot of guys running nitrous go this route.


If you want more power, look into getting (easiest to most expensive)
1. an inake kit (sounds like you only changes the filter)
2. Cam mod
3. New cams (recommend the crower Gen3 intake cam or Webs +2.5)
4. Boring your carb
5. Portwork
6. High Comp Piston

Rev boxes do nothing more than get you closer to floating the valves.

It use to be that NASCAR teams would put a higher rev chip in for qualifying, and use a lower one for race. I can remember a RCR engine lease tuner, "Tick", at Phoenix a few years ago warning us about these chips. We went ahead and used the higher chip, and I watched and helped him have to beat the tool (with a hammer) to remove the valve keepers after that qualifying run. The valves were stretched.

Yea, we qualified really well, but in "happy hour" the valves went away and we had to put a new motor in before the race. $ 50.000 in the toilet! And due to the change, a top three qualifying spot turned into a 43rd qualifying spot.

Yamaha engineers spend a lot of time and effort to set a rev ceiling that produces both maximum power and still provide a durable engine. And the valve springs take a beating.

Thanks alot OCBC for the info and the advice. But should you change the cam and do the cam mod or is that one in the same. Thanks alot.

They are not the same. You can do the cam mod to the stock exhaust cam. (which is free and adds nice power to the top end) Depending on the cam company, aftermarket cams can do the same.
- Hot cams sells a set of cams (intake and exhaust), you cannot put these in the modded position.
- The crower Gen3 is an intake only cam. So you can put the stock exhaust cam into the modded position. (this is what I have)
- The webs is a set (intake and exhuast), you can put the exhaust cam into the modded postion

There are many options. If you really want to learn more about your power options check out www.yfztech.com as mentioned before. A good number of these guys know what they are talking about. Do some searches and ask questions.

Late

I seem to recall that the cam timing in the 2006 model is very close to the mod for the 2004 and 2005 models. Has anybody done some research on this?

Duck,
Im not sure, but riding both it sure feels really close.

After talking with a couple differentengine builders for my 04 yfz - the rev box will really only help if you port/polish the head, add cams, and of course have all the other bolt on goodies.
They recommend it with caution though.
Alpine ATV and Fox suggest putting it on the dyno to find the peak HP and torque before adding the box to see if it will really aid the bike and rider.
On another note - after all said mods - Sprocket work becomes the #1 thing to do next to keep that HP on the ground. Adding a tooth to the front is first - then on the dyno - begin playing with single tooth additions and subtractions on the rear to find the sweet spot. They dont have the ability to perform the calculations from a stop - but you can punch in things like 2nd gear to 5th gear accelateraion and find the fastest combo..

looks like chummins been doing his home work....


poor chumm doesn't like to loose

The cam MOD CAN BE DONE on the 06

I am very sceptical about rev boxes.... I just think of it as pushing your engine harder than its ment to be. there is a sweet spot in your rpms that is going to make the most HP anything over is just wearing out you piston and rings

similar to adding a pipe and jetting?? I mean, if you really look at it that way - why change out from stock at all? The factory finds the best possible combination for reliability and power in stock form.. Adding anything is only getting more from the motor - Cant be "good" for it, but who gives an eff as long as your standing on the top of the podium..

touché

Negative! The cam timing is the same 04-06. If you do the cam mod, as I have done. you will gain power just as the 04/05. Many have done it, including myself.

http://www.yfztech.com/forum/index.php?sho...20mod&st=20

I did some research and spoke to some technical forks at Yamaha Motor US. The cam profile and timing are the same from 2004-2006.

The cams are essentially the same as the WR 450.

My bad.

Good call ocbc... I'm going to edit my post so there is no confusion

looks like I have somthing to do this weekend :)

It wakes up the motor alot! Good luck. Feel free to give a call if you need help. ITs a relatively easy process.

Cam mod Video from www.yfzcentral.com
http://video.google.com/videoplay?docid=66...46&q=yamaha

Also Here

http://prez.yfzcentral.com/cammodp.htm

I've heard it's really really really bad for the engine, specially you guys that plan on racing and stuff. Works much better if you just leave your quad stock

http://prez.yfzcentral.com/cammodp.htm

TD... unless you throw cones at me during my race... you will NEVER come in ahead of me again

Make sure you pay attention to those rings and which way they come out. THis is something easily overlooked.

Good luck. Its really straight forward. Oh yeah, if you were thinking about putting any kind of cam in.... youll have it open.... hint hint.....

Have fun with it.

Late

OK.. just finished up on the CAM MOD. Took me an hour and a half...

Not to difficult. you just need to take your time and pay attention to how you take it apart ... Put a rag around the cams to keep the c clips from falling down in the engine. Also you have to remove the covers for both cams to get enough slack to rotate the cam gear.

The worst part was not having a small scredriver to prload the cam tensioner.. so I had to grind a good one to fit.


I would give this a 4 on the dificulty level, you really can't bang htis one out quick, you need to pay atention to what you are doing or you're going to eff somthing up

Also I didn't notice any difference at all in my c clips... there wasn't any difference with the end thickness...

am i wrong on this?

If you look at it from the side, one side tapers back. No one has confirmed that it really matters which way they go in. I just made sure I put them in the way they came out. I didnt really look and thin or thick. Just made sure the way I pulled them out is the way I put them back in.

Hmmm I am going to have to do some research on this.... I want to replace the plug so I didn't put it all back together yet. I guess I can pull the valve cover off and check. but I need to find out which way they should be.

what plug??

the spark plug... not the decompression plug that went out on yours. the 2006 models don't have it anymore. :)

yeah yeah yeah I know.. Actually lots of the 05s dont have the plugs either..

By the way. Sorry for hijacking your thread Blackhawk. If you live around san diego and want to do this mod... I can give you a hand

No worries, and no i don't live in SD I live in oregon(but thanks for the offer Bugsy) and just looking for some advice on what mods to do next. This thread has been very helpful. Thanks everyone for the input. I will be doing the new cams and the cam mod soon.

Thanks agian,
BlackHawk

Ok, tore the thing apart again this afternoon in 5 minutes! ... and found what we are talking about.

to clarify yes there is a thick and thin side of the circlip. no we don't know if it matters which way they are ut in, but we do know the way they come from the factory.

As alba450 on yfzcentral stated, the fat side of the circlip goes towords the throttle side of the bike the skinny side should be otwords the cam chain when installed.

Here are a couple pics that you can actually see the thisckness variation of the circlip.





Again, thanks for all of the help

You got it. Your mind can rest now.... haha

damn dude.. You got some fugly effin fingers..

thanks

I'm running the fingerprints through the FBI database now!

you wan't find anything

Black Ops Bugsy.. He dont exist!!!!

the clips can go in either way, the only purpose they serve is to align the cams to the caps. I've done countless yfz motors, from top to bottom, including my personal motor, and never once had a problem with the clips.

On the matter of rev boxes, as was mentioned before they really won't help a stock motor much at all. I have a grower gen II intake cam, port and polish, 06 crank, custom piston, and a couple other little goodies, along with a sparks pipe, and a custom intake, and I don't really see myself needing any higher rev limit.

On the other note, an ignition like a dyna that actually changes the ignition curve will make a difference on a modified motor.

And one other issue with the rev boxes is the aftermarket ones, even stock ones at times, but mostly aftermarket, have a history of going bad, and the bike will act like it's hitting a false rev limiter at around 1/4 throttle.