bike revs out too fast

[mad4106]

Im racing my friend he has 400ex as well, he has a fat boy slip on and jet kit and k&n air filter and he beats me on top end all the time. I have way more work done than him i have 11:1 standard bore wiseco piston, stage 2 hotcam, uni filter wo lid and curtis sparks x6 exhaust im pulling him in quickly in 5th gear im side by side passing him by a foot and then it whines out and he comes by me slowly im thinking its the carb im unsure

[quadmanw]

Maybe you could use a rev limiter if you have a lot of work done. Could also be your gearing.. What are your sprockets? Could be the carb but I'm not too good with those

[mad4106]

i have stock gearing its a 2005. When u say a rev limiter u mean a aftermarket cdi box?

[steve181]

Originally posted by mad4106
i have stock gearing its a 2005. When u say a rev limiter u mean a aftermarket cdi box?

cdi boxs are junk..... your ex makes PEAK hp way before the stock rev limiter

suggestions
bigger rear tires ( 20in+ )
bigger front sprocket
smaller rear sprocket

i see in this forum way to much that people have to the rev limter to be fast

in all the years ive owned an ex ive only hit the rev limiter 1-3 times just for ****s and giggles, not once could i hit the rev limiter going through the gears

[CJM]

Originally posted by mad4106
i have stock gearing its a 2005. When u say a rev limiter u mean a aftermarket cdi box?

Its 14/39. Switch to a 14/38 or 14/37 to pick up more top speed. Larger sprocket in the front or smaller in the rear gains speed. You wont run out of gearing to easily this way.

[quadmanw]

Ive always rode with aftermarket cdi boxes on the 400 and I like it with my motor and gearing. Might to feel the difference with a stock motor

[CJM]

I just bought a WB one for the heck of it cause it was cheap. Lets see how many issues I have after I put it on when it gets here.

[mad4106]

thanks guys! ima go with a 1 tooth larger in front and im about to put a 450r carb very soon! so that should help! Cjm let me know how that cdi works on your bike im curious some people say they work and some say they dont i might just buy a used one off of ebay and give it a try.

[CJM]

i rode a few with cdis before but they didnt do much. maybe my setup can benefit from it, I just hope the notorious starting issues they usually have dont happen to me. CDIs simple tho, I can change it in 5 mins lol..

[chevymanrick]

Hey man if ur gonna get a cdi box get one from an xr250 its the same thing and a Hell of a lot cheaper, just a heads up

[russellsroost31]

all a cdi box does is lets the motor rev more causing more wear and tear in it so id say just go down a couple teeth on the rear sprocket and its also cheaper to do that

[quadmanw]

Lol a cdi does not wear your engine.. It expands your rev limits farther.. If that makes sense. Will not harm a built engine at all

[Honda5]

Most aftermarket cdi change the timing curve also. The xr and WB had a little problem with starting but I never had that problem with any of the others. If you change your gearing to add top speed you will loose acceleration speed.

[TheAwesomehonda]

Ok if both the quads r newer then 05 and have the same sprockets then its most likely your carb is rich or lean, or the motor wasn't built well.

[JOHNDOE83]

Originally posted by CJM
I just bought a WB one for the heck of it cause it was cheap. Lets see how many issues I have after I put it on when it gets here.

After I tested many CDIs the WB was the best out of all of them, Id like to know what your impression is after you try it out CJ.

[JOHNDOE83]

Originally posted by TheAwesomehonda
Ok if both the quads r newer then 05 and have the same sprockets then its most likely your carb is rich or lean, or the motor wasn't built well.

I would deffinetly say your to rich or to lean if your tires are the same size and you have the same size sprokets.

[BlasterEaten250]

Is your clutch slipping?

[dxcody]

Originally posted by BlasterEaten250
Is your clutch slipping?

Didnt think about that... Good call!

[TheAwesomehonda]

Originally posted by JOHNDOE83
I would deffinetly say your to rich or to lean if your tires are the same size and you have the same size sprokets. Or if your shifting at different times an the rpm range.

[CJM]

Originally posted by JOHNDOE83
After I tested many CDIs the WB was the best out of all of them, Id like to know what your impression is after you try it out CJ.

Just waiting for it to come John. Should be here by next week.

[duneslider]

Have you switched bikes to make sure it isn't rider error? I have a brother who doesn't shift well and is always a little slower.

[Thumpin440ex]

Your running out of gear. Your bike is making more power in turn pulling the gears harder, faster. Just because you have work done, doesn't make it faster, it just makes it get there faster. Go up a tooth on the front, or drop to a smaller rear sprocket. As for the CDI, I have a sparks box, it most def runs diff then with the stock ex CDI.



John

[mad4106]

Yes i do have stock tires and stock sprockets im thinking it is the carb cause when i slow down to down shift it starts popping. My cluthes are good too. We also didnt swap drivers either

[Thumpin440ex]

Simple way, run up to 5th gear the same time with out racing each other, then both hit it, see what bike runs out of gear first.


John