65 HP out of a yzf400?

seems like about $60 worth of sprockets will solve this issue.


or go to 426 or 444cc

at 290 lbs, GET YOUR SPRING RATES CORRECT! Sorry for the shouting. The point needed to be conveyed.

You will see better corner speed, better handling and a more effective, less tiring machine (and yes, faster in the rough ground) by making your suspension work for you. Once the chassis is under control, play with gearing. What clearances do you currently have in your valvetrain?

Then look at that rotating hand grip thing on the RH side of the handlebar.

Around 42, which happens to be the answer to the meaning of life.

this is because the yz/wr400s are the best bike ever built. High MX HP, low enduro maintenance :thumbsup:

but to echo whats already been said :


-lose some fat?

:ride: :ride:

Go as big as possible on the rear sprocket. Don't get a smaller front sprocket. Going smaller with the front will reduce the life of your chain.

Around 42, which happens to be the answer to the meaning of life.


Loose fat!!!!! Ivebeen lifting got over 20 years!!! It isn't fat hous!

Try not to take anything personal around here.

Do the simplest things first. Go up two teeth on the rear sprocket. Very cheap and easy to do, and see where you are.

Ivebeen lifting got over 20 years!!! It isn't fat hous!

?que? :thumbsup:

Would going up 4 be too much? I've been told as long as I get the matching set the chain will be fine? I've got a 14 tooth on the front now. Im thinking the rear is a 52? I will have to double check that?

Its your money my friend. I would go up 2 first, ride with that, see what you got...

ive owned a yz400f and am now on a 04 yz450f and i think my 400 was faster but the difficult starting/ some of the weight and dated body style was a fair trade also my 450 4sp tranny is nice heres what was done to the 400f, dsp pipe, jd jetting kit,hotcam stage 2 weisco piston ti valves applied triple clamp flexx bars fit handguard system, 13/50 gearing.

I've been told as long as I get the matching set the chain will be fine? I've got a 14 tooth on the front now.

I was thinking you had a 13 tooth. You can switch from a 14 tooth to a 13 but most guys will tell you not to go smaller than 13. A 'matching set' doesn't play a role in chain/sprocket longevity.

I mentioned going to a 13 tooth in a earlier post. The bigest problem im having with it is technical hill climbs! When its just me and my buddies riding we ride fast enough its not a problem. Bit when im riding with my son and daughter this bike is geared way to high. My son is getting faster now but going slow up steep hills is a bear trying to show him which lines to pick. I've got him on a XR100R now but im normaly in 1st gear or 2 gear almost idoling. I've got my bikr fixed as far as the hard start. I jetted and completely went through the carb. Tweeked the timming a irmidium plug and adjusted the valves and this bike will start on the 3rd or 4th kick cold and by the 2nd when its hot.

im just wanting more low end power out of this bike to make it easier to ride slower with my kids but still have enough speed to rip it up when im riding with my buddies!

Like mentioned before by other people, you cant really gear the 4 speed for both top end and slow stuff. Unless you're already in high rpm/4th gear when riding with your buddies, you should be just fine.

As for the iridium plug, they do not alter the timing. Here is a post from grayracer513.

Grayracer513 - "Iridium plugs improve ignition reliability by offering less resistance to spark. This leads to easier starting, reduced tendency to foul, and reduced likelihood of a low speed misfire that could cause a stall. Because the iridium electrode is more resistant to erosion by combustion gases, they also last longer.

That's what they really do."

I put that plug in but that's not what I did for the timing.

when im riding with my buddies I am normal in third gear. My 400 is a 5 speed not a four.

thanks for the tips. I will try the sprockets for this summer and start getting more into the motor this winter.

just ordered a 13 tooth front sprocket... I have a 50 tooth rear sprocket on the bike now with a 14 tooth front..

I'm hoping by going down one in the front it will put me where i need to be..

I put a 13 tooth on the front and a 50 on the rear.. Wow what a differance that made!!!

This bike is a ton more trail friendly and i can wheelie on command now!!!

Just got back from a trip to Hatfield and Mccoy trails. I rode it over 300 miles and it never missed a beat!!!!

Im a lot happier with this bike now... Ive got plenty now down low and i still got all the top end i need to blast the trails.!!!!


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