Want to get all the power I can out of KZ440?

Hi, I bought a 1983 Kz440 a month ago. Picture below, it is the black one up front.

This is my first bike, I have owned a few dirt bikes and raced motocross from age 13 to 17. im 23 now.

So far, I have sealed the diaphragms which had terrible holes, and wouldnt let me go over 55mph. I sealed them with rubber sealer. It works okay but new ones are on the way. With that done, it will do 70mph, but barely. I also used seafoam and it worked great. Yesterday I sanded down the timing advancer, and today got to 50mph in 3rd gear (BIG DIFF) before i could only do maybe 40 in 3rd. Didnt get to top it out, but am hopeful of results.

Is their anything else I can do to get all the HP I can out of this motor? It has 16k miles on it. Id like to take off the service stand, electric start, and any extra wieght i dont need. I wiegh 150, pretty light. Would this help make any difference by stripping off some extra wieght?

If you have any ideas please let me know! Thanks guys! happy riding!

***UPDATE***

- So, today I took the air filter out. I blew threw it and no air was passing thru hardly!!! It was a junky filter cutout! THANK YOU PREVIOUS OWNER!

So I fashioned one myself. Now the bike is running very good, much better than before. I tried to top it out but there are state workers clogging my road today. But got to 70 no problem. Not too mention the RPMs are finally rising like they are supposed to.

General maintence will be your best bang for the buck.
Get yourself a repair manual and happy wrenching.

Andy, if you are primarily concerned with top speed, then the weight loss won't help you much there. If you lose the weight, it will will help more with acceleration. Top speed is more a function of horsepower, and wind resistance.

With that said, your best bet is to get that bike tuned really nice. Get a service manual, and go through ALL of the maintenance procedures. You cannot assume that anything ever got done to that bike. I doubt that there are too many performance hop up parts for a 440, but I'm no expert. Lots of good info for the 400/440 bike available here: www.kz400.com/

Cover the basics, make sure you have good compression, valve clearances are in spec, timing is to spec, and the advancer works. Carbs functioning perfect, new spark plugs, and new air filter element will get you a long way.

A well streamlined fairing will add some top end by reducing drag. I would not take the starter off. You might want to replace the coil if it's original, they don't age well. Z1 has a $36 EMGO that works great.

a baby bottle sized version of this! :woohoo:

Wireman, you mean this?: www.energyfiend.com/2008/03/nos-power-shot :evil:

Just kidding- DON'T do that!

Sounds like your bike needs a good carb cleaning. My dad had an 80 440 LTD that I rode once and it should do 75+ easily.

mtbspeedfreak wrote: Wireman, you mean this?: www.energyfiend.com/2008/03/nos-power-shot :evil:

Just kidding- DON'T do that!

HAHA, you saw that thread on GSX-R? (or wherever)

Besides what's been posted, double check your gearing.

"Is their anything else I can do to get all the HP I can out of this motor? "



For how long?

I had my little 400 at 80 today and still had more room. I've found with mine though that I'm limited to approx 10mph per 1000rpm in 6th. So 80mph was 8000rpm. So if you go with the theoretical redline of my 400 of 11000 rpm I could do 110mph! Of course that's only a theory and I'd probably have all sorts of pieces flying off at that point. Mostly pistons shooting through the head...

Ive now gotten the bike up to about 75. I dont want to push it anymore because it doesnt feel like it wants to go much higher than 6k rpms.

I dont know much about carbs, but I made my own air filter that flows more air and it seemed to help out alot with richening the mixture. I think its probably obvious that too much gas is being fed to it

:woohoo: :woohoo: