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KX85 with KX100 top end HELP PLEASE

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Ok here is the deal about 2 years ago i bought a mint condition 2008 kawasaki kx85 from a guy that no longer needed it. I Paid 1000 bucks for it.

It has:

Pro Taper Bars

Renthal Chain and Sprockets

V-Force 3 Carbon Fiber Reeds

Weseico Piston

KX100 Top End

Upgraded Suspension

Now here is the problem i ride it on the road mostly i dont ride it at top speed all the time i mainly cruise at about 45mph in 6th gear. It pulls hard and everything works great but... It needs rebuilt every 6 months, a 400 dollar rebuild that consists of top end kit and getting the cylinder bored and replated. I run 93 octane gas and 40:1 kawasaki racing oil. I do everything the kawasaki place tells me to.

Is there anyway i can fix this and i would like to know what causes it so i can prevent it from happening cause 800 bucks a year is alot for a 15 year old (my parents to pay for everything, they help alot but im not a spoiled brat)

Thanks,and any help is appreciated

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The cylinder should not need re-plated every time you rebuild. I could guess at a lot of things here but with the info given here is what I would do... Up the main jet one size, go up to 5 ounces of oil per gallon of fuel, that's about 25:1. Start watching the compression and when it drops more than 10% put fresh rings in it to help save the cylinder.

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aight sounds like a plan thanks for your help as soon as i get it rebuilt i will start doing that

Do u know what the compression should?

When i blew it up the first time i had 0 pounds of compressions.

This time i had 40 pounds and 2 big chunks out of the cylinder walls.

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Check it when it is new. Then check it after the first 1/2 hour and you will have a baseline with your gauge. Every gauge may be a little different but around 180 psi is a good number for that bike.

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The cylinder should not need re-plated every time you rebuild. I could guess at a lot of things here but with the info given here is what I would do... Up the main jet one size, go up to 5 ounces of oil per gallon of fuel, that's about 25:1. Start watching the compression and when it drops more than 10% put fresh rings in it to help save the cylinder.
Excellent advice.

I would add, stop trying to run the top-ends so long. It's not a little foo-foo trail bike, it's a screaming 14,000 rpm race engine. If you push the bike hard at all the top-end is worn out in twenty hours.

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Put a 14 front sprocket on it if you're mainly riding roads.

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Excellent advice.

I would add, stop trying to run the top-ends so long. It's not a little foo-foo trail bike, it's a screaming 14,000 rpm race engine. If you push the bike hard at all the top-end is worn out in twenty hours.

I normally dont ride it that hard i get up to the speed and i want and then stay there i normally cruise at like 3000 rpms. But there are those days where i just have to use the powerban in ever gear.

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Put a 14 front sprocket on it if you're mainly riding roads.

Would any brand be good or do i need a certain brand?

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I normally dont ride it that hard i get up to the speed and i want and then stay there i normally cruise at like 3000 rpms. But there are those days where i just have to use the powerban in ever gear.
A KX100 won't even run under a load at 3000 rpm. Hell, they idle at around 1700 rpm. I doubt very seriously you're EVER doing less than 8-10,000 rpm when riding it, otherwise it simply won't even pull you around.

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A KX100 won't even run under a load at 3000 rpm. Hell, they idle at around 1700 rpm. I doubt very seriously you're EVER doing less than 8-10,000 rpm when riding it, otherwise it simply won't even pull you around.

I might be wrong iv have never stuck a tach on it and seen what my rpms are your probly right i havent riden it in awhile cause its in pieces in my garage.

Thanks for the help.

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how much road riding are you doing as a 15 year old on a dirt bike?[/quote

I ride about 45 minutes to an hour 4 days a week.

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