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04 KX 250F to 05 KX 250 transition

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I am fed up with the valve train issues on my 04 kx 250f, and will be selling or trading it in the next few weeks or so. By the way if anyone is interested in an 04 kx 250f let me know. I fell in love with the easy riding and power that the motor delivers instantly. I moved up to it from an 03 kx 125 and became a much better rider. Unfortunately the valve train/head problems outweigh any of the positive aspects that the bike delivers. I haven't encountered any major problems yet, but the head is starting to show signs of needing to be replaced in the future. Along with that will come valves and so on. All I want to do is RIDE not become a valve train expert.

I have never owned a 250 two stroke, but I hear that the 05 kx 250 is a pretty good choice. I am looking for the pros and cons of moving to a 250 two stroke from a 250f from you members that have made the transition or ride both.

Thanks,

Disappointed in Kawasaki 4-stroke technology!

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About a month ago, I went riding with my nephew, and he has an '03 RM-250, and we switched bikes for a little bit, and we both agreed that a 250 2-stroke has just uncontrollable power compared to the 250F. But, the problem isn't the amount of power, but rather the ferocious delivery. Once you get used to tractable power, it's hard to go back to that.

I would suggest you try a YZ250F. They don't have valve issues, and perform very similar to our limons. They are very reliable (I know 2 people with '01 YZFs that race regularly that still have the original valves and valve springs in them).

If you really like the 250F power, I'd try that route. Or, find someone that will let you take a quick spin on their 250 2-stroke to see for yourself. But, Yamaha's been at it a while and they have it figured out.

~Tex

RMZ (...w/vlave issues)

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A friend of mine just purchased an 05 RM 250 and hopefully he will let me ride it at the track. I know that Yamaha yzf's are awsome bikes and have ridden a couple of them, they just don't feel like a kx to me. I do have a few weeks to decide, and maybe I can post another message after I have ridden a 250 2-stroke.

Thanks for the advise

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Hey kawacor i know what you are on about it gets very innoying but there are solutions first i dont know where you are im in australia and here we have a guy that specializas in four stroke heads and they are cutting copper berylium into the valve seats with great results the major problem is that the valves are hitting home way to hard and this copper berylium is cushioning the valve which makes it last longer and from what iv heard a lot longer also they say race fuel is bad for the engine but in australia we have a fuel called shell 100 which is a 110 octane leaded race gas which i have been useing since i last shimmed my valves and so far the results 12 hours riding and the valves havent moved 1 thou so trust me stick with it find out what you can get done to valve sets as in materal they use and you will be happy email me dude borderlinemfg@austarnet.com.au if you have anymore questions seeya

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I have been riding the 04 KX 250 and my KXF back to back for a couple of weeks now. I ride and race off-road only. The KX is great as it doesn't hit quite as hard as the RM or YZ (I have also ridden 04's of both the RM and YZ) so it is pretty good in the woods.

Overall....I am still way faster on the KXF. The power is more manageable but I don't get as tired either which plays a pretty big part in a 3 hour race.

I am lucky as I am friends/sponsord with the mechanic at my Kawi shop and have recieved free labour for my valves.

I am hoping the 05's ability to have better cooling will help with the valve issues.

For me, the little thumper is the best for the woods.

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Kantoniak,

Yes I agree that the kxf is very easy to ride fast, and I must say I enjoy it the most out of all of the mx bikes that I have ridden. The problem with it is that it is a self destructing design that I don't feel the 05 parts will fix the problems. Only time will tell! I also don't have unlimited funds for parts and labor and have decided that I have spent enough.(stopped counting at 11,000.00) I don't have to like getting rid of it I just have to do it!

Thanks for the info on the 04 kx. I hear the 05 is even more improved, and the power delivery more linear.(for a two stroke) I know I will become tired early on but hopefully with some seat time I will be able to do everything that I can on the 250f.

Thanks for the reply

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If you want a 2-stroke with linear power look at a KTM 300 MXC or EXC or a Husky WR250. The 300 is a do-all motorcycle that is very popular. I rode a WR360 and I really liked it. It was like a XR or TTR on the bottom but by 1/2 throttle it was flying. It was balanced and ported, but I've heard stock they are similar.

Otherwise you can add a fly wheel weight or have your 250 2-stroke ported to smooth out the power.

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If you love the kx250f, look into a KTM 200 mxc or exc... when I try to explain my bike to a 2 stroke guy, that is the bike I use as an analogy. It's the closest 2 stroke that I've ever ridden.

FWIW- I've always been a kawasaki rider, and I had no problem adapting to the 200 KTM

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Hate to see you give up on a fix to you problem, we had valve problems with our 04 kx. Part of the problem is that it is not getting equal dist. of fuel to both int. valves.

The 05 have a longer divider in the int. port to solve this problem. Another part of the problem is the valve springs are getting weak as early as 10 hrs. on bike. When they get weak the valves start to float and bounce around causing more premature wear. Replace with aftermarket spring kit to fix that problem. WMR and Pro Circuit both make a great spring kit. overheating problems are magnified when springs get weak and start to float. If you replace you vavles with new kawi valves DO NOT LAP NEW VALVES IN, check valve seating with mach. blue. If you lap you new valves you will wear the coating off of the valve and it will wear out very fast. Just a reminder, all of the 4 strokes have issues of there own, yes even the yz.

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Hate to see you give up on a fix to you problem, we had valve problems with our 04 kx. Part of the problem is that it is not getting equal dist. of fuel to both int. valves.

The 05 have a longer divider in the int. port to solve this problem. Another part of the problem is the valve springs are getting weak as early as 10 hrs. on bike. When they get weak the valves start to float and bounce around causing more premature wear. Replace with aftermarket spring kit to fix that problem. WMR and Pro Circuit both make a great spring kit. overheating problems are magnified when springs get weak and start to float. If you replace you vavles with new kawi valves DO NOT LAP NEW VALVES IN, check valve seating with mach. blue. If you lap you new valves you will wear the coating off of the valve and it will wear out very fast. Just a reminder, all of the 4 strokes have issues of there own, yes even the yz.

Finally someone who knows what they're talking about! Good write-up, MTracing. :thumbsup:

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MTRACING,

I just had new kawasaki valves and pro circuit springs installed, and after 6 rides one of the intake valves is so tight that is unable to be shimmed. We think that the pc springs are too strong for the stock valves/seats. I know I can have it fixed but the question is how long will it last? I can't afford to be the guinea pig anymore.

I will keep my eye on the kxf/rmz forum for a while just to see what happens to the 05 model.

Thanks

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So are you stating that this is the reason for the valve failure, My younger sons f is a year old and I decided to put in a new piston and rings in it as well as new springs and intake valves, measured the old springs and they are still within specs listed in manual, aside from a broken sight glass thats all we've encountered so far, I put in 2 new stock intake valves and shimmed them at there loosest specs, bike is still running great, as I stated before, about every six months piston and rings and 2 new intake valves and decarbon the head, 93 octane gas 20 /50 oil and change it every other ride, More maintnance more performance its the price you pay, we have 2 kx250fs and 1 rmz and 1 kx250{we don't tell the rmz its a suzuki though we just tell him he's a yellow kaw so he doesn't get a complex}

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Art I am happy that you are having good luck with your bikes. I am now soured by the repair bills to my KXF (more problems since my post above). I will find out today the extent of the issues. I guess for me, owning two Yamahas never presented the "same" problems. I have ridden more and harder this year so it is not an apples to apples comparison. I love the handling, light feel, ridability, and power of the KXF and that is why I am having such a problem with deciding if I should get something different. My shop is tops and very supportive so that definately makes the problems I have easier to deal with but it is the wallet that is starting to suffer.

I know I haven't preformed the maintenace I should have (I followed the Yamaha schedule I had last year ((if it starts the valves are good)) so that may be the problem. Also, I never had overheating issues early on but once I did the problems started to crop up very quickly.

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My older sons f had problems early on busted bearing in trans, cracked piston and a broken valve at 10 months, kawi covered all my parts in every incident, I to have a great shop Rainbow cycle in Rogers Arkansas, But still satisfied, as a matter of fact I'm going to take all 3 another year, after the season is over I will go through the usual teardown ritual, I like to tinker.

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the kx250 will be less maintenance IMO. The power delivery may be a bit differnt but if you spent enough time on it, im sure you'd get used to it. if you like riding enough you'll get used to it :thumbsup: just prepare to buy extra premix and maybe a spare tire. 2-strokes are less maintenence and easy to rebuild when the time comes. The only valves you'll need to worry about are powervalves, and I hear KIPS are a [@#$%&*!], but o well. Have fun with your pinger!

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ive recently mad the switch from an 06 kx250f to a 07 kx250 and i wont be switchin back to the 4s for a while

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go 2stroke you ll never go back i dont think people know what there talking about when they say 2 strokes are hard to handle, cause mines a dream plus youve got alot more pick up and top end power than a 4 choke. i went 2stroke id i dont think ill ever go 4 choke.

------------------------------

2004 kx 250 monster energy

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