I have been thinking about the big bore kits / parts for the klx250 and had a few questions for you guys that might know. I know we can buy the 300cc Kit from Kawi via the parts list here. But what about this 330cc upgrade. Is there a Kit for that too or is it a matter of just boring out the 300cc barrel to 330 and fitting a piston. If it is just a bore job can it be done to the 250 cylinder or can just a 300cc bore be done to the 250 cylinder.

I ask because I dont know and If i'm gonna spend 500 bucks on a big bore it should be the 330cc right. I'd hate to buy the 300cc parts only to find out I have to buy Another cylinder to get the 330. And what about heads. seems to me that if your gonna do a big bore job maybe do a little headwork to go with it.

The other thing I think about is the Reliability of it all. Lets say that you are a hard rider but not abusive to the motor. How reliable is a 330cc klx250 gonna be.

Finally if anybody has any links to the to places that do 330 conversions or parts please post the links.


Thanks


LV

 

I've been doing some research on this myself. While I love what the 300cc did for our bike, I think it will be even better at 330cc. The place you want to talk to is http://www.kustom-kraft.com/ . I had several questions and mine were:

1) does the price include the jug - the cylinder
Answer: no, you have to buy the 300cc jug and they bore it out, or they buy it, but that price is not part of their price quote on the web site of $440, I think it was.

2) can they bore the 250cc to 330cc?
Answer: no - not enough metal left for reliable operation. This was important for me, because I still have my 250cc jug on my bench and I could just ship that to them and keep my KLX running without having to remove my 300cc cyl. But that was a no - my 300cc has to come off.

3) can they go even higher? I've seen references to 340cc, 364cc, and even 380cc
Answer: no - the guy there said that sounded like a Stroker engine rebuild which replaces the crankshaft and piston rod if I'm not mistaken which higher strength components. This requires a whole lot more work and is a lot more expensive. They said they could do it, but I didn't even ask about the price - I figure its way up there, a lot more than I'm willing to spend.

So, the deal is that you send them a 300cc KLX300 cylinder, they bore it out, do their magic treatment on it - plating, etc, then diamond hone it and send it back to you ready to bolt on. They also send the piston, rings, etc. I believe they maintain the stock compression ratio of 11:1.

That's what I know now - I plan to call them tomorrow to finalize the details. With my collar bone broken and me out for at least 4 or 5 weeks from riding, I figure this is a good time to have it done, since I have to take off my 300cc cylinder anyway. Otherwise, I was going to wait until winter when the weather is not so great, but my recent unfortunate event opens up this new opportunity.

 

Sounds real interesting, The down side however is just what I thought, You have to get the 300 cylinder first and then have it bored. Looking at close to a grand to go to 330cc. For use guys who havent invested in the 300cc kit yet it would be a little cheaper but not much. Just dont buy the 300cc piston, rings etc and go straight to 330cc. Please keep us updated. I bet a 330 klx would Rock...



LV

 

A word of caution.

The 300 kit is a genuine kawasaki upgrade.
Here in Aus my dealer offered it to me and we cut a deal.
No warranty issues. It's all covered.
(it will be fitted at it's first service)

The bottom end, clutch, gear box etc are all designed to take the 300cc kit.
Going more again could reduce reliability.

Just my opinion or am I being over cautious?

 

For my money I'm with you Neil. More power, more wear, more potential damage.

I know this isn't a bike but I think it's relevent, I have a remote control 4wd 1/10th electric scale car. It was reliable and I have never replaced any parts, except of course tyres. I put a "hot" motor in it and it was a lot of fun, out running gas powered models. However after a short time powertrain parts started to wear rapidly and would have quickly cost me heaps in repairs if I had left the hot motor in. Not to mention crashes were a lot faster and potentially more damaging.

Just my 2c

cheers

Garry

 

I don't doubt there's merit in what you say. The 330 kit would be about 32% increase in bore size, while the 300 kit is about 17% increase. I'm going to try to research this a bit more before jumping in on the 330. I don't want to overstress other engine / transmission components any more than the next guy. Also, my theory of using my down-time to get the work done is not quite as water tight as I originally thought - it's awfully hard to do the dissassembly job with one arm in a sling so I may need to wait a bit at least until the tenderness subsides anyway.

Perhaps I'll wait until the new carb gets here and see where things are at before making the final decision. That would be the responsible thing to do ... ha ha.

 

lol I was wondering how you were going to work on it with one arm