Klx250s melted piston help?
 

Hey guys this is my first post, I've lurked around here for a while and I've come across an issue.

My Klx250s died the other day on the way to work, just pulled it apart today to see that the piston has a huge hole melted through it. I have read and had a few conversations with mates and the general idea was that it was running to lean, now I'm not sure what way to go. Do I just replace the piston and put it all back together or do I go a big bore kit?

I've researched the kits around and I'm more focused on the 330cc < 351cc kits from Bill, now I haven't been able to get in contact with Bill to ask him questions about the kits, and I don't even know if he posts to Australia.

Can someone lean me in the right direction? Maybe even any other available kits. All I really want is for a reliable bike that isn't as gutless as it was before :rolleyes:

Cheers. Lockie

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Lockie so sorry to see that.

I live 500km away but have put in a 300cc kawi kit. Which means I have a 250cc piston, pin and barrel with 4,500km on them, but in great nick.

I was not planning on parting with but in reality it would be unlikely I would put back in the bike on sale or detonation of the 300cc so if I can help you with a 250cc rebuild send me a pm and we can sort something.

OEM 300cc kit from kawai has gone up to about $700 from memory, so Bills kits seem decent price, depending on freight.

Given you think it may have been too lean, what had you done to the bike.

If it was so lean to cause this, could it also have been so lean to cause the lack of power you mention?

Hey mate, yeah I bought the bike second hand. Came with Muzzy powerpipe and a K&N airfilter. I haven't really played around with it until now, so the history of the bike is unknown really. I've not ridden another KLX250 to notice how much of a power loss it was. I noticed more and more how much power I was losing until the day the piston blew threw.

Either way the cylinder is scored so I'm going to need to get that fixed too, so a bigger bore kit is looking to be a good option. Anyone know what bills pricing is for the kits?

Whoa! Lockie that sucks. I guess it's good excuse to upgrade though :D
Bill Blue will mail to AU. As far as your trouble getting in touch with him, he is a one man operation, so you can only catch him when he's home. He had trouble with his website a little while back, but has a new one up and running. For all I know he went to visit family for the Thanksgiving holiday here, or he went riding somewhere. :D He's a nice guy and answered all of my questions when I called before getting my 351.
Dan

Mr Blue:

bandbcyclerestoration.com

Wow! That was running a bit hot :)

Just get the 351 since you need a new cylinder anyways. Will probably be about the same price as rebuilding the 250. Only difference is you'll be looking at the sky when you crank the throttle instead of wondering why you're riding a moped :)

Lockie:
Welcome to the forum.
Too bad with the meltdown. That really sucks. How many kms on it?
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Bill doesn't have much up on his new site yet, so it's not too useful except for some contact information. If I recall right, the 351 kit was running around $450, but please don't quote me on that.

If you get a chance to do a little forensic investigation on the possible causes of the meltdown, some of use here would appreciate your findings. Inquiring minds want to know.

A lot of folks claim a better flowing muffler without appropriate jetting changes can cause an overly lean condition. Others claim not. Besides knowing about your muzzy, as you find out could you tell us about the air box (lid on/off stock or KDX200 snorkel), and carburetor jetting (pilot & main jet sizes, needle stock or aftermarket, and shimmed or clipped)? As you dig in, if you don't know the answers, with a pic or two we can probably tell you.

Wow, that suck for sure! I think you better figure out what happened before you slap in another piston. Was the plug the correct one for the bike?

damn thats nuts! Im thinkin that if he had the air filter, and pipe without a jet kit or richer fuel mixture it could definatley cause that. i slapped a two bros on mine from the get go and put 3000 miles on it before doing a jet kit or any air box or filter mods.

Good luck!