KX250 Chassis With 500 Motor

[BigGreenMachine]

The deed is done, pending payment. I want to do the swap but the motor is paying my ticket and where I'm going will not have access to the tools I have here at home.

A 310 will still make good power and I get to keep my trike for the girlfriend to use. 

[MadKaw]

well good luck man, you need a motor or you got a donor 250 powerplant? still got the engine from the bike I sent ya, needs bored out anyway.

[gwcrim]

More from Bryan from Everything 2 Storke:

Thanks for the reply. 

There are a few of us at a forum on kxriders.com that are scheming to do the same swap.  I would really appreciate any help you could come up with.  My e-mail is gwcrim@yahoo.com.  What was the fellow's name who made it?  Who does he work for? 

George

I got ahold of my guy and he told me that they are no longer stamping two stroke pipes and the dies for stamping them have been destroyed.  He thinks he might have three sets left, if he does these are going to be in my hands next weekend.  I know one set will be used for the kx450/500  I'm going to build these would be the last raw stampings to build my pipe left in the world makes me want to shed a tear for my two stroke I have been trying to get ahold of him becouse my intent was to produce this pipe myself along with radiators to make the Kx450/500 swap easy for others to do if you are going to do the kx250/500 swap use a 03/04 kx250 the head stay is on the back the same as kx500 and you can get tanks from ims that are only a little bigger than stock trust me your life will easier.

I invited him to stop by here and check the place out.  He seems to be our kinda guy.

[stewart]

thats nice work there bryan ....... stewart

[demographic]

I knew my ears were burning. what's up!

Looks very neat, good job.

[racemx]

BDI, how much would you charge to make me one of those head brackets? Thanks.

[racemx]

It wouldn't have to be as pretty as yours just structurally sound. I was kind of hoping to keep it around $100. Do you have any of your rough drafts left?

[gwcrim]

Bryan!  Glad you showed up.

Keep me on top of that list for the..... well.... you know what.

[Deviousfred]

This thread rules!!!  I just bought an 05 125 frame and swing arm.  My plans are to do a 500 swap but am also open to just building it into a 250.  I have plenty of questions.

Would the 05 125 frame be a good candidate for the 500?  I've been told on other sites that it would not work.  But I figure you guys would know more than anyone else.

Would the 125 frame be a better candidate for the 250?  Would the 250 powerplant bolt right in or would modifications till need to occur?

Thanks for any help in advance.

[gwcrim]

l have a question regarding this whole thing.  Really how much difference is there between a regular old 500 and a 500 in an '02 250 chassis?

I'm the kinda guy that likes stuffing big motors into small packages, but before I start down this path, I was just kinda curious as to what exactly I'd be gaining?  Is there a big weight difference?

[don46]

l have a question regarding this whole thing.  Really how much difference is there between a regular old 500 and a 500 in an '02 250 chassis?

I'm the kinda guy that likes stuffing big motors into small packages, but before I start down this path, I was just kinda curious as to what exactly I'd be gaining?  Is there a big weight difference?

Not only is the chassis stiffer, the suspension is head and shoulders better than a 500 suspension. the rear suspension hasn't changed dramatically since 89, different valving and maybe a larger diameter shaft, the 250's have gone through at least a 6-8 updates. The bike is much narrower than the K5 just an all around better handling bike. I used the K5 radiators and made the brackets for the lower mounts, they work perfectly. I've had a number of K5's, a Rocket Science racing framed K5, 2 K5's in 250 chassis and 1 in a KX250f chassis, and I can honestly say the newer chassis rule, the 250f is the best but way to much work.

As for Deviousfred, if your the guy from the other kawasaki forum, you can obviously make anything fit into a frame, my comment was that it wasn't easy and if you were going to do it find a 250 frame and save yourself alot of headaches. You could do a 250/500 mod in a weekend.

[SPD FRK]

I have a '93 KX125 and a '91 KX500. I was told (possibly incorrectly) that this series of chassis is the same between the 125/250 and very similar to the '98 model year.
I have not really torn (or looked very hard) at the two bikes side by side yet... I have some top notch resources for fabrication so that is not a deterant (short of spending $3k and 100 manhours).

What a KICKASS SITE BTW!!!

[Woodsplitter]

Hello,
   I've been a member for about a year and been lurking mostly,and I've learned alot. I've got a 5hun motor and a possible good deal on a 03 kx250 chassis. I am curious Don46 why you mentioned to stay away from that particular year? If not the 03 then what would be the best kx250(steel frame) candidate for the transplant.Any and all suggestions appreciated. 

[BDI]

Im not sure why don would say not to use a 03 chassis. When I built my bike I used a 02 chassis there are a few things the are a pain in the but one of them is the head stay, 02 chassis the head stay Is on the front this Is a pain to work around O3 the head stay is on the back just like the 500 all you should have to do is cut it off  and shorten It up and weld It back. I would assume every thing else to be the same as far as mods go but I am very anal so I did a lot of stuff that other people don't bother with so doing things my way gets involved.

[don46]

The reason I would stay away from an 03, its kind of a 1 shot wonder, 99-02 are pretty much the same, 04-07 pretty much the same. If you were to get the whole bike the 03 would be fine, but if your going to try to get the parts don't use the 03 as there aren't as many, primarily swingarm and linkage are the biggest difference. I've pieced them togather from parts off Ebay and rarely do find 03 parts. I had an 03, it was a great bike, just all alone in design.