my 2001 KX 250/500 conversion

[KXer]

Well the time finally came to get off my butt and get the K5 engine (that has been sitting in my garage for 6 months) in my 01 KX250.

Well, got the project started, no big headaches just yet.  Got the 500 sitting in the frame with the bottom engine mount bolted.  I have the front engine mounts ground off as well as the rear head stay on the K5.  I was also able to mount my kx250 radiators using the stock mounting locations without any modifications needed.  Unfortunately that is where my project is at a pause since I am waiting on a new swingarm and my shorty plugs to arrive in the mail.

Left todo:
-Shorten the swingarm mounts and spacers once I get the new swingarm.
-Fab new front engine mounts.
-Fab a new head stay.
-Figure out my pipe situation.  (I am thinking though that I will just bite the bullet and buy the one from AJ that he uses on the KX500AFX - I think it will fit)
-Helicoil (sp?) the oil plug as the previous owner of the k5 jb welded the plug in, so I am assuming it is stripped.
-Should also get a new clutch/case cover as this one has been "repaired" - this would just be a peace of mind deal though.
-Reassemble.
-Fire her up.

Here is the frame:


and the power plant:

[sintax]

sounds good man. Its a fun project. Let me know if you have any questions about anything. I'm having a pipe made for mine right now. I MIGHT have it back next year if i'm lucky. I can already tell this guy is a total slacker.

As for AJ's pipe, from what I read it wont be a bolt up deal, you'll need to modify it "some" but it is the closest premade pipe for the job.

[KXer]

Ya thats what I read in your thread.  It still seems easier than getting a custom one done up, but we'll see.

Any chance you have some pictures of the head stay you made.  I understand how you did it, but pics make it easier.  Oh and I decided to do all the work myself too (not that shop that you and I talked about via PM's), its been a WAY easier project than I anticipated.

[sintax]

I'll take some pics of the headstay when i get the bike back.

[KXer]

FedEX brought me my new swingarm in the mail today and it came with good needle bearrings and spacers.  Now I just need to find a machine shop to cut down the spacers, the swingarm I can do myself.

[KXer]

Latest Update:
- Drilled out the engine to the 17mm (much harder than I thought, what is that a hardened steel sleeve?)
- Cut down the new swingarm and spacers
- built a new front engine mount, and fabricated a 1 piece head stay.  (we had to build it out of thinner metal than I wanted, but we will see how long it lasts)
- With the use of a heat gun I was able to fit my desert tank (waiting on my shorty plugs to complete fitment)
- Made a exhaust "sleeve" so I can use all of the 250 silencers that I already have (spark arrestor, shorty, and some other one)

Tomorrow I will be putting the bike back together, still waiting on my pipe from service honda and a new spring from Fineline to complete the bike.  I will take some pictures tomorrow as well.

[doordie]

Latest Update:
- Drilled out the engine to the 17mm (much harder than I thought, what is that a hardened steel sleeve?)
- Cut down the new swingarm and spacers
- built a new front engine mount, and fabricated a 1 piece head stay.  (we had to build it out of thinner metal than I wanted, but we will see how long it lasts)
- With the use of a heat gun I was able to fit my desert tank (waiting on my shorty plugs to complete fitment)
- Made a exhaust "sleeve" so I can use all of the 250 silencers that I already have (spark arrestor, shorty, and some other one)

Tomorrow I will be putting the bike back together, still waiting on my pipe from service honda and a new spring from Fineline to complete the bike.  I will take some pictures tomorrow as well.

Be sure you got enough of ID(innerdia) for your silencer of a 250cc,easy to blow a hole in piston,better safe and sorry!

[KXer]

Doordie,

It really makes that much of a difference?  The 250 silencer ID is the same as the ID on the 500 pipe.  But if it is that much of an issue I'll buy a new silencer for sure.

[doordie]

Doordie,

It really makes that much of a difference?  The 250 silencer ID is the same as the ID on the 500 pipe.  But if it is that much of an issue I'll buy a new silencer for sure.

Is it same ID,no problem!

[KXer]

So the SH pipe came in on Wednesday last week.  As noted, to get it to fit I had to dent it in a bit around the water pump hose, and I cut off the rear of the pipe all together.  and for mounting I used my KX250 head stay triangle plate and bolted it to the pipe and then hose clamped the mount to the frame (ran out of time, to get this pig to the desert, I will be welding it to the frame).  Hope that makes sense.

Finally fired her up on Thursday, and she sounds healthy.  Headed out to Glamis on Friday where apparantly I didn't dent the pipe enough around that hose, and it finally burnt a hole through it and I started dripping coolant.  Headed back to camp where I pulled the pipe off, dented it some more, then used a 90 degree elbow piece of radiator hose and fit it back in to place (with the bend going towards the cylinder, not the pipe).  Then I added high temp silicone, and wrapped it in tin foil.  And finally, as I put the pipe back on I can see where I need to add a new rear mount.

Bike ran great after that until Sunday where I either blew the water pump seal or my base gasket as I have coolant in my transoil.  So I will be tearing in to the engine in the next week or 2, but man is this bike fast now.  Pulls like a freight train.  I think I am going to go down a tooth in the front and run a 15/48 combo and see how she likes that.

Plans now for the bike are:
new chain and sprockets,
new carb spring (seemed too loose for me)
10 cup rear paddle
possibly a new piston and rings as I don't know how hard this engine was run before I bought it)
More loctite for ALL of the bolts hahaha
rear view mirror so I don't have to turn around to see my friends on 250 2T's and 450's haha (just kidding)

I have pics that I will try to upload later.

[KXer]

Oh, and also to finish the desert tank fitment as this thing is a thirsty girl.

[gwcrim]

I'm getting ready to fit a pipe to my '02 project so your info is timely.  Please post pics of the pipe fitment issues if you can.  I really don't want to screw up a new pipe.  It's hard to imagine how there was a clearance issue with the rad hose. 

How did the silencer situation work out?

[KXer]

Sorry if that wasn't clear.  Not the radiator hose connecting the radiators, but the hose coming from the cylinder to the waterpump.  I don't have pics of how I had to dent it in as it isn't pretty (banged it out with a couple different hammers).

The silencer worked out great as it is the same inner diameter as the pipe is.  So I slid a piece of chromoly over both and used high temp RTV silicone to seal and hold them.  No issues with that at all.

I'd just like to say that I am STOKED on the Service Honda pipe as it made the job very easy, and only took minor modification to complete.  I had a shipping issue with them and I am waiting to hear how that gets resolved.  AJ went above and beyond to make sure the shipping department sent my pipe in time, Thanks again AJ.

[KXer]

Here are 2 pics that I have right now.


Scratch that I can only access this one right now.  Don't mind the clutch cover, that will be replaced as soon as I can find a replacement.

[KXer]

Here is the front.


You get the idea of what I am going for with that front mount.  I will be welding on 2 small tabs onto the frame and then bolting the triangle bracket (I will also be making this out of steel) to the new SH pipe.