BUILDING A KX500AF with a 2007 KX250F chassis

[Sandblaster]

Experimenting with bolting the engine mounts on.
Talk about chatter

2.JPG (24.92 KiB) Viewed 16077 times

1.JPG (44.42 KiB) Viewed 16077 times

[Sandblaster]

Got it welded and then assembled:

3.JPG (38.05 KiB) Viewed 16077 times

4.JPG (59.72 KiB) Viewed 16077 times

Then I put a torque wrench on it.
Set it for 30lb and started putting pressure on it.
I was never able to get the wrench to click and I started pulling the bolt through
Better to find out now then drill out my frame and have it ruined.
I think I will try to use a cap screw.
It will stick out slightly but it will be much stronger as I won't have to counter sink the hole.

Socket Cap screw.jpeg (5.48 KiB) Viewed 16077 times

Stay tuned

[Sandblaster]

Well, I was heating and bending my tank and managed to burn a hole clean through it
Oh well, at least I have a better idea how much to try and heat...
Another member spoke of using a 99 kx125/250 petcock valve.
That may work on a 450 conversion but you would gain no advantage on a 250 conversion at least from 06-08.
The trick is bending the petcock valve out away from the head and forward.
So, if anyone has a stock 06-08 kx250f tank, I'm looking for one

[Sandblaster]

It's been a while since I posted on this thread.
Although I am working on a few different projects for this bike.
A two piece clutch cover and some cooling system mods...
This is the latest, I am needing to adapt a air box to carburetor boot for this conversion.
The 250F air box boot is just too small for the needs of a KX500.
So I have been trying different air box boots from different bikes and so far I like the boot from a 99-02 KX250 - P/N 14073-1743.
I still haven't made up my mind for sure but so far it looks the best out of all the one's I have tried.
Here's what I am working with...

1.JPG (32 KiB) Viewed 15972 times

2.JPG (30.03 KiB) Viewed 15972 times

3.JPG (30.85 KiB) Viewed 15972 times

4.JPG (21.21 KiB) Viewed 15972 times

5.JPG (32.89 KiB) Viewed 15972 times

6.JPG (31.49 KiB) Viewed 15972 times

7.JPG (67.39 KiB) Viewed 15972 times

As you can see, I will need to make some sort of adapter plate to go from one to the other

[Sandblaster]

After trying several other options, I have decided on the 98-99 CR250 boot part number 17253-KZ3-J00.
It will be embossed on the left side with KZ3R.
It is just a little shorter then the 99 KX250 boot and makes the boot a little less squished when installed..

KZ3R - FITS 98-99 CR250 17253-KZ3-J00

92-96 cr250 air boot 1.JPG (38.72 KiB) Viewed 15962 times

KZ3R - FITS 98-99 CR250 17253-KZ3-J00

92-96 cr250 air boot 2.JPG (39.66 KiB) Viewed 15962 times

KZ3R - FITS 98-99 CR250 17253-KZ3-J00

92-96 cr250 air boot 3.JPG (47.7 KiB) Viewed 15962 times

KZ3R - FITS 98-99 CR250 17253-KZ3-J00

92-96 cr250 air boot 4.JPG (42.26 KiB) Viewed 15962 times

It isn't a perfect fit but it is certainly good enough and the best I have found so far...
Of course either will work but you will need to make an adapter..
More on that later.

[Sandblaster]

Just received my 2000 CR250 air box boot today and it is very close to the 98-99 CR250 boot but the 2000 is just a little slimmer and a bit more refined.
So that means I will be using the 2000 boot unless I find something better I like.
The 98-99 boot is on the left and the 2000 is on the right.

98-99 VS 2000 cr250 air box to carburetor boot 1.JPG (61 KiB) Viewed 15956 times

98-99 VS 2000 cr250 air box to carburetor boot 2.JPG (51.89 KiB) Viewed 15956 times

98-99 VS 2000 cr250 air box to carburetor boot 3.JPG (49.53 KiB) Viewed 15956 times

98-99 VS 2000 cr250 air box to carburetor boot 4.JPG (40.06 KiB) Viewed 15956 times

[Sandblaster]

Looks nice Motorrad.
Thanks for sharing

porting 1.JPG (42.44 KiB) Viewed 15864 times

porting 2.JPG (36.31 KiB) Viewed 15864 times

[Friar-Tuck]

I'm sure you probably know why Mo is wanting the leading edges round. http://www.teachengineering.org/collect ... dl_dwc.pdf
The Idea is to get that Laminar flow we talked about previously over those leading edges, and possibly Mo has info on how to direct that flow to specific spots in the Cyl.. I know it's not the most exiting part of engine work, but stick with it!
Tuck\o/

[Sandblaster]

Thanks Tuck, reminds me of a few classes I had in college
I'm a little further along then is suggested in this article.
Work is finally showing signs of life and the weather is better so I'm either working or playing... Lot's of work, little play.
Here is some pics I sketched out last week to show what I am attempting to do.

CROSS SECTION A.JPG (16.98 KiB) Viewed 15846 times

CROSS SECTION B.JPG (27.4 KiB) Viewed 15846 times

I use to build and fly RC aircraft.
The P51 Mustang is one of my favorite aircraft and I use to play with laminar designs
Back to the cylinder, Motorrad has been helping me and I have been using his pics as a guide.
The problem is that it's hard to see curved or angular surfaces in pics so I have been asking him 1000 questions a day
I'll post some of my questions later.
And your right, there is huge rewards in this, so while I am nervous about it and it can be tedious, it's also fun.
And, this is a practice cylinder.
If it looks good when done I'll get it plated.
If not, well someone will want it, or maybe I'll cut it up and use it for demonstration purposes

[Sandblaster]

I was asked by a guy how could I tell if something was a casting flaw or if it was intentional.
That's a good question....
Motorrad has helped me tremendously on this.
It also helps if you have another cylinder or two to compare with...

comparisons for casting.JPG (71.89 KiB) Viewed 15841 times

If there is a big wad of rough jibbly gunk on one cylinder but the other 3 stock cylinders don't have it, I think it's a safe bet that it can be removed.
Then again there is always the exception to the rule....
If your not sure, better leave it.