Author Topic: How well do you like your KX250F/K5 conversion  (Read 64366 times)

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Offline sandblaster

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Re: How well do you like your KX250F/K5 conversion
« Reply #60 on: July 16, 2012, 11:35:26 AM »
There has been some controversy over that issue recently.
I have not got that far but that is next after I get the frame back from the welder.
It may be a few weeks as I will be out of town this coming weekend.
I have looked at ALL the designs on this site that showed a pic of the head stay.
I have a few idea's of incorporating the best of the designs I have seen but I have to wait until I get it all back to see if what I'm thinking will work.
I'll post pics when I get that far.
The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline sandblaster

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Re: How well do you like your KX250F/K5 conversion
« Reply #61 on: August 03, 2012, 09:35:27 AM »
Finally.
Here is some pics of the frame after out first trip to the weld shop.
We are having it welded in 3 steps so we can get things a little more dialed in rather then trying to weld it all at once.
It was Mig welded using 5356 filler.
The frame rails are made from 6063 aluminum.













The next step will be the head stay brace and the engine mounts.
The last step will be the new radiator mounts.
« Last Edit: August 03, 2012, 09:38:16 AM by sandblaster »
The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline Brute

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Re: How well do you like your KX250F/K5 conversion
« Reply #62 on: August 03, 2012, 11:45:23 AM »
The aluminum conversions are cool. But. The 'but' for me is I do not ride motocross or crazy fast on trails any more. I am thinking I do not need the ground clearance the K5 has now. With going to 17's for the motard and aggressive tires I will loose about 3" overall but still have some dirt/sand ability. Anyone use a lower chassis for a conversion, say an enduro type? That would make it street legal easily, and have the stupid big power of the beast. Just curious. I think the majority of folks on here are either track guys or desert guys, but someone may have heard of an 'other' conversion.
Things Are More Like They Are Today Then They Have Ever Been Before...

Offline SS109

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Re: How well do you like your KX250F/K5 conversion
« Reply #63 on: August 03, 2012, 07:19:21 PM »
You could always try stuffing a K5 into a KLX/KLR chassis.
'90 KDX 200 (rebuild - DONE!) - '94 KDX 250 (soon to be a KDX250af)

Offline sandblaster

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Re: How well do you like your KX250F/K5 conversion
« Reply #64 on: August 04, 2012, 01:32:02 PM »
Some time ago I saw a post on here where someone used a flush mount insert of some sort to attach the engine mount tabs to the frame.
The nice thing about this design was that you could completely remove the mounting tabs to make removing and installing the engine easier.
I can't find the post on here anywhere.
Does anyone remember where that post is at?
Also, if anyone has any pro's or con's about using a head stay in the front of the engine rather then coming off the back I'd like to hear about it.
Thanks!
SB
The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline sandblaster

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Re: How well do you like your KX250F/K5 conversion
« Reply #65 on: November 07, 2012, 12:06:22 PM »
The head stay made it in today:



Now I can start making all the mounting brackets and get them welded on.
The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline brooksie

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Re: How well do you like your KX250F/K5 conversion
« Reply #66 on: November 16, 2012, 02:49:58 AM »
Keep the info coming. I'm a few steps behins you! lol
Want to get the bike ready to race next year in the "over 40's". (More like "over the hill!)
Just need to get some metalwork removed from my knee, then I'll be sorted.

Cheers

Offline sandblaster

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Re: How well do you like your KX250F/K5 conversion
« Reply #67 on: November 16, 2012, 03:36:10 AM »
I'm working on it but I have to divide my time and money between this build and my SM  :-(
Hey, it's only money  :-)
The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline sandblaster

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Re: How well do you like your KX250F/K5 conversion
« Reply #68 on: November 20, 2012, 04:44:48 PM »
I ordered some aluminum plate for my mounts.
Should be here in about a week...  :-(
The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline sandblaster

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Re: How well do you like your KX250F/K5 conversion
« Reply #69 on: December 04, 2012, 01:23:39 PM »
This is what the aluminum plate is for..

The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline Larry Wiechman

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Re: How well do you like your KX250F/K5 conversion
« Reply #70 on: December 04, 2012, 01:55:53 PM »

 How does the wall thickness of the new lower rails compare to the stock frame?

Offline sandblaster

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Re: How well do you like your KX250F/K5 conversion
« Reply #71 on: December 04, 2012, 02:40:07 PM »
Hmmm,,, I'll check it out tomorrow and let you know.
From memory they were very close but I'll verify
The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline sandblaster

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Re: How well do you like your KX250F/K5 conversion
« Reply #72 on: December 04, 2012, 03:00:17 PM »
In the mean time I am trying to figure out how I want to mount the engine mounts.
I know a lot of guys weld the mounts directly to the frame but it will make engine removal in this 250F frame all that much harder.
So, I am thinking about drilling through the square tubes and welding in aluminum tubing and running bolts all the way through the frame tubes.
Here is an example:



What do you think about that?
Or, do you have a better idea?
« Last Edit: December 05, 2012, 03:06:05 AM by sandblaster »
The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline sandblaster

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Re: How well do you like your KX250F/K5 conversion
« Reply #73 on: December 05, 2012, 08:01:45 AM »

 How does the wall thickness of the new lower rails compare to the stock frame?

The replacement wall is .125"
The stock is approx .100"
The four stroke engine: That's one stroke for producing power and three for wearing the engine out.

Offline sandblaster

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Re: How well do you like your KX250F/K5 conversion
« Reply #74 on: December 05, 2012, 08:26:57 AM »
Here is a more detailed pic of the mounts:

The four stroke engine: That's one stroke for producing power and three for wearing the engine out.