KX Riders

Maintenance & Technical => KX500 Steel Frame Conversion (SFC) => Topic started by: VON DEM on January 09, 2011, 02:41:16 AM

Title: GEARBOX CASE SWINGING ARM MACHINING KX500 INTO KX250 2003 SF
Post by: VON DEM on January 09, 2011, 02:41:16 AM

HI CAN ANYONE HELP , I AM PUTTING A KX500 ENGINE INTO 2003 KX250 STEEL FRAME , I CAN MACHINE CASES DOWN TO FIT SWINGARM , OR MACHINE SWINGARM TO FIT ENGINE CASES OR DO A BIT OF BOTH , I WONDERED WHAT THE BEST OPTION IS ALSO I WANTED TO USE EASILY AVAILABLE SWINGARM BUSHES & BEARINGS IF I MACHINE ARM , MY ENGINE IS A EARLY ONE WITHOUT THE STEEL SPINDLE BUSHES IN CASES BUT I DO HAVE A LATER ONE WITH THE STEEL BUSHES IN CASES SO I HAVE A LOT OF OPTIONS , I JUST DONT WANT TO RUSH INTO A MISTAKE , MANY THANKS

Title: Re: GEARBOX CASE SWINGING ARM MACHINING KX500 INTO KX250 2003 SF
Post by: PowerFiend on January 11, 2011, 05:54:47 AM

The common method is to bore the 500 cases to 17mm(KX250 swingarm bolt size), and cut the inside of 250 swingarm and shorten its bushings to match the 500 case width.

Title: Re: GEARBOX CASE SWINGING ARM MACHINING KX500 INTO KX250 2003 SF
Post by: sandblaster on January 11, 2011, 09:09:20 AM

I used the 17MM drill for mine but found it was a bit too tight.
I found that the 43/64" drill worked better which is 17.06MM.
The holes on my frame measured 17.05MM so I know it's really close  :-D

Title: Re: GEARBOX CASE SWINGING ARM MACHINING KX500 INTO KX250 2003 SF
Post by: The Flyin Hawaiian on January 12, 2011, 04:05:50 PM

Quote from: sandblaster on January 11, 2011, 09:09:20 AM

I used the 17MM drill for mine but found it was a bit too tight.
I found that the 43/64" drill worked better which is 17.06MM.
The holes on my frame measured 17.05MM so I know it's really close  :-D

I had the same problem, will try the 43/64" bit.

Title: Re: GEARBOX CASE SWINGING ARM MACHINING KX500 INTO KX250 2003 SF
Post by: sandblaster on January 12, 2011, 04:15:53 PM

Yeah, after I used the 17mm drill I used a brake wheel cylinder ream to clean it up a bit.
After 30 minutes or so it was still a little too tight.
It would work but I felt after a few years it might corrode to the point where I wouldn't be able to get it out very easily.
So, while the 43/64" bit is a little over sized it leaves a little wiggle room which may be used later on  :-)

Title: Re: GEARBOX CASE SWINGING ARM MACHINING KX500 INTO KX250 2003 SF
Post by: BDI on January 12, 2011, 05:18:05 PM

43/64 if the bit I use. It works great. I recomend drilling the cases as a unit or you may not get the pivot bolt threw to to the tight tolerances.

Title: Re: GEARBOX CASE SWINGING ARM MACHINING KX500 INTO KX250 2003 SF
Post by: sandblaster on January 12, 2011, 05:26:48 PM

Ditto.
I drilled them together with the clutch side resting on some parallels.
It made a nice perpendicular hole through both cases.

Title: Re: GEARBOX CASE SWINGING ARM MACHINING KX500 INTO KX250 2003 SF
Post by: VON DEM on January 15, 2011, 06:11:51 AM

THANKS FOR REPLIES , JUST I LITTLE WORRIED ABOUT MACHINING ARM TO MUCH , HAS ANYONE HAD PROBLEMS WITH BREAKAGES , THANK YOU