KX Riders

Maintenance & Technical => KX500 Steel Frame Conversion (SFC) => Topic started by: alexander-vmann on May 25, 2013, 03:50:45 AM

Title: 1990 kx250/500 engine swap
Post by: alexander-vmann on May 25, 2013, 03:50:45 AM
i found a cheap 1990 kx250. and was wondering if a 500 engine will fit without any major changes? Like cutting welding etc
Title: Re: 1990 kx250/500 engine swap
Post by: motopunk on June 15, 2013, 07:43:14 PM
not very dificult ... at the 90/91-kx250 frames you could use the original kx500 radiators and front motor mounts. the lower and rear motor mounts are similar between kx250 and kx500. bolt on an modified cr500 exhaust and the tank need some work with a heatgun to fit with the right clearance to the bigger k5-cylinder . thats it... :-)

some pics of the last factory bike kx500sr

Title: Re: 1990 kx250/500 engine swap
Post by: alexander-vmann on June 15, 2013, 11:46:44 PM
not very dificult ... at the 90/91-kx250 frames you could use the original kx500 radiators and front motor mounts. the lower and rear motor mounts are similar between kx250 and kx500. bolt on an modified cr500 exhaust and the tank need some work with a heatgun to fit with the right clearance to the bigger k5-cylinder . thats it... :-)

some pics of the last factory bike kx500sr


                   just found out this bike is a 89 model! with the single bone frame!
Title: Re: 1990 kx250/500 engine swap
Post by: motopunk on June 16, 2013, 06:21:57 PM
the bike on my pics is definetly  the perimeter-frame that came first in 1990.it is on of the 3 last real factory-bikes with many handmade special parts. this bike is the ex-gp-bike ridden by billy liles in 1990/91 .here is the link of the private museum where it sits today. www.mxclassicracing.com

post a pic of your 250 and question: which vin-code is on the frame? the frames of 88 and 89 are completely the same like the kx500 88-2004. only diferent vin-code caused on the diferent engines...
Title: Re: 1990 kx250/500 engine swap
Post by: alexander-vmann on June 18, 2013, 09:14:29 AM
i was not talking of the bike in the pictures! here is the ad for the bike iam talking about http://www.autodb.no/mc/search/?merker=2100240&sort=price,asc#AdItemId1575232