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kx500/580

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demographic:

--- Quote from: 2001KX5 on July 22, 2006, 11:15:19 AM ---You absolutely have to tell us what you know about the KX580 stroker set up? Is can not be as simple as using a CR connecting rod and a 40+ oversize piston? Could this be also done with just the connecting and if so what cc size would that yeild?

--- End quote ---

Just changing the conrod won't alter the stroke as the cranks the same and its the difference between the height of TDC to BDC that gives you the stroke but it will alter the port timing slightly and if the conrods longer it will decrease primary compression slightly.

One other way that using a long rod motor does is mean that theres less pressure on the thrust faces of the piston which can be better for high RPM running.

An animation of this can be found on this page...

http://www.eatel.net/~stentorian/wristpinplacement.swf

Click inside the yellow circle and rotate the crank with your mouse while keeping an eye on the green piston top lines and look at the angle of rod for both the short and long rod motor.
Bear in mind that that animation wont show the difference in primary compression as that animation also has a differing gudgeoun pin (Wrist pin to the Yanks :wink:) location.

I am only just learning about this myself so it's quite new to me also.

scarykxer:
sorry guys for not answering your posts,not being very mechanically minded i was given a phone number of a guy who runs the same set up as me,he has actually dealt with an old engineer guy who supposedly came up with the idea,he then proceeded to build 4 engines..the guy told me to write down the following figures that mean absolutely nothing to a non engineer like me..here goes       .786 X BORE DIAMETRE SQUARED X STROKE PLUS HEAD VOLUME..23cc HEAD...29.7  SQUISH..GIVING 52.7 cc OVERALL....sorry but i dont understand a word of that,but i got a marine engineer to make me a small end bearing to match the conversion with a stronger roller cage and he seems to think it made sense..i will see if i can wean anymore info out of the guy,but he said it was a long time since he had worked on a kx..the guy who did all my porting/barrell work (steve clitheroe,top uk tuner) said it was a fairly common conversion in the late 90,s with uk sidecar racers,that is as much as i could find out,so if it helps please let me know. :?

scarykxer:
Hi guys,i just wondered if anyone made sense of the info i posted about my 580 conversion,seeing you have had a while to check over the figures   :? :? :? :-D

KXRider107:
Wassup guys I am new to this site and also own a 2001 KX500. I have no pics up yet of the beast but they will be coming soon. I have had this bike brand new since I was sixteen and currently still own it. Ive blown it up once in 03' and had the cylinder ported and polished and bored .20 over. It has an FMF Gnarly pipe, Boyeson Power Reeds, straight rear fender with graphics, pilot jet and main jet are also different. It gears at 14f and 45R, this thing will really scream at around 100mph. Any tips on transmission maintenance becuz the dealer tranny oil isnt cutting it.
Ian.

Long live the 500!

hughes:
Welcome to the site, Try AFT Type F, been using it for the last two years with great results.

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