1975 KX 250

splime 738
Edited Date/Time 1/20/2012 9:52am
Hi there any body got any good tips for the 75 KX 250 particularly the front forks
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newmann
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newmann 9/17/2009 5:47am
9/17/2009 5:47am
Have you got them apart yet? Post up a photo of the dampener rods showing the oil holes and I'll fill you in on what you can do to get better progressive dampening. Most of the old style dampener rods just had one or two big oil holes near the bottom that allowed the oil through under compression. If that is how the KX rods are, this should work. Weld those shut and drill a series of small holes (1/16 in) up one side from the bottom on up about 6 1/2 inches. Drill one hole every 1/2 inch. The bottom hole can be drilled larger as necessary after testing different weight oils. Basically as the fork compresses it will close off oil passages increasing compression dampening as it travels through the stroke. Vintage Iron sells Progressive fork springs for the 35mm forks. You will probably have to cut them to length, don't leave them too long as you don't want too much preload. You only have seven inches of travel to play with so you might as well make it as good as possible.


Another option would be to call Race Tech and inquire about their Cartridge Emulators and fork springs for your weight. The Emulators are an oil control valve that drops down on top of the dampener rods that are adjustable. They have them for 35mm forks.

splime 738 9/18/2009 7:23am
9/18/2009 7:23am
Hello Newman, thanks for that info thats great as you said there are just 2 small holes towards the bottom of the leg. So i will try your mods, will speak to Race Tech first tho and see what they come up with. Thanks again. I am looking to do some engine mods as well. Some of the guys in my class race 73 Elsinores which they have got bolt on reed valve blocks on, gonna look into this as our class in the UK doesn't get scrutinised like the older bikes.

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newmann
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newmann 9/18/2009 9:36am
9/18/2009 9:36am
There are a few KX fanatics over here, maybe some of them will chime in with some info on engine mods.
splime 738 9/19/2009 3:13am
9/19/2009 3:13am Edited Date/Time 4/17/2016 2:15am
That would be good, i race a few different KX's 75, 78 & 79 although the latter 2 don't need any engine mods they are fast enough. What model YZ is that you race ?
Nuklear
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Nuklear 9/23/2009 11:05pm
9/23/2009 11:05pm
Danny Turner raced a `76 for a couple of years. Seems he gave up on the stock forks and put some Works Showas on it. I know he had Works Performance shocks (yes, plural!) out back. The rotary valve motor was a rocket. I think he holeshot the 1978 Anaheim LCQ but only finished 15 or 16 in the Main. Broken front brake lever or clutch lever and the low pipe was pretty flat after casing the deep whoops on that muddy night. So off to the Wax Museum and the Aligator Farm we went to celebrate. . . . And I had too many Olympia`s or Hamm`s or whatever was cheap and I plastered the side of the van. Did you know the enzyme`s in your stomach will remove paint better than Jasco`s.

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