KX Riders
Maintenance & Technical => KX500 Aluminum Frame Conversion (AFC) => Topic started by: cmotodad on November 15, 2012, 02:51:32 PM
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Does anyone know if the manifold to cylinder at the reed valve has a different angle from the 250 to 500? My carb is too close to the shock and the angle is too straight. Looks like on the fishce, the 250 is more angled.
Thanks for the help.
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Don't hold me to this,but I want to say after reading some of the many,many 250/500 conversions on here over the last year,that someone said the KDX manifold was the way to go.Maybe one of the members that actually have the hands on experience on this problem can verify this.
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That was me. The 91-94 KDX250 manifold angles the carb away from the shock nicely. Uses the same reed cage as the 500 also. This was on a 04 KX250 chassis conversion.
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That was me. The 91-94 KDX250 manifold angles the carb away from the shock nicely. Uses the same reed cage as the 500 also. This was on a 04 KX250 chassis conversion.
I thought it was you Flyin....was'nt sure.
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Thanks for the info. I will order one up today.
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Flyin,
Do you know if the KDX and the KX are the same? I purchased a KX mainfold and it is longer than the stock 500. It has a little more flex but puts the carb closer to the shock spring. Any ideas are appreciated.
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I dont know if the KX manifold is the same. Im using the 91-94 KDX250 manifold and it worked out well for me.
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I looked on ebay and the kx manifold looks different that the kdx. I will look for a kdx manifold to check before purchasing.
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I've run a KX250 boot on my 500 in the stock frame as it was shorter and placed the carb closer to the cylinder. Believe it's a '94 boot. Dont know that the angle is much different but was definitely shorter.
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I ran a 03 250 intake on my sf conversion and it fit but the inner diameter was much smaller and the airbox boot was too close for comfort (to the shock) for me. The KDX was longer, angled further away and uses the same reed cage as the 500.
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For some reason unknown to me, the KX 250 manifold I purchased is longer than the one that came on the 500 motor I have.
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The 92/93/94 "KX250" manifold is the same as the "KDX250" manifold & is shorter than the "KX500" manifold & the "250" manifold has more angle than the "500". The later KX250 manifold has the same angle, but they are designed to be used with reed stuffers & thus the hole on the reed cage area is quite smaller. Depending on what reed cage you plan on using would determine which to use.
Hope this helps,
DoldGuy
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Correction (on my part), the KDX manifold is longer than the 03 KX250 manifold I used. It put the carb deeper into the airbox, as it should. I also used the V Force reed cage from the 03 250 and didnt like how it ran. I figured that the manifold from one or more of the early KX250s would be the same but never cross referenced the part #s.
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The 250 manifold I have has the rubber reed stuffers built on the manifold. Would like to find the best angle for shock clearance.
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What year KX manifold did you get?
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The early (92/93 style) kx250 manifold has the rubber "Ears" extending into the reed cage (like the KX500). I will try to get some pictures uploaded of the different years compared to the KX500 which should answer many questions, but will be after Christmas.
DoldGuy
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Any news on the manifolds? Thanks in Advance. Bob
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Bump...Anyone??? And while we're at it, what airbox boot should I be buying???
Cheers
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Here's some pics comparing the 88-93 kx250 carburetor boot to the 89-04 kx500 boot
http://www.oem-cycle.com/forum/viewtopic.php?f=48&t=353&p=1065#p1065 (http://www.oem-cycle.com/forum/viewtopic.php?f=48&t=353&p=1065#p1065)
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so with your knowledge in this manner, what do you think would work best with an 1988 kx500 motor and an 09-11 kx250f chassis? i need somewhere to start
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so with your knowledge in this manner, what do you think would work best with an 1988 kx500 motor and an 09-11 kx250f chassis? i need somewhere to start
Me too. And the airbox boot...
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Thanks for the photos to compare. The 250 manifold I have has the wings like the 500. I made a reed spacer with @ .050 taper to help move the carb away from the shock spring (pipe side thicker). I do not think it will affect the flow into the cylinder enough to notice.
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http://www.ebay.com/itm/170997383355?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649
Is this a good deal?
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So an 88-93 kx250 manifold, a custom cut spacer and what airboot do you recommend to try first?
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After reading some posts on the KX250F builds, it looks like they are close to the shock too. I tried to taper the reed spacer to help carb to spring clearance. It was a no go, it pushed the carb further back into the spring. I am now try to heat the manifold while spacing it away from the spring. Right now I have @ 3/32' from the spring but would like more. I may end up making a manifold (like Boyseen).
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I managed to get my engine in the frame tonight. I fitted the carb to see what the clearance to the shock was like. Seems pretty good. But I had a quick measure up of the manifold anyway. On the front left corner of the carb, there is only 4mm gap to the manifold. So a shorter manifold, or one that kicked the carb more to the left would not be practical. (This is on the standard KX500 manifold)
One issue I didn't forsee. There isn't enough clearance to fit fit the clutch cover with the engine in the frame. So I'll have to remove the engine bolts and tilt the engine forward to get it on.
Once again, if somebody can suggest which airbox boot to use???
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I have the same clutch cover issue with the CRF frame. That is why I made a removable cover for it.