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I've been having some issues with my 2000 KDX220 cooling. 1st off, I'm not a newbie. My jetting is/should be spot-on, all fluid mixtures are w/in spec. I've had boiling-over issues for awhile now, mostly on gnarly trails. I almost boiled-out in Idaho last month (2000' less than usual) - mainly due to the 35 miles of road to get back to camp. My question is, do KDX's have a thermostat? My water pump works fine, coolant flow is fine...I do have Devol Rad Guards, but I was at a track last weekend, in cool (<80°F) temps, not much dust, and my bike died several times throughout the day and was puking coolant. WTF? Also, does jumping and hammering the bike cause fuel-flow issues? I'm trying to diagnose 2 problems, here. Only engine mods are Wiseco Piston, FMF pipe/TurbineCoreIIQ silencer, freed-up airbox. Any ideas as to why I'd be boiling-up? Don't say I'm not riding fast enough, ya jerks ;) I've been wanting to get a few of you Colorado jokers out for a ride, anyway. TIA for your advise and wise-a$$ remarks...

-- C.J.

Your in luck!

This is a great thread on the subject!!

http://www.kdxrider.net/forums/viewtopic.php?t=1044

Proly a bad cap or air in the system. Get a higher pressure cap.

CM has a 1.6 Radiator cap off a CRF450 on his and solved the issue...

Indawoods wrote:Your in luck!


Proly a bad cap or air in the system. Get a higher pressure cap.

CM has a 1.6 Radiator cap off a CRF450 on his and solved the issue...

I'll second that.

Oh, and ride faster!

cap is spot on the first to cause a problem. most don't think to check it or replace it. as a Surfer in Hawaii I spent my time out of the water working on cars the most common things were radiator caps and distributer cap and rotor.

Yeah, what they said. I wouldn't bother with the 1.1 cap, go to a 1.6 to avoid problems that could occur if something else goes wrong in the future. Here is a link that has even more info: http://www.kdxrider.net/forums/viewtopic.php?t=1054

Just looked on ebay under KX250 cap and found a 1.6 cap for about 16.00 plus shipping. Just my $.02

Darnit, I shoulda mentioned I already got a 1.6 cap, months ago, at the recommedation of an old-school dirtrider. Sorry about that.

Boy, do I have you guys by the short-hairs, now! In the immortal words of Dom DeLouise, "OK, faggot! What's next!" (No disrespect to y'all gay riders, I just love that line from History of the World, Part I )

I'm thinking the bike cutting out at the track had something to do with fuel flow. Also, air bubbles in the system were my second-guess (thanks, Inda). And Quail, I already know I need to ride faster, buddy

It's a quandry, and I'll finger it out. The advise I get from y'all helps in my diagnosis of the problem.

-- C.J.

I would bleed the system. The start up, take that cap off, fill and let the bubbles come to the top. Also, squeeze the hoses in and out or tap with a wrench to get the bubbles free. Your cap may be bad also, try a new one

Do you still have your puke tank on?

>>Do you still have your puke tank on?

Yes, I do. However, at the track, I didn't use hardly any from the overflow. I expected much more fluid to be sucked up. When I drained the system the other day, the rads were full as well.

I suffered boiling-over last weekend on my '94 220 (Jap import) - UK-based enduro course; ground VERY heavy going; woods work/2nd gear technical low speeds (ambient temp low... it IS the UK!), so will flush/bleed the cooling system and try the 1.6 rad cap before anything else.

One question... what 'type' of cap do I need for the 220 - I can see references above made to a CRF 450 1.6 cap and also a KX 250 cap ... are they a universal fit, or model/year specific?