ERIC HELP - 100s of KDX 220s overheating

[Robcolo]

Eric, Everyone I know with a KDX 220 experiences severe overheating. The 200s don't. My KX 250 runs very cool - I can lay a hand on the cases & pipe after a hard run - not so with the KDX.
Have you seen anything in the 220 engine -[squish band ? timing? pipe dimensions?] that would cause it to run hot ? We've stopped the boiling and coolant loss by running a non-aqueous propylene/ethylene glycol [bp 375 F], but the engine still runs quite hot. It would be better to find the cause and fix it.

 

[jtorres]

I have the same concern, just guessing maybe the 33mm carb does not provide enough gas/air mixture and when you lean the engine it raises the operating temperature. So, has anyone seen an improvement on the engine running temp. when installing a 35mm or 36mm carb.

 

[ACGUY]

My 97 KDX200 runs cool...... Gnarly pipe, and KX250 Silencer, 155/45 jets.
Perhaps your 220, needs a pipe, and silencer.... I think it is money well spent... I have heard about the 220 carbs being too small though..

 

[JSTUCKI]

My 2002 KDX 220 has been run hard with no problems with overheating. I was concerned at first due to the magazines saying they had boiled over there test machines. I've run mine in deep mud at slow speeds with no problem. I am running stock jetting with a FMF Gnarly pipe with the stock silencer.

 

[Robcolo]

Sorry, this post was supposed to go on Eric's forum but somehow it ended up here. As I'd mentioned only the 220s seem to have this problem - whether modified or not. Mine has the FMF Gnarly desert pipe and carb is bored out to 35.6mm. A friends completely stock 220 doesn't boil but he has it jetted so insanely rich that it really doesn't make any power.

 

[WoodsRider]

Sorry, but I know of only one 220 that has ever overheated and that was due to a leak in the radiator hose. Contact Fredette Racing Products and ask Jeff about the problem. He's got thousands of hours on 220s and almost always can diagnose a problem over the phone.

 

[RJ-KDX]

Same here, I have an '01 220 and haven't had any problems with overheating. I've got all the usual mods on it. We run pretty good on the weekends, and do some good hills. Not a problem yet. Hhhhmmmm.....

 

[keetkdx220]

I have a y2k 220 and I have noticed it ran a tad bit hotter rding in pits than i the trail. My 93 200 never had a heating problem trail or pit. I bought some waterwetter and added it to my 220 and have noticed a difference in both trails and pits...I have been usiing it since. Just follow the directions on the bottle and it's pretty cheap I paid $8 for mine

 

[Mrobbins]

I have a 97 220 with Fatty pipe, Power Core SA, stock carb and usually run it slow and hard in tight rocky stuff and never had it boil over. Coolant level is the same after every ride.

 

[jaguar]

I wonder if heat range selection for the spark plugs is a determining factor here. best if you all who previously posted here would repost listing the spark plug you use.

 

[Simon Fuller]

My 220 only overheats on muddy hill climbs, then it dumps all the coolant, rest of the time seems ok. FMF rev pipe and silencer #8 plug.

 

[FLBob]

97 KDX 220 - FMF Knarly, lost air box cover, I haven't looked at the jets in a year so don't remember, BR8ES, run as hard as I can in H/S in Florida heat, never overheats! Reminds me - time to change the coolant.

 

[kdx_John]

I've never had mine heat up either, it's a 99 220 with the burly pipe and turbine core 2 silencer and boysen reed valve and reeds i believe. I'ts been riddin hard on tight trails in texas, single track in colorado and in oklahoma. Just take a look at my webpage for proof... http://www30.brinkster.com/dirtbikinjohn/

 

[Canadian Dave]

No problems with overheating here either even when riding in the mountains with long hill climbs, slow speeds etc.

Not to worry too much about the choice of spark plug. The engine adds heat to the plug not the other way around. If you are running an excessively hot plug you my see a pre/auto detonation problem which would cause excess temps but that would be obvious as the engine would knock.

My guess is that the over heating problems you are talking about are likely jetting related . . . . a lean spot some where. It possible it could be an issue with timing, again I'd expect you'd hear the engine knock if that were the case but its worth pulling the flywheel and checking it out if you're concerned.

I second Woodsriders response you might consider giving Jeff a call.

David

 

[Nevada Sixx]

didnt someone say a faulty radiator cap can make a bike run hot? i wonder if it was really boiling over, or if it was just water moving into the reservoir...or maybe a clog in the radiator hoses somewhere..

 

[alleycat]

I think Nevada Sixx may have hit the nail on the head. I would look at the radiator cap first. This could be a easy fix.

 

[Robcolo]

Canadian Dave--At what elevations are you riding? I suspect that jetting has something to do with it--The only 220 rider here that doesn't have the problem has his jetted way [too] rich. Since we're at high altitude we jet considerably leaner than most of the rest of you in the country --and there is quite a bit of cooling to be had from the vaporization of liquid fuel. Water also boils at a lower temp here so a bike boiling at 235 at sea level may boil here at 220 - and they boil violently. I have problems clear "down" to 4500ft. Some riders have installed higher pressure caps but that just seems to delay the inevitable. Air being less dense is less efficient at removing heat from the radiator. I'd like believe that some of the above explains the problem except that my other bike is a KX 250 and it runs so cool under the exact same conditions that you can't warm your hands on the engine or pipe on a cold day. We've completely stopped the boiling and coolant loss by using a non-aqueous mix of Propylene & ethylene glycols [BP 375F] but that's like taking a pain pill for a sprained ankle--the underlying problem is still there.