03 KX 500 build

[lundracing]

With a valve to stop the heating of the carb right... I found without that my carb would get too hot on none powder days...

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Yep


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[needpowder]

With a valve to stop the heating of the carb right... I found without that my carb would get too hot on none powder days...

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I wonder if that wasn't your carb that caused that. You were running a lectron right? with my stock PJ carb, I never had a problem leaving the carb heater on all the time. I had a valve on there, and I think it's a good idea to, but when I took mine apart at the end of the season I noticed my valve was broken and was actually on all the time.

 

[wwillf01]

Very well could have been .. but if he does not have a tunnel cooler he will be hitting 220 on a regular basis I would think that would be messing with the jetting somehow...maybe not though?

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[needpowder]

Very well could have been .. but if he does not have a tunnel cooler he will be hitting 220 on a regular basis I would think that would be messing with the jetting somehow...maybe not though?

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Not sure. Hot air holds less oxygen but i don't know if a really hot engine will effect the air being pulled into the bike or not. I'm thinking the cold air from outside doesn't spend too long inside the motor before the oxygen does it's job.
Definitely don't want your 500 running at 220° too much. But, I also don't think 160-170° is any problem and might even be beneficial rather than running at 130 like I was all the time. If I do end up rebuilding my CR, I might change the temperature in my thermostat to 140 or 150°. The guys at Lindsey machine have me convinced my bike wanted to run a little bit hotter.

 

[M5-]

I can't remember if you said you have a real stator or not but if you have some decent power an electric cooling fan might be the action. I may try it myself this year.

M5

 

[GlennRMK]

Looking good!

Get that kick starter stripped or powdercoated!

 

[lundracing]

Do you use the good waterless coolent? I need to strip the kick start for sure. Kind of got lost in the project. Didn't think of it till I was ready to put it back on.


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[highflyernick]

Not sure. Hot air holds less oxygen but i don't know if a really hot engine will effect the air being pulled into the bike or not. I'm thinking the cold air from outside doesn't spend too long inside the motor before the oxygen does it's job.
Definitely don't want your 500 running at 220° too much. But, I also don't think 160-170° is any problem and might even be beneficial rather than running at 130 like I was all the time. If I do end up rebuilding my CR, I might change the temperature in my thermostat to 140 or 150°. The guys at Lindsey machine have me convinced my bike wanted to run a little bit hotter.

Even with the 130 thermostat/right radiator/tunnel cooler. I find that mine runs at 140-145 almost constantlly. My tunnel cooler is a bit smaller than a lot of the ones I've seen tho. Maybe that is beneficial

 

[portgrinder]

best power is made at 90F.

there are some changes you can make to the cooling system that help alot. first one is to shim the water pump impeller outwards until it almost touches the cover. thats where its most efficient. have a look and measure up the clearance on yours. that, as well as a few other tricks dropped my temps significantly on the trail

watch those fans. plastic is harder than aluminum. seen a couple wear a hole right through the rad where they touch.

 

[lundracing]

Well I decided to back it up a step and go with the tunnel cooler option. I just don't want to have to struggle with temps again this year.


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[lundracing]

Got NOS all hooked up tunnel cooler installed. All that is left is hooking up the cooler with the elbows I ordered and waiting for my sprocket I ordered. Going to go with a 14 T.


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[lundracing]

https://vimeo.com/193490089
She is alive


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[lundracing]

So I took it out for a rip tonight. Mixed results. Wow as far as power. But I am having trouble over heating. Not sure if it is a stuck thermostat or air lock in system. The hoses to the rear tunnel cooler are not getting hot. The carb heat hose is hot. What you guys think


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[ravenous]

I think you have air in there! Bleeding the tunnel exchanger can be a challenge. I have used low pressure compressed air at the rad cap to push coolant through the system. With the bleeder on the head open of course.

 

[HalfBrit]

hoist the forks in the air so the air in the tunnel cooler can bleed to the top?

 

[Grr]

Yeah you need to hang it almost vertical to get the tunnel cooler bled

 

[lundracing]

Thanks for advise. I will give it a try


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[portgrinder]

Shim up your impeller. Lots of work to push coolant that far. Probably why it didn't bleed itself

 

[lundracing]

Well i am very happy with power. Need to work on gearing. Top out at 42 mph with 14 tooth gear.


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[needpowder]

Well i am very happy with power. Need to work on gearing. Top out at 42 mph with 14 tooth gear.


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Looks good! I definitely miss the power of my CR 500 a little bit. my new yz is close but it's not quite there. I do however love how fast it goes!!