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durhamwd

1986 Kawasaki KLR 600 Overheating

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I have owned this 1986 KLR600 for about 15 years and it has been converted and used for trail riding. It has about 9000 miles on it and has never had any major issues. The last time out in 85 degree weather the bike started to overheat and then started to backfire and lose power. When it cooled down it was OK until it overheated again. I have keep the anti-freeze changed every few years and it currently looks like new in the radiator. The thermostate and pump appear to be working since the water gets hot in the radiator and the anti-freeze appears to be moving when you look in the radiator with the cap removed. The fan also turns on and off automatically. Any input on how to resolve this issue would be appreciated.

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Try popping the thermostat out...

Check out this vid for the Thermobob install if your not sure where it is...

I realize you see flow but the KLR cooling system does not have a bypass at the thermostat. There is always coolant flowing past the thermostat even when the valve is closed and that may be what your seeing when you look in the radiator. Of course it flows wide open when the valve is open.

Try running the bike without the thermostat and see if that fixes your overheat issue. If it does, go buy a new thermostat or even better, buy one of the thermobob kits.

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Thanks, advise sounds good. I can not work on it for a couple of weeks because the bike is at my cottage.

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Try popping the thermostat out...

Check out this vid for the Thermobob install if your not sure where it is...

I realize you see flow but the KLR cooling system does not have a bypass at the thermostat. There is always coolant flowing past the thermostat even when the valve is closed and that may be what your seeing when you look in the radiator. Of course it flows wide open when the valve is open.

Try running the bike without the thermostat and see if that fixes your overheat issue. If it does, go buy a new thermostat or even better, buy one of the thermobob kits.

Pray tell, CRF420X, HOW ON EARTH CAN A THERMO-BOB ENHANCE COOLING OF A MOTORCYCLE??????????

After the thermostat opens, does the Thermo-Bob magically increase the cooling capacity of the OEM water pump and radiator?

While the Thermo-Bob stabilizes coolant temperature more fully and at a HIGHER temperature than the OEM system, I can see no way the device enhances cooling (the OP has an overHEATING problem, not a problem running "too cool," an allegedly destructive malady the Thermo-Bob addresses).

If you can explain how a Thermo-Bob corrects an overheating problem on a Kawasaki engine, please do.

Thanks!

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Pray tell, CRF420X, HOW ON EARTH CAN A THERMO-BOB ENHANCE COOLING OF A MOTORCYCLE??????????

After the thermostat opens, does the Thermo-Bob magically increase the cooling capacity of the OEM water pump and radiator?

While the Thermo-Bob stabilizes coolant temperature more fully and at a HIGHER temperature than the OEM system, I can see no way the device enhances cooling (the OP has an overHEATING problem, not a problem running "too cool," an allegedly destructive malady the Thermo-Bob addresses).

If you can explain how a Thermo-Bob corrects an overheating problem on a Kawasaki engine, please do.

Thanks!

SOoooooo..... if you go back and re-read the post from the begining, you're not going to find a single place where I said the ThermoBob would correct an over heating condition. I suggested he simply pop out the stock thermostat.

Try popping the thermostat out...

I also suggested that he try running the bike without the thermostat and see if that solves the problem.

Try running the bike without the thermostat and see if that fixes your overheat issue

I think the part where you got lost and began yelling was when I referenced the ThermoBob video. I wasn't suggesting that the ThermoBob mod was the answer to his overheat condition (although get this, it probably would since the Thermo Bob kit includes a new thermostat!) I was simply providing a video that he could look at to see where the thermostat was located.

Try popping the thermostat out...

Check out this vid for the Thermobob install if your not sure where it is

I then bodly went on to suggest that in essence, if he was going to have to place an order someplace anyway that he should consider upgrading to a ThermoBob since I happen to believe its a worthy mod and he his going to have it all apart anyway. See this is one of those forum places where people with the same interests share ideas and people will sometimes make suggestions.

Hows that pray tell?

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I am having an overheating issue with my KLR 600 1988 model. the gauge was always up in the higher third of the scale. I recently installed a 1mm oversize piston and got the engine re-bored, renewed the balancer chain, cam-chain and installed a Eagle Mike Dohickey upgrade. It has now been run in at 500 miles at 4000 rpm or less and I have just replaced the the oil and filter. I live in Scotland and summertime temperatures are 20 deg C or less I notice that when I am driving the temp gauge is always up just below the red zone. 

 I removed the thermostat and checked it in a bowl of hot water and it is opening the correct amount (about 3mm) according to the manual so I believe it is working fine. I checked the water pump is working and not loose or damaged. So I decided to remove the thermostat and see if that made any difference. Lo and behold without the thermostat in the bike it now runs pretty cold. Driving around on open roads it barely gets above 1/4 of the scale (where the circle is on the temp gauge).Around town it never gets above 1/2 way on the gauge. 

 I am reluctant to buy a new thermostat as I believe the one I have is working fine. Perhaps the engine now is running hotter due to the re-bore and over-sized piston. Has anyone else experienced this? And is there any issue with riding the bike with the engine always at the low end of the temperature scale?

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