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Question for those of you with an autoclutch. I’m have a problem with the bike overheating (99 220). Gary at EFM felt it is because I’m riding in too tall of a gear and letting the clutch slip too much. He suggested switching to ATF which he feels doesn’t hold the heat from the clutch as much but mostly riding it at higher rpms to engage the clutch harder. I’m racing it the next two weekends, a hare scramble and an Enduro in AL. I just wondered if anyone else experienced this.

I don't have auto clutch experience but both my KDX and ATC were getting hot and new radiator caps fixed them.

I have had Rekluse clutches in both my KDXs and no overheating. I also use ATF type F.

John_S wrote:I don't have auto clutch experience but both my KDX and ATC were getting hot and new radiator caps fixed them.

So how did new radiator caps fix the problem? Bad thermostat?

doakley wrote:

John_S wrote:I don't have auto clutch experience but both my KDX and ATC were getting hot and new radiator caps fixed them.

So how did new radiator caps fix the problem? Bad thermostat?

Sorry I don't know technically. I think it has to do with system pressure and the spring being worn out. Unfortunately for me it was the last thing I replaced on the ATC after a water pump rebuild and hoses didn't make a difference. When the kdx started getting hotter than normal on a few rides I would pull off and let it cool down. I started that fix with a new cap and it was back to normal.

It may not be your problem but it's worth a shot considering it's cheap. I went to the nearest dealer which is Suzuki and grabbed one. The guy there told me most Japanese bikes use the same basic cap.

When I had the Dyna-Ring in my old E-series I was running ATF, larger aftermarket radiators, and a higher pressure radiator cap yet still could overheat it. Never had that problem with the stock clutch, stock cooling system, and ATF.

doakley wrote:

John_S wrote:I don't have auto clutch experience but both my KDX and ATC were getting hot and new radiator caps fixed them.

So how did new radiator caps fix the problem? Bad thermostat?

The higher the pressure the more it raises the boiling point.

Soooo...should I get a rad cap with a higher pressure rating? Current is a 1.1. And If I do, what pressure and what’s the downside risk of higher pressure if any?

If the clutch maker says you are riding in too high a gear, what did you tell him?

Can you just try to ride in a lower gear and see how it goes? Outdoor temps will be a few degrees lower compared to your last ride.

Do you have the radiator catch tank?

What coolant brand and mixture are you running?

A new or higher pressure cap may help. Also, look up Water Wetter, Evans, Engine Ice, etc.

Good questions, Jason. Gary @ EFM only said that after we had talked about how I ride. I do tend to ride in a taller gear at lower rpms. I ride much smoother then and overall faster with better bike control. It does mean that I am sometimes/often in too tall of a gear coming out of a corner or in tight trees for example. With the manual clutch I would typically blip the clutch a bit to raise the revs. With the autoclutch I've been simply rolling on the throttle and the clutch would slip until the rpms built back up. I know that is hard on the autoclutch and that's what Gary felt was the most likely cause of overheating. I,be never had an overheating problem with the manual clutch but I have lost coolant in the past in especially tough (lots of slow,tight, woods sections). What I'm looking for are suggestions or experiences from others for things that might reduce the overheating tendency. Changing coolants might help too, good suggestion. (I currently run a 50/50 mix of off the shelf regular antifreeze and water.)

I'll try to change my riding style and not let the autoclutch slip as much obviously, but am just looking for any tips to help.

I would do a coolant flush if it's been over a year since last done. Use the old vinegar trick then refill with a fresh 50/50 mix and a 1.6 radiator cap. That's as good as it gets IMO/IME without replacing expensive hard parts.

Yes, how old is the coolant?

Definitely take a look at the "high dollar fancy" coolants.

Also, do you have the stock catch tank?

On the fancy coolants/additives, I'm not a fan.

All the "water wetter" types I have seen provide no protection against corrosion or from freezing temps as they work best when used only with pure distilled water and not antifreeze. Engine Ice types only give a false sense of your bike not overheating. Yes, you don't boil out coolant, however, that doesn't mean your engine isn't overheating and you don't know it is until the engine starts running poorly or worse.

Just my .02!

Ok. I'll flush with vinegar, rinse that with water then fresh 50/50 std coolant before the race this weekend.
Jason, yes, stock overflow tank.

Be sure to use distilled water, never tap

I did use distilled. I skipped the vinegar flush since the radiators and top end are all less than 2 yrs old.
Could not obtain a 1.6 cap before this weekend's enduro so put on a new 1.1 cap. Hopefully this helps.

Give em hell!

Enduro is in Maplesville,AL. Is that anywhere near you, Jason?

It's a couple of hours or so away. I am up north. Maplesville is right in the center.

http://www.wbrc.com/weather/

It looks like rain today and zero percent chance on Saturday and Sunday. It should be great! 66 or 69 degrees!

anytime I buy a used bike on craigs, I always do a few cheap things to make sure they dont ruin my day on trail:
New radiator cap, cheap and makes sure the pressure in system is correct, new fluid in radiator: also makes certian that its fresh and works to its best potential, cheap things to make sure the system works correct
new spark plug to make sure
usually run seafoam thru a couple tanks to make sure all internals are clean and well lubricated, seafoam can also lube top end and make run a littler cooler (debate-able) but I can say I torture my bikes on slow trails and dont over heat or run hot when Ive had mutliple KTM buddies boil over, and Im fine
if your overheating: new water pump blades, and o rings , seal can go a long way
I bleed my brakes to get new fluid, Im a big believer in putting ALL possible NEW fluids in bike
I also change oil very frequently to keep engine / tranny clean: I run T6 shell syn oil and have no issues shifting