Anyone an ATV mechanic type?

[tobyw]

I've got an '03 Suzuki Eiger with the 5-speed manual trans. It sat for about 20 months while we were in Idaho, and I recently went through the fuel system and got it back up and running. Trouble is, the crank case/transmission gets HOT. And by hot I mean well in excess of 300*F while it's just sitting there idling in Neutral. The head and exhaust are running about 170-180, which is where they should be. Why in the world is the crank case so hot??? And more importantly, how do I fix it?!

[79chevy39.5's]

arent these air cooler with a oil cooler/fan up front? could it be plugged from sitting, i take it theres fresh oil i the crankcase?

[tobyw]

I do need to change the crankcase oil... I suppose it's possible that the system is plugged from sitting, although I don't know or understand how... Maybe I'll pull one of the lines off the cooler and turn it over to see if it flows...

[79chevy39.5's]

i would start with the lube i assume its a wet clutch like a dirtbike and if the oil brakes down doesnt pump ect the clutch discs could be dragging

[Wrench]

I dont see how the crankcase can get that hot on an air cooled engine like that unless you have a bearing seized up.

The primary heat source is the combustion chamber, assuming all else is correct. If your head is cooler than the crank case, there is another heat source you need to find. What are you using to verify these temps? I would use a laser thermometer and start scanning the outside of the engine.

Run a 20% solution of Marvels Mystery Oil through it and report back.

[tobyw]

Yep, using a laser temp gun. I will try to get around to changing the oil over the weekend, and try some MMO in the mix and report back.

[79chevy39.5's]

i would start with the lube i assume its a wet clutch like a dirtbike and if the oil brakes down doesnt pump ect the clutch discs could be dragging

[OldGreen]

Just an observation:

I like Paul's troubleshooting methodology. Think about the system as a whole and then isolate the possible causes based on the symptom. Eliminate them one at a time starting with the most obvious or probable. This works much better than "conventional wisdom".

The trouble I'm having with the whole thing is that crankcase heat that isn't accompanied with heat from the top end is typically caused by friction. If there is enough friction in the bottom end to create excessive heat then the damage may already be done.

Just in case it isn't, I think that I'd break it down and inspect the crank and bearings before ever starting it again. At the very least see if there are any shavings in the oil.

Since I'm not a bike guy like Graham and Paul are, I can't speak to this potential clutch issue, but I have certainly seen motors spin rod bearings on the first start up after long periods of storage.

Fingers crossed for you.

[Wrench]

The clutch would only cause heat if there is a load on the trans. No load, no slippage. You said "sitting at idle in Neutral".

I am inclined to assume like Jim that if there truly is a heat source in the trans, the damage is already done. You would have to drain a little oil out to add MMO anyway, take a quick look at the oil for metal shavings.

Sure your temp gun is not being finicky? 300 degrees is a ton of heat for a trans. There would usually be some associated squeeling or grinding/growling when running, and "tink-tink" sounds of metal expansion/contraction right at shut-down.

A lean fueling condition will cause the heat, but you would see even higher temps in the head (closer to the source).

[tobyw]

Brief follow-up to the saga here...

After (much) more tinkering, the issue is resolved. It was not heat from the crankcase, but rather heat from the exhaust that was soaking the crank case housing. The carb was gummed up pretty badly (%*@& ethanol fuel ) and caused a terrifically lean idle, which produced severe exhaust heat. The exhaust heat shielding was doing it's job in deflecting heat from going UP toward my knees, and instead directing it back DOWN against the crank housing. Once I cleaned up the carb (took 3 trips through the bucket of Berryman's Chem-Dip ), the idle mixture was back in spec and the exhaust cooled down accordingly, which seems to have eliminated the issue.

[SPR]

Thanks for posting the conclusion to this issue. Having so many gas operated toys/tools, I'll benefit from your experience.

[tobyw]

Definitely lesson learned for me... These newer ethanol blended fuels break down pretty quickly (like within 30 days) and leave behind gum/varnish that used to take literally years instead. If you've got minimal use gasoline-powered engines, either invest in fuel stabilizer treatments or completely empty the fuel system if it's going to sit more than a few weeks. I'm not sure what I'm going to do with my motorhome, as it sits much more than it's driven, and it'll cost an extra $50 to keep it topped off with stabilizer every time we shut it down after a trip

[SquirrelCrusher]

I've had some good luck with Kreen engine cleaner. We've had some small engines that weren't running good from the fuel sitting and going bad. Changing fuel didn't help, but add a bit of this stuff and boom the engines are purring. I've used it on 2-stroke weed wackers/leaf blowers, a tractor, and I add it to my ATV every once in awhile. It doesn't take a lot.

http://www.kanolabs.com/engCle.html

Kroil oil is amazing also. Way better than PB Blaster

[OldGreen]

I've had good luck keeping the tank completely full....but not for more than a few months.

[Wrench]

Those additives to help with Ethanol fuel dont seem to really work well. Toby hit the nail on the head: the fuel evaporates much quicker and causes varnish in a much shorter time than normal gasoline does. Not an issue with a pressurized system (fuel injection), but a real problem with anything carbureted.

The only real solution is:

http://www.pure-gas.org/

They have a handy little phone app too.

[Wrench]

Those additives to help with Ethanol fuel dont seem to really work well. Toby hit the nail on the head: the fuel evaporates much quicker and causes varnish in a much shorter time than normal gasoline does. Not an issue with a pressurized system (fuel injection), but a real problem with anything carbureted.

The only real solution is:

http://www.pure-gas.org/

They have a handy little phone app too.

[iaccocca]

Thanks Paul. Just last night I was trying to remember where to get 'ethanol free' gas.

[79chevy39.5's]

pacific pride has it, i dont buy enough tho (only use it in my motorcycle) so i just get it at conoco by winco in kennewick

[Wrench]

In the last 10 years, I have also noticed a dramatic increase in degradation of just about everything rubber in the fuel systems (especially fuel lines). I initially thought the problem was cheap fuel line, but now am much more inclined to believe it is from the ethanol fuels. It is affecting EVERYTHING, including rubber o-rings and diaphrams. Motorcycle CV carb diaphrams are NOT CHEAP! That ethanol fuel really is bad stuff!

[Wrench]

In the last 10 years, I have also noticed a dramatic increase in degradation of just about everything rubber in the fuel systems (especially fuel lines). I initially thought the problem was cheap fuel line, but now am much more inclined to believe it is from the ethanol fuels. It is affecting EVERYTHING, including rubber o-rings and diaphrams. Motorcycle CV carb diaphrams are NOT CHEAP! That ethanol fuel really is bad stuff!