Cooked Motor--Need Advice

[Zhack]

I just got back from a 10 day trip to Moab, UT with my 16 yo son. We had an incredible time and made great memories, but the story did not end well for the bike.

On our last day of riding, my son was riding a 2011 EC300 and unknowingly punctured the radiator. Unknown to him, all coolant was lost and he ran the bike until idle was very erratic and the clutch started misbehaving (obviously due to excessive heat). When I finally caught up to him (youngster likes to twist it on) pulled over on the side of the road, the bike was VERY hot and the rads bone dry.

After allowing the motor to cool, we patched the rads up as well as possible with JB weld and refilled them. To my amazement, the bike started up and ran just fine--which was a huge relief as we were 20 miles in the desert by now. I thought it better that I ride the bike now so I could nurse it along an observe motor behavior and coolant leakage etc.

I observed the following:

1. Clutch (Rekluse EXP 2.0) was overengaging (swollen clutch pack due to heat) so I pulled over and adjusted the installed gap.

2. Idle was very erratic

3. coolant was blowing out of rad overflow but I could not identify any other coolant leaks.

4. The bike settled to a halt at one point....I could not restart it until I pulled the plug and noted it was very wet. We were in a creek section, so I don't know if it was external water sucked in or water (coolant was long gone) from rads that was migrating into the combustion chamber and fouling the plug. I put in a fresh plug and everything fired up again.

5. Coolant was leaving bike very quickly. Rads would be empty in 20 to 30 min of running, mostly vented through overflow. Eventually, I stopped pulling over to refill (as all our supply was exhausted and there was non to be found in the desert, it was also getting dark and by this time I was more concerned with not spending a night in the dez than minimizing engine overheating/damage)

6. Thankfully, we arrived at truck as sun set. All safe. The next morning, I dropped the clutch/tranny oil after all the clutch overheating and it was fine.

7. I then inspected the cooling system. I filled the rads with green coolant and when the bike was fired up i saw coolant bubbling out between the cylinder and the head. I then noted that most of the head bolts were slightly loose and the two furthest forward were quite loose.

8. I tightened the head bolts as tight as I could, but was never able to completely eliminate the leakage from under the head.

9. After flogging the bike in 2nd gear for several hundred meters, I continued to observe copious belching of fluid from the overflow and slight leakage from under the head.

10. After this high rpm/high temp test run, I dropped the oil and this time found it to be profoundly white and milky.

At this point, the riding trip was obviously over. The bike was loaded up on the trailer and driven 27 hours home.

So.....

I'm thankful the motor didn't seize and that we got home. I need some advice on what damage is done and how to assess that. I also need to know what needs to be replaced.....how deep a tear down should be done.

Water pump seal failure?
Warped head?
Head gasket failures?
Main crank bearings/seals?
Complete engine rebuild?

Or do I just to one thing at a time and "see how it goes"? I do need to be able to rely on the bike getting me home as we do a fair bit of remote riding. I don't want to put my son out in the boonies with a timebomb.

Advice is appreciated.

Thanks

[twowheels]

Ooof! Sounds like a complete tear-down to me if you want to be able to trust it in the wilderness again. At a minimum check for head and cylinder flatness, look at the waterpump impeller and gears and inspect the crank seals. New gaskets and o-rings all around.

[Zhack]

I will probably take it to a local mechanic for an inspection.

Until then, I'm just trying to think this through.

Why would the head bolts come loose?

I can understand that the leakage around the head is from damaged head gaskets and/or head warpage but why would the head bolts come loose?

[twowheels]

If the head o-rings are cooked from lack of coolant and erode from coolant or combustion leakage, it's easy to see how the head bolts could come loose.

[nknudsen]

Hot engine=detonation=rattled loose head bolts.

Good luck with the repair.

[Jakobi]

He did a number on it. Geez these engines are resiliant beasts! Amazing that it kept on running.

I'd personally just rebuild the whole engine. All up I think it set me back around $700-$800aud to do my 2010 and that included having the crank pressed and trued, and well over $100aud in postage costs for parts.

I'd start pulling her down and inspect the damage along the way. Sounds like the head o-rings are done (both) which explains the coolant loss out the overflow (over pressured) and down the side of the cyl. You'll be able to see the effects of heat on the rod and if its blued, without a doubt its time to split those cases.

[Zhack]

I must say I was rather impressed with the little motor that could and did not leave us stranded in the dez. Definitely time to give her a little love.

[gasgasman]

Originally Posted by twowheels

If the head o-rings are cooked from lack of coolant and erode from coolant or combustion leakage, it's easy to see how the head bolts could come loose.

To add more detail.
With the o-ring head gaskets,the head tightens up against the cylinder.
The o-rings are basically squished between the two surfaces in the o-ring groove.

The head bolts got loose due to the head bolts "stretching" from the excessive heat.

I would do a complete engine overhaul.
The crank seals are probably damaged from the heat too.

[AZRickD]

I did three seven-mile laps at a sandy hare scramble with what I discovered was a hole in my radiator. No damage, but the idle was staccato after the high speed wash runs.

Rode it for a year afterward. Good thing I jet rich with 40:1.

[andoman]

Zhack,
Glad you made it back OK. Sorry to hear about the damage.
Not to hijack, but I just got back from a week in Moab. Where did you ride up there?