Overheating? Bike shut down.

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sandt38

wheelchair class racer
Jun 20, 2012
#1
So we went riding today and intermittently we were smelling coolant. we looked at all the bikes and saw no coolant leaks, and all our reservoirs were full, none were blowing over, and no overheat lights came on. I got into the bike to climb a hill and it died. Just like someone cut the key off, not like it was starving for fuel. I cranked it over and it fired right up again and I got maybe 10 feet and it shut down again. Then it wouldn't crank, like the compression was too high. We tried to pull start it and it fired up after a few tries. I got about 50 yards and it died again.

Fortunately we were near my buddy's house so we dragged it to his house. Unfortunately I was pulled by a Polaris and my other buddy was riding circles around us in his Kawie. I was worried about a blown head gasket (thinking my hard crank might be hydrolock) so I yanked the cap off the radiator. It was full of the fresh coolant I put in there a few months ago. So I tried to fire it up and it started up right away. After about 5 minutes it shut down again.

We had to load it up to get it home, and it fired up right away. After running less then 5 minutes it shut off again, and I smelled coolant again. My radiator was hot, both radiator hoses and the bypass hose were hot as well. Again, no overheat light was present (and my fan did not come on). I felt the entire radiator thinking I may have a blockage, but the entire core was hot. My infared gun is at the shop so I could not take temp readings on the bike. I have seen my fan cycle on before but it runs rather slow. I started it again a few times and it ran for a few minutes each time. I cannot keep it running by giving it throttle, turning up the idle screw, nothing. I tried to remove as many factors as possible to help explain what I see and hopefully get some advice. I did pressure test the system and found no leaks or leakdown (IMO eliminating a head gasket). I also did not smell exhaust in the radiator (I am pretty good at sniffing out blown head gaskets on cars, as I have been a mechanic for ~30 years now) so I feel pretty confident it is not a head gasket.

So explain these cooling systems to me. Is it possible I have a cooling issue and it is just shutting down because it is getting hot? While on a car I would expect the upper hose to be cool if the t-stat is sticking I can see this tiny system being different. What about the water pump? why is my fan not coming on like it should if it is getting hot? What else should I be looking for?

Is it possible it is something else?
 

CJM

Truck Yea
Jan 5, 2013
#2
Possible air bubble in the system. Id run it without the cap and see what happens.

id also take out the t-state and physically check it in a boiling pot. Radiator fins are good and not bent? Possible bad headgasket as well. I cant recall where I got the kit (maybe autozone or maybe it was was work IDK anymore), but they make a kit to check for exhaust gasses in the coolant-it tests positive deff bad HG.
 

sandt38

wheelchair class racer
Jun 20, 2012
#3
Well, it got worse. I yanked the oil filter and it is full of copper or brass. If it was a car I would say the bearings are shot... but in this case (please give me good news)...

The bearings in these engines are steel rollers, yes? If so, talk to me about the stator. I assume that is the only copper in the engine.
 

450R

Active Member
May 11, 2012
#4
Sorry dude but your crank is shot.

That there is from the bearing of the big end of the connecting rod.

Time to pull the motor apart and swap cranks.
 

450R

Active Member
May 11, 2012
#5
Also these cranks are known to lock up then when they cool down will restart and lock up again.... Just consider yourself lucky it didn't grenade destroying everything.
 

CJM

Truck Yea
Jan 5, 2013
#10
Its not so much the cranks as the bearings if I recall were the issue.

Sucks, but such as the way it goes.
 

El Mamito USMC

Zorros Racing Team..
Staff member
Apr 11, 2012
#11
yeap its looks like my engine.. lol.. just hope no damage was dont to the cilinder... use <OEM.. its a great quality, also check the lil cable that is conected to the thermo and helps turn on the fan... some times it unplugs it self and fan wont work..
 

sandt38

wheelchair class racer
Jun 20, 2012
#12
yeap its looks like my engine.. lol.. just hope no damage was dont to the cilinder... use <OEM.. its a great quality, also check the lil cable that is conected to the thermo and helps turn on the fan... some times it unplugs it self and fan wont work..
It was plugged in, and when I grounded it the fan came on. I'm gonna say I need a new switch.