good day gone sour

[beadle]

well it all started yesterday when I installed my new radiator hoses and cool head on my tri z everything went well got it all together sealed the pipe and waited for morn to do two heat cycles to make sure there was no air bubbles in the coolant. Again al went well so now its time to ride it and do a shake down for at temp at rpm leaks nothing everything good, decide to go for one more spin and she seized on me, im thinking wtf did I screw up... hose wrong something?? well took the top end of to realize the rod bearing seized on me and it feels like the crank bearings are also screwed. not really sure what happened!:wondering and if wondering I use lucas semi synthetic 2 stroke oil at 32:1 and never have had a problem

[DeePa]

Who made the cool head?

[beadle]

its a sprock cool head you can get them thru cosmic quads or mosh, mrs. mosh on here

[Dirtcrasher]

Who made the cool head?

Great question Mikee, thats where the problem began.

Not here to offend anyone, but he has had his share of "FAILS".....

[MTS]

Did you change your crank seals recently..? if you put the mag side in with the numbers Out it will cut oil flow to the mag side crank bearing, sounds to me like old rod bearing syndrome...they dont last forever...especially when you get them running "right":D

[Howdy]

Great question Mikee, thats where the problem began.

Not here to offend anyone, but he has had his share of "FAILS".....
Sorry Steve but with the information given so far doesn't lead me to believe the cool head had anything to do with the crank bearings going bad.

I'm not posting this to defend or attack anyone or products the make. Just want clear though and diagnosis to find what the cause is of the problem.

If it was the cool head causing problems I would tend to believe the piston would have melted / wore before the crank bearings went bad. Last I knew the cool heads didn't have a cooling line running to the rod or bearings.
Lots of questions need to be ask and answered before jumping to conclusions.

Just a couple questions to ask / answer:
Has the rod / crank ever been rebuilt?
Was the proper fuel / oil mixture used? ( I have thought I had the proper mixture and found out afterwards I mixed it wrong for a chain saw ).
Was their any coolant in the crank area?
Any scarring on the cylinder / Piston?
Any air leaks that could have caused it to run lean? Intake boot good? Ect
Is the carb jetted properly?
Hows the air filter?

Howdy

[RIDE-RED 250r]

Well guys, Mr. Beadle just left my house an hour ago. We tore her down and replaced the crank. He already removed the engine from the trike and pulled the top end. The bottom end was still together when we laid it on my bench and got to work...

Here is what we found:

-The only damage to the top end was minor and I'm convinced it was caused by bearing debris from downstairs. The cylinder just needed a light hone and we replaced the piston because it took most of the damage. And like I said, it was minor.

-The lower rod bearing flat out failed big time. Alot of blue on the rod and the main crank halves at the pin. There was nothing left of the lower rod bearings and the rod was very difficult to rotate on the crank pin. In fact, you couldn't spin it a full revolution.

-The crank bearings (that were new along with seals in november) were bad as well. They didn't have any blueing, so I assume the damage they sustained was do to debris from the rod bearing failure as well. They still rolled but you could feel roughness to them.

Now, what we did NOT find:

-We did not find any erosion/melting of the piston crown on the edge adjacent to the exhaust indicating a lean condition.

-did not find any damage/erosion on the top of the piston indicating detonation

-did not find a washed clean piston crown that can be indicative of an engine taking in coolant

As stated, the damage to the top end was light. One small piece of debris was still stuck in the top of the piston. And surprisingly, only 2 small marks were found in the dome. Nothing with any protruding pepper marks that could cause a hot spot.

I'm really not sure if it was just a random rod bearing failure or a lubrication issue. It was not an OEM rod, it was a Hot Rods rod. I can't remember the details of it, Eric got it late last fall when we went through that engine in the first place. I'm sure he will chime in here at some point. He told me tonight where the crank assembly came from, but over the course of the evening working in the garage I forgot...

End result, we replaced the crank assembly with a crank he was told was rebuilt with very little run time on it that he got last fall. Replaced the piston, lightly honed the cylinder, and replaced the crank bearings and seals.

Got it back together and running tonight before he left. He will put 2 more heat cycles on it tomorrow most likely.

I'm really hoping it was just a random bearing failure because I did not find a "smoking gun"....