2010 Over Heating after New top end

So my bike dropped an exhaust valve. Had both exhaust valves replaced and the seats cut. Since I had the head off I did a piston and timing chain too. Bike started 3rd kick after reassembly. Its been about an hour since the rebuild now. Yesterday when I was riding the bike just didn't seem right, it was getting hot and back firing a lot. It felt like it had more compression braking than normal too. So I rode back to the truck and the bike died. It felt very hot at the time. Kick it quite a few times to get it started again, and it kept dying after only

10 sec or so of running. Got it started again and took it for a very short ride around the truck, but it just didn't seem right, so I rode back to the truck where it died right as I came to a stop. At this point the kick starter was locked up. I waited about 5 min and the kick starter moved through the stroke again just fine.

There is plenty of compression

Coolant was topped off

Water pump looks good

Just a couple tiny flakes of metal in the oil

Timing is still dead on

Now I didn't check my ring gaps before installing the piston, But the rings were indexed on the piston correctly. I used all OEM parts.

Any idea where to start checking for the problem? I'm thinking I need to tear down the top end again to check for damage. I hope the cylinder is ok. The bike seems to run great until it gets hot, then it feels down on power and back fires a lot. I just don't know where to start.

Edited by luckyguy19

I'm no expert, but I have a couple guesses..

Did you put a new head gasket in ? Some guys re-use the old one, which may cause the bike to spit out all of it's coolant if there's a leak.

I'd pull the valve cover and check your clearances, may as well rule that out as having something to do with your issue.

That's about all I've got for ideas... Good luck.

Did you follow the head torque procedure in the manual?

I used all new gaskets, and I folloed the torque procedure in the shop manual to a t.

I guess it's possible there is an air bubble trapped in the head?

I guess it's possible there is an air bubble trapped in the head?

Not really.

Well got the head and cylinder off, every thing looks ok. Ring gaps measure to spec. So I must have had a bubble or something in the coolant system. Gonna reassemble everything tomorrow with all new gaskets and see how it runs. I was worried a ring or something damaged the cylinder, but the cylinder looks the same as when I reassembled it last time. I'll take the cylinder to the dealer tomorrow to have him hone it for me.

Did you check your cam journals closely? The caps are very sensitive to proper torque and any foreign matter/debris that may be in there. I've seen binding due to these issues. Also make sure to release the cam chain tensioner and let the internal spring bring the chain to the proper tension. I've seen people crank that thing down counter clockwise until the engine couldn't turn over. Not trying to insult anyone just trying to help make sure all bases are covered.

I checked all the journals and they look perfect. I think I found the problem. I put aftermarket radiators on just before the rebuild. I used the stock radiator cap instead of the one that came with the new radiators. The shape and depth is a little different, I don't think the cooling system was pressurizing. Fingers crossed

So the connecting rod is locked up on the crank. Is this something that can slowly go bad? Seems like the bike was just getting worse and worse. Now the question, just put a new rod on, or a whole new crank?

So the connecting rod is locked up on the crank. Is this something that can slowly go bad? Seems like the bike was just getting worse and worse. Now the question, just put a new rod on, or a whole new crank?

When you drop a valve and it comes in contact with the piston its common knowledge that you should rebuild the crank as well. Not sure if this was your case or not. It costs pretty close to the same amount to get a crank rebuilt vs. getting a new OEM crank assembly, it's more of a decision on your part since you can upgrade to a carillo rod etc if you feel like it at this point.

I did not know that, but makes sense. I hope that is the problem and not the oil pump. But the head is in perfect condition and that would have been the first thing to go if it was an oil pump.

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