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Bike seems to hydrolock randomly...?

8K views 11 replies 4 participants last post by  T-1000 
#1 ·
Every so often in the past few months when I start my bike it'll make the normal starting sounds, turning over and everything, then go "CLANK" and lock up. Then the starter just clicks when I push the button and doesn't turn anything over.

The first time I figured there must been gas in the cylinder...so I took all the plugs out, cleaned the carbs and checked the needles to make sure gas wasn't leaking in. It ran fine and didn't do it again for a while after that.

The next time it happened I just took a spark plug out, turned it over, put it back in, and it cranked right up. Ran fine.

Well it happened again the other day. This time the plug removal didn't do the trick. So I took the stator cover off to see what was what with the starter...with no load it spins fine. And the engine turned over very easily with a crescent on the rotor bolt so I don't think gas is actually leaking in.

So I'm thinking maybe a bad starter motor??? But that wouldn't explain the locking up all of a sudden...any ideas?
 
#4 ·
All the needles are brand-new...:/ Cleaned the seats too...never changed the oil, it didn't smell gassy or anything.
What about your float height level then? improper float height adjustment can tell the needle to do the wrong thing and keep letting fuel into the bowl, overflowing, and then it dribbles into the carb thru the jet circuits.
 
#5 ·
What about your float height level then? improper float height adjustment can tell the needle to do the wrong thing and keep letting fuel into the bowl, overflowing, and then it dribbles into the carb thru the jet circuits.
Hmm...well I did adjust them when I rejetted the carbs about 6 months ago. Maybe they need to be readjusted. Dammit I hate taking the carbs apart...maybe I'll just put a new starter and relay in just in case ha.

The choke needles are pretty worn out but I think if those leaked they would leak down the block.
 
#6 ·
I've put in a new starter, and checked for gas in the cylinders. It turned over a couple of times, then locked up tight...again.

So I'm starting to think I have a timing/valve problem...is there any way to see if the timing is off or if the valve stems are bent without dropping the engine?
 
#7 ·
Welp...looks like it was not a sticking float or anything like that; unless maybe that was the problem at first and that caused a hydrolock and messed up this rod. I suppose that's possible.

Anyways, I took it all apart (head off and split the cases) and found a blown rod that was stuck into the side of the block.

Punched a neat little hold under the starter where I'd never see it...right under the foam insulation under there.

Must've been running on 3 cylinders for quite a while ha.





 
#10 ·
I found it just as unbelievable as you but it didn't make any noise; the broken piece of rod left on the crank was short enough that it didn't interfere most of the time. IDK...I guess it's possible that I just didn't hear it over the sound of it running but I'm pretty anal with how my engines sound. I thought it was a bit more sluggish but other than when it locked up there were no symptoms.

Apparently this is not uncommon according to my mechanic here.

IDK I'm thinking I'm just gonna weld up the hole in the block, throw a new rod in and call it good...How much do you want for the engine though? How many miles are on it?
 
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