05 Yz 250

I have o5 Yz 250 and it has about 6 hrs on it and I did a 2hr enduro at about a hour and a half it started making this ticking noise and started to loose power bogging down what would cause this issue with only 6hrs on piston

I had a problem with the o rings on top of the leaking coolant into the cylinder on my yz 125. You could check those. Ticking is usually in the bottom end.

Stick jammed in your rear brake pedal?

Stick jammed in your rear brake pedal?

You need to do some more investigation. The list of "possibilities" is huge with the info you gave.


Ticking? From where?

Bogging? Under what conditions? All rpm and throttl positions? Only certian rpm ranges, or under certian throttle conditions?

Does it idle on it's own?

Did you do a compression test?


Could be as simple as a worn out reed.

Or as major as a roached crank bearing coming apart and taking out the piston, cylinder, powervalve, crankshaft, etc etc.

You could take the expansion chamber off and look up in the exhaust port and turn the motor over slowly and you can get a good look at the piston to look for anything weird. But ticking, in my opinion might be a rod bearing top or bottom. Or possibly a ring snagging a port?

Edited by Bremer120

Yeah it won't start now there's not much compression it would bogg at high rpm and it just shut down and it wouldn't idle

Best case: what originalmonk said

Worse case: detonation >> damaged piston >> no compression.

Remove any non-essential sticks which may have caused the ticking. Take a picture of the plug and up inside the exhaust port. Post here. Conduct a compression test at WOT if you have a gauge. Post result here.

Unfortnately, valve clearance probably isn't your problem (unless you're lost).


Edited by Swappa

Time to pull the jug

I pulled the jug everything looked good but it sucked some dirt into air box and carb and spark plug looked a little lean what recommended jetting for 05 Yz 250 with fmf fatty and shorty silencer

Does the crank rod have any up and down play?

If there is dirt in there and low compression then I doubt everything is good.

There's no up and down play just a little side to side there wasn't dirt in the head just the carb but I'm gonna re jet it and throw new piston and rings in

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