Bike locked up. I'm stumped

Bike: 05rmz250

 

So I started her up yesterday and was letting her idle. Here in MI it's been real cold so I've been starting it about once a week and just going over everything. Everything was running good. I gave a bit of throttle, may have got a little carried away and gave it too much. Engine came to a halt and the kickstarter wouldn't budge an inch. I'm immediately thinking, I sent a valve through my piston or I broke my crank, seized it up, etc.

 

I started to tear her down, and right when I untensioned the cam chain to take the head off, the kickstarter freed up and the piston moved in the bore along its stroke just fine. I pulled the head, valves look great, piston and bore look great. No gouges or dings in either. I haven't gotten into the bottom end, I will this weekend. One thing I haven't done, which is what I'll do today after work is pull my oil filter and check for metal shavings, although I didn't see any when I drained the oil.

 

Anyone have any idea what could have happened? Engine locked up, then freed. The piston, cylinder, and valve train all look in great shape.

So I started her up yesterday and was letting her idle. Here in MI it's been real cold so I've been starting it about once a week and just going over everything. Everything was running good. I gave a bit of throttle, may have got a little carried away and gave it too much. Engine came to a halt and the kickstarter wouldn't budge an inch. I'm immediately thinking, I sent a valve through my piston or I broke my crank, seized it up, etc.

 

I started to tear her down, and right when I untensioned the cam chain to take the head off, the kickstarter freed up and the piston moved in the bore along its stroke just fine. I pulled the head, valves look great, piston and bore look great. No gouges or dings in either. I haven't gotten into the bottom end, I will this weekend. One thing I haven't done, which is what I'll do today after work is pull my oil filter and check for metal shavings, although I didn't see any when I drained the oil.

 

Anyone have any idea what could have happened? Engine locked up, then freed. The piston, cylinder, and valve train all look in great shape. Rmz 250

How many hours on the timing chain ?Did you check the timing before you took it apart?Let us know whats up.

How many hours on the timing chain ?Did you check the timing before you took it apart?Let us know whats up.

Take a close look at your kickstarter gear and shaft when you take it apart.  The gear may have temporarily seized on the shaft while engaged, in other words it may be working now but trouble is a short way down the road.

I bought it used. Apparently the timing chain was recently replaced, but I don't know if I trust it. The timing looked good with a quick check over of the dots on my cam and the piston at tdc before I took it apart, but I didn't count the links on the chain or anything, just compared marks on my cams.

 

If the gear kickstarter gear is the problem, is that the only thing that might need replacment? While I'm in there I might throw in a new piston, but I'm worried that I'm screwed. I'm probably just being a worry wart as always, but a "seized" or locked up engine almost made me shed a tear haha.

Thanks for replying too guys. First time I've made a topic on here. :ride:

Take a close look at your kickstarter gear and shaft when you take it apart.  The gear may have temporarily seized on the shaft while engaged, in other words it may be working now but trouble is a short way down the road.

 

So what steps should I take to avoid these problems down the road? Suggesting that when I get into the bottom end the crank isn't damaged.

So what steps should I take to avoid these problems down the road? Suggesting that when I get into the bottom end the crank isn't damaged.

 

Stuff just happens with use sometimes, no matter how well you maintain it.  Last year, one of my sons' 07 CRF450R seized the crank, the bike was meticulously maintained.

How many hours on the timing chain ?Did you check the timing before you took it apart?Let us know whats up.

 

Apparently it was replaced not long before I bought it. But I don't know if I trust the persons word.

So a little update. Got home today and pulled the oil filter, oil color and filter all looked good. Nothing unusual. So with the head off the engine, I started inspecting the cam chain. There's little pieces of black plastic all over when I run it through my fingers. Thinking it's the plastic chain guides or whatever. What would cause these to get eaten up?

Sounds like the tensioner is bad, I would put a manual one on it.

Sounds like the tensioner is bad, I would put a manual one on it.

 

Any word on the tokyo mods one? Thinking about getting it. 

I got a new one off Thumper Talk several years back and have never had an issue with it.

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