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03 z400 wont start!

228 Views 17 Replies 3 Participants Last post by  Mech
So I was riding my 03 z400, did a wheelie and then it died about 10 seconds after the wheelie.. now when I try to start it it sounds as if tge starter is just free spinning.. and sounds like weak or no compression. But as I try to start it and let go the clutch it does try to move forward. Before that wheelie it was doing fine! I checked gas, spark and air filter. I'm confused. Unless I dropped a valve. Any help is appreciated thanks
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Take the valve adjusting covers off and check the tappets are moving.. You might have dropped the cam chain.
You'll only need to take the valve adjusting covers off. Check the valves go up and down, and/or that the cam is turning if you can see it.
It has probably jumped off at the bottom.
You will have to take one side case off, and the cam/top cover off the head.
You need to figure how it came off though. If the chain is really worn they can come off, but they do need to be really worn, or, the chain slippers wear out badly, or, the most common cause(IMO), the ratchet on the chain tensioner slipped.

Top off and side case off, clutch off and some gears off, one chain slipper will pull out, the other one needs the head taking off to get out. Once the top is off you can look down and inspect the slipper that stays in. The tensioner is on the back of the cylinder. Take the chain out and check it for wear as per the book. Inspect the slippers for wear(grooves) or bits fallen off. Check the tensioner really carefully. Because the ratchet mechanism in the tensioner might just have a worn bit right where it had been sitting, but be good enough everywhere else, I'd replace it if in doubt..
It is probably possible if you take the top cover off, and undo the cam sprocket and drop the chain a bit, that you can get it back on the bottom sprocket. That might be a good idea so that you can then temporarily put it back together and check it has compression still. When the chain jumps they can bend valves.

The other way to check the valves is to take the cam out or rotate it till all the valves are shut, then blow air into the cylinder through the spark plug hole and check for air coming out the inlet and exhaust. It would be a good idea to do that anyway before deciding what you need to do or in the way of parts.
Oh.. And all this is in the assumption that we are talking about a honda z400..
Oh ok.. haha.. Much the same though.
So check the chain for wear. If it's not worn bad it shouldn't have broken.. Inspect it looking for munted links where something went through it, Check the sprockets and the tensioner..
Links don't seize up on those things.. Those links must have got damaged as the chain came off, which doesn't normally happen.. Chains don't usually break either. They normally jump off before then wear so much they break.

One you have the bottom end off you should look for anything that could have got caught between the chain and the sprocket.
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