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HeWasRidinDirty

2003 quadsport z400

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I got this 400, that wouldn't start. It would try, but wouldn't catch. I checked the valves and the L intake was tight at .002. The compression came in around 120. It didn't improve after a couple of drops of oil into the cylinder. So,I figured it was the valve causing the problem. So, I got the valves squared away, but it still won't start. I checked the spark and it seems like it's getting an intermittent spark. It fires a few times then nothing. If l let up on the button and then hit again immediately, it will fire a few more times, then repeat. So, what am I looking at as a possibility? Electrical issues are not my strong point. LOL

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Oh, and also the camshaft timing seems odd to me. I watched a couple of utube vids and both pointed out a "3" on the intake cam sprocket and a "2" on the exhaust sprocket. The one I'm working on has neither. Each sprocket has EX on one side and IN on the other, not directly opposite each other, either. Someone had painted IN/EX on the sprockets and put some white dots on them where they line up with the top of the cylinder head. IDK if these are some aftermarket camshafts or what.

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Could be a bad cdi. 

I would start by testing some of the regular components to see if there within spec.  

Stator, pick up coil, secondary coil and the regulator/rectifier.  If all of that tests fine then all indications will point to a new cdi.   

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Thank you. It seems like the spark is ok with a new plug. But also when I crank it over it struggles when ever it hits the compression stroke. I thought it was a weak battery so I got new larger lawn equipment battery, fully charged, and I hook it up via jumper cables and it does the same thing. You think the starter is bad/weak? It pops and acts like it wants to start, but, it seems if it was spinning faster, it would. I wonder if I could bump start it with a truck or quad? That might answer that question.

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Honestly if that engine is having trouble at the top of the stroke plus the backfire makes me thing the timing jumped a spot.  I would double check before you keep cranking.   

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1 hour ago, Frank Angerano said:

Honestly if that engine is having trouble at the top of the stroke plus the backfire makes me thing the timing jumped a spot.  I would double check before you keep cranking.   

I may have to take a look at that. It did the same before I took it apart and checked the valves. Someone has had it apart before that, tho. Read my 2nd post. It doesn't have marks on the cam sprockets like described in the Y.T vids that I watched. 

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There are marks.  Someplace on there.   Unless the sprocket was put on backwards and your not seeing them.  It’s either a dot or a line. 

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Backwards?? that may be it. These cam sprockets have bolts in them that look out of place. Like someone "made it work" at some point. I'll put some pics up later. On this video there are no bolts on the cam sprockets. Weird

 

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So ,here is the cam sprockets. This is at TDC. I didn't do any of the paint. Notice those bolts? 

20190821_095614.thumb.jpg.930e7bd3dd7660739d20e9fd63c8d240.jpg

20190821_095619.thumb.jpg.fb4e7472a0523ddd7dfc0543bf679ade.jpg

The white dots on the cam lobes denote the center of the lobe. I did those. Aren't those supposed to be 180 from each other at TDC? 

20190821_095830.thumb.jpg.7432527b2f8932cda8e410fb30317b8c.jpg

 

 

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I would say forget any white marks.  You should have a clear stamped line that’s supposed to be 180 from each other that aligns with the top of the engine head cover. Just like you seen in that video.  And make sure the flywheel is on the T mark on the sight hole. 

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There are no marks on the sprockets other than the IN that you can see at about the 10 o'clock position in the first pic. There is an EX stamped opposite side. Same on both sprockets. You might be onto something about them being on backwards. I'm gonna pull them out.

 

 

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Hmmm IDK. If you look at the diagram that you put up, and also on the video, you will notice on the intake cam that the keyway is at about 1 oclock and 11 oclock on the exhaust. Now, look at the first pics I put up before I took it apart. On the intake the key is at about 11 and on the exhaust it's at about 3 oclock. Fuuuuuuuu... something smells here. LOL

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Lol well get after it and make sure timing is properly aligned.  If so great, if not then well hopefully no hits between the piston and valves.   

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2 hours ago, Frank Angerano said:

Have you followed the diagram I sent you ?

You can see the position of the cams in that image.  

Didja look at the pics that I posted? Those 1 2 3 marks aint on there. That's the crux of the matter. 😉

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