TOPIC:

Hi boys. Long time reader, first time poster. I figure if anyone could, you guys could help.
A buddy of mine just gave me a "79" KZ650SR to play with. He got it as a project to restore and could never get it to start. (He's not that mechanically inclined)So I figured I'd try. I've gone through the electrical. Found a couple small problems but nothing major. The electric starter works okay. There's spark at the plugs. So the coils are fine. I don't know much about condensors and points.
I even took the pipes off when I was trying to turn it over.I figured that I'd see or atleast smell raw gas or something. I see or smell nothing from the bike.
I've had the carbs off a couple times and there's gas in the bowls. I've checked every hole for blockages. Nothing is getting to the cylinders. Even with the choke and throttle wide open. Not even a dribble. I can't even get a cough. I've got a Hynes manual, but it doesn't help much. The carb in the manual isn't whats on the bike.I've also got a Clymer manual on order. Hopefully here in a couple weeks. Can anyone think of something else to try? I'm stumped.

Welcome to the site. Check the compresion. I like the factory manual, you can find them on eBay.
Mark

Maybe the camchain is broken or not timed and tensioned right. Compression check was a good suggestion.

If you really suspect fuel delivery problem, take the carbs off, and shoot starting fluid into the intake manifold and run the starter, see what happens.

Will be interesting to see what it turns out to be.

1. spark
2. compression
3. gas

If you got all three and the engine is timed properly (cam / valve timing), the bike will start. You obviously don't have one of the three.

Problem is, you THINK you have checked things but may be fooling yourself a bit. I suggest, you restart your troubleshooting without assumptions.

1. FIRST CHECK COMPRESSION. If you valves are sticking open because they lack clearance, none of the other things you try will work. The bike will never start. Since the bike has a checkered past, you will also need to check the valve timing. I am SURE that the Haynes manual has a description of how to do both these things. If the cam timing is off, you may have bent valves. Checking compression will tell you if either of these issues might be a problem. To check compression, buy a compression guage at the autoparts store. You can buy one that has a rubber tip that press fits into a plug hole. Remove your plugs. Open throttle and turn starter over to pump up the gauge as far as it will go. A 650 should have 130-150 PSI per cylinder with no more than 10 PSI difference between cylinders allowable (actually, the Haynes manual will give you the exact spec). Once done checking compression if the compression is up to snuff, then go on... if not, ask about fixing the compression issue.

2. spark. You have spark? How do you check for spark? OK... say you held each plug next to the engine case and watched spark jump from the electrode to the case... First thing here is to check the wiring. You have two sets of points/condensors. The LEFT set as viewed from the side of the bike is for the 1/4 coil/plugs and the RIGHT is for the 2/3 coil/plugs. The left points/condensor has a black wire that goes up and connects to a coil. MAKE SURE THAT THE WIRES coming off that coil connect to the 1 & 4 spark plugs. The right points/condensor has a green wire that goes up to the other coil. Make sure the wires on this coil go to the 2 and 3 spark plugs. OK now we are sure the wiring is OK, get that Haynes manual out and check that the points are not pitted and gapped properly. Get a test light and make sure that the points are opening/closing at the right time using the static method... it isn't hard and it will help allow your bike to start. Once you have static timing set... go to the carbs.

3. Carbs.. gas in bowls but no gas in cylinders? That really isn't all that likely to happen. That means there is absolutely no vacuum to draw gas up out of the bowls OR the pilot jets are totally plugged. Try spraying some starting fluid into the carbs (you might want to spray it through the air filter to avoid backfire fires. If the the bike now starts on starting fluid, we can go through what is needed to make the carbs work and ident them to make sure they are not grossly mis-jetted by some past owner.

Thanks boys. I have spark at the plugs. But the points thing is a mystery to me. There is a green on one condensor and a black on the other. Also a green and black set of wires going into the condensor area. Does the black condensor and green coming in connect to the same point? Same with the other set. I checked the cams today. The chain is fine, the timing marks line up and there is good tension. I also did a compression check. Just number two is a little low. The other three are almost dead on. Everything is closed today, so I'll get some starter fluid tomorrow. Could the floats in the carb be set to close to soon and not letting enough fuel in? I haven't check the fuel level yet in the bowl. I can't get two of the drain screws out. How can I do that without screwing the bowls up?

Jeff
Halifax
I will find a way or I'll make one.

As Wiregeorge mentioned, you check compression but did you check valve clearances while you had that cover off, especially with the one with weak compression

I rechecked the compression again. I think the gauge I was using is screwed. So I got me a new one. I found that the one cylinder that was low was actually no good. And the ones that were good were low. I took the head off and did some cleaning. The no.2 cylinder had a bent valve. No damage to the piston. I put in a couple new valves. I got the compression on 1 and 2 up to 120 psi. But 3 and 4 still only have 65 and 35 psi. I never took those valves out. But gonna this weekend.
Valve clearance wise is 3-7 thousands. I'll probably look for some help this weekend. Does anyone have any perls of wisedom for this type of job.

Drop a teaspoon of motor oil in cylinders 3 and 4 and see if the compression goes up considerably. If it does then the rings are the problem there. If it doesn't then it points back to the valves or head gasket.

Thanks guys. Turns out that the rings are super worn. I'm gonna chop over to the engine forums because this is now an engine thing. Now I have to figure out what size rings to get. The piston and bore don't matche the manuals. Oh ya. This Clymer manual is the bomb. I like it better than Haynes.

I have a similiar problem.. I got to it starts with starter fluid but cuts off almost immediatly. What do I try next?