Valve Clearances?

[thovda]

I have a 74 KZ400D, 5500 miles, has been sitting since 1978, same old fuel and oil was in it....So I've still been fouling plugs and the carbs are set so lean I'm thinking something else is going on. Ignition timing is spot on, so I take a look at the valve clearances. In the workshop manual I have it doesn't say anything about adjusting the exhaust valves, just the intake valves(.10 mm to .15 mm). But when the intake valve is in the down position on one side shouldn't the exhaust valve be up when the same side intake valve is down? If it should be up, i think I found why I'm fouling so many plugs? Does that make sense...Thanks for any help!

 

[ako]

There will be some valve overlap. Not sue how much ou engine should have as stock.

Look up a generic 4 stroke cycle on wiki or something to explain with pictures easier than I can with words.

 

[thovda]

I get it, so if I watch when I'm turning the crankshift at some point the exhaust intake will open and I can check it then?

 

[Sonreir]

Valve clearances are checked when the valve is closed and there is no pressure on the rocker arm.

 

[thovda]

I'm thinking I checked it right. The manual said to turn the shaft counterclockwise until the valve compresses and comes back up, then go another quarter turn and line up the T mark with the other mark, and to check the other side go one rotation and check the other side.
With the amount of soot buildup I'm getting on the plugs, the lean setting I have on the carb, and no mufflers at the moment, i just can't figure out why I'm getting so much soot on the plugs. I was thinking all the exhaust isn't exiting the piston, that's why I was wanting to check the exhaust valves, but it isn't in the manual anywhere so I'll rotate the crankshaft until it's widest gap and check it then, I'm thinking it should be a tad larger than the intake valve?

 

[Sonreir]

Yes, but only the slightest amount.

I think the settings are .003" for intake and .004" for exhaust?

 

[thovda]

Thanks for the info! So I think I found a problem, my left exhaust valve doesn't seem to be opening, or opening much at all. In theory i should be able to find when the right exhaust valve is wide open, mark that spot, rotate it one rotation and the left one should be open? With that problem i wouldn't think I'd be fouling/sooting both plugs, that's been the problem, but maybe there is something I'm overlooking? If the left isn't running like it should the right won't either, that's why both plugs are fouling?

 

[Sonreir]

I'm not sure about the angle of the crank on KZ400, but I wouldn't worry too much about the "rotate it one rotation" method. Just give the crank two full turns and make sure everything is moving properly. Find the slack spots (when there is no pressure on the rocker arms) and make your adjustments at that point.

 

[thovda]

Thanks for the help Sonreir, i really appreciate it. i adjusted it at lunch now and I think it may have helped a bit, but didn't solve the issue. I still have black smoke coming out the pipes and sooted plugs. I need to drop the pilot jet from the 20 that's in it now. All the combinations i've read on the internet for this bike don't go below 20 on the pilot, but it looks like i need to head in that direction.

 

[Sonreir]

Have you checked compression and ignition timing? I can't remember...

 

[thovda]

I've checked timing, but I haven't checked compression with a gauge yet. My brother in law has one, need to get that done. I figured since it hops up to 70 mph so quickly(don't dare go any faster with the 1974 rubbers on it) and has lots of power it wouldn't be compression, but I need to eliminate all possibilities at all now. Running out of options-besides compression and it running so rich, though carbed so lean...Thanks.

 

[joea]

hi,
if you have black smoke and sooting plugs it's too rich somewhere......can you tell us where? low end, off idle, middle, top or throughout the rev range? if all check air filter and it's inlet, needle seat seal or float settings or actual float for being compromised (fuel inside). if at low to middle it may be you have used a carb rebuild kit and it has bad parts(normal with many kits) or your jet needle and needle jet are worn or someone shimmed or adjusted it incorrectly. do you have all the correct parts in the carb? does it have rubber plugs in the body and are they both there? more information will help .
good luck, joe@ Vcycle
www.joesvcycle.net
www.joesvcycle.wordpress.com