pulled my head off last night i have one exhaust valve kinda white looking, the other exhaust valve is black and caked up with a tar substance, and the 2 intake valves are black and ugly also. the cylinder does not have any scratches in it is there a way to check the rings on the piston with out taking the jug off?

 

2Big,

As far as I know, the only way to check for rings is with assembled engine, so yes you don't have to take Jug off, lol.

And all this rich running Lectron stuff is bizzare to me, but if you always look at chromed headers on Norton Commando's, BMW R twins, etc... one side will always be colored. So there is a tendency for one side or the other to run hot on dual cylinder exhaust valves if not exactly synchronized. This is not a dual cylinder 2 valve, but the effect seems similar with a single cyinder 4 valve (path of least resistance in pair of hot exhaust valves).

But BigBaja said his pistons looked clean (though didn't say anything about valves as I remember). Tuning, always go rich to lean, but if you don't adjust to proper a/f mixture soon, carbon deposits would appear likely. From now on, I'm going to have egt (exhaust gas temp), cht (cylinder head temp), and a/f (air fuel mixture) if a/f seems like it adds info to tuning. Cht is not as critical but useful in tuning with egt.

 

the head ,carb, valve cover everything is off. i was just wondering if a ring was cracked would it scar the cylinder or something. if i do pull the cylinder off what am i looking for on the piston?

 

how thick is the black tar substance on the valves. Most valves should look black from simple carbon deposits. Having one exhaust vavle different than the other is a little odd, but if I had to guess, the valve that was black was the valve on the left side (cam chain side). Am I right? I tend to see a little more carbon on that side as apposed to the right side exhaust. The reason is pretty simple..... look at your spark plug location. You have one spark plug dead center, and the other is far right. This simply means that the most intense burn is middle/right side.

Guess the real question is or would be, how thick is the black junk? Is it caked on and looking 3-D? You should probably see a thick black texture to the valves. Let us know on that one. I can even post a pic of a good used valve to give you a comparison. Lectrons like to run a little rich, the carbon is just a trade off.

As far as the rings go.... if the walls are not scored, and there is good pressure. It's probably not your rings. With 13:1, I like to see at least 175 psi on a warm compression check (without the decompression lever). Get below 135 (on a 13:1 motor) or so, and it's time to throw in a set of rings.

Let us know 2Big.

 

posted a picture of the valves not good quality but after editing thats what i ended up with.

 

2big, where did you post the pic? Looks like you don't have any pics yet... probably have to be approved for the first time.

 

check out on-dunes

 

2nd row middle picture. man this is disgusting[img]i/expressions/face-icon-small-sad.gif[/img]

 

what motor is it, how many hours...or years?

you got the head off, its just a couple more little bolts to pull the jug, and a $7 base gasket. I would go ahead and pull it, then remove the piston, remove its rings, put the rings in the cylinder and check ring gap, simply because you are this far already so why not go all the way. as rings wear, the gap widens and that's where the compression loss comes from. if you end up replacing the rings, spiral hone the cylinder wall first reassembly, and be certain to properly gap the new rings prior to installing on piston.


I've had my head off my DS twice now, and it along with other motor heads I've had off or seen have always had carbon buildup on the exhaust valves and ports, while the intake valves are clean. I'm talking about the part of the valves that are in the ports, not the faces - of course the valves faces should have carbon on them, just like the rest of the chamber and piston face.


trying to ponder why your two exhaust valves are different in appearance, and also why the intakes have buildup....for the two exhausts it kinda sounds like the white chalky one wasn't sealing and getting the blunt of combustion, the other one having tar kinda sounds like oil is burning - oil from either bad rings or bad valve seals. the valve seals might also explain the intake valves being black. has the head ever been apart? you cannot re-use valve seals, their lips get compromised with one single removal.

 

dam dude, just seen the pic at ondunes, that's a lot of crap built up. looks like oil to me too.

you can take the head apart, and use a little brass wire brush in a dremmel to clean it all off, clean the chamber and the valves and valve stems, and clean out all the crust in the exhaust ports cause it cuts the flow down considerably, and the brass brush will not mar the valve seats. then hand lap the valves back to the seats and reassemble with new valve seals. use assembly lube when installing the valve seals. don't forget to put the spring bottoms in before installing the valve seals, they will not fit over the seals.