Stumped! Carbs valves electrical or what?

Hey All,

I got the float level tool and set the levels but plugs 3&4 are still carbon fouling. I even went as far as to set those problem plug's float height to 4mm below the gasket but no luck. I can take the plugs out and clean them off with a contact cleaner and wire brush and the bike runs fantastic for a while until enough carbon builds up on those two plugs once again. I've put new plugs in and tried switching cleaned ones between cylinders and it's always 3 and 4 with the problem At one point I backed the air mixture screws in those two carbs like 3.5 turns just to see what would happen and the bike acted like it was lean ( it lingered up in the rpms when i bumped the throttle) so I put them back down to 1 turn out (where it stops acting lean) and ran the bike only to have em foul again. Is the dry powdery carbon fouling always caused by either the carbs or electrical system?
What plug would you guys recommend for my set up? I've got b8es in now but have also run the stock b7es with the same results.

Dirtyhands wrote: . . . #4 spark plug is carbon fouling and other 3 range from great to a bit rich looking. . . .

Dirtyhands wrote: . . . plugs 2 & 3 are still carbon fouling. . . .

:huh: #4 no longer fouling?

Incomplete combustion can result from issue(s) involving carburetion and/or ignition and/or compression.

Results of cold compression tests?

Would double-check valve clearances.

Possibly a problem with one or more of the BS30/97 air jets.





Might also benefit from new pilot jets.


Good Fortune!

I run the b8es-R plugs in my 1977 kz1000. Also run the "R" plug in my 2-stoke ktm 300. I've been told the "R" designation stands for racing, but have no clue honestly. I will say that this plug performs great in the 2-stroke set up, and my kz since that bike does burns a bit of oil. not sure running this plug will solve your issue; may only give you a bit more time before it fouls.

The "R" stands for resistor not racing. The KZ engine does not call for resistor plugs, so using them can cause issues especially if resistor caps are also used. Ed

The R stands for resister. They are of no benefit to fouling, perhaps less. I ran BP8ES plugs when I was fouling plugs due to bad valve guide seals. I'd get 400 miles, then have to clean them. You might try that. They have a longer reach. I also ran one step leaner pilots to help burn the oil. Once I did my valve train overhaul with Viton valve guide seals, the bike wouldn't run for SHT. Went back to richer pilots. I'd try the longer reach plugs to buy some time so you can stop chasing your tail and get your jetting issue worked out. The mains DO have a effect on idle in a small degree. They can mask the improvements you are making with the low speed jets. Go back to stock then go from there.
Steve

It's ur carbs.....clean them...no way a little oil is going to foul ur plugs .
I ran my 77kz1000 for nearly 20kmiles smoking and little gas dripping from the over fill tubes with no problems. Started and ran like hell every time.
Did cost me a quart of oil every week thou..lol

Oops! Time for some new plugs. Thanks for the heads up Ed.

Oops, I meant 3 and 4. I'll go ahead and order another valve cover gasket so I can check out the clearances again. I changed out the main and pilot jets already (the PO was running a 135 main and 20 pilot with a higher needle setting)but will take the carbs apart and give them another dip and deep clean before I check the valves again. Borrowing a compression tester from a coworker today so I'll have some results up tomorrow on that

I've attached the latest plug portrait as well 1-4 is bottom up

Dirtyhands wrote: . . . the PO was running a 135 main and 20 pilot with a higher needle setting . . . .

Would use the jet needle's middle clip position.






Good Fortune!

Alot of us have re used the valve gasket over many times without replacing....... try tapping it gently to brake it loose and you should be able to re use it......maybe changing the nettle settin too like Patton says..... I'm gonna back mine off when I put mine back on but I ran my open before no cleaners.......... and wouldn't you guys recommend the stock NGK bp7s over the 8s as 8s are cooler ???


Hey Patton school us on the air screw and sync too will ya please .... it seems like I remember you saying it should be under 1 turn maybe 1/4 or 1/2 turn out from closed way back and also they should only be bench sync'd cause with the tops off and adjusting them with a sync gauges they will be off as the slides leak air and throw you off.......... I will admit the 2 times I used a ground rod to bench shim them they were closer than I ever had them with the mercury sync.

KZB2 650 wrote: A lot of us have re used the valve gasket over many times without replacing..........

That's for sure! I'm only on my second one after 38+ years! Be sure to put the gasket on dry (no sealer, gunk, goop, etc.) as that will make removing the cover very easy without damaging the gasket. Unless someone has damaged the head or cover, it won't leak. Considering how many fasteners are holding that valve cover on it's pulled down pretty darn tight! Ed

This is true of any gasket (except head, obviously): Just lightly coat at least one side of the gasket in anti-seize before installing. It'll never stick.