Oil Fouled #1 Plug

[xj-wxman]

I have just got my XJ back on the road this Summer after finally fixing the first gear problem. Ran great most of the time - now it keeps fouling the #1 plug only after only a few miles of driving. Gets to the point it stops sparking. I have had the carbs apart and cleaned them @20 times - did have a gas overflow problem earlier in the Summe - I think that's fixed.
What are the signe for a bad valve seal? The bike doesn't smoke at all. The oil level stays up (though the oil light intermittently comes on when its hot). I kept checking when the oil light comes on and levels are good.


Any ideas on the plug fouling before I rip the head off and rplace the valve seals?


Thanks

[xj-wxman]

Just checked the plugs again - only #1 is covered with soot.
I am leaning toward carb prblems. My question is that if the
main jet is plugged - why would the plug be sooted. I am thinking more along the lines of the enricher stuck open.

Any words of wisdom out there?

[prometheus578]

Yup... oil fouled is usually wet and stays wet and shiney. Fuel fouled give the sooty/carbony look, though can appear wet when first fouled.
Yeah, I'd suspect carb #1 is loopy(good mechanical term).
enrichener could be stuck open, providing too much fuel. Float level incorrect providing too much fuel(but shouldn't foul that quickly.
"And the number one answer is.... Needle and seat valve not shutting off when float rises. (Carb doesn't overflow when not running 'cause the vacuum petcock shuts off the fuel) But when running, and if the needle's not moderating the fuel flow into the float bowl, you'll be getting way too much gas as the float bowl fills and it runs into the intake fouling the plug
Just a thought.

[xj-wxman]

Thanks - That is what I'm suspecting

Once the family gives me a chance to - I'll rip off the carbs again and reclean!!!!

These bikes get real tricky when old - I even put an inline fileter on that line to keep the crap out of the carb/float needle seats



SWMBO is callng - back to work - I'll "play" with the bike later!!!

[pggg]

XJW, like prom says, if it's carboned rather than sludgy oil, the No1 culprit is most likely the choke circuit. Strip and check the plunger on that carb. Dodgy float valve also. Blocked air jet - main air jet has a very fine hole. Pilot air jet also. The pilot air jets have a bigger hole. Maybe a kinked air breather hose too. Bad news if the oil light comes on at idle - usually means the crank bearings are on their way out. But if you're lucky it might 'only' be a worn oil pump.

[pggg]

Also - some people will disagree- but that inline filter could be causing overly rich fuel troubles. Don't like them myself. They can create extra problems. Sorry TC

[TopCatGr58]

Well, Pggg,

I'm running a pair of Mike'sXS filters on my Godzilla, and have NO problems with flow. And if it was restricting flow, then I would think that would lead to LEAN condition problems, not rich like he's having? Whatever works for you and me is fine!
T.C.

[pggg]

Back to this inline filters versus no inline filters business (Jeez, I must be bored!) TC, things might not be quite what they seem! The motor will be getting enough fuel to run, but guaranteed the motor is working harder to get that fuel flow. A fuel filter IS restrictive. Small, seemingly innocuous things can upset the balance. For me, working on chainsaws everyday, fuel restrictions in the form of blocked fuel lines and blocked fuel breathers are a daily problem. Any tiny restriction is immediately noticed - the symptoms are loss of power and alternating rich/lean conditions.

Stuffing rags in your airbox will give the same results! Sure, 1100cc 4-strokes aren't the same as 70cc 2-strokes, and the effects will be a lot less noticible, if noticable at all. But the principle still applies. Suck/blow through a fuel filter - you feel the drag. A comparison may be if someone stuck strainers in their veins! - the poor heart might keep the blood pumping, but it'll be a strain! (no pun intended)

Fuel filters cause suction bottlenecks in the fuel lines. Remove them, the engine will run freely, and you'd very likely get better economy, higher top speed, and more power up hills! If the fuel line and taps are in tip-top condition(as they should be!) - then the extra drag of inline filters are an unnecassary impediment to the engines' efficiency. (I need to get a life, I know)

[LoHo]

About the fuel filters...

If I filled my tank with gas an allowed the gas to flow out through the filtered hose, it would take only a few minutes for gravity to empty the tank. With the bike going full blast, it takes over an hour to drain the tank with or without the filters. How could the filter be creating drag at that low rate of draw? I can't imagine a clean filter having any effect on the rate of carb draw...

[pggg]

Loho, people underestimate the power of gravity. Gravity forces are HUGE. A free falling object accelerates from a standing start 3 TIMES faster than a puny XS11 can manage. May the force be with you.

[prometheus578]

Ha!
The main point is being overlooked.
Sure, an inline filter might slow the flow a little, but....
No one has mentioned the significance of the carb float bowl.
1. The gas in the bowl is what supply's fuel to the bike and keeps it running.
2. The rate of flow through a hose with a filter is faster than what is sucked up through the carb's jets.
3. Chains saws do not have float bowls to store fuel.
Agreed... a chainsaw's fuel pump gets it's gas directly from the tank,(and the fuel line is narrower) so any restriction may affect performance, but a bike gets fuel from the bowl, and the small amount that it takes to run is more than adaquetly supplied by the line, filtered or not.
Isn't this why we have needle and seat... so that we don't get too much fuel and overflow? (Yes, I know fuel level is for mixture richness, too )

[pggg]

Ha! Ha! The rate of flow is not an issue. The force required to flow it is.

[skids]

Yep, you hit that nail on the head! :-) Besides, restricted fuel would probably mean lean conditions if the floats were to somehow drop a little by not keeping up. Now, a restrict air filter is a different story!

Originally posted by prometheus578
Ha!
The main point is being overlooked.
Sure, an inline filter might slow the flow a little, but....
No one has mentioned the significance of the carb float bowl.

[prometheus578]

Oh, a double Ha Ha!

I'll see your "Ha Ha" , and raise you another!
Have one o' dem K+L auxillary fuel tanks at work... with an inline filter on it.
Hang the tank from the handlebars to run bikes with their tanks off. Bikes run fine... seem to get enough gas with an inline filter.
And furthermore.... to prove my stupidity.... If I do a lousey job rebuilding the carbs, the bike still runs on the lift, even with fuel overflowing and p*ssin' out the airbox!
Hence... it is my brain-addled belief that, even with an inline filter the carbs get more than enough fuel flow.
Now, a chain saw, with it's vacuum activated diaphram fuel pump (and it's Tillotson or Walbro carb), there could be issues with adequate fuel flow.
See....
I did more than just sleep in class at that crappy tech college for two years. (Ok, drank coffee and played cards, too)

[pggg]

Prom, I know I'm in a corner and my back is against the wall - a lone voice in the wilderness fighting a losing battle against a juggernaut of deception, brainwashing, and lies!

INLINE FUEL FILTERS ARE THE BIGGEST SCAM EVER PULLED AGAINST AN UNSUSPECTING MOTORING PUBLIC!

An efficient fuel delivery system starts at the tank breather and finishes at the tail pipe. Any imbalance along the way has a negative impact. Float bowls or no float bowls! All the aftermarket manufacturers on the inline filter bandwagon (no doubt receiving secret kickbacks from the oil companies) will deny it - but your motors are now constantly battling the inevitable vapour locks and blockages these insidious and evil products create.

Trust me, remove and destroy these con-artist inventions, and the world will become a better place. Your bikes will literally breath a sigh of releif!