Oil Fouled #1 Plug

[xs650mike]

Oh pshaw! Now we've got a conspiracy theory going. pggg is pulling our chains. I've been running in-line filters for 42 years and have never had one cause a rich condition, only lean and then only if the filter is clogged or too small for the fuel flow required. Additionally if this was the cause it would affect all of the carburetors (Kiwi translation: carburettors). If you remove the petcock you'll find a filter attached unless it's fallen off in which case (unless you have an inline filter) the first time you switch to reserve all the crud and rust in the bottom of your 25 year old tank will go into your carbs. Yamaha certainly didn't put these filters on to make your carbs run rich unless you think that they're getting revenge for Hiroshima. (I think that about the shocks that came on my XJ750RH which permanently maimed mine and SWMBOs 5th lumbar discs!)

Since it's been determined not to be oil fouling I vote for: 1. dirt under float needle; 2. too high float level; 3. sunk float, unlikely because you'd have gas coming out of the carb at idle. First eliminate the first possibility since it's the easiest to deal with by closing the petcock and draining the float bowl. Then open the petcock to prime and see if the carb overflows. If not repeat. I've done this process numerous times over the years and if there's dirt under the needle it works 98% of the time. If you drain your float bowls into a glass jar you'll be amazed at the crud from the bottom of the bowls. It's good practice to run inline filters and drain the carbs periodically, you'll head off a lot of problems. Don't ask me how I know.

[Pat Kelly]

The engine runs from the fuel in the float bowls. Remove the fuel tank and (at least mine does) the bike will run for another 3-4 minutes. As long as the fuel flows into the carbs at a faster rate than it is drawn into the engine (despite any number of filters) then the engine will run fine.

As to wxman's problem, another possibility is a bad float in #1 carb. If the float has a hole in it it would be heavier that the other 3 and cause a higher fuel level in that one carb (despite being adjusted the same as the others).

I don't have the in-line filters. If I was to use a petcock that didn't have the screens (filter) in the tank then I would use in-lines.

[xs650mike]

Right you are Pat, a partially sunk float could definitely cause this symptom.

[skids]

You are the rust devil and are trying to lure us all straight into carb HELL! =;-)

Originally posted by 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!

[pggg]

Damn! My theories were burnt and kicked to hell! Theres still a slim hope for me yet though - someone might post that they're getting better milage without inline filters than with. Truthfully, I've had motorbikes with them, and remember often having niggly fuel supply problems. I know they can cause both rich and lean symptoms. Air locks or vapour locks they're called, give the same results as blocked fuel breathers - running rich one minute - then running lean the next. Really noticible on chainsaws with partially blocked tank breathers.

[xs650mike]

Blocked breathers are one thing and filters are another, fuel supply to MC carbs is controlled by the level in the float chambers, as long as the engine's demand doesn't exceed the supply everything is hunky-dory. There won't be a vapor lock in a gravity fed system, throw a fuel pump into the mix and it's a different story.

[pggg]

Mike, I've always assumed vapour locks in fuel filters are caused by excess heat from the air-cooled motor.

[xj-wxman]

All -

I did not mean to open up a fuel filter debate - I just cleaned the carbs - checked the float levels and found the one cylinder
that is fouling had the float set wrong. Fuel was up to the carb body!! I reset it by the book and it runs like a champ now. I have always used fuel filters on my bikes - no problems so far!!!


Thanks for all the suggestions!!!

[Pat Kelly]

Glad to hear the problem's repaired.
Debate is good. I like hearing as many viewpoints as possible (then I'll still do whatever I want).
As to the amount of flow thru a clean fuel filter..... my LG runs off of one petcock (removed the octopus) and runs just fine. <reminder to fix that other petcock>

[John]

Hey Pat

If you start using the other petcock, then you'll have to remember to turn it off also. I too only use one petcock. If I can forget something as serious as raising my kick stand, then I'd be screwed if I had to remember TWO petcocks.

[TopCatGr58]

Well, John,

Then my brain must be in better shape than I thought, 'cause I can remember both of my petcocks AND my sidestand! And I even turn off my non-self cancelling signals after a turn!!!

XJ-wxman, ditto congrats on finding your problem!!
T.C.

[skids]

Show off!

Originally posted by TopCatGr58
Well, John,

Then my brain must be in better shape than I thought, 'cause I can remember both of my petcocks AND my sidestand! And I even turn off my non-self cancelling signals after a turn!!!

XJ-wxman, ditto congrats on finding your problem!!
T.C.

[xs650mike]

Glad the problem's fixed. Can't help but have the last word pggg. I live in a place where summer temps are 100 to 110F and I've never had a MC vapor lock, overheat and sieze yes, vapor lock no.

[John]

Originally posted by skids
Show off!

Don'tcha hate showoffs?

[xj11john]

using one petcock?

Hey John,

How are you using only one petcock since each petcock goes to a set of two carbs? have you bypassed the octopus to accomplish this, and how many t's are you using and does yours have prime reserve, on and off, like my xj?

just curious.