oh, the good old mikunis...

well, having now pulled the carbs off for the third time due to engine flooding (i have ordered new everything - gaskets, petcock, needles and valves). why?

why indeed would i go ahead and basically rebuild the entire fuel delivery aspect of the carburetors...

the flooding kept happening, even after taking them off and cleaning them thoroughly. the trying the trick of taking the fuel screws out and spraying some carb cleaner up there. still flooding the engine, the airbox, my heart, etc...

decided to wrench the valves off and in every single one of them, is a mishmash collection of what looks likes rust or dirt or...paint flecks? paint flecks. same color as the pain on the tank and its all just crammed in there.

(thus - figured it was time to order new gaskets, valves and needles simply out of principle)

now, with the four bowls, you've got the main fuel delivery tube


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and the main entrance valve from the fuel line.

i started looking and listening and feeling a little closer and, danged, if in twisting that main spigot coming from the tank, you just can't feel the grit in there.

sprayed carb cleaner all through the delivery tube, sent compressed air through it as well. don't even want to go near dismantling the carb (as a unit) into it's constitute carburetors so i can get at that fuel entry area, clean it out for good and all, and figure out a way to put a gasket around the openings to help prevent dirt and particulates from seeping in (thus - crudding up my float valves again).

any ideas out there? or should i even be giving such a sh!t? is it a concern, or something just to spray some deep creep or wd-40 into every now again to make sure at least the crud is lubricated and not scratching and damaging the fuel delivery tube?

thanks guys (and no doubt - the occasional woman around here) for the time and thoughts.

 

Sounds like the tank is shedding. A little overspray is normal from the factory. Has your bike been painted recently? Possible that the particulate matter you found is also from rust. Clean out the tank, pull and clean the carbs. Back-flushing the carbs wouldn't be a bad idea but make sure you have sufficent volume to accomplish this, a can of WD-40 ain't gonna cut it. Failing that, pull the carbs apart and blow them out that way.

 

are you recommeding dismantiling the carbs as a unit to get to the grit that is prevalent in the linkages b/w the individuals?

i've ordered a petcock kit,new float gaskets, valves and needles to set the stage for neutral but am incredibly hesitant in attempting to rebalance the carbs as a whole. trying to find a way that i can clear the gunk out w/out having to re-adust level and such.

any ideas?

 

You don't need any gaskets usually or valves and seats either unless yours are badly worn. Usually just a good cleaning will do but you have to polish the inside of the seat with something like the small end of a golf tee to get it shiny clean so the float valve will seal. Then adjust the float level and you should be in good shape.

 

The flooding is from one or more stuck floats, and/or the float levels are set too high. You're going to be needing to schedule carb tear down & cleaning (see the XJCD), and I'd reccommend installing an in-line fuel filter.

 

Let's do a quick overview so we can center in on the right course of action and concern. Fuel comes through the petcock and into the carbs where it must get past the float valves "someway" in order to fill the float bowls. It doesn't not have to get past the float valves to cause fuel to spill out onto the engine. If the fuel is leaking out of the main fuel tubes which pass through the carb bodies thne the float valves are doing their job and the fuel passage orings are shot. If the fuel passages are not leaking and fuel is getting past the float valves, filling the float bowls and spilling into the intake and air box then the petcock is definately not working or set to PRI. and the float needles are not seating for one or more of four reasons. 1. the needles are worn and can't seat. 2. the float is stuck and unable to rise and the needles can't seat. 3. the float height is set too high and the needle can't rise enough to seat. 4. grit or gunk is obstructing the needle so it can't seat.
So if you replace the needles #1 is taken out of the equation. That leaves #2. The float will stick for two reasons. 1. unable to pivot on the float pin. This can be due to rust, a bent pin or a part of an old gasket obstructing it's path. So no need to replace the float but a good reason to check the gaskets to see if they need replacing. The pin can be straightened and polished to allow free movement.
#3. Failure of the float to rise sufficiently is due to either a miss set of the float tang or the float is leaking and filling with fuel or the float has been installed upsidedown. The float needs to float. Best check is to remove and shake it and listen for fuel inside the float "then" in case the fuel has leaked out submerge the float in fuel and look for bubbles. The bubbles will lead straight to the hole. This is the only reason to replace the float.
Now if the floats are allowing the carbs to flood there is no real problem with fuel delivery but there could be a problem with gunk or grit delivery. So when cleaning the carbs remove the floats and blow out the passages above them. Since they are interconnected ter is no reason to seperate the carb bodies to clean them. You only have to seperate to change the orings. Spray them out with Berrymans B12 followed by compressed air.
Then reassembly the carbs and check fuel height via the clear tube method and you will know that the height is correct and that the float needles are seating.

 

is it possible you could provide me with a photo of the o-rings you are mentioning?

i know i've got flooding issues b/c of the petcock, but the main leak/flood seems to be coming from bowl #2.

 

One more to add: if the tank or fuel lines are "shedding" particles of whatever, that can also get stuck in the needle seat area, which also will cause the the needle to not shut off fuel flow.

another way that gunk from the tank can get through the petcock filters is if one of the screens has come off of the petcock "towers" located inside the fuel tank. There are 2, with the "reserve" tower and screen being the shorter of the 2.

BTDT with the XJ9. HTH,

-Matt

 

Did you ever get this sorted? I have a similar problem. This quote from one of the posts particulary intrigued me, is it correct?

"If the fuel is leaking out of the main fuel tubes which pass through the carb bodies thne the float valves are doing their job and the fuel passage orings are shot."

 

Partially. You can have leaks from the fuel supply tubes even if the floats aren't doing their job; they're "upstream" of the float valves.

My "project 650" has completely failed o-rings, it absoltuely PEES gas out of the junctions between the fuel distribution tubes and the #2 and #3 carbs. It also has at least two solidly stuck floats. Two independent problems...