Topic: fuel leak on sidestand

[bikebodger]

one annoying thing my 750a sems prone to is fuel leakage from the lh carb when on the side stand.i have to always turn the fuel off..the stand is not bent but the bike leans quite a way.the stand is the correct one with the bracket for the neutral selector.is this typical or could i have a 400 stand fitted.the carbs are fine,float height etc & bike runs idles great.

[MoMo]

It was common practice back in the day to turn the fuel off.  You should do that every time.  Don't like the center stand?...Larry

[raymond10078]

Yeah - the fuel leakage when parked isn't an "auto-only" thing - I've read the same comment on this site many times (on the other non-auto forum threads).  The Owner's Manual says to close the fuel valve when parking the bike, and in another place says to turn the fuel on for use (implying that the fuel valve should be in OFF when not running).  Maybe that's why Honda later used a vacuum operated valve in the petcock's?

[MoMo]

I am sure you are right about the vacuum, plus the danger of fuel leaking on a hot exhaust leading to the possiblity of fire and subsequent lawsuit...Larry

[bikebodger]

thanks thats what i thought ,i always use the centre stand as where i park with the wide bars the bike takes up 2 parking slots.bike has just done more miles in a week than the last owner did in a year & all seems well.touch wood.

[750Ksabin]

Shutting your fuel off is good practice. But it still should not leak. There is a problem. Recheck float settings and look for wear at the float hinge.
Also check the overflow tube in the float bowl for damage especially near the top. On the side stand the fuel will be slightly higher in the bowl on all the carbs there for putting more  force on the needle so they should not leak.

[raymond10078]

IMO, if the carb doesn't drip on the center stand - I wouldn't do anything about it.  If it drips on the center stand, I may think about doing something.

Otherwise - from a "do less" approach, you could check the float levels easily without doing much of anything.  Just need some small clear hose - fit it on the bottom of the carb (to temporarily replace the drain hose), loop the hose up towards the top of the carb, and then open the fuel drain screw (on the bottom of the carb bowl).  If all of the float levels are the same (within a mm or so), then I wouldn't do a thing right now.  If one is off markedly, then you may want to do something about it.

Otherwise, you could pull the left/right plugs and compare them.  If one is rich/black and the other is white/lean, you should diagnose/repair the bike.

[LesterPiglet]

Heat alone Will not ignite your fuel so don't worry about that.  :-)

Sent from my GT-S5363 using Tapatalk 2

[bikebodger]

i have checked the float heights & all good.plugs are nice tan colour .however the lean when the bike is on the sidestand is a bit extreme.the pivot bolt is slightly worn & the bike has a nice new set of shockers.what is the standard shocker length.the rear wheel only just clears the ground when on the stand .i think slightly longer shocks have been fitted hence the lean.

[750Ksabin]

There is very little room inside the float bowl between the float and the side of the bowl. If the hinge is wore or one of the float sides is bent a little when the bike is leaned it will bind on the side of the bowl. This could cause the needle to stay open slightly. Keep in mind that on the side stand is not the only time a bike leans. For instance a sharp corner or a aggressive ride into a long sweeping curve. This will most likely never cause a major problem but could cause the offending carb to run rich for just a bit. (Just a note the float height may be correct and still be bent to wide.)

[raymond10078]

Keep in mind that on the side stand is not the only time a bike leans. For instance a sharp corner or a aggressive ride into a long sweeping curve. This will most likely never cause a major problem but could cause the offending carb to run rich for just a bit. (Just a note the float height may be correct and still be bent to wide.)

When riding the bike the centrifugal (some say centripital (sp?)) force is such that the fuel in the carbs stay pretty much like normal - at least side-to-side (as are the forces on the floats).  Your statement is true for a car, but not a bike that leans into the turn.

Regardless - it is a good thing to check - if need be.

[raymond10078]

Just re-read your first post - is the leakage around the gasket area only?

[MCRider]

one annoying thing my 750a sems prone to is fuel leakage from the lh carb when on the side stand.i have to always turn the fuel off..the stand is not bent but the bike leans quite a way.the stand is the correct one with the bracket for the neutral selector.is this typical or could i have a 400 stand fitted.the carbs are fine,float height etc & bike runs idles great.

I skimmed all the posts but i may have missed this. But its important enough to repeat.

On our old bikes, you should always turn the gas off when parking. In fact if you turn it off a few hundred yards from where you will be parking is even better. It pulls the float level down a bit. Modern bikes have vacuum operated petcocks which do this job for the owner, as no manufacturer could ever convince or educate the owners to do this sufficiently.

Still, as someone said, it should not leak with the gas on. But "should not" is not "will not" hence the rule to turn it off manually.

Also, you should not park the bike on its sidestand for extended periods. In your case, a float may be hanging up causing your overflow. Again, this should not hapen but using the CS makes it more likely it won't happen.

In the bigger picture, the oil will drain away from the uphill side of the motor. Using the Centerstand is a nice way to get the tire off the concrete as well.

[bikebodger]

the leakage is from the overflow pipe on the carb.the float level etc is fine & float is not sticking etc.i tried placing a piece of 1 inch thick wood under the stand.bike still leans but not as severe .result no fuel leakage.i think it is because of the angle it leans at.it only leaks a small amount of fuel & then stops it does not keep on flowing .

[MCRider]

the leakage is from the overflow pipe on the carb.the float level etc is fine & float is not sticking etc.i tried placing a piece of 1 inch thick wood under the stand.bike still leans but not as severe .result no fuel leakage.i think it is because of the angle it leans at.it only leaks a small amount of fuel & then stops it does not keep on flowing .

I'm no expert on carbs, but the basics. If there is fuel coming out the overfolw, either the float level is bad, the float is stickiing, or the float valve (I suspect this) is worn out and needs replacing.

Your experience with the lean and shimming the sidestand would be expected.

[stinkfinger]

No doubt theres a leak issue here but, Id get that kickstand leaning issue
fixed and see where your at. Ive had a few bikes with too much lean
on the sidestand and they all got worse over time. Mostly, just too much bending force
applied to a small area. Take a pic, lets see how mean that lean is.....lol

Tony

[bikebodger]

finaly sorted the damm thing,an occasional flood turned into a perpetual flood.checked everything all seemed good.however the lh carb float valve circlip attatchment affair that clips it to the float seemed to be touching the brass flat valve seat .removed the clip & all seems ok.either the valve seat is a bit worn or the float needle is a bit short.the floats & jets etc all look new so probably pattern stuff.main thing is the bike is back on the road,whoopee

[MoMo]

Perserverance pays off ...Larry