TOPIC:

I had a thorough carb cleaning done a couple months ago. From what I understand, these bikes are notorious
for the "down stream" carbs leaking if the side stand is used. Is this a gasket problem, or is it something internal that is not keeping the gas from overflowing?
Would switching to a standard petcock help solve the problem as well? And if so, what would be involved in converting to a standard petcock? This is a completely stock bike (for the moment) and therefore has all of the emmisions systems still in tact. I plan on lowering the bike and will be removing the centerstand.
Is there a way to keep the carbs from leaking while on the side stand?
Thanks for the help.

I have had problems with this myself. I have cleaned and rebuilt my carbs and replaced my petcock to no avail, the problem remains. If your bike is leaking fuel, check to see if any of it is getting into your crankcase, if it does, you'll want to change your oil and filter. This happens to me if I leave the fuel on overnight. The easiest solution (if your petcock doesn't leak) is to remember to shut the fuel off when you're done riding it and/or put your bike up on the centerstand. I have had a heck of a time learning this, but the $15 it cost to change the oil and filter help to keep me from forgetting. If you still leak fuel with the petcock turned off, check your vaccuum lines or replace your petcock with a manual one, this costs about $20-30.

There is no "OFF" position on a vacuum operated petcock.
The carbs only leak when I use the side stand. they leak outof the 2 downline carbs and drip fuel onto the case, leaving a nice stain in the process. They are fine when I use the center stand. However I plan on lowering the bike and taking the centerstand off of the bike.

You do not say where the fuel is leaking .
With the fuel shut off the only fuel available to leak would be that in the bowl unless the shut off valve is not working properly.
With the bike leaning on the side stand the carburator float would also be tilted with the fuel in the bowl remaining level. I believe this could cause some fuel to leak out the overflow and, also, leak into the cylinder.

The 750E has an overflow tube so I would suspect they leak out the overflow. On CV carbs not equipped with an overflow, the gas comes out the needle jet and out the intake side venturi (also leaks into combustion chamber). The reason for the leak is that the bike's fuel supply isn't shutting off when vacuum from the engine stops. In other words, you need to fix your vacuum diaphragm on the petcock. If fuel shuts off, the leak stops. The leak is due to the only gas shut off being the float needle/seat. This mechanism was never intended to be the ONLY means of shutting off gas supply to the bowl if the bike is parked. If you buy a gravity petcock, you will have an OFF position that shuts off gas and this will work or, as noted, fix the diaphragm on your current petcock.

It seems to be seeping out between the bowls, and the carb bodies. I'm not getting any fuel in the oil that I can tell. No gas smell, and no problems starting or running. Also no signs of fuel coming out of the overflow tubes.

I'll take a pic after work so there is something visual to refer to. Thanks for the input so far

Post edited by: Draco, at: 2006/08/11 14:47

Post edited by: Draco, at: 2006/08/11 14:48

Draco wrote:

It seems to be seeping out between the bowls, and the carb bodies.

Bad bowl gaskets ???
These are O ring type gaskets and there are some junk ones out there which expand when the bowl is removed and are next to impossible to put back in place properly.

JR - Sending you a private note. Please have a look at your U2U. thanks!
wg

JR wrote:

Bad bowl gaskets ???
These are O ring type gaskets and there are some junk ones out there which expand when the bowl is removed and are next to impossible to put back in place properly.

throw them in the freezer for awhile to get them back to normal size, just watch out for condensation