Carb leak (or fluid on carbs)

[Joe Garfield]

Ok so I'm back at this problem. After cleaning things up, the bike has sat for awhile and was transported. I just started paying attention to it again and noticed a good amount of fuel on #1 and #2 and decided it's time to start pulling things off.

I noticed a lot of fuel around the intake port - I thought that was a little odd. See pic (link).

The tank is sitting in normal position with both petcock hoses in a clear container. It doesn't look like anything is dripping but I want to give it another day (check when I get home from work today). The petcock was recently replaced with OEM unit.

I removed the carb assembly with the float bowls full of fuel. If I tipped the carbs slightly, fuel visibly seeped from #2 where the float bowl meets the carb body.

The carbs have been cleaned and rebuilt. I do recall seeing a slight tear or hole in one of the diaphragms, so my thought was to replace all the float bowl gaskets, and probably replace the diaphragms with aftermarket. I also want to look closer at any O-rings at the carb interconnections.

http://s36.photobucket.com/user/JoeGarfield/media/IMG_1389_zpsoaqzxgam.jpg.html?filters[user]=141891675&filters[recent]=1&sort=1&o=0
http://s36.photobucket.com/user/JoeGarfield/media/IMG_1386_zpsnfa3bp2c.jpg.html?filters[user]=141891675&filters[recent]=1&sort=1&o=1

The reason I'm saying all this is I plan on leaving the jets alone, and I'm not doing a complete overhaul (although I'll check the condition of the jet plugs while I'm in there). The carbs were fully rebuilt within the past 2 years, but I forget exactly if anything was reused other than the slides and jets/hardware.

I also don't know if the float valve should have stopped fuel prior to it reaching the height of the gasket? I'll inspect the floats and pins and measure the float height, and I'm planning on getting the homemade plug barb so I can measure fuel height.

I assume I'll need help balancing the carbs, again, after this is done (well, after I complete the top-end refresh I'm planning).

[Joe Garfield]

It looks like its all coming from the float bowl gaskets. The float bowl screws weren't very tight (I unscrewed them with an Allen ratchet bit and 2 fingers), and the float bowls' sealing surfaces look like they'd been filed at some point. All the leaking was between the float bowl and gasket, not between the gasket and carb. I'll replace the gaskets and either have a shop dress the bowls, or maybe do it myself if I can get a free granite sample or something big and flat enough to work on.

The diaphragm I was worried about (which shouldn't affect a fuel leak) was #2 - two or three tiny pin holes at the crease where it folds away from the groove in the carb. Its hard to justify a new set of diaphragms for that at this point - I'd rather get to the top end refresh and leave the carbs alone until next scheduled (or needed) service. If I had the work space, I'd love to take the carbs apart and refresh some other parts (springs and nylon spacers on starter lever, e.g.) But...I don't.

The petcock is working fine. So the last thing I have to do is check float valve function and fuel level. I can't believe it's proving to be this difficult to find a ready-made tool tool! There's one on Z1Enterprises' website (https://www.z1enterprises.com/fuel-l...ki-suzuki.html) but it says it's for the VM carbs, which have a different P/N than the BS34 for the drain screw; I've read the BS34 drain screw is 6mm by either .7, .75, or .8 thread pitch. I'll bring one out to measure but I can't spend endless amounts of time on these things like I used to. There are cuts in the threads in the carb so I don't want to try the 'threading a plastic hose' method.

I also need to figure out how to check float valve function. I'm hoping I can do this with the floats still in the carb. I'm basically working in a small space on a garage floor so intricate parts are not as easy to work with.


I guess I'll add in here that there are a few main things I'm trying to address with this and a top end refresh. So these are my main priorities - if something like the diaphragm was a likely cause for any of it, I'd go ahead and replace the set. I don't think it is though, especially since it didn't show up with the carb sync, but that's really more of a guess. I'm sure on some small level it has an affect but I'm assuming it's hidden in the noise of everything else.
1) obviously a fuel leak
2) heavy oil use and smoke
3) one broken exhaust stud
3) vibration - most noticeable below 5000rpm - even after carb sync