Smoke from carbs and oil leak

[Guest]

Hello all, this would be my first post to this website. I'm having a bit of a problem with this GS650E that I bought a while ago. I have a some mechanical experience from my previous bikes but this one has given me the most challenging tasks. It runs fine, I think. The problem is the oil leaking from the 4 caps that are on the ends of the head cover. I'm not talking about the circular metal caps, I'm talking about the half moon seals that are under the circular metal caps. The oil seems to be leaking past those four seals. I bought a head gasket and unfortunately it wasn't a perfect fit. However, it was only slightly off. Replacing the head gasket did fix a few other leaks but not the seals. RTV doesn't work because I can't dry the oil on the engine enough before applying it. No matter what the oil seems to find a way past the RTV. I ordered new cap seals to see if that might fix the problem. Has anyone else dealt with this?

My other dilemma is the smoke coming from the carbs. After reaching normal cruising temperatures, the carbs seem to emit smoke that smells like gas. Could this be a jet problem? Or seal problem? I'm not sure what to think of this. It only recently started doing this.

[tom203]

If it smokes and leaks oil, it ain't running "fine". The camcover gasket should be perfect fit- get a suzuki one (for right year) not aftermarket. Get new half moon seals. Spend lots of time carefully cleaning gasket surfaces and don't even think about rtv sealant.
the carbs smoking could be a sign that your petcock has failed and is dribbling gas into crankcase where it evaporates and heads to airbox and on to carbs courtesy of that hose on top of camcover. Do you understand the three positions on your petcock?
Note that there are two versions of the camcover gasket for this bike- one has extra bolt hole.

[mikerophone]

First of all a little clarification is in order - the head gasket and the valve cover gasket are 2 different things. The half moons are in the valve cover gasket, and you may need some hondabond or permatex grey RTV. Some gaskets come with them attached, some separate, depending on the model. Clean the half moons really well, as well as the metal mating surfaces (I've used a little simple green or alcohol to clean them, VERY lightly smear inside the half moon openings with a small amount of hondabond or permatex and place the VC gasket on/in there. Make sure it's even, then turn all the bolts down (criss cross pattern so they are evenly seated) but do not fully torque them yet.

Let the Hondabond or RTV set up a bit then torque them to spec - which isn't very tight...don't go gorilla on it, and yes you need a torque wrench, until you get a feel for it.

Smoke coming from your your actual carbs seems very unlikely. My best guess is that the smoke is jut coming up around the carbs from your exhaust or crankcase. Gas could very likely be leaking out of the overflow, vent or fuel tubes in which case - STOP RIDING AND STARTING THE BIKE UNTIL YOU REMEDY THIS. Fires can and will start this way and your bike will be a smoldering heap of metal if you aren't careful. Sorry to sound harsh, but this is a real possibility if you smell gas and see smoke.

[chuck hahn]

The seals ( half moons ). Remove the cover before the gasket gets set and stuck down too much. Remove the half moons. Next use some carb spray on a rag and clean the head where the half moons sit in. Spray the half moons off good too and let them dry..or dry with the compressor air.

Next apply RTV ( I use either Ultra Black or Threebond 1184 ) to the half moons and insert into the head and settle them in but not quite tight to the bottom and see that they are pretty level across the tops in relation to the gasket surfaces. let them set about 15 to 20 minutes to let the RTV start to set but not fully cure. Next apply a thin smear across the top of the half moons and a little past the edges and reset the gasket and cover.

As for the carbs. Have they recently been rebuilt??? I would check the float hts and be sure they are correct. I also would be looking at the sight glass to see if the window is completely full or not. A completely full window ( without a little air bubble gap at the top ) is indicitive of a possible crankcase getting fuel into it from a malfunctioning petcock. remove the oil fill cap and stick your nose in the hole and take a good whiff. If it even remotely smells like there may be gas in the oil drain it and the filter. NOTE::: The proper way to check oil level is with the bike on the center stand. Reading oil with the bike on the side stand gives a false level and you will over fill the crank case.... Check the petcock does stop fuel flow.

Never leave the petcock in the PRIme position. Prime should be used only to refill the bowls if carb maintenance is done or the bike has sat a long time and fuel has evaporated from the bowls.

There are two ways a petcock can leak. From the diaphram not shutting off flow from the main fuel line nipple or down the vacuum to the carb suction tube. To see what is possibly leaking, get two soda bottles and two lines. Run a line from each nipple to its own bottle and let it set a day or so and then see if there is fuel in ether bottle. If there is this will confirm the petcock is going south...and which side is actually leaking. Rebuild kits are a waste of money. get a new OEM Suzuki petcock if one is needed.

[chuck hahn]

Do a valve adjustment also when the cover is off. What year is the bike??? There are a couple 650 service manuals here..center column. And there isnt one thing wrong with reusing the half moons and some sealent..just dont go bat crap crazy with it. I have reused the same half moons dozens of times ..but its your choice i guess if you want to buy new ones everytime theres a need to remove the cover.

http://members.dslextreme.com/users/bikecliff/

[notalex92]

Ok so I received the new half moon seals today in the mail. They definitely have a more rubbery texture unlike the old ones which felt like hard plastic. After installing them, the oil leak seems to have completely stopped. Now my only problem is the smoke coming from the carb area. I opened the oil cap after warming up the engine a bit and there was smoke coming from inside the crankcase. It definitely smells like gas. i removed the gas tank to check the petcock functionality and it seems to be working as it should. Prime lets gas pour into the carbs, on stops fuel flow unless the vacuum of the engine pulls. The petcock is working as it should. How does fuel manage to invade the crankcase anyway?

Also, thanks for the help guys. This is my first 4 cylinder bike. Twice as complicated as my first bike which was a twin cylinder.

[notalex92]

The valve cover gasket that I bought came straight from a Suzuki OEM parts distributor. I even bought both gaskets, one for each engine number, because the VIN search utility to find out my engine number wasn't working for my VIN. The one had an extra hole. The other was almost a perfect fit but it wasn't completely perfect. This is my only transportation to and from work so I had no choice but to use it and it seems to be doing what it's meant to do.

[tom203]

"Prime lets gas pour into the carbs, on stops fuel flow unless the vacuum of the engine pulls. The petcock is working as it should. How does fuel manage to invade the crankcase anyway?"

to be sure about petcock, get some clear vinyl tubing that fits snugly on petcock's vacuum fitting. Suck on it- fuel should flow down outlet to carbs, but no fuel should be visible in the vinyl tubing. No fuel visible ? Then your carbs need attention , as one or more are overflowing and fuel is running down intake track into cylinders and winding up in crankcase diluting the oil.

[JTGS850GL]

Gas will get into the oil if your carburetor float valves are not closing properly.