XJ1100 running rich and not sure why

Alright, this bike had been sitting for about 10 years and was rough. I cleaned the crap out of it (motor and carbs) and it will start now. Everything on the bike was stock, the exhaust fell apart when I took it off so I replaced it with a 4-1 system which should (I believe) flow better. I do not have the airbox so right not when I am running it there is no filter on the carbs. It is just being run in my garage at the moment since it is not street legal.

The problem shows up a couple minutes after start up you can see small amounts of smoke coming from the tail pipe. It produces a lot more when you rev the engine. The smoke stinks but as far as I can tell and have had a few others look too (mechanics) it appears to be black smoke. Stinks really bad too (stings your eyes) but does not smell like raw gas.

Looking at the plugs they are all dry and sooty black and when the carbs are pulled the boots going into the head are soaked in fuel.

I've had the carbs off and set the float level from the 20mm i found it at to the recommended 23mm, it made no difference in the amount of smoke.

Shouldn't a free flowing exhaust and intake create a lean condition rather than a rich one?

Since it smokes at idle and under throttle it makes me think that it could be my float level, but they are set to spec. The only thing that I can think of is that either the needle and seats are not sealing and over filling my bowls or the fact that I have removed the octo valve in favour of some on/off petcecks are somehow causing increased fuel pressure that is sinking the floats and over filling the bowls.

Are the overfilled bowls even able to make the bike smoke badly?

Anyone have any suggestions?

Needles in factory position, stock jets, float height @ 23mm.

 

Are you idling with the choke on? Thats my first thought. It is hard to tell a rich or lean condition without riding the bike. It is normal to see black smoke running it in the shop while goosing the throttle. My suggestion would be to finish the bike to get it rideable and then check your plugs. The idle mixture might be rich, a color tune will help with that. Be sure to adjust those valves before carb tuning.

 

I think you're probably burning oil.

Easy to check since you put on/off fuel valves on it. Start it up and turn fuel off. If it's still smoking when it stalls it's oil.

 

what color is the smoke blue means oil, white condensation, black is fuel. It is probably black since you said the plugs are sooty. if it was oil would be wet. My guess is float problem they are not at the right level or they are sinking from being out of gas for so long and they are soaking in the gas

 

I keep flip flopping back and forth to whether it is oil or running rich. Sometimes I think it looks blue other times black. Had a couple of mechanic friends look at it and they figured it was rich after looking at the smoke and checking the plugs. They are not wet at all but black and dry.

I tossed the floats in a small bucket of gas when they were all out to see if they were sinking and they all floated. Not sure if that test was any good or if they were in there long enough for a thourough evaluation. Seems weird that more than one would go bad.

Could possibly be running rich and burning oil? :roll:

I was expecting the bike to be lean, not rich. I checked all the plugs again today and they all look similarly black with #1 being the worst and #3 almost being perfect. I' ll post a picture of the plugs.

http://http://i593.photobucket.com/albums/tt20/stevestrom/project%20bike/P1020535.jpg?t=1294623811[IMG]

[IMG]http://i593.photobucket.com/albums/tt20/stevestrom/project%20bike/P1020535.jpg?t=1294623811[IMG]

 

The plugs in the picture are in order 1-4 from left to right.

I just stuck my nose in the crankcase and I am smelling gas in the crankcase so it's definately a problem with my floats sinking or seat not sealing. Somehow fuel is overfilling the bowls. Looks like I'll be pulling the carbs again.

 

Definitely gas. Check your floats make sure they float. check the needles and wet set the levels


Here is the link to stevestrom pic so you do not have to copy and paste it
http://i593.photobucket.com/albums/tt20 ... 1294623811

 

Alright, I don't think that I am much further ahead. I pulled the carbs tonight and hooked some gas up to the lines; I get no fuel coming out of the carb bodies, it all stays in the bowls. I then pulled the bowls off and took off each float to make sure that they float, they are all floating. I inspected the needle and seat for damage and couldn't see anything that would cause a leak.

I then put the floats back on and with the bowls off the carbs I lifted all four floats and poured more gas into a couple of lines fueling the carbs. I found no leaks, so the needles are seating fine.

So if its not leaking needles and seats, or sinking floats, and the float heights are all set at 23MM (checked again) Then what could it be?

Maybe I am measuring to the wrong spot on the float when setting the height. I am going to try to put everything back together and wet set the levels like cutlass suggested.

 

Well, I couldn't wait and I wet checked the float levels. They are all bang on. I have no idea where to go next, I guess smaller jet sizes?

 

What bike are you working on? How many miles on it? Battery good full charge? Gas or oil or condensation not sure which then hold a piece of paper in the exhaust stream and let it get saturated toss it on the work bench. Gas evaporates fastest then condensation (water) oil does not evaporate. The float level test you are doing must be the dry setting with the numbers your quoting you need to do it wet. If you want to make your life easier do a compression test Check/adjust your valves Check your coils before you start tunning. Do it right and you will be out riding screw around and you be right where you are now

 

Did you or the previous owner replace the jets in the carbs? I have found that most all pilot jets that come in carb kits are the wrong style and size. There are two different styles of pilot jets for Mikuni carbs. Most kits come with the VS style jet that is too large, the XJ1100 needs the BS style. I have had this happen several times, the VS jet will make the bike run rich. I usually have to order a set of pilot jets from Mikuni.
Here is a link to explain the difference.
http://www.mikesxs.net/products-39.html#products