Running rich

[BLOWCLVL]

You said 26 for the floats? You may want to check that again if it is an 80SG.

What should they be.

[skids]

You said 26 for the floats? You may want to check that again if it is an 80SG.


Here is a good thread (if it works) for carb floats on an SG:

http://www.xs11.com/forum/showthread.php?t=45977&highlight=float+height

It seems that some 80 models had earlier carbs, and some had morphedited carbs with earlier and later parts.

PS, the later carbs floats are said to nee 23mm heights as measured upside down and no gasket in the way.

[motoman]

Custom pipes but have baffles. It was stock rubbers used and they are not blocking anything. I just ordered a set of 100 mains plus a set of #40 pilots.

As Ray stated, 42.5 pilot jets are stock for that yr. model

110 mains across all four are stock main jet size for that yr. model.

23mm is float level setting(carb body gasket surface WITHOUT gasket).

BTW, whats happening is float levels are way to low(26mm) and fuel ends up being drawn to much and too fast based on venturi velocity making it too rich....and all at once!

[BLOWCLVL]

You said 26 for the floats? You may want to check that again if it is an 80SG.


Here is a good thread (if it works) for carb floats on an SG:

http://www.xs11.com/forum/showthread.php?t=45977&highlight=float+height

It seems that some 80 models had earlier carbs, and some had morphedited carbs with earlier and later parts.

PS, the later carbs floats are said to nee 23mm heights as measured upside down and no gasket in the way.

floats were set to 26 with the gasket as per Yamaha dealer. (don't trust them usually) I will set them at 23 without gasket and se how things go.

[motoman]

floats were set to 26 with the gasket as per Yamaha dealer. (don't trust them usually) I will set them at 23 without gasket and se how things go.

Unless that dealer himself was 55+yrs. of age AND factory trained on the XS1100, AND was actually the one who did the work........neither him nor anyone else there had a clue when it comes to working on these ole' scoots.
Best to learn these bikes yourself and from the knowledgable ones here.

[BLOWCLVL]

Unless that dealer himself was 55+yrs. of age AND factory trained on the XS1100, AND was actually the one who did the work........neither him nor anyone else there had a clue when it comes to working on these ole' scoots.
Best to learn these bikes yourself and from the knowledgable ones here.

well he was about 50 ish lol but yes I learn as I go and from help here

[motoman]

well he was about 50 ish lol but yes I learn as I go and from help here

Very good!........and your best option to sort out bikes issues based on any mods. made(exhaust,etc.).

[skids]

I am 61 so I guess I am a damn EXPERT! :-D

[skids]

As Ray stated, 42.5 pilot jets are stock for that yr. model

110 mains across all four are stock main jet size for that yr. model.

23mm is float level setting(carb body gasket surface WITHOUT gasket).

BTW, whats happening is float levels are way to low(26mm) and fuel ends up being drawn to much and too fast based on venturi velocity making it too rich....and all at once!

These things will probably get you closer. Bear in mind that once you do those, you should start with mains and once you dial them in, then work on the pilot circuit. You drive yourself crazy when you change too many variables at the same time (except for the above).

[motoman]

I am 61 so I guess I am a damn EXPERT! :-D

.....still younger than I, but your getting there.

[TopCatGr58]

Hey there,

What someone said in an earlier post raised a red flag for me. In 80, Yamaha had some carb bodies left over from the 79 year and did some strange stuff until they used them all up and moved on to the proper 80 carbs.

The 78-79 use a larger MAIN partly because they use a SHARING TUNNEL between the Main jet tower and the Pilot jet tower....and the fuel for the pilot jet was supplied from the main jet and thru that sharing tunnel,and so the Pilot jet tower was actually sealed with a large head screw!

In 80, some of the carb bodies STILL had that SHARING TUNNEL and the Main Jet NEEDLE/Emulsion tube also had the opening in it to allow the fuel to go from the main jet tower into the Pilot jet tower to fee the Pilot jet, and so even though they used the smaller 110 sized mains, they also had RUBBER caps covering /sealing the Pilot jet towers so that the pilot jet would only feed from the sharing tunnel supply....BUT if the caps were left off, then the pilots were DIRECT feeding from the float bowl AND the sharing tunnel, and would cause them to be overly rich!

SO...check your carb bodies for that sharing tunnel and opening in the main jet NEEDLE/Emulsion tube and if it has it, then your pilot jet towers need to be capped/sealed with those rubber caps, and this is what may be causing the overly rich condition. But if they don't have the sharing tunnel, then would still suggest you closely review/examine the pilot jets for the Mikuni Logo to ensure they are GENUINE....the aftermarket K&L and other brands are not sized/metered the same and run much richer than the Mikuni.

T.C.

[BLOWCLVL]

Hey there,

What someone said in an earlier post raised a red flag for me. In 80, Yamaha had some carb bodies left over from the 79 year and did some strange stuff until they used them all up and moved on to the proper 80 carbs.

The 78-79 use a larger MAIN partly because they use a SHARING TUNNEL between the Main jet tower and the Pilot jet tower....and the fuel for the pilot jet was supplied from the main jet and thru that sharing tunnel,and so the Pilot jet tower was actually sealed with a large head screw!

In 80, some of the carb bodies STILL had that SHARING TUNNEL and the Main Jet NEEDLE/Emulsion tube also had the opening in it to allow the fuel to go from the main jet tower into the Pilot jet tower to fee the Pilot jet, and so even though they used the smaller 110 sized mains, they also had RUBBER caps covering /sealing the Pilot jet towers so that the pilot jet would only feed from the sharing tunnel supply....BUT if the caps were left off, then the pilots were DIRECT feeding from the float bowl AND the sharing tunnel, and would cause them to be overly rich!

SO...check your carb bodies for that sharing tunnel and opening in the main jet NEEDLE/Emulsion tube and if it has it, then your pilot jet towers need to be capped/sealed with those rubber caps, and this is what may be causing the overly rich condition. But if they don't have the sharing tunnel, then would still suggest you closely review/examine the pilot jets for the Mikuni Logo to ensure they are GENUINE....the aftermarket K&L and other brands are not sized/metered the same and run much richer than the Mikuni.

T.C.

So how do I know then if the towers are sharing. Is there something visible I will see?

[Bonz]

See this thread, post #5 for a pic. Please someone correct me if what I say below is incorrect as a simple summary of the plugs.

http://www.xs11.com/forum/showthread.php?t=46114&highlight=Tunnel

If your carbs have the pass-through shown by the paperclip, there needs to be a plug over the smaller hole. If you don't have the passage then no rubber plug is needed.

[BLOWCLVL]

See this thread, post #5 for a pic.

http://www.xs11.com/forum/showthread...ghlight=Tunnel

Perfect I'll have a look tonight or tomorrow.

[Bonz]

Excellent! Keep us posted.