Won't take any throttle.

[Lbrown311]

Yo fellas...I got one of the bikes fired up today. The battery was the major issue on why it wouldn't stay running. Problem now is that once I give it even a little throttle or take the choke off it dies. I am going to clean out the carbies completely even tho the last PO said he did this. He also had the floats way out of wack and I believe 3 different kinds. (Anyone know the right floats to get for the 81H?) I will bench sync and set the idle mixture to spec while doing this. Is there anything else that I could be looking for. My thought is that it isn't getting enough fuel and too much air so it won't run as soon as air is let thru. My guess is the carbs are nasty. I did put the old style floats in and set them to height, but didn't mess around with anything else. I adjusted the Cam chain cuz it seemed loose. That helped a bit but it just doesn't want any throttle. Let me know any thoughts to try before I rip the carbies off to see if I can get it to accept any throttle. Thanks boys.

[BA80]

The carbs are where to start.

[TopCatGr58]

Hey Lance,

The 81's take the plastic floats, not the brass ones! The pilot jets are probably all clogged up as well as the main/nozzle. Mine acted that way after sitting for several months during the winter and I had forgotten to put seafoam in the fuel before parking it! Cleaned the carbs and it then responded and accepted throttle input, until then it would die with any attempt to give throttle!

T.C.

[Lbrown311]

Sounds like no fix but to take em off.

TC-

The 81's take the plastic floats, not the brass ones!

-do you know which ones I can purchase that will fit, cuz my 80SG had a float in there that would not rise to close the needle due to the geometry of it catching on the bowl. I know parts'n more has some, but they have two different ones. Does MikesXS have the correct ones? Just wondering so I can get the right floats the first time. Does anyone else have an 81 that would know the number that is written on the float. The 81H I have has three different numbers on the floats that are in there. If I can figure out which ones are the right ones I can maybe just order the correct floats that are like the others. Unless all 4 of the same new ones would be a better idea. Which may be the case. Not sure if the plastic floats get affected by the gas and aging over time which would make them unlike the new ones. Therefore creating different boyancies and affecting the mixture in each cylinder. I think I just talked myself into getting 4 new ones LOL. So the correct float will be all I need.

[natemoen]

Mikesxs does have the plastic floats, although there have been some quality complaints but many are using them problem free.

If you went with genuine yamaha/mikuni oem floats (if they are even available) I think you could get away with only replacing the oddball ones. If you go will mikesxs float do them all case I would not trust them to float the same.

[TopCatGr58]

Hey Lance,

The Official Yamaha Part # is:

3H5-14985-00-00 MSRP= $47.36 EACH

Mikes XS and Partsnmore both carry the float # 20-6502

Mikes is $20.00, PNM is only $13.00
[quote] Partsnmore listing:
Carb Float

#20-6502 | Yamaha XS1100G (1980-1981)

US$ 13.00

Fits: XS1100G (80-81)

Plastic Carb Float OEM Ref#3H5-14985-00-00


Partsnmore says the 20-6502 is the match for the Yamaha #, and PNM and Mikes use the same #'s, from probably the same supplier.

It's a little hard to find on PNM, don't look at the 80SG, but just the 1100 and then universal, carbs, and you'll see them!

T.C.

[Rasputin]

Like the guys have said it is likely a dirty carb issue. The one thing that comes to mind is that you may have a vacuum leak. Quicker to check for that than to clean carbs.

[petejw]

i noticed u said u set the floats to 'height",
there are 2 different settings for the early
and late model carbs, what height did u set them at?

id also be checking ur pilot jets for blockage.

[Lbrown311]

I set the floats to the correct height for the late models (23 or so mm...can't remember off the top of my head.) which is what the 81H uses, but with the brass floats. I also read a thread that stated that it doesn't matter which float you use, but you set the float to the year of the carb VERSUS the float to the year of the float. The PO said he checked for vacuum leaks and is on the site. That doesn't necessarily mean anything so I might have to check that. Either way I will be doing the carbs myself as the first bike I did them on works like a champ. I kinda left that one alone as I did some inventory on my parts today and worked on the 79F. Starting to look like a naked 79 Standard finally.

[BA80]

Why have you downgraded to brass floats Lance? You still have the SH carbs on there right?

[crazy steve]

...I also read a thread that stated that it doesn't matter which float you use, but you set the float to the year of the carb VERSUS the float to the year of the float...

Nope, got that backwards; you match to the float, not the carb. Two very different shapes....

And you managed to get the brass floats into the '81 bowls? Those are smaller than the early style, that may part of the problem too.

[BA80]

This is a perfect example of what I've been ranting on lately. Get it running good on the STOCK parts before you go changing $hit up or your just creating problems upon problems.

If you don't know how it's supposed to work in the first place how are you going to know how your "improvements" are affecting it.

[Lbrown311]

Well the thread I read said that the dude tried out the different floats and said you set them to the height it says in the manual for that year of carbs. Wish I had time to find it but maybe I will try later. I don't want the brass floats in there just wanted all the same ones to check it out. There was a float in that didn't shut at all cuz it caught on the bowl and leaked like a stuck balloon. I am buying all new ones it sounds like.