Carb OEM specs as per factory manuals

pilot AND needle height shim for low end rescue

Mr. endlessGSgeek,

I have a manual in pdf format. I have a couple others in hard copy that I can scan when necessary. Sometimes it's easier to copy/paste/upload/post the specific information when a picture is worth a thousand words. I hope I'm not violating copyright when posting little bits like that.

BassCliff

I am sure you have nothing to worry about BaseCliff.

Lots of very useful tips in this thread. Thanks to all. The BS34 and smaller BS series Mikunis are good performers, but I have heard lots of nightmares about getting the low rpm range to behave. It is a high performance engine, and has to have intake valves (in particular) opening at the right time (clearance), need to be synchronized, need to have the right pilot jet to start with if you want it to behave when it isn't making much power. This is because power output needs to be balanced across the four cylinders. If two or three cylinders are not working as hard as others at low rpm because of jetting or synchronizing, YOU NOTICE IT!

I recently got a Morgantune (CarbtunePro) and synchronized my 1982 GS1100G. I have pod filters and a low restriction dual exhaust system (4into 2). George Lesho upped the main jet to a 150, and it DOES launch willingly above 4500rpm when it is warmed up (Jeez). Anyway, MUCH better after synchronizing, but still cold blooded as heck! Coughs and sputters below 2500 rpm, and even shows signs of being to lean when gently cruising at 3-4000rpm. I tried a Colortune, but it didn't fire near idle (not really a spark plug), so I could only guess on the airjets. I think I need to install one size higher, and maybe lift the needle by one ring.

Am I on the right track? Getting the needle to lift slightly soone may solve it, but It is SOOO cold blooded, it really seems to need a bigger pilot jet. Full choke, even when it is warm. High end performance is good though (main jet OK). I think it needs both needle shim (maybe one ring) and bigger pilot jet, because it won't idle and needs FULL choke when it shouldn't (pilot jet symptoms) and coughs and sputters at modest speeds cruising (needle not high enough). Can any body advise me on this??

I am really getting desparate

Bass Clef.. Where the heck did that info come from ? It looks like a table out of a factory manual.

Mr. endlessGSgeek,

I have a manual in pdf format. I have a couple others in hard copy that I can scan when necessary. Sometimes it's easier to copy/paste/upload/post the specific information when a picture is worth a thousand words. I hope I'm not violating copyright when posting little bits like that.

Thank you for your indulgence,

BassCliff

factory manual??

Bass Clef.. Where the heck did that info come from ? It looks like a table out of a factory manual.

BS34 for 81 GS1100G

I'd like to know what the stock GS1100G settings are (were, that is). George Lesho rebuilt my BS34 rack (after three months and sent me someone else's BS32 for a GS850G!). I was told he was a real professional, but he didn't even send a single piece of documentaion back with them. I expected notes on the rebuild, and at the ver least, a jetting report. I did pay the extra $28 for rejetting. I synchronized them and borrowed my buddy's colortune for airscrew adjustment, but I sure would like to know what was in there, and what is in there NOW!!

Anybody have 81GS1100G jetting info (OEM)??

The legend in the upper right hand corner says:

Unit: mm (in)

I would assume that means 22.4mm +/- 1.0mm or 0.88 inches +/- 0.04 inches for the float height. Doing the math, that's roughly 7/8" +/- 1/32".

I was told there would be no math today. :-D

Thank you for your indulgence,

BassCliff

carb oem spec as per factory manuels

Of course, I dont know what all the numbers mean for float level such as float height 24.+/-1.0 (0.95 +/-0.04). Needs to have more information as they do on cars like "float height 3/8 inch"

1980 GS850GT carb specs

Do you have these already?

GS850GT carb specs



Thank you for your indulgence,

BassCliff

I have more of a question

I have a 1980 GS1100. Love the bike, however I do have one problem. When I first start bike and ride, it runs fantastic, but after it gets warm, it tends to die if I come to a stop. So, I nurse the throttle when at a stop, and it is very sluggish, feels like it is loading up. Any ideas?? I just finish tearing down the carbs and cleaned them in hopes it would correct it. No luck. HELP

For 83 GS550E & ES. As promised...enjoy!

83 GS550E
Mikuni
BSW30SS
30 mm

It should have 43410 stamped on the side

Fuel level: 6.5 +/- 0.5mm (.26 +/-.02in)
float height: 20.5 +/- 1.0mm (0.81 +/- .04in)
Main jet:
cylinders 1 and 4: 95
cylinders 2 and 3: 102.5
main air jet: 1.0
Jet Needle: 5C64
Clip position: 1 groove from top
needle jet: P-2
Throttle Valve: 120
Pilot Jet: 35
Bypass: 0.8,0.7,0.8,0.8
Pilot outlet: 0.7
Float valve seat: 2.5
starter jet: 55
Pilot screw: Preset

Quick one, 2 of my clips are on the 3rd groove from the bottom and the otehr 2 clips are 2 from the bottom? Is this the proper setting? This post siad 1 groove from the top? the carbs have different size main jets so are the clip positions different to match the different jet sizes?

Thanks

Any update?

This thread has a lot of great info. Has anyone completed compiling the info into a more organized presentation?

PS: I'll add 1985 GS550E/ES specs for Mikuni BSW30SS twin two-barrel carbs soon.

Would this be the same for a 1980 gs850l?

CV Tuning Link

Hi Folks,

found this link on fine tuning CV's which looks like it might come in handy for some.

http://www.factorypro.com/tech_tuning_procedures/tuning_carbtune,CV,high_rpm_engines.html

Cheers,

Spot

Is the pilot screw refering the the screw on the bottom of the carb?? I have been trying to figure out wot this screw does, haynes does not mention it and my other manual on cd-rom just says, do not touch. If this is the pilot air screw, then great cause i doubt that it is set right and may be why my bike just wont run right.

so when i turn this screw out is it allowing more fuel or more air?? Im guessing more fuel as it is a mixture screw.

Missed the sticky somehow.

Looking for the info on my 86 550L. Pilot and needle jets, if there is 2 different needle jets in the same carb, what one is what? strange carbs, could have some strange settings. Float height. Needle? Needle setting?