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Carb OEM specs as per factory manuals

OK, I'll give this one crack.
What pilot jet do have in there?
I believe stock main jet is 80, so 95 with stacks sounds about right.
The fuel screw under the carb should be closer to 1 full turn out.
Air screw is close.

You might get a better response if you start a new thread.....
 
allojohn said:
OK, I'll give this one crack.
What pilot jet do have in there?
I believe stock main jet is 80, so 95 with stacks sounds about right.
The fuel screw under the carb should be closer to 1 full turn out.
Air screw is close.

You might get a better response if you start a new thread.....
Click to expand...

Thanks for the answer.

Pilot jet is 15" original
Main now 80" original Mikuni
I newer buy aftermarked jets again ! They dont work at all.
Will go for 95" Main Mikuni.

Should the Air Screw on Top be fully closed ?
 
Pfaffe1 said:
Thanks for the answer.

Pilot jet is 15" original
Main now 80" original Mikuni
I newer buy aftermarked jets again ! They dont work at all.
Will go for 95" Main Mikuni.

Should the Air Screw on Top be fully closed ?
Click to expand...

Air screw should about 2 full turns out.
Use the highest idle method - adjust the idle to about 1,250 rpm and adjust each air screw in half a turn then back it out as you listen to the engine for highest idle.
Then adjust the idle to 1,250 rpm and move to the next carb, repeat.

BTW, have you adjusted your valve shims lately? If the valve shims are not within spec you'll always have trouble adjusting the carbs.....
Then of course you will need to balance the carbs with a vacuum sync...
It's a continuing battle with these old machines.....
 
allojohn said:
Air screw should about 2 full turns out.
Use the highest idle method - adjust the idle to about 1,250 rpm and adjust each air screw in half a turn then back it out as you listen to the engine for highest idle.
Then adjust the idle to 1,250 rpm and move to the next carb, repeat.

BTW, have you adjusted your valve shims lately? If the valve shims are not within spec you'll always have trouble adjusting the carbs.....
Then of course you will need to balance the carbs with a vacuum sync...
It's a continuing battle with these old machines.....
Click to expand...

Hi, bike is running nearly fine. 105# main, 15# pilot jet, needle midt pos. ( was on 4 th. ?), Mix screw down 2 turn out, air screw up 2 turn out, float 24 mm, new O-rings, Engine Valves shims correct.
I need new needles ( worn ) 5DL36

Thanks for help and answers
greetings
Bernd
 
Thanks for the link.

Light snow today....warmed up a bit from the weekend. Think -25ish vs -32.....not bad lol
 
I have a 1977 gs750 that was my dads, I have recently did a tear down of the carbs and a did a complete rebuild, I would like to know if anyone has the factory settings for the needle valve, fuel/air, and how I need to sync the carbs. the bike has the stock airbox and exhaust.
 
jamuso, not to be too snippy about it but why not use the "Search This Thread" box? Putting '"GS750" into it gets me all kinds of 750 stuff.

also for a shop manual that has the info and much else goto BikeCliff's Website
 
Burque73 said:
Lets see if this works. I've been following your search for answers on this and found specs in the GS 700 manual linked to on Cliff's site.

View attachment 61084

Rats, it's too small to blow up. Check here though.http://zeus.mtsac.edu/~cliff/storage/gs/GS700_supplementary_service_manual.pdf
Click to expand...


Cool, thanks Roger! I also found this:

View attachment 61094 http://gsarchive.bwringer.com/bikecliff/images/carbspec_float_height.html

Not sure why my jets are different than the specs. Could it be because the previous owner had a K&N filter in the air box? I got K&N pods and a Dynojet kit which calls for the Main Jet to be 130. Would I need to change other jets for this reason and if so what do I put if the Main Jets are 130? This is what came on the bike when I bought it:

"(in parenthesis)" = Chart/Manual specs

Main Jet: #120 (#122.5)
Main Air Jet: ? (1.7 mm)
Jet Needle: 5D10, but with the kit its a DNT604 (5C-28)
Needle Jet: Y-7 (Y-5)
Pilot Jet: #40 (#37.5)
Throttle Valve: 135 (manual says 135, but not chart... weird)
Pilot Outlet: ? (0.7 mm)
Valve Seat: ? (2.0 mm)
Starter Jet: ? (#45)
Pilot Screw: 2.5-3 turns (pre-set)
Pilot Air Jet: 155 (chart not specified, manual says pre-set, part #09493-3200 says 160)

I would like to know the ones I have "?" marked. How can I find these? Starter jet, is that the one that's built in, for the choke?
 
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Hello mate. I got hold of a '79 850 and did the same. Did you work out the turns to get the mix initially right? And the needles? If you had any success and can remember the settings, it would be really cool if you can divulge. I'm over in the UK in Cornwall so it's probably night time over your side. Hope to get a response from you soon. All the best.
 
LOTS of pages here so I don’t know if it’s been posted before (did a few searches so I’m fairly confident it hasn’t lol).

GS 550 L
1983
Mikuni BSW30SS Model

Carb (2 separate carbs, twin bore)
bore size 30mm (1.2in)
id no 43510
idle r/min 1100 +/- 100r/min
fuel level 6.5mm +/- 0.5 (0.26 +/- 0.02)
float height 20.5mm +/- 1.0 (0.81 +/- 0.04)
Main jet: cyl 1 and 4 #95 cyl 2 and 3 #105
Main Air jet 1.0mm (0.04in)
jet needle SC64-1
Needle Jet P-3
Throttle valve # 120
Pilot Jet #35
By-pass 0.8/0.7/0.8/0.8mm (0.03/0.02/0.03/0.03in)
Pilot Outlet 0.7mm(0.02in)
Valve seat 2.5mm(0.10in)
Starter jet #55
Pilot Screw............. pre-set
pilot air jet # 150
throttle cable play 0.5-1.0mm(0.02-0.04in)
choke cable play 0.5-1.0mm(0.02-0.04in)
 
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