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GS850 carb jetting driving me nuts.. what's stock?

  • Thread starter Thread starter 86turbodsl
  • Start date Start date
8

86turbodsl

Guest
I've got a 79 GS850 with an 80 head and CV BS32 mikunis. Done the full teardown, and carb dip, etc. This bike hasn't run yet. I have two full racks, one carb on one rack was missing all jetting. So after cleaning everything, what I have doesn't fully match any commonly described jetting posted here or in my haynes manual.

For mains, I have 112.5 and 115. Most commonly seems to be 115's on US bikes.

For pilot jets, i have 40 and 42.5's

For pilot air jets, i have 170 and 180s

For emulsion tubes I have X5 and Y4.

needles I can't see any writing, but I haven't taken them out of the slides.

I've read a lot of conflicting information various places. What's the right combo to start with?

I'm in the midwest, about 1000 ft elevation.

I really don't want to install and pull carbs 5 times until it runs right. Bike is stock other than the changes I mentioned. Carbs are black magic in my opinion. I'm far more comfortable with EFI and a wideband sensor.

Any suggestions on a calibration to start with? I'm ok with buying jetting if needed to get the right parts.

Thanks!
 
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Ok, that link says to use the following:

main jet needle jet jet needle pilot pilot air jet pilot jet
115 X5 5D50 preset ? ?

The haynes I have says this:

115 X5 5D50 na 190 40

or

115 x6 5D57-3 3.5 200 42.5

another post here says :

115 x6 5D50 2 180 40


they can't all have been stock or can they? different cals for different locations?

Just pick one or ?
 
OK I can safely say our BS32 took a #40 pilot jet As we just had to replace our Pilot Jets.

The rest from what I can see goes like this:

Main Jet: # 115
Jet Needle: 5D50
Needle Jet: X-5
Pilot Jet: #40 (As stated above)
Starter Jet: # 32.5

Air/Fuel Mix Screw is preset no need for adjustments.. Though in our chilton book it states anything 1978 and older is 1.25 turns out (But this appears to be for the VM26SS carbs) just for future reference.

Hope this helps ya!
 
At the top of this forum is a carb spec sticky. It's there so people can find it easily...if they look that is. Here is a direct link from that thread to the 1980 GS850 carb specs... http://www.thegsresources.com/_forum/showpost.php?p=286664&postcount=20

You can, should, download the factory Suzuki GS850 service manual from basscliff's site (for free). The manual has the carb specs too, in fact the info on that thread came from the FSM's. Knowledge is power.http://members.dslextreme.com/users/bikecliff/
 
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Hi,

I found this on some guy's website.

Click the link...

Carb Specs: Float Height/Jetting/Tuning




Thank you for your indulgence,


BassCliff​
 
I currently have a few 850s in stock, and most of them are ... well ... stock. :rolleyes:

The jetting I have seen in all of them is:
main jet: 115
pilot fuel jet: 40
pilot air jet: 180
jet needle: 5D50
needle jet: X-5
starter jet:
shrug2.gif
(I have never looked)

I am also in the midwest at about 1000' elevation, but have travelled around a bit and been from sea level to over 8000 feet with no problems.

.
 
You guys appear to be getting a bit testy with me, but the issue still remains.

Nessism posted the sticky which says
42.5's and 200's for pilot.

Racinma posted he used
40's for pilot. No word on pilot air jet.

My haynes and the factory service manual don't even agree.
 
86turbodsl said:
My haynes and the factory service manual don't even agree.
Click to expand...

So which source are you going to believe? A manual from the company that built your bike, or a manual from an aftermarket company?
 
I work in the automotive OEM world.

I've seen factory service manuals be wrong too. Many times.
 
Hi,

No one's getting testy. We're just relaying the information we have. Plus, jetting is one of those areas where there can be some wiggle room. Jet according to whatever makes your bike run the best. I would start with the factory settings and adjust from there if you notice anything like bad plug reads or lousy engine performance.


Thank you for your indulgence,

BassCliff
 
You ask a question.
People try to answer your question.
People are getting testy?
I don't get it.
 
Well, Nessism pointed to the sticky and said people find it if they look. that sounded kinda testy to me. Maybe I'm just too sensitive. Sorry!

So the gist of the replies has been stay factory. I guess I have to decide what the factory actually used. I'm still confused on that one.

The factory manual i have doesn't list anything for pilot air jet. I can't get to the basscliff manual from this location. I'm gonna go forget about this for today....
 
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86turbodsl said:
You guys appear to be getting a bit testy with me, but the issue still remains.
Click to expand...
What do you mean "testy"?

Here is your original question:
86turbodsl said:
GS850 carb jetting driving me nuts.. what's stock?
Click to expand...

We are providing answers.
shrug2.gif


86turbodsl said:
So the gist of the replies has been stay factory. I guess I have to decide what the factory actually used. I'm still confused on that one.

The factory manual i have doesn't list anything for pilot air jet. I can't get to the basscliff manual from this location. I'm gonna go forget about this for today....
Click to expand...
You are right, there is no listing for the pilot air jet. Here is a cut and paste from the '80 portion of the manual:

GS850carbjetting.jpg


I can only offer the fact that ALL of the carbs that I have worked on for 850s (and that has been quite a few) have had 180 pilot air jets.
If you get a carb rebuild kit, they will sometimes include 180 and 190 jets, but all the stock carbs I have seen had 180s.

Good luck with your frustrated search, we can only provide facts from the books and carbs that we have seen.

.
 
Steve,

I appreciate your feedback very much.

I am sorry if I seemed ungrateful. I appreciate everything you guys do here. I'm just frustrated because I'm trying very hard to finish the bike for my birthday. End of the month. I got the bike in a box. It's been a while since it ran.

I'd pretty much decided the specs you posted originally are my starting point. Now I'm having trouble finding sources for these parts that won't take 2-3 weeks.

www.motorcyclecarbs.com seems to be offline.

Thanks again.
 
That motorcyclecarbs place was a rip off business. Stay clear. Several members here have posted negative info about them.
 
For parts at reasonable prices and shipping that should arrive in a few days,
CALL the good folks at Z1enterprizes.com
They have just about everything that you need for your carbs or can get them for you.
Most of what they carry/supply is NOT on their website.
Again, CALL THEM.

Daniel
 
Now that's what I needed to hear. I'll call them first thing tomorrow.

THANK YOU!!!
 
It's not looking good. Z1 doesn't have most of the parts.

I can get them from dealer maybe... anyone have mikuni parts sitting around?
 
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