• Required reading for all forum users!!!

    Welcome!
    Register to access the full functionality of the GSResources forum. Until you register and activate your account you will not have full forum access, nor will you be able to post or reply to messages.

    A note to new registrants...
    All new forum registrations must be activated via email before you have full access to the forum.

    A Special Note about Email accounts!
    DO NOT SIGN UP USING hotmail, outlook, gmx, sbcglobal, att, bellsouth or email.com. They delete our forum signup emails.

    A note to old forum members...
    I receive numerous requests from people who can no longer log in because their accounts were deleted. As mentioned in the forum FAQ, user accounts are deleted if you haven't logged in for the past 6 months. If you can't log in, then create a new forum account. If you don't get an error message, then check your email account for an activation message. If you get a message stating that the email address is already in use, then your account still exists so follow the instructions in the forum FAQ for resetting your password.

    Have you forgotten your password or have a new email address? Then read the forum FAQ for details on how to reset it.

    Any email requests for "can't log in anymore" problems or "lost my password" problems will be deleted. Read the forum FAQ and follow the instructions there - that's what we have one for...

  • Returning Visitors

    If you are a returning visitor who never received your confirmation email, then odds are your email provider is blockinig emails from our server. The only thing that can be done to get around this is you will have to try creating another forum account using an email address from another domain.

    If you are a returning visitor to the forum and can't log in using your old forum name and password but used to be able to then chances are your account is deleted. Purges of the databases are done regularly. You will have to create a new forum account and you should be all set.

Main Jet Question

  • Thread starter Thread starter Good Times
  • Start date Start date
G

Good Times

Guest
Ok fellers,

I'm waiting on brake parts to arrive so I decided to take a float bowl off and see what jets were installed in my 82 GS850GL CV carbs.

Am I correct? Is this a main jet from a Dyno Jet stage 3 kit?

b7d25cec.jpg


The stamp says 170 RD.

I am running K&N pods and a 4 into 1 Vance and Hines megaphone. If this is the case then I think this is the right setup correct?

I have wondered if the carbs were jetted correctly for the pods and pipe because of the amount of bluing on the pipes. But it could have been running lean from the old intake boots and "flat as a pancake" o-rings. Those have been replaced.

Thoughts?
 
Stock jets are Mikuni 115. Jetting for pods and a pipe should be about Mikuni 130 or so. Mikuni 130 is about a DynoJet 138.

If those are, indeed, DynoJet 170s, you are SERIOUSLY overjetted.

Are you sure those are main jets and not the pilot air jets that fit in the intake throat? Those can easily be 170s to be correct.

.
 
Actually I'm not sure about anything with the jets. This is the big jet that is between the floats when you remove the float bowl. That's the main jet correct? The one that picks up the fuel from the float bowl.
 
Last edited:
Yes, that is the main jet, but I think the pilot air jet is also capable of screwing into the same threads.

Some bozo might have put a pilot air jet in there just to have bigger jets.

.
 
Sooooo.....it ain't right.......

Looks like I'll be ordering up a DJ stage 3 kit.
 
Do you also have the rubber plug that goes over the pilot fuel jet?

If not, you had better get a set of those, too.

.
 
That is an EBC RD Precision brand Mikuni-Style Slot Head (SJ Prefix) Main Jet. Also 170 is the largest one they make.
 
Good Times said:
Looks like I'll be ordering up a DJ stage 3 kit.
Click to expand...

Why not just order (4) 120 main jets from Z1 Enterprises for about $12.00 with shipping and save a bunch of money first and see how that works?
Oh yeah, and the (4) well plugs for another $10.00 from Z1 while you are ordering some parts anyway.

Eric
 
Last edited:
Steve said:
Do you also have the rubber plug that goes over the pilot fuel jet?

If not, you had better get a set of those, too.

.
Click to expand...

Yes, I have that. I just took it out to see what was in there.

Steel Toed Tank said:
That is an EBC RD Precision brand Mikuni-Style Slot Head (SJ Prefix) Main Jet. Also 170 is the largest one they make.
Click to expand...

Just saw that after a quick search. It looks like a PO's motto was go big or go home. It was running a tad rich! :eek::eek:

Dang it.

Shouldn't surprise me with other stuff I've found on the bike. I'm betting he just stuck that jet in there.

I'm also betting that when I get these carbs right that I won't recognize this bike when I ride it. I already don't recognize it when I look at it.

:D
 
7981GS said:
Why not just order (4) 120 main jets from Z1 Enterprises for about $12.00 with shipping and save a bunch of money first and see how that works?
Oh yeah, and the (4) well plugs for another $10.00 from Z1 while you are ordering some parts anyway.

Eric
Click to expand...

Wouldn't you know that I am waiting on parts from Z1 right now. LOL
 
7981GS said:
Why not just order (4) 120 main jets from Z1 Enterprises for about $12.00 with shipping and save a bunch of money first and see how that works?
Click to expand...
The 120s would work if he had a rather quiet (restrictive) header and a stock airbox. That is what my son has on his 850.

However, Good Times also has pods, which is why I was suggesting something in the 130 range.

Might end up with 127.5, 130, 132.5 or something else, but it should be close.

.
 
Steve said:
The 120s would work if he had a rather quiet (restrictive) header and a stock airbox. That is what my son has on his 850.

However, Good Times also has pods, which is why I was suggesting something in the 130 range.

Might end up with 127.5, 130, 132.5 or something else, but it should be close.

.
Click to expand...

Ok, so this brings up another option for me as well. Here goes the can of worms.......open!

I also have a stock air box that I could go with. I think if I had a stock exhaust I would do that, but with the pipes I lean toward putting the pods back on.

Of course no one on the board has any opinions about pods vs. stock box right? :D
 
I had pod air filters and stock exhaust on my '80 850 and the cure was to just simply change the main jets from 115's to 117.5's on it.
As I ride at 4,000 feet and up elevation, that is why I suggested going to 120's.
Kentucky is a little lower than where I ride thus the 120 main jet suggestion. ;)
Jet as necessary.

Eric
 
Good Times said:
Of course no one on the board has any opinions about pods vs. stock box right? :D
Click to expand...
Take a look in my sig, see where it says "#2 son: 1981 GS 850G"?

Click the link to see what I think of that combo. :p

As I mentioned in post #11, we are running 120 mains in there with good results, which is why I was suggesting a few more sizes for the addition of pods. That header is rather quiet, so I would guess that most other headers would need another size or two on the mains, probably ending up around 130.

.
 
Just checked the pilot air jet and those are 175's. Definitely not jetted correctly.
 
Good Times said:
Just checked the pilot air jet and those are 175's. Definitely not jetted correctly.
Click to expand...
OK, the stock pilot air jets are 180, so the 175 is not that far off.
Interesting, though, I have only seen those in increments of 10.

Stock pilot fuel jets are 40. Even with your mods, you should do OK with them.

Stock main jets are 115, but with your mods, I still suggest about 130 (Mikuni). DJ jets would be 138.

.
 
Steve said:
OK, the stock pilot air jets are 180, so the 175 is not that far off.
Interesting, though, I have only seen those in increments of 10.

Stock pilot fuel jets are 40. Even with your mods, you should do OK with them.

Stock main jets are 115, but with your mods, I still suggest about 130 (Mikuni). DJ jets would be 138.

.
Click to expand...


Crazy that they had 170 mains and 175 pilot jets. Way more fuel than stock and less air than stock.

Thanks for the input Steve! :cool:
 
Good Times said:
Just saw that after a quick search. It looks like a PO's motto was go big or go home. It was running a tad rich! :eek::eek:

Dang it.

Shouldn't surprise me with other stuff I've found on the bike. I'm betting he just stuck that jet in there.

I'm also betting that when I get these carbs right that I won't recognize this bike when I ride it. I already don't recognize it when I look at it.

:D
Click to expand...

Just a guess, but I'll bet he jetted up that far to compensate for all the air leaks

Your gas mileage may vary
 
You must log in or register to reply here.
Back
Top