GS1000 Vance & Hines Exhaust Carb Settings

[RyanBiggs]

Hey guys,

I'm getting close to the downhill slope on my top end and carb rebuild of my '79 GS1000E, and when I'm done I'm planning to put a Vance & Hines exhaust on it. I'm waiting to lay down the cash until I'm ready for the pipe, but I'd like to go ahead and finish up the carbs.

Anyone know what the carb settings (jets/needle) are for the Vance & Hines GS1000 pipe? Everything else will be stock.

Thanks!

[TeamDar]

The instructions that come with the V&H exhaust recommends the following: Remove the stock airbox lid and increase the mail jet to a 117.5 or 120. Adjust fuel screws one to two turns from seated. Dar

[RyanBiggs]

Thanks. So the needles don't move?

[TeamDar]

They don't recommend moving the needle. On the GS750 2 valve model they say to raise the needle one notch (lowering the clip). I would try it without raising the needle and if it doesn't like it then raise it. Dar

[RyanBiggs]

Fantastic, thanks, I'll start getting these things together. Let me know if there's anything else I should know!

[blizzard]

The instructions that come with the V&H exhaust recommends the following: Remove the stock airbox lid and increase the mail jet to a 117.5 or 120. Adjust fuel screws one to two turns from seated. Dar

What did the 79 1000 have for stock jets? I am interested in comparing this to the 78 1000 with a no-name 4 into 1 header that still is running stock jets.

[TeamDar]

95 is stock

[blizzard]

95 is stock

That is the same stock jets as the 78, so theoretically my bike would need ROUGHLY the same jet change for a header?

[drhach]

I just went through this on my 78 GS1000. I have a 4-1 of unknown origin. I think it is Vance and Hines but I don't know for sure. Also, I have a stock airbox and filter setup. Only the exhaust is aftermarket. Your Mileage may vary but I ended up with Mikuni 107.5 Mains jets, the Mikuni stock jet needles raised to the fourth position (highest/richest) and stock pilot jets (#15 I believe). She's running like a top now. I'll tell you, it's worth it to take the time to get it right. Don't settle for anything less.

[Big T]

That is the same stock jets as the 78, so theoretically my bike would need ROUGHLY the same jet change for a header?

It's really hard to know for sure, you just have to rejet until you get it right.

Good source - www.jetsrus.com

You should probably order some 110s, 115s and some #20 pilots as a starting point.

[TheCafeKid]

No...dont tell people that. Thats pretty irresponsible honestly, and would cause people to spend money needlessly.

First, there are PLEANTY of people on here who have put a VH pipe on a 1000, or just about any other available header on a 1000. Ask around, talk to some people. Someone will give you a better baseline to start than "you just have to keep jetting untill you get it right"

In general, with JUST the header, running the stock airbox and a Uni or KN filter in it, you're probably looking at 3 sizes up from stock. I dont know off the top of my head what the stock jet size on the 1000 is, but someone will. Your Manual will..(if you dont have one, get one.) So say your stock size is a 105 main. Go up three sizes 107.5, 110, 112.5. SO 112.5 would probably be where you want to be, but bracket it. Jets arent expensive, and its easier just to order some extra sizes rather than wait around if you guess wrong. You THINK you need 112.5 but I would also buy a set thats one size smaller, and one size larger than what you think you need.

Secondly, #20 is too big on the pilot for such a move. thats TWO sizes on the pilot if your stock jet is a #15 (which im pretty sure it is?) You SHOULD be able to get it to work withthe STOCK pilot jet, but some guys have had to move up. ONE SIZE to a #17.5

The final trick is getting the needle right. With your simple mod, i would try it in the stock position first, then if that seems too lean, drop it one notch. Jetting the VM carbs is WAY WAYAAAAAYAYAA easier than dealing with CVs, you just have to have a decent idea of where to start, and think about it logicly.

[RyanBiggs]

Hmm, makes ya wonder about the 117.5 or 120 V&H recommends then. But I suppose that's probably because you are leaving the airbox cover off?

Oh yeah, and I guess I should ask which pipe these numbers are for! (I forgot they make more than 1.) Is it the Pro Pipe or the "Megaphone" street exhaust? I'll want the quiet(er) one, already had my run-ins with cops over loud pipes!

[TheCafeKid]

Hmm, makes ya wonder about the 117.5 or 120 V&H recommends then. But I suppose that's probably because you are leaving the airbox cover off?

Oh yeah, and I guess I should ask which pipe these numbers are for! (I forgot they make more than 1.) Is it the Pro Pipe or the "Megaphone" street exhaust? I'll want the quiet(er) one, already had my run-ins with cops over loud pipes!

I dont KNOW what your STOCK jet sizes are so I am just giving you an example. You'll have to do the math yourself. If VH recommends a 117.5 or 120, what set up are they recommending it for?? Just the pipe? or pods? Lid off? Their recommendations, while again, might get you in the ball park, are just what they are. They're guessing just as much as you might be. But, if you do the common math, and bracket the jet size you come up with, you'll probably be safe and figure out what works best instead of just throwing money at it untill you get it right.

[TeamDar]

The instructions that come with the V&H exhaust recommends the following: Remove the stock airbox lid and increase the mail jet to a 117.5 or 120. Adjust fuel screws one to two turns from seated. Dar

This is for the street megaphone, on a 78-79 GS1000. They don't give instructions for the drag pipe. The airbox lid is the key. You must remove the lid for the instructions to be effective. Take the lid off of a bike that has been jetted correctly for the lid on and it won't run on the main jets. Try it. Dar

[RyanBiggs]

Sweet, perfect. Yeah, makes sense about the lid, that's a pretty clever way to get more air - never thought of that before. Makes me feel like this pipe might make more difference than I anticipated!

Thanks once more Dar!

CafeKid: The mains on this bike are 95s, as noted elsewhere in this thread. So that's why the recommended 117.5s or 120s seem big by your logic, but taking that airbox lid off is going to remove a big restriction so I believe it. It's a V&H tested configuration for a stock bike, so I would suspect it'll get me pretty close...