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V&H 4:1 & K&N Inbox - suggested jetting

salty_monk

salty_monk

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Past Site Supporter
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For my GS1000G - leaning towards fitting the V&H pipe now as long as it will fit with my Krauser cases.

Anyone got any idea of jets I'll need. I know Kent has this setup in his 1100 & I believe he runs a 120 main with a DJ kit.

I was thinking of trying the 122.5 mains I already have, stock canadian needle up 1 groove & give the pilot screws a turn out...

Stock main is 115 on my bike but it runs quite lean with the K&N Inbox & stock exhaust although with the 122.5 it seemed it ran rich.

I also wondered whether I should drill the slides out a little as I know Kent did this. Currently they are stock at 2.4mm.

Any thoughts?

Dan :)
 
Hey Dan,
I'd try the 122.5's since you already have them, and move the needle like you noted. Don't mess with the slides until the mixture is right at steady state, the slide vent hole will effect transition mixture.

Good luck.
 
I did your V & H mod on my 1000L with the K & N last summer and bumped my pilots two sizes and left the orig main jet in. I also shimmed my stock needles with two Radio Shack washers. I am currently a little rich on the pilot circuit at approx 3/4 turn out on the pilots. I am thinking of going down to one size over on the pilot, opening up the new pilot to 1 1/2 or 2 turns out and bumping the main one size. It runs almost perfect thru all ranges but searches a little bit on idle when coming off of harder throttle. My plugs are a little on rich side but I prefer to run slightly rich than lean. I get a little intermittant light popping on hard decel but think I am pretty close to having it where I would like it. Good Luck, I love the new pipe and seemingly extra power. I have a straight pipe H/D person across my street and the "hood" needed some sweet inline four cylinder music.
 
On my 1100 before mods, 4-1 and K&N in the box I ran 47.5 pilot (2.5 over stock) 127.5 main (107.5 stock) and shimmed the needle rich 1.5 notches or three washers. (not adjustable needle)
I also have a complete Dynojet stage 3 kit without needles and 138 mains.
 
80GS1000 said:
Dan-

I've got the stage 1 Dynojet mains from the jet kit I bought for the pods. Want 'em?

The stage one is for the stock airbox plus a good pipe like your V&H.

Here's their jetting directions: http://www.dynojet.com/pdf/3103.pdf
Click to expand...

Hi PJ,

Yes please! Thanks mate. Presume they work ok with stock needles?

Changing the mains is the worst bit... I don't mind so much messing around with the needles after that as they are easy enough to do whilst the rack is on the bike so if I know I have those correct then it should be half the battle.

I presume that part number they give for the drill is actually in inches. 7/64" is 2.78mm. This makes sense as stock mine are 2.4mm.

On the needles that I have at the moment there is a small washer under the Eclip (which I can set in 1 of 5 grooves). Is that normal to have a washer there? I figured it was there to make a better interface with the spring but perhaps someone did it to go half a stage richer.....
There is a thick plastic one on the top.

By the way, did you here DJ just got fined a million bucks by CA for selling products that can mess with emission control equipment (power commander's I think...)

Cheers,

Dan
 
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I hate those air boxes. That is the main reason I switched to pods.
 
Typically, megaphones make their power at higher rpm's and above 2/3 throttle, so they want more fuel at higher rpm's, 2/3 to full throttle. The jet needle and pilot circuits aren't effected as much.
With basically a stock intake, I'd try 1/2 position richer on the jet needles.
I'd try a 7.5 increase over stock for the mains. Maybe 10 considering the K&N.
I'd try richening the mixture screws before considering a larger pilot jet. 1/2 to 1 full additional turn richer is probably good.
I'd leave the vacuum passage to the diaphragm chamber alone. If after testing you feel the throttle response is poor, then enlarge them. I don't think your mods will require drilling them.
 
Do I need a washer between the E clip & the spring as is there at the moment or would that be something added on by someone else rather than being stock?

To 1/2 richer I could move the Eclip down one groove lower but remove the washer that's there... would that work or am I already one half setting richer?

Thanks for advice as ever!

Cheers,

Dan :)
 
salty_monk said:
Do I need a washer between the E clip & the spring as is there at the moment or would that be something added on by someone else rather than being stock?

To 1/2 richer I could move the Eclip down one groove lower but remove the washer that's there... would that work or am I already one half setting richer?

Thanks for advice as ever!

Cheers,

Dan :)
Click to expand...
I'm not sure about the washer you mention. I'd look up a parts illustration on your model to see if it belongs there but I'm too lazy. It could be factory or it could be placed there by a PO thinking he was altering the jetting. But for your purposes, jetting, that washer isn't effecting the jetting placed as it is.
If you want to go 1/2 position richer, then find out first what the stock/factory jet needle e-clip position is (often position 3 from the top but you need to verify that).
If it is position 3, then place the e-clip in the 4th position from the top (1 lower) and place a jetting spacer directly on top the e-clip to achieve position "3 1/2". Generally, a full position is approx' .045", so you want a spacer about .022" (standard jetting spacer).
 
V&H 4:1 & K&N Inbox - suggested jetting

What I have is V&H 4:1, K&N pods and for the main jets 137, no other modification to the carbs, plugs seems to be rich, but I prefer to be in the rich side. The bike runs very good at low RPM's but like a beast at high. The bike is a GS1100E '83
 
Thanks Keith, yes stock is three & I'm pretty sure I have a set of washers the right size too. I'll probably leave the washer under the E clip then, it makes a nice transition to the spring & if it doesn't affect jetting placed there then that's fine.

I think the mods will be done towards the end of Feb then I'll report back.

Cheers,

Dan :)
 
OK. Good luck with it.
I just took a look back at the post that had the DJ stage 1 info, which is the stage you would be using. I was curious about their main jet choice.
I can't understand how their suggestion of a 118 would work with a K&N drop in and a quality 4-1 pipe. Based on what you said, your stock main is Mikuni 115. The approx' equivalent DJ main would be a 122 or close to. So their 118 would be even leaner than stock?? Makes no sense to me.
I'll still stick to my suggestion of an increase of 10...a 125 Mikuni main.
 
Maybe they are comparing to the stock on some of the other 1000's which is 107.5 from memory....

Dan :)
 
82 gs1100s katana

82 gs1100s katana

interesting thread. thank goodness for the search button....

last winter i put a v&h 4into1 along with the k&n filter in the airbox. the vance and hines suggested a 122.5 main so thats what i put in. it ran good but seemed a little boggy in 5th at high rpm. still i rode it most of the summer. when i pulled the seat off to do a little maintanence i noticed the filter smelt of gas. i figured it was rich and switched to a 117.5 main with no other changes. 107.5 was the stock main.

after reading as much as i could on jetting i am thinking i should make some fine tuned changes. at first i thought about lowering the main size from 117.5 but after reading this thread maybe i shouldn't. its 10 difference as someone suggested. now what? change the needle position? which way? from what i read the main only comes into play at full throttle. was i running lean all summer by not changing the needle circlip? i checked my plugs after a ride and they seemed fine. rich(smelt gas) with the 122.5 but fine with the 117.5. didn't do the chop but if it was lean it still should have shown up as i didn't change the pilot or the needle.

another thing i am thinking is how can a change of the main not effect anything until full throttle. when the fuel passes the needle it still has to go through the main. i understand that the fuel has to pass the needle first but still it has to go through the main. if the main was to small the position of the needle would make no difference as the fuel flow could only flow at the rate that could pass through the main. does this make any sense to anyone? now i am really confused.

the more i learn about working on bikes the more i realize i don't know anything at all.

p.s: i have read the pdf files "in search of free lunch", "things the factory never told you...", and "needle and needle jet". good theory but now i need a little practical.
 
Yes, in your case, the bike would be running lean on the pilot circuit and jet needle.
As for the main, it's the SMALLEST opening in the combined jet needle/main jet circuit that controls fuel flow.
The fuel first enters the main but the space between the TAPERED jet needle and needle jet is smaller at any throttle position less than 3/4. As the needle rises up through the needle jet, the thicker portion actually leaves the jet needle area and the lower/thinner portion comes into effect more and more. As the needle rises, the space between the two parts becomes larger than the opening of the main jet. At that point the main now controls flow because it is the smallest opening in the entire circuit.
As you can see, the tapered needle is designed to make a smooth/gradual transition to the main jet.
 
thanks for the explanation. i will move the needle position before riding.

anyone have a good site to order jets?
 
You can still order the Mikuni OEM jets from Parts Unlimited, or others. I ordered pilots from PU last year and they were about 2.50 each as I recall. There are a lot of posts here on bad aftermarket jets.
 
So I went with the V&H. Looked at the Jardine 4:2 set I had, they would fit but more hassle & I couldn't be bothered!! Want to ride.

Ended up with Mikuni 122.5 main, Canadian Needles Up one notch, air jets are 180's, pilots are 40's. Screws out about 2.5 turns. Floats set to bang on stock, both sides etc checked with a vernier.

Short run today, different bike, much smoother, will pull better through all the gears, do things in third it wouldn't have wanted to do before etc.

Couple of things....

1. There is just a "hint" of "popping" when on overrun, I figure this might be normal with the V&H can

2. If I really gun it & open up the throttle too quickly in 2nd gear I get a backfire through the exhaust (doesn't happen if I am more progressive with the throttle).

One thing I should note, the gas is at least a month old in there & has some "sea foam" in it plus maybe remnants of carb cleaner etc from having the carbs out.

Dan :)
 
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Dan,
Might be worth the experiment to move the needles up another notch; richens the mixture accross the range which usually doesn't hurt anything.
 
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