Four into one rejet

[duaneage]

I'm going to install a Marshall 4-1 on my 81 650G just as soon as the flowers come back out. My GS has the airbox and is bone stock, the only change will be this exhaust.

I've read old reviews that considered the 650G a little lean from the factory so I'm thinking of taking the main jet from 110 to 112 and shimming the needles slightly.

Anyone else have a 4-1 on their 650 G or L and done any rejetting? I don't want to blue the pipe with a lean mixture, I'd rather be too rich and back it off if anything. I don't think I'm going to need a full on DJ kit since it's a stock engine with airbox and foam filter in place. But the 4-1 will probably liven it up a little. It will also sound real nice too.

Anyone with a set of 112 jets in their case they can spare for my testing?

 

[Big T]

I don't have any experience with that combination, but I think you'd want to go 115 or 117.5 and go up one size on the pilot. I don't think one size will be enough

And, I'd shim the needles

Go to www.jetsrus.com - great service and great prices

 

[Nessism]

I don't think you will have to mess with the pilots with the stock airbox installed but I agree with Big T about needing more on the main.

 

[Guest]

I don't have any experience with that combination, but I think you'd want to go 115 or 117.5 and go up one size on the pilot. I don't think one size will be enough

And, I'd shim the needles

Go to www.jetsrus.com - great service and great prices

I agree
Remove the stock jet needle spacer and replace it with two washers.

 

[salty_monk]

I ran a V&H with a K&N Inbox. Up from 115 to 120 mains & up one slot on the needle.

That agrees with everyone else...

Dan

 

[landshark]

For my knowledge as much as everyone else's:
Wouldn't it be better (easier?) to go for a stage 1 Dynajet kit?
Or does the cost difference out way the effort?

 

[salty_monk]

The DJ kit will work as well but there is no need for it. A set of Jets is about $12 & $2 for a big bag of washers. A DJ kit is $120.

I ran my 1000G both ways, no real difference between the DJ or Stock.

I may have some 115 Jets still unless I sent them to Chef1366...

Dan

 

[landshark]

The DJ kit will work as well but there is no need for it. A set of Jets is about $12 & $2 for a big bag of washers. A DJ kit is $120.

I ran my 1000G both ways, no real difference between the DJ or Stock.

I may have some 115 Jets still unless I sent them to Chef1366...

Dan

Thanks for the info, i put in a DJ kit stage 3, but i am running pods and a race exhaust(dont know if the race exhaust makes any difference).

 

[Steve]

One more opinion here, agreeing with the need to go up more than one size. Two sizes would be the absolute minimum, three might be better.
My son's 850 has a similar setup (but with a pipe of unknown manufacturer), and jets two sizes larger.

I also agree about shimming the needle, just wanted to point out that the spacer that Chef mentions replacing is the plastic one above the clip on the needle.

Why not a DJ kit? Most of them also include new needles. With the minimal changes you will be making (just the pipe, no pods), a needle change will probably not be necessary. In this case simply changing the main jets and shimming the needle should be enough. If you were also going to switch to pod filters, the DJ needles would also be necessary.

.

 

[twr1776]

Today 12:54 AM salty_monk I ran a V&H with a K&N Inbox. Up from 115 to 120 mains & up one slot on the needle. That agrees with everyone else... Dan

I have essentially the same set up on my 1000 as Dan and I also bumped the mains two sizes (120), pilots one size (42.5), and shimmed the needles. It reads a touch rich but I prefer it that way and my mileage only dropped from approx 40 all over to around 37. I get no decell popping from any rev range and it pulls good all the way through.

The one thing I have heard is the DJ needle supplied with the kit is that it is more tapered than the OEM needle so you get more adjustment per the height notches but I do not know that for sure and have been happy with my results. It cost me about $ 30 to do mine for new OEM jets and the Radio Shack washers.

 

[Steve]

It cost me about $ 30 to do mine for new OEM jets and the Radio Shack washers.

You must have gotten raped on the main jets.

They are $1.60 each at Z1 for a total of $6.40. Add $6 for shipping, total of $12.40. The bag of washers is $1.99, should be at just about every store, but if you need to have it shipped, add a few bucks. Maybe a total of about $20 for the jets and washers. :-\\\

.

 

[twr1776]

Today 09:23 AM Steve Quote: You must have gotten raped on the main jets.
They are $1.60 each at Z1 for a total of $6.40. Add $6 for shipping, total of $12.40. The bag of washers is $1.99, should be at just about every store, but if you need to have it shipped, add a few bucks. Maybe a total of about $20 for the jets and washers.

But at least I got kissed.

Actually, the pilots and mains cost me $ 2.50 each x 8 from the dealership with no shipping cost. I also included the float bowl gaskets and washers in my rough cost estimate although the bowl gaskets are were in good shape and are now my "spare" set. Typical GS project, while I was in there I replaced the float bowl gaskets, air screw o-rings and float valve o-rings as well. I always figure there is no point in taking something apart and not replacing the rubber bits & gaskets if they are OEM or of unknown age. Now that I think of it, I might be low on my original estimate.

 

[duaneage]

I'm going to go with 114 and a set of shim washers. If the jets are cheap enough I might get 115 jets as well.

 

[Steve]

I'm going to go with 114 and a set of shim washers. If the jets are cheap enough I might get 115 jets as well.

Whose jets are you using that are 114? :-k

Mikuni jets go up by 2.5 and will be 110, 112.5, 115, etc.

Mains are $1.60 at Z1.

.

 

[Guest]

I have alot of jets I can slip in an envelope for you.
115 and 117.5? I'll have a looksy

 

[bwringer]

115 mains are stock on the 850+ shafties, so there are probably plenty of these rattling around in drawers out there.

 

[duaneage]

I have alot of jets I can slip in an envelope for you.
115 and 117.5? I'll have a looksy

That might be the way to go. I've not rejetted before and I'm not sure what to expect. I'll PM my address

 

[Skateguy50]

While everyone is on the subject got any links to pictures of this needle valve spacer adjustment stuff? I dont plan to open up my carbs again but curious if it may or may not help me. I get a little bit of hesitation up around 4-5k rpm then lots more power after that, well when my tach is actually working that is... (need to put stock valve cover gasket back in)

 

[rideOn]

I get a little bit of hesitation up around 4-5k rpm then lots more power after that, well when my tach is actually working that is... (need to put stock valve cover gasket back in)

I had the same symptoms around that engine speed. I also had some major decel popping. I just re-built the carbs with a soak and new o-rings. Have not put them back on to see the improvement yet. I'm waiting on new gasket and o-rings for the cam chain tensioner and tach fitting at the engine.

I had previously sealed the airbox up with rubber sealant and the needles were already shimmed, so i'm hoping for the best. Just have to wait and see and go from there.

 

[haggis905]

Not to highjack the thread, but my 79' 1000S has a Vance & Hines 4-into-1 and the original jets. I know that I need to rejet the vm carbs since I can't find original pipes, but can anyone tell me whether the main jet for the vm carb is the same as for the cv carbs? I have been looking for some time and cannot find any information.

TIA