Vance 4-1 GS850 Exhaust Jetting Question

[snowmobilejon5000]

1981 GS850, stock-sealed air box, new oem filter, Vance & Hines Street 4-into-1 Megaphone Exhaust System I just bought

http://www.bikebandit.com/vance-hines-street-4-into-1-megaphone-exhaust-system?b=287624

What jets should I run? Mains, pilots, shimmed yes or no? I tried to contact Vance and they said the information is not available for this model.

Any information would be greatly appreciated.

Thanks,
Jon

[Big T]

Stage 1 Dynojet kit- for the needle

[snowmobilejon5000]

what jets should i go to? All I find are stage 3 kits. Where can I get a stage 1?

[chef1366]

Mr. Big is trying to give you the easiest way to get your bike to run perfectly. The Dynojet needle is what you really pay for. It is an adjustable needle with a nice taper to let more fuel flow which is what you need with a free flowing pipe.

http://www.dynojet.com/jetkits/

They do not sell them as cheap as some other places so you may want to shop around.
You can also go a few sizes on the main jet and shim your jet needle. Shimming the needle is removing the pastic spacer on top of the needle and replacing it with less heigth of washers. You can find the washers at Radio Shack.
On the the main if you run a stock 115 I'd install a 122.5 or 120. They go in 2.5 increments. Check Denniskirk.com for jets.

[snowmobilejon5000]

cc 850, suz 80-83 all gs850 8 valve, stage 3, part#3306, price 125.89. They only have stage 3, will this have the correct taper needle? I already have a whole slew of jets. The jets included in this set are 155, 160 and 165 mains which are way too big.

[chef1366]

As I said the money you pay for is for the needle. You can by mikuni jets the size you need, The stage three kit is for pods and aftermarket pipe.

[AJ]

With the stock airbox and stock air filter, you may not need to re-jet much at all.

Read this article: http://www.factorypro.com/tech/carbt...m_engines.html and try it. You won't damage your engine by short runs and you'll know pretty quickly if it's got good power or not.

You can try shimming your stock needle using the little washers from Radio Shack. You could buy your own parts to go up a main jet or two, but at that point you might as well buy the jet kit.

Also, the K&N filter for the stock airbox is pretty cheap ($35 from Amazon).

[Steve]

Look at the '81 850 in my sig (#2 son's bike).
It has a pipe that I am told might be a Jardine.
Not real loud, so might not be considered "free-flowing".
We have 120 mains and stock needles in there and it runs quite well.

.