'78 GS1000 Carb OD - Prepping for Velocity Stacks

[Guest]

I am currently running K&N Pods but will be going stacks in the not too distant future. I will not be installing them until I add the Motogpwerks exhaust. I currently have a V&H 4-1 header running to a Yoshimura RS-3 muffler. I have a Dynojet S3 ready to be installed but just need to know if Im missing anything additional in preparation for the stack install. Also, what is the OD of my carbs?

Matt

[Big T]

the OD is 43 mm

You might need bigger main jets when you switch to stacks, but some retuning is going to be required

[azr]

Why do you have a Dynojet stage 3 kit for VM carbs? With the VM carbs the main needles are adjustable. You'll need some extra main jets I guess, possible one up on the pilot as well? but you've probably already done that with the pods and 4 into 1

[stetracer]

I am currently running K&N Pods but will be going stacks in the not too distant future. I will not be installing them until I add the Motogpwerks exhaust. I currently have a V&H 4-1 header running to a Yoshimura RS-3 muffler. I have a Dynojet S3 ready to be installed but just need to know if Im missing anything additional in preparation for the stack install. Also, what is the OD of my carbs?

Matt

if you already jetted for K&N pods then your jetting will be very close as the K&N filters flow very well and will be close for the velocity stacks well maybe up one size on the main jet for the exhaust or move the needle clip down one notch.
I myself would not run on the street with stacks. It just for racing on a clean track. Way to much dirt on the street to run with no filters. You jet it to run mean which is just on the lean side and it will run fine with the filters on the street.

[mattfeet]

Why do you have a Dynojet stage 3 kit for VM carbs? With the VM carbs the main needles are adjustable. You'll need some extra main jets I guess, possible one up on the pilot as well? but you've probably already done that with the pods and 4 into 1

Well, the carbs haven't been rebuilt since I bought the bike from the PO last summer. I rode it quite a bit and there is a noticeable hesitation until ~3,500 - 4,000RPM, at which point it RIPS. I assume a good carb cleaning isn't a bad idea and I purchased a new Dynojet S3 kit and O-rings to replace everything with as I'm not sure what's already installed. I could always just reinstall what's currently there but was told by folks on here that, for my GS1000 with 4-1 and pods, a Dynojet S3 is the recommended setup.

Matt

[Big T]

Matt

I'm all for just rejeting a VM, but I think you'll find the DJ needle is thinner and should cure that midrange bog

[Sliim280]

Ive got a 78 gs1000 with pods, 4 into 1 mac and no baffling. I have just installed a stage 3 dynojet kit and am still having some trouble getting it. I have the 142 jets installed and the needles adjust in all but one clip and still getting a bad bog at about 5500 revs under heavy throttle. It was popping at idle so i turned mix screw all way in until it stopped popping but still have bog at 5k revs. Any suggestions? Thanks