GS 1000 with 4-1 and airbox and K&N replacement

[jknappsax]

I have a 1979 GS 1000 that I'm getting ready to start carb jetting. I have what are supposed to be a Two Brothers 4-1 with a nondescript can muffler, and plan to use the stock airbox and a K&N replacement but no filterbox. My first question is: do you guys think using the replacement without the filterbox is OK, or use the filterbox and leave the lid off, or drill additional holes in the filterbox? I want better performance, reliability and stability, and decent fuel economy. I know, I'm asking for the world. With this setup, can anyone even hazard a guess as to various jet sizes and other settings for either the VM 26s or VM 29 smoothbores?

[robertob]

The instructions that came with my V&H exhaust said leave the lid off the filter box and install 117.5 main jets.

It works pretty good. I think the midrange is a little lean and WOT is a little rich but it's good enough for now.

This is with the stock 26s.

Old bikes like this have pretty crappy airboxes and there is a lot of power to be gained from ditching it. It's not like a modern bike where everything is carefully tuned...

[jknappsax]

Thanks for the input, Robertob

I appreciate the advice. So, you have a V&H, stock airbox and filterbox without the lid? What kind of filter are you using. I just ordered the K&N oem replacement.

[robertob]

K&N replacement.

I have a set of pods waiting to go on, I just need to scrape up the extra $100 or so for a DJ kit.