Just do something

[wymple]

I had an exhaust leak on my recently acquired 850G. It sounded like a header gasket, but I felt the escaping gases down under, so I figured it was the packing on one of the inside cylinders. Off came the pipes and CRAP, the whole damn crossover collector is a rusted POS. I can't put that back on, I need the bike in a week for a biking weekend, and I don't have the time to wait for, nor the cash to buy an aftermarket set of pipes. So I put the pieces back on the bike without the crossover, and with a couple pieces of pipe set in place. Tacked it all together, took it off and welded it all up. I now have a pair of 2 into 1 pipes instead of 4 into 2. It is super quiet, and no more popping on deceleration. I can find something better anytime, but these are fine. I did have to use a little rust converter and coated everything with black high heat paint cause there was too much surface rust underneath for me to tolerate. I have good luck with the heat paint, the 1st time I fire the bike up after painting the pipes I head straight for the highway. A good 30-40 minute ride lets the paint cure properly without getting hot enough to blister or burn off.

[Griffin]

Congratulations on using your head to fix a problem.

Some of the older GSes originally had two into one exhausts on each side. I think they sound better like that anyway. If it's not too noticeable when looking at the bike, I'd sync the carbs and leave it as-is.

[robertbarr]

Congratulations on using your head to fix a problem.

Some of the older GSes originally had two into one exhausts on each side.

Yep, I'm about 99% sure the 79 GS850 had that setup. It was changed later -- probably with the CV's in 1980. I never noticed any difference in the exhaust sound from the 79 to later bikes.

[srg]

Are there any downsides and/or benefits to having a pair of 2-1 pipes as opposed to a single 4-2?

[wymple]

Darned if I can tell any difference

[jbthomp]

Speaking from my experience with car exhaust which is basically the same as a bike. The crossover pipe balances the pressure between the two banks of pipes and creates a flatter more even torque curve. Some people say that the exhaust note is different whether or not a crossover tube is used but i can't tell a difference. I would doubt you would notice a difference in a stock bike anyway.