GS1000G with pipes from GS550

[von reckless]

Just bought an 81 GS1000G. When checking the final drive gear oil, I noticed that my pipes are not attached to the frame of the bike. I checked the frame for stays; they're there, but the exhaust is not bolted to them. Then I check the pipes for mounting brackets; they're there, but facing down and not attached anywhere to the frame. On further investigation, I see "GS550" stamped in the pipes. First, the pipes don't seem loose (I don't think they'll fall off). BUT, my questions are about the valves and carb jetting. Is there sufficient back pressure found in these pipes so as not to create valve or other engine damage? And, secondly, should the carbs be rejetted to accommodate these pipes? Ultimately I want to know if I should keep the pipes or look for either original pipes or good alternatives (I read some comments about Harley pipes in this forum). Advice?

[Guest]

I do believe those pipes are just too restricted. The engine needs to breathe, and it's stopped up with those pipes.

[Agemax]

yep, the 550 pipes will probably give you too much back pressure as they will be smaller internals than a 1000cc pipes. they will restrict performance. also having no secure mounts on the rear will be putting excess strain on the down pipes if that is all that is holding the exhaust onto the bike.
you should get some correct GS1000 pipes of some description.

[Brendan W]

Sounds like the PO was a bit of a bodger. Hopefully all he did was bolt on the 550 cans and left it at that. A stock 1000 set up will bring you back to a reasonable starting position.
The nightmare scenario is that he tried to 'derestrict' the 550 cans and started tricking around with jets or even attempted to put 550 ....... no not going there.
Somehow I think if he left the cans hanging that hasn't happened and he just bought the first thing that would fit.

[von reckless]

Thanks for your comments. I shall begin to look for stock pipes. Indeed, the PO was a bodger (I'm not sure what that is, but it sounds too mild): drain plug stripped, filter cover not put on tight enough such that sandy grit was inside the filter area (fortunately the spring was holding the filter in place and so I don't think grit got into the crank case).

Thanks again.

[Brendan W]

Bodger is a fine word with a distinguished history featuring fine craftsman and wood spring powered lathes in the woods back in the day.
It's modern usage refers to a repairer who uses parts originally intended for something else. They are humanoid, believe that duct tape is a natural resource and their natural habitat is dumpsters.
For the stripped plug and loose filter another word is required