Yoshimura exhaust, jetting the carb to match?

[MB2]

I picked up a '91 GS500 with a yoshimura exhaust, and it seems to run really rich and likes to back fire...specifically back fire when letting off the gas/revving. My question is, what set-up should I run in the carb with this exhaust? I have a stock air filter, but I'll consider an aftermarket filter if ultimately it will improve performance and change the carb adjustments I'll want to run (I'd rather do it all at once then repeat a process).

This may or may not be enough info...I'm a total noob to the motorcycle world (I'm a Jeep guy, bought the GS a week ago after commuting on a scooter for a month) so please fill me in.

~Scott

P.S. Yes, I searched.

[BassCliff]

Greetings and Salutations!!

Hi Mr. MB2,

This is a very knowledgeable group and even though your bike is outside the focus of these forums, I'm sure you will get some good advice. There is a pretty good forum devoted to your bike over at http://www.gstwin.com.

Anytime you change the intake or exhaust you need to compensate for the added air flow through your engine. Sometimes this can be done rather easily with a Dynojet kit, a Stage 1 for a pipe only and a Stage 3 for a pipe with pod filters. Or you can manually change your own jet sizes until you get the right combination. A procedure known as "plug chops" will tell you if all of your carb circuits are adjusted properly. You'll find information about carb tuning and plug chops, enough to get you started anyway, on my website and in your "mega-welcome". Let's begin...

I just stopped by to welcome you to the forum in my own, special way.

If there's anything you'd like to know about the Suzuki GS model bikes, and most others actually, you've come to the right place. There's a lot of knowledge and experience here in the community. Come on in and let me say "HOoooowwwDY!"....

Here is your very own magical, mystical, mythical, mind-expanding "mega-welcome". Please take notice of the "Top 10 Common Issues", the Carb Rebuild Series, and the Stator Papers. Now let me roll out the welcome mat for you...

Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

Thanks for joining us. Keep us informed.

Thank you for your indulgence,

BassCliff