GS650 carbs and fuel

[tom203]

Hopefully this can save a few 650s from being abandoned because of jetting issues, or let people pick them up and save them.

In my area, most of these bikes seem to develop problems due to poor maintenance and get passed around on craigslist- I'm amazed that folks think they can just hop on a 30 yearold bike and expect no problems. I respond to many CL isters and offer advice- less than 30 % seem interested in fixing stuff.

[Old guy]

Hopefully this can help a few people in regards to 650s that have been craigslist pass around bikes.

Like, "the PO said they rejetted the carbs for the mods"

[Sci85]

My stumble, and it is very slight, is at light roll on from steady state cruise.

And yes, I agree with you that the inner and outer cylinders might need different jetting as my plugs and the coloring on my headers indicate the outers are a little leaner running than the inner if I remember correctly. I need to pull the plugs and verify that however.

I really need to find a dyno so I can really get it right on. I'm oh so close but could would love to get her spot on. STL just isn't a hot bed of hot rodding. If anyone knows of one in the area for use, please let me know!

And finally, I agree with you that the 650s should not be jetted richer unless major engine work has been done.

[tkent02]

You guys are way overthinking this. A well maintained stock 650 G runs beautifully with excellent power at every RPM, great throttle resonse and good economy. They don't have issues running hot, they have adequate cooling fins and don't need the inner cylinders jetted richer.

They are very sensitive to changes in intake or to a lesser extent exhaust, and yes even a dirty air filter will have a large effect on how well it runs.

If yours doesn't run perfectly find the real reason, don't go reinventing the wheels.

Maintenance is the key.

[Steve]

Steve, Did you have to rejet your 650 when the pipe went on?

No, I didn't, but it came to us with (cheap EMGO) pods and a pipe.

I have cleaned the carbs ONCE in the twelve years that my son has owned the bike.

I know the main jets are larger, but don't remember what they are.

I am reasonably certain that the pilots are stock, the needles have not been shimmed.

.

[Sci85]

With all due respect Kent, bikes this old are not gonna be in factory type running condition. In my case, I have a Mac 4:1 which is not the same as the 4:2 oem and I also am running non stock air box? Why, because I want to. And like Old Guy and myself have already stated, we like to tinker. I don't mind playing around with the jetting striving to make it better. Plus, I'm a,ways learning something along the way so it's all good.