'81 650G carbs? raise the needle?

[snowbeard]

so on my carbs can I actually change the needle height or is it fixed?

if I can, can I access it from the top by taking off the cover and diaphram?

thanks

[Dave8338]

Yes, they are. You may be able to get the outer two slides out without removing the carbs from the bike, but good luck at getting an angle on the inner two. Best bet, remove the carbs and work on them on the bench. There will be groves in the needle and also washers so that you can move them in 1/2 steps. What is your reason for asking...are you running lean in the midrange?

[snowbeard]

I'm actually looking to increase across the whole range. I changed my pipes to some harley shorties and it gave it some more room to breath. I have been wondering if I'm running lean and a plug chop this evening showed it to be true.

so what does raising the needles accomplish? is across the range or only in the beginning? sounds like maybe the jets cover all of it?

I need to do something, so have a choice, I might have to either change the actual jets, block up the exhaust somehow, or maybe raise the needles.
here's one of my posts detailing my self induced dilema...

http://www.thegsresources.com/_forum/showthread.php?t=101248

[rkubik]

needle clips

You can raise/lower the needles. But you will need a pair of very long-nosed needle nose pliers to undo the circlip securing things in place down there. And it can be 100 kinds of fun getting that clip back in place.

Word to the wise from the not-so-wise: when popping the clip off the needle, find a way to hang on to that dark-coloured little clip. If it flies down onto the ground or into the frame, it's very very hard to find. Found that out the hard way

Lowering the clip means the needle is lifted a tad higher out of the main jet, so more fuel can flow past, i.e. you get richer mixture. But only in mid-range.

Past mid range, the needle is raised all the way out of the main jet, so its effect is over - you're on the main jet then.

Also, when I installed a similar (but quieter and I think more restrictive) set of muffs, I was able to successfully seal the joints with Permatex Ultra Copper high-temp silicone - orange stuff in a tube, about $5. Worked well all summer. After it cures, you can just cut or rub any excess away from the outside, it hardly shows after that.

[chef1366]

Do a search for a "throttle chop" and you can jet through all the circuits.
Your carbs operates on throttle position and not RPMs.
Pilot circuit; idle to about 1/8 throttle.
Needle circuit; 1/8 throttle to about 3/4 throttle.
Main circuit: full throttle.
When I say "about" the circuits do overlap each other.

[brveagle]

I installed shims on my carb needles, on my "gs650" when the carbs were still on the bike...

Just take your time and go slow and you'll be fine.

I would recommend adding atleast 2-3 shims though... I added just one and barely noticed a change

[snowbeard]

hmmm, I usually keep it around 70 top speed, which I know isn't really full throttle. maybe I can get away with just the needles?

I bailed on riding her today of all days (beautiful) because I was worried about damaging er...