Here's the snap, and he stumbles.

[Guest]

79 GS1000L - Over the winter i installed a stage3 dynojet kit as i'm runing K&N pods. I chatted with a gent. on this site who assured me that the jets are WAY too f'n big. I agree, the jets are huge and i will need to change them but if possable i'd like to put some KM/Miles on it first to see what else i need to deal with. That said here's my problem, at idle i can throttle roll just fine (when she's warm) but when i'm rooling and come to a stop the RPM drops less than a grand causing the stumble. my main concern is doing damage. also i don't have a slack gauge and i'm going off the base settings right now. i'm an automotive tech but these carbs are...well a pain, and out of my comfort zone. Thanks for reading this long winded post.

[Big T]

VM carbs are as easy as it gets

Did you follow the Top 10 Newbie mistakes?

Are they clean?
New O rings?
Synched?

Do you have the stock exhaust?
How big of jets did you put in there?

[eil]

Can you just turn up the idle adjust screw a bit to compensate?

[azr]

This is the second thread I've ready recently where guys are putting Dyno kits in their VM carbs......am I missing something here? I've never known VM's to need a jet kit, the main needles are adjustable. Ok, on to your situation. You should pull your plugs and make sure you're not running lean, that's the only thing that will cause damage to your engine really. I'm not sure what a "slack gauge" please educate. Usually when the rpm's drop like that it can be caused by a lean condition. So if you put in a stage 3 kit that means you drilled your slides, is that right? I'm not a carb guru by no means so I'm sure some others will chime in on this. Have you done the valve shims already as well?

[dorkburger]

Im assuming by slack gauge he is referring to a liquid type manometer- basically a u shaped tube with liquid it and markings on it with a hose connection to measure pressure or vacuum.

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[13013]

-azr- slack gauge is a manometer. drilling the slides is only needed on the kow as far as i can see. I'm not sure what you mean about shimming though.
-Big T- dunked, all new gasket and rings, because this aint my knowledge base. But syncing, no. as i said i don't have a slack gauge (manometer) that works. they're synced manualy but not per cylinder. take into acount that this old girl didn't even idle befor the carb rebuild.
-Eil- not realy, i mean i can snap the throttle and it acts fine while idling, it's when i'm moving that i have issue.
-The jet in the kit are the same as a 130 mikuni (huge i know) and the needle setting is the #2 groove. i'll look at my notes on what the other gen. said i should use but if at all poss. it'd like to try to tune this as best i can. I'm sure i'll run into more that needs to be done but i need to ride her to find out. -thanks for replying all.

[13013]

ya. i have one but it's for trucks...the bike pulls too hard.

[13013]

PS Big T, these vm's are really nice to work on BUT i don't have alot of experiance with carbs or trying to sync them. i put mikunis on mt 70 bonnie ans though "oh ya no prob" but two and four...well a bit of a bitch.

[Big T]

Yeah, 130 Mikuni are way too big. go down to a 125 or 122.5 and the needle should be raised a notch from center

A good sync is essential

[Steve]

... and the needle setting is the #2 groove. ...

Counting from the pointy end or the blunt end of the needle?

When suggestions are made to "raise the needle", remember that you need to lower the clip (move it away from the blunt end).

.

[13013]

the POS dynojet kit comes with a new needle with 6 grooves not 5, guess i should have mentioned that. Ya i counted down. Any ideas why the rpm drops so low when stopping but not when stationary? It seems like a fuel thing but i could be wrong, i mean the old girl would barely run when i got her and the snow/mud is to thick to even go for our first ride. Really all i want is to take that ride and see what shakes loose, i just don't wanna do any damage.

[Charlie G]

I think what azr ment by shimming the valves, was a valve adjustment. Important to check them first.

cg

[13013]

thanks CG. I wasn't sure. And no i havn't, the compression is spot on so i didn't figure rings as much of an issue. remeber i live in Canada and even though she's got years on her that dosn't really mean she's been riden, we're talking 20,000km. down side to the short season is unseasond riders not doing a propper break in after the "long sleep" each year and lacking in the proper care. This old girl was 50/50 he changed oil'n such acourding to the book...then his chain snapped, that with the clutch rattle(yes i put new spings in) he sold it for $500(cnd). The stumble is gone...not sure why but i assume it's like the somking out of 3or4, the more i run it it just seems to BUG then calm down. Thanks all for your interest and i'd like to say that this site (not so much the G&A but the tech sheets) have been a huge help and i hope it will continue to be
THE BEST GS PAGE ON NET
I'm on many sites, and if i hear GS questions i send them here. again thanx. bikeGSspring 283.jpg

[Spyderman]

where in alberta are you im in calgary maybe i can help you get it sorted out if your close

[13013]

I'm inbetween Red Deer and Rocky Mnt. House. I'm in Calgary often though.
1.5 to 2hr drive.