vm carb tuning 78 gs 1000

[chuck hahn]

Yup..I agree. get the gauge syncing done. And if anyone nearby has a color tune then utilise that to see the exact color of the flame in the cylinders. remeber that your using the side mixture screws to make the adjustments.

[GateKeeper]

I have a 24 of canadian that been sitting in the closet un opened since x mas .. hahaha ,

Hey Spyug, you hear this.......well I should say, you see this......

come on free beer......what more can you ask for....

and we get to wrench on a bike.......

.

[lrgguy]

Yup..I agree. get the gauge syncing done. And if anyone nearby has a color tune then utilise that to see the exact color of the flame in the cylinders. remeber that your using the side mixture screws to make the adjustments.

Just watched the gunson colour tune video .. pretty cool little gadget !
How much do they cost ?

[lrgguy]

Hey Spyug, you hear this.......well I should say, you see this......

come on free beer......what more can you ask for....

and we get to wrench on a bike.......

.

I have 2 bikes sitting there so niether of you feel left out ..lmao
I think there is a 26 er of jack Daniels , crown royal , and rum all sitting there un opened too ...
Just love those Lcbo card people give out at christmas !! Not much of a drinker ....fridge is always open and you will find cold beer inside ..

[GateKeeper]

you can get it all here....

http://www.carbtune.com/

.

[chuck hahn]

Yeah I really like the colortune I have. Absolutely no question as to how lean or rich it is when you can SEE for yourself right into the combustion chamber.

I prefer a tad on the edge of richness so as to not burn valves, so what I do is turn the mixture screws in till uit start to just barely give a yellowish orange flicker and then go out 1/8 turn. and thats at a high idle..I set it at 2000 RPMs.

Then I watch as I run it up to around 4500 which is the average RPMs if your cruising at 70 to 75ish. May get a flicker or two of what Gunsons instructions call an ice blue color. Then if that happens I go in at 1/8 turn ( to richen it a tad ) and see how it looks. Its a little playing to get that perfect little balance but its worth it at the end.

[Rich64N]

This thread is very timely for me as I'm at about the same stage of a carb rebuild on a 79 GS1000 with VM carbs (yes, Berrymans, cycleoring, new intake boot o-rings (were brittle square-rings, etc.). Lots of my questions have been answered (and fears alleviated) in this thread. I've spent more time researching than wrenching. [Results so far are much better than before]. I'm good mechanically, but I don't know carbs and points and such (My cars all have EFI, even my 82 garage queen).

Not trying to thread-jack, but Chuck Hahn's postings in this thread have answered a dozen issues I've had in the past couple of days (Thanks) so I'm jumping in rather than making something new (same bike, similar issues). I've run the bike a few times for up to 20 minutes (yes, with fan) and I'm planning on doing the vacuum synch tomorrow (MotionPro SynchPro) but have a few issues/worries:

- When engaging the starter, sometimes it hangs/stalls after a few rotations, with a thunk, particularly if battery is a bit low. (Clutch in to start (safety not bypassed). In Neutral)
- Not-quite-a-backfire sound occasionally, with change of RPM. More an air movement (like a small turbo BOV, or fart), not a over-rich ignition in the muffler. 1000-1200rpm. In the carbs or airbox. Once it blew out the golf tee in #3 vent about 10 ft.
- Idle screw adjustment doesn't have enough travel. After it hits the throttle plate, I only have about 6 full turns until I hit a stop. About 2 turns after engaging the throttle plate gives me 1000 rpm, bottomed out I get maybe 2000 rpm. Can't get to 2500 rpm for carb synch. Maybe my pilot jets are off? (about 1 turn from bottom (Air mix screws all set at 2))
- Clatter noise at low RPM - answered in this thread - thanks
- Running with the ignition cover off, I see an occasional spark on the 1-4 points (can't see the 2-3 points). Normal? I'm guessing so

Other maintenance (just in case there is something related I'm not seeing):
- Did valve clearances. 2 in spec, 2 tight (under 0.3mm), other 6 at 0.3mm minimum spec. After #2 intake too loose (.13), but might be carbon holding it open - will recheck, better loose than tight.
- Replaced ignition parts - Sudco kit of breaker points and condensers. Not planned but one of the breaker point brackets was bent, and static test on other was out of spec. Static timing preformed - after spraying everything in the ignition with electrical contact cleaner (made a big difference).
- Cold compression check all ~150 psig (carbs off)

[This is short version, will post long version after running perfect in 2020 or so]

[Big T]

This thread is very timely for me as I'm at about the same stage of a carb rebuild on a 79 GS1000 with VM carbs (yes, Berrymans, cycleoring, new intake boot o-rings (were brittle square-rings, etc.). Lots of my questions have been answered (and fears alleviated) in this thread. I've spent more time researching than wrenching. [Results so far are much better than before]. I'm good mechanically, but I don't know carbs and points and such (My cars all have EFI, even my 82 garage queen).

Not trying to thread-jack, but Chuck Hahn's postings in this thread have answered a dozen issues I've had in the past couple of days (Thanks) so I'm jumping in rather than making something new (same bike, similar issues). I've run the bike a few times for up to 20 minutes (yes, with fan) and I'm planning on doing the vacuum synch tomorrow (MotionPro SynchPro) but have a few issues/worries:

- When engaging the starter, sometimes it hangs/stalls after a few rotations, with a thunk, particularly if battery is a bit low. (Clutch in to start (safety not bypassed). In Neutral)
- Not-quite-a-backfire sound occasionally, with change of RPM. More an air movement (like a small turbo BOV, or fart), not a over-rich ignition in the muffler. 1000-1200rpm. In the carbs or airbox. Once it blew out the golf tee in #3 vent about 10 ft.
- Idle screw adjustment doesn't have enough travel. After it hits the throttle plate, I only have about 6 full turns until I hit a stop. About 2 turns after engaging the throttle plate gives me 1000 rpm, bottomed out I get maybe 2000 rpm. Can't get to 2500 rpm for carb synch. Maybe my pilot jets are off? (about 1 turn from bottom (Air mix screws all set at 2))
- Clatter noise at low RPM - answered in this thread - thanks
- Running with the ignition cover off, I see an occasional spark on the 1-4 points (can't see the 2-3 points). Normal? I'm guessing so

Other maintenance (just in case there is something related I'm not seeing):
- Did valve clearances. 2 in spec, 2 tight (under 0.3mm), other 6 at 0.3mm minimum spec. After #2 intake too loose (.13), but might be carbon holding it open - will recheck, better loose than tight.
- Replaced ignition parts - Sudco kit of breaker points and condensers. Not planned but one of the breaker point brackets was bent, and static test on other was out of spec. Static timing preformed - after spraying everything in the ignition with electrical contact cleaner (made a big difference).
- Cold compression check all ~150 psig (carbs off)

[This is short version, will post long version after running perfect in 2020 or so]

Well you did hijack the thread

Start your own, it's easy

[lrgguy]

Well you did hijack the thread

Start your own, it's easy

he totaly hijacked it !!! hahaha no worries

after following Chucks suggestions on setting up the carbs , my bike has been running awsome !!!

i havent done the carb tune yet .. but after taking bike for a good ride , i made some minor adjustments to each air screw , im talking 1/8 of a turn to the plus and minus on all four carbs , and my plugs look great when i do a chop stop !!! im using half the amount of fuel i was using pryor to all the adjustments done to my carbs and im riding the bike twice as hard ...

waiting for chucks reply on him coming to ontario canada to help me rebuild my top end ..... hahaha

again Thx Chuck

[GateKeeper]

We have to get Spyug down to do the carb sync, I will go and tug on his ear, to get him down here, he keeps coming up with excuses, or he is just not up to riding anymore......

worse case scenario, we can ride to his place.......

.

[lrgguy]

We have to get Spyug down to do the carb sync, I will go and tug on his ear, to get him down here, he keeps coming up with excuses, or he is just not up to riding anymore......

worse case scenario, we can ride to his place.......

.

Who doesnt like to ride ???? lol since you know where he lives we can just park in his drivway till he comes out ... hahaha a friend knows a guy that has the carbtune , but he wants $50 to do it , id sooner buy my own !! then give him $50 lol

[GateKeeper]

I will see if I can get Spyug down here, after all it's a long weekend, plenty of days to get it done.......I hope

50 bucks, sheeeeesh

we only charge a few beer, and you have paid in advance already......LOL

.

[lrgguy]

I will see if I can get Spyug down here, after all it's a long weekend, plenty of days to get it done.......I hope

50 bucks, sheeeeesh

we only charge a few beer, and you have paid in advance already......LOL

.

you probably already drank all the beer i brought !!!

[GateKeeper]

NOPE !!!!

well OK 2, and I have not touched the Organic one.....almost afraid....LOL

.

[OldVet66]

Chucks Pilot fuel screw setting is a real good starting place, and the ColorTune is good, but it can be dialed in even better. Pilot fuel screw settings change air screw settings, it moves the turns out at highest idle on air back and forth a bit. If you adjust the Pilot fuel screw so the air screw at highest idle is as close as possible to 2 turns out they seem to run best. Highest idle on the air screws with the Suzuki tack can be tough to determine sometimes. The equipment I would invest in is an electronic tach so you know exactly where you hit highest idle for each carburetor. That takes all differences into account and is more precise. Tweaking the Pilot screw settings from Chucks starting point, you don't want to move the screw much more than a screwdriver blade width at a time, then check highest idle with the air screw. A ColorTune can be a bear to determine the best setting, I might be wrong, but I believe Chuck said he was color blind, that might explain his accuracy with the tool over most people. My bike has a stage three jet kit, so the starting settings are closer to 1/2 turn out tweaked slightly to the richer side.