GS1000 8 valve with 3000 rpm problem

[PeterBoomhut]

Suzuki
Gs1000
60785km
Cylinder revision 0.5, new timing chain and exhaust guides
Carbs 6/19/2019 Cleaned Ultrasonic and fitted with new O-rings (did 250km)
7/9/2020 New Inlet rubbers (Cruzin Image)
Engine has stood still for a year since carb cleaning.
What I have been doing since Thursday 7/9/2020:
Places new pistons/rings
Placed topend with new gaskets.
Head has new exhaust valve guides
Valve clearance checked.
Compression test:6.8 - 6.8 - 6.9 - 6.7 bar 98 - 98 - 100 - 97 psi
Temp Exhaust after 1 min. 85-75-100-70 Celcius
Temp Exhaust after 4 minutes 130-120-150-100

Problem, Machine start @1200 rpm, but when the throttle is touched, the machine rises his rpm tp 3500rpm.
Little explosions in the intake at cil 1 en 2.
I thinke some vacuüm leaks but can't find any
synchronization is difficult
What can cause this?

[chuck hahn]

Some possibilities:

Grip sticking inside switch box
Cable itself sticking
Cables routed wrong
Intake manifold oring leak
Clamps not sealing intakes tightly to carbs....stretched clamp syndrome
Air screws running too lean..turning them out will lean the mix and in richens it. Set bottom pilots at 7/8 out from lightly seated and leave them alone.
Adjusting VM carbs is via the side air screws. start at 1 1/2 to 2 turns out.

[chuck hahn]

And assuming non of the above..or adjustments have been made..the last thing will be the sync..a good syncs gonna change idle speed and idle knob adjustments as you start bringing cylinders into sync

[chuck hahn]

Got the vacuum nipple on carb 3 capped while trying to sync? big leak there if not.

[Big T]

Some possibilities:

Air screws running too lean..turning them out will richen the mix and in leans it out. Swt bottom pilots at 7/8 out from lightly seated and leave them alone.
Adiusting VM carbs is via the side air screws. start at 1 1/2 to 2 turns out.

Chuck, when did this change occur?

Opening the air screws leans the mixture

[chuck hahn]

oopss i typed what i was thinking backwards. yes out lean...in rich.

[Big T]

Peter, what year 1000?
Because, Chuck and I are assuming 78-79 with VM carbs

[PeterBoomhut]

Some possibilities:

Grip sticking inside switch box

Could you explain what you mean (grip, Switch box)

Cable itself sticking

Oil the cable?

Cables routed wrong

! shall take some prictures

Intake manifold oring leak

new one by Cruzinimage

Clamps not sealing intakes tightly to carbs....stretched clamp syndrome

I did a brake flued test, cycle didn't react.

Air screws running too lean..turning them out will lean the mix and in richens it. Set bottom pilots at 7/8 out from lightly seated and leave them alone.

7/8 is very low, books say a 1979 US 1 turn?

Adjusting VM carbs is via the side air screws. start at 1 1/2 to 2 turns out.

Ok Thanks !

[PeterBoomhut]

Got the vacuum nipple on carb 3 capped while trying to sync? big leak there if not.

Yes i did!

[PeterBoomhut]

Peter, what year 1000?
Because, Chuck and I are assuming 78-79 with VM carbs

Yes, a 1979 with VM Carbs!

[chuck hahn]

set up carbs as i described. book doesnt give a pilot screw setting ( bottom ones )..it says they are preadjusted do not adjust. Set side air screws at 1 1/2. This isnt my first rodeo. Youll be real close and a colortune will get each jug perfect.

Brake fluid test?? AHHHH you spray starter fluid on intakes to detect vacuum leaks.
GRIP... it rides in a groove inside the right switch housing. I once had a cable end that dragged and i had to file the flat sides of the furrel to free it up.

[PeterBoomhut]

set up carbs as i described. book doesnt give a pilot screw setting ( bottom ones )..it says they are preadjusted do not adjust.

They have already been detached by the previous owner, you say 7/8 is that of 400 decimal degrees (= 1 turn around)

Set side air screws at 1 1/2. This isnt my first rodeo. Youll be real close and a colortune will get each jug perfect.

Ok thanks, I've a colortune

Brake fluid test?? AHHHH you spray starter fluid on intakes to detect vacuum leaks.
GRIP... it rides in a groove inside the right switch housing. I once had a cable end that dragged and i had to file the flat sides of the furrel to free it up.

Oh, now I get it, this is clear

[Rich82GS750TZ]

Please don't spray brake fluid anywhere. Maybe something got lost in translation here. Not a good idea. It will destroy paint.

[Big T]

OK, do the Colortune adjustment
Then, regarding the sync, are you trying to adjust the height up, or down?

[PeterBoomhut]

Please don't spray brake fluid anywhere. Maybe something got lost in translation here. Not a good idea. It will destroy paint.

What do you propose as a replacement?