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GS1000S AUS type cam + sprockets

  • Thread starter Thread starter Jackbob
  • Start date Start date
J

Jackbob

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My bike is a USA model 78 GS1000EN.
I have converted from the "stock" VM26SS head and carbs to a GS1000S Aust spec head and carbs - the carbs are VM30SS slides and the head has the larger CV style inlet ports.

This S head came with a set of S cams minus sprockets.

The cams appear identical to the VM26SS/head set of cams except that they have the 0.5mm extra lobe height and a number 2 cast into them as opposed to the 1 on the others.

I am aware that cam timing should be set differently and have the diagramme etc (19 pins vs. 20)

I want to use the #451 cam sprockets i have. I believe that this will be OK except that the position reference marks on the sprocket/s may be out by one tooth when the cams are set correctly as per GS1000ST specifications, and was wondering what effect there will be on the position of the cam notches which should be parellel with the can cover surface.

If i just position the notches parallel to the cam cover surface and disregard the markings will this be correct or retarded?

Any thoughts?

Thanks
 
Why screw around GUESSING when you can just put a degree wheel on it & find out EXACTLY where they are?! Then you could slot the cam sprocket bolt holes & set the cams where they work the best! Ray.
 
Jackbob,

Regarding your question I think you answered your own question. The Aussie GS1000S intake cams are spaced 19 links while all other GS1000's cams are spaced 20 links. I am sure you have seen this link from your fellow mate down under . . .

http://www.theflyingbanana.com/gs1000s2.htm

Near the bottom I quote, " But whatever sprockets you have, or indeed whatever model of GS you have, the main thing is that when you have cylinder #1 on TDC (top dead-centre) on the compression stroke, that the notches on the ends of the camshafts (coloured green in the diagram above) are directly facing each other, as they are in the diagram. If either of the notches are pointing away from the opposite camshaft, you know that the timing is out, and you will need to reset the camshaft(s) so that the notches will directly face each other."

So a 49S Exhaust sprocket coupled with a 451S Intake cam sprocket requires 19 pin spacing and will produce cam notches which are parallel to the cam cover surface. Hope that helps
 
Last edited:
rapidray said:
Why screw around GUESSING when you can just put a degree wheel on it & find out EXACTLY where they are?! Then you could slot the cam sprocket bolt holes & set the cams where they work the best! Ray.
Click to expand...

Thanks Ray - I knew some one would suggest this logical step - i just have no idea how to do this. Can a degree wheel be purchased at a low cost?
 
srsupertrap said:
Jackbob,

Regarding your question I think you answered your own question. The Aussie GS1000S intake cams are spaced 19 links while all other GS1000's cams are spaced 20 links. I am sure you have seen this link from your fellow mate down under . . .

http://www.theflyingbanana.com/gs1000s2.htm

Near the bottom I quote, " But whatever sprockets you have, or indeed whatever model of GS you have, the main thing is that when you have cylinder #1 on TDC (top dead-centre) on the compression stroke, that the notches on the ends of the camshafts (coloured green in the diagram above) are directly facing each other, as they are in the diagram. If either of the notches are pointing away from the opposite camshaft, you know that the timing is out, and you will need to reset the camshaft(s) so that the notches will directly face each other."

So a 49S Exhaust sprocket coupled with a 451S Intake cam sprocket requires 19 pin spacing and will produce cam notches which are parallel to the cam cover surface. Hope that helps
Click to expand...

OK thanks rsupertrap for that i think i can move forwards on this info.
 
I'm sure some racer in New Zealand has one & knows how to use it. Have you searched locals or gone to the race track to talk to people? It's worth a try. Ray.
 
Ray is right - Ask the Auckland Post Classic guys to recommend someone to help you.
I'm in the SI so not much use to you and I don't know many of those guys but given the number of GS1000's running I'm sure someone will help
Given the best eyesight in the world, just lining up the notches can leave you 5 - 10 degrees away from where they should be.

Greg T
 
KiwiGS might be able to help you out. He's an ex-racer and on here now & again. I'm sure he'll chime in shortly and at least offer some advice (now I've dumped him in it). :D
 
Thanks Guys,

Anyway some feedback.

I re checked things after work today using the diagramme link.

The original cam sprockets are both #490.

Then - I remembered i had a couple of sprockets stored away that i had bought along with a box of spares a while back.

These are numbered 451 (inlet) and 470 (exhaust).
So decided to try both sets of cams and sprockets on the head.

To cut to the chase - the sprockets #490 if set at "20" pins means the slots line up correctly as do the pointer marks.
The other sprockets 451 and 470 if set up at 19 pins ditto.

Any other combo and the slots do not line up, irrespective of which set of cams they are on.

Placing the non paired sprockets together and lining up the holes, the teeth are maybe 5 degrees out.

Thanks.
 
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