Timing ignition adjustment issue

[mikebgs]

Hello. I am having some problems getting the timing adjustment correct on my 1979 gs750
I have set the points gap for 1-4 & 2-3 at 0.018.
I have adjusted the contact breaker plate correctly for 1&2 so my timing light comes on when the index mark(F) is in line with the timing Mark.
Now when adjusting the breaker plate for 2-3, I cannot get enough lineal travel. My test light comes on a few degrees before the index mark and timing mark are in line.
I was wondering if this is a common problem with a simple fix.
Does it indicate that the points are worn out?
I was considering lengthening the adjustment slots in the 2-3 contact breaker plate the give me more travel.
please see the photo attachment that i will add.
Any advise appreciated. thanks.Mike.

 

[Brendan W]

Where is the top screw on the back plate top slot?
It should be close to centre with 1&4 set.
Is the advance mechanism returning fully to home position?
Get it out and clean up anyway.
I wouldn't go anywhere near messing with slots.
Static test is, well just static. The real test is running. The electrical opening will be later than the mechanical.
I seem to recall the last four cylinder bike I had with points, I just set the gap I wanted at the high point of the cam and the timing took care of itself. Then the strobe for fine tuning but static was never a big thing.

 

[mikebgs]

http://IMG_5627.jpg

 

[Brendan W]

Hmmm........... can't open that for some reason. Server not found?

 

[mikebgs]

Thanks Brendan. The bolt is in the centre of the top slot on the back plate.
I need to take a look at the advance mechanism. I have not removed the contact plate yet. Tomorrow I will give it a clean.
maybe I could retard the 1-4 timing a bit to allow the 2-3 to advance? to make them similar if possible.
I am only able to do a static test at the moment.
Yes sorry. I need to reacquaint myself with how to post photos.Mike.

 

[mikebgs]

I gave the Timing advance mechanism a clean and light lube with lithium grease.
Now I am not sure if the mechanism cam lobe faces towards the 2-3 timing mark like in my photo or the other way ,facing 1-4 ? cheers.

 

[Brendan W]

Is there a pin on the crank that locates into a slot on the back of the advancer?

 

[mikebgs]

yes, I got the timing advance mechanism seated as you described.
But I had previously disassembled the mechanism when cleaning . I pulled the sleeve off the spindle without taking note of it's orientation. When reassembling the cam sleeve it could go in the direction of 2-3 index mark on the base of mechanism or face 180 degrees towards 1-4 index mark on the base of mechanism. please see photo.

 

[Brendan W]

The little notch on the sleeve, at six o'clock in the picture, lines up with the notch on the spindle.

 

[mikebgs]

Ahh ok. I'll take a closer look. Many thanks.

 

[mikebgs]

Hello. I am having difficulty locating the notch on the spindle of the timing advance mechanism,please see photos. There is a pronounced notch on the cam/sleeve but no coinciding notch on the spindle that i can see. Maybe it is a different aftermarket brand mechanism? Mine is Nippondenso.
I have managed to reassemble the mechanism with the cam lobe notch facing 2-3 timing mark and set the timing with static test successfully. Maybe I should trial it the other way around and see if that doesn't work. Then I'll know I was right the first time? Thanks.
Mike.

 

[mikebgs]

mechanism spindle 2-3

 

[mikebgs]

Tried it both ways and found that, with cam notch towards 2-3 timing mark is correct.Thanks.