500 Four ignition timing

[bobv7]

Afternoon All

I had to take the advance retard unit out to free off the stuck bob weights. My question now is how to reinstate the cam tube in the correct position because as I see it, it is possible to set it 180 degrees out as fit fits back over the bob weight legs. I noticed a small mark on the edge of the cam but can't see any corresponding one on the inner part?

[deltarider]

See parts in white frames in pic. After reassembly it should look like this.

[bobv7]

Mine looks a bit different to that but the numbers seem to be the same?

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[florence]

Not sure what bike that is from, my 500 looks like the first picture.

You can work it out, turning the engine over slowly by hand with a spanner, when the F 1.4 lines up with the timing mark, you can see if the high point of the cam is about to open the points on the left side, i.e. points for 1 and 4.

[Johnwebley]

Not sure what bike that is from, my 500 looks like the first picture.

You can work it out, turning the engine over slowly by hand with a spanner, when the F 1.4 lines up with the timing mark, you can see if the high point of the cam is about to open the points on the left side, i.e. points for 1 and 4.

The advance unit does have 323 stamped on the bottom RH corner.



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[Bryanj]

The two advance units are different manufacturers but both 500

[deltarider]

Mine looks a bit different to that but the numbers seem to be the same?
(Attachment Link)

Yours is a Hitachi, ours is TEC (Toyo Denso). Now the one in the pic seems to be (re)assembled incorrectly by a 180^o. I have understood the little carve in the rim is supposed to face the Hitachi logo.

[JezzaPeach]

I have just been doing the same. Mine is the Hitachi and the notch is on the opposite side to the hole in the plate. However I’d follow the advice to examine the cam etc, as it occurs to me there may not be a fixed ‘rule’ having seen the forum pics although in Ash’s pic of 4 different sets the Hitachi ones are like mine. I did try it the wrong way and of course the timing light lit for the wrong set of marks. Simple and quick to switch back anyway.

My big question is does anyone find the central bolt and hex ‘special washer’ go off centre a bit on final tightening. Mine does by a mm or two POSSIBLY due to a very slight bend in the assembly due to it being dropped in the past. (The washer was scraped so it certainly happened)
However it sets ok and is running very well touch wood, and maybe this slight ‘off centre’ is normal up to a point ? and either was not likely to eg cause vibration

[Bryanj]

The bolt and washer should not go off centre all you are doing is tightening twobparallel surfaces to a flat one

[bobv7]

Right. Looks like I put the cam back in 180 out so that the timing lamp went out instead of coming on. Just back from the garage with aching knees having corrected this. Lamp comes on just as the points open as I expected it would. Lesson learned, and next time put the bloody bike up on the bench instead of crawling around on the floor!

[deltarider]

Mine is the Hitachi and the notch is on the opposite side to the hole in the plate.

What hole?

[JezzaPeach]

In my post? (if that’s printable!!🙄)
There’s a hole in the plate under one of the springs, on the Hitachi one.

[deltarider]

In my post? (if that’s printable!!🙄)
There’s a hole in the plate under one of the springs, on the Hitachi one.

This^ is confusing. There is no hole on the Hitachi one that matters for alignment. Have a look at the pic below.
The one on the left is made by TEC, and the one on the right is by Hitachi. In this pic, on the TEC unit, the points cam is reassembled incorrectly by a 180^o. Notice the dimple on the edge of the cam at about 10 o'clock; it should line up with the hole in the base next to the TEC logo. The one on the right is the Hitachi one and on that one the cam is reassembled correctly as the dimple is facing the Hitachi logo.

[JezzaPeach]

The hole on my Hitachi -2 one is under the spring the screwdriver is pointing at. Yes the notch is close to the Hitachi symbol. I only refer to the hole on the other side for relating to the notch on the cam not for ignition timing.
Yes the Tec works the opposite so the notch is close to the hole in the plate.

[bobv7]

I'm glad I asked!