1959 G12 BTDC 3/8" or 11/16"

snatchpiece · Post by **snatchpiece** » Thu Feb 21, 2008 11:47 am

I need to set the ignition timing on my 59 G12, I can't seem to find whether I should mark the rod that goes down the spark plug hole 3/8" or 11/16" higher than TDC. I've done a search on ignition timing but that brings up mainly single stuff. I know this measurement altered but I don't know where my bike fits in.

Merlin · Post by **Merlin** » Thu Feb 21, 2008 2:57 pm

Most timings are BTC not after.

Dougie · Post by **Dougie** » Thu Feb 21, 2008 3:00 pm

Merlin

Snatchpiece () knows this. He is asking by how much!

Biscuit · Post by **Biscuit** » Thu Feb 21, 2008 3:38 pm

From the manual 11/32" or 35 Deg. BTDC.

snatchpiece · Post by **snatchpiece** » Thu Feb 21, 2008 3:50 pm

Alan,

Once again, thank you.

Mick.

Eric · Post by **Eric** » Thu Feb 21, 2008 5:17 pm

Snatchpiece just to be absolutely clear Alan (Biscuit) said 11/32" not 11/16" as mentioned in your original posting. 11/16" would give you excessively advanced timing. When using a piece of rod or wire its always a good idea to bend the top end in some way that prevents it falling down the plug hole whilst doing your settingsEdited by - Eric on 21 Feb 2008 5:21:47 PM

Biscuit · Post by **Biscuit** » Thu Feb 21, 2008 5:41 pm

Good point Eric, although I suspect that Snatchpiece isn't one of those who sees but does not read.

I dropped a piece of 1/8" down a single once, I carefully turned the engine forward and it gradually re-emerged. I bet that wouldn't happen twice!

thomthom · Post by **thomthom** » Thu Feb 21, 2008 10:26 pm

I wouldn't bet it would happen once

snatchpiece · Post by **snatchpiece** » Fri Feb 22, 2008 8:14 am

quote:
Snatchpiece just to be absolutely clear Alan (Biscuit) said 11/32" not 11/16" as mentioned in your original posting. 11/16" would give you excessively advanced timing. When using a piece of rod or wire its always a good idea to bend the top end in some way that prevents it falling down the plug hole whilst doing your settingsEdited by - Eric on 21 Feb 2008 5:21:47 PM

Well spotted Eric, it was a typing error on my part (age thing).

All my bits have arrived now and I'll be re-fitting my magneto this weekend hopefully. If you see no further posts on this you can assume all went well (or I've given up and gone over to the other side).

Circlip · Post by **Circlip** » Tue Feb 26, 2008 1:31 am

quote: I dropped a piece of 1/8" down a single once, I carefully turned the engine forward and it gradually re-emerged. I bet that wouldn't happen twice!

Possibility of gouging the cylinder walls. Or jam the rod sideways between the piston and the plug hole locking the engine as I have seen done, pehaps damaging the top and bottom threads.