Ignition Timing on TY175

[ed_bremner]

Hi all,

I wondered if there are any clever types out there who might be able to help me on this:

I am trying to check the timing on an old Yam TY175.  The Haynes manual gives the timing as 1.80 mm BTDC.  I don't have a micrometer....and have always made a real pig's ear of doing this way.  I wondered if anyone knew or if it was possible to work out the degrees so that I could use a timing disk instead.

Any thoughts really appreciated.

cheers

eib

[L.A.B.]

The ignition timing needs to be accurately set with a dial gauge on these two strokes otherwise there's the chance of holing a piston.
It would be possible to work out the degree setting from the given piston distance BTDC but both the piston stroke and the exact length of the con rod between centres needs to be known in order to accurately work out the equation (finding the stroke would be fairly easy, finding the con rod centre length probably less so!).

A reasonable quality dial gauge can be purchased for around £20 (UK) and plug hole adaptors are available, although one can be made from an old spark plug, and the correct length extension rod made up from an old wheel spoke or something similar?
http://www.machinemart.co.uk/product.asp?p=040218070