Checking timing with DTI

[steve452]

I recently bought a DTI to check that the timing marks on my Z1-B are accurate before I make a final attempt to set the carb mixtures and sych before I decide enough is enough and hand it over to an expert to sort out (it's still not running well).

However, I can't find any details of ignition advance measured in mm BTDC, only degrees. As my DTI is calibrated in 0.01mm divisions I need to know the BTDC figures for idle and full advance as a measure in mm. A line graph with axes in revs and mm/BTDC would be even better.

Do any of you guys know these figures or have a link to such a line graph?

[zed1015]

You need a degree wheel to verify the timing marks , not a DTI.
Apart from TDC comfirmation the dti won't give a true mm measurement of the piston sweep due to the angle of the plug hole unless of course you are doing this with the head off.
The timing marks though are never far from true and what little variation there may be will be less than a degree and won't effect the bikes running.

[steve452]

Many thanks Rob. I will use the DTI to at least confirm TDC. I also realised after posting that a graph of revs against piston distance before TDC would be a bit pointless, as the DTI might tend to poke a hole in the piston with the engine running. Doh!

I will get a degree disc though just for peace of mind before I start on the carburation. I looked on Bikers Toolbox but the one there has a 6mm hole and IIRC the advance assy retaining bolt is at least a 10mm (I have a Jan ' 75 build Z1-B). Can you suggest a good degree disc that will fit?

Many TIA.

Steve

[zed1015]

Most degree discs come with a small pilot hole which you have to enlarge to suit your application.
The one from Ralph will do the job, just drill the hole to the size you need.

[chrisu]

Most degree discs come with a small pilot hole which you have to enlarge to suit your application.
The one from Ralph will do the job, just drill the hole to the size you need.

as in http://www.bikerstoolbox.co.uk

[ADRIAN H]

Many thanks Rob. I will use the DTI to at least confirm TDC. I also realised after posting that a graph of revs against piston distance before TDC would be a bit pointless, as the DTI might tend to poke a hole in the piston with the engine running. Doh!

I will get a degree disc though just for peace of mind before I start on the carburation. I looked on Bikers Toolbox but the one there has a 6mm hole and IIRC the advance assy retaining bolt is at least a 10mm (I have a Jan ' 75 build Z1-B). Can you suggest a good degree disc that will fit?

Many TIA.

Steve

Steve contact Ralph at bikers toolbox (southwest area rep Z1OC)
I am sure he’d drill it out for you.

[steve452]

Further to this, is there a preference for setting carb mixtures before synching or vice versa, and is there a reason for doing it in a particular order?

On another matter, whilst looking for my tyre pressure gauge in the garage I came across something I thought I'd lost years ago (see pic). This is the one issued to the dealer for my Z1-B which I ordered on 1st May 1975.

[zed1015]

Fuel mixture screws only adjust the pilot/idle mix so just set them all at 1-1/2 turns out for initial syncing.
Once you have all cylinders pulling the same using vacuum gauges can you go back to the mixture screws for fine adjustment if needed.

[steve452]

As always many thanks for your advice Rob. I shall attempt this gargantuan feat (for me anyway) in the promised warm weather next week.