Series D timing advice

[Bill Thomas]

Hello Dave, Maybe you have a bit of carb trouble as well, One thing will upset another, It's funny how we talk of 5 degrees and 15 degrees, With these old motors with slack all over the place, It's very hard to say forsure what we are running, I was told years ago by one of our top builders to set valve timing at TDC with both valves rocking, It will run OK but it won't be fast, I have found it has to be a long way off to be very bad, Good Luck Bill.

 

[macvette]

Hi,
Thanks Bill and hello Dave haven't heard from you lately. I decided to check my timing mainly because my pipes are blueing but I also want to replace the cast exhaust nuts with some bronze ones which are a better fit in the heads so it seemed a good idea to kill two birds with one stone. The bike starts easily on the previous setting and seems to run OK but since I'm running in on pretty small throttle opennings and generally sticking to no more that 60 mph in top, I can't really tell but I feel it should be a little smoother.
The books I am using are "Know Thy Beast" and "Richardson" and I decided to check the timing because KTB states that too much retard causes blueing. Richardson also says that the static timing should be 4 degrees BTDC on the rear cylinder fully retarded which equates to 38 to 40 degrees fully advanced ( I'm quoting here). I have picked up from a number of sources including local Vincent riders that 34 degrees BTDC seems to be a good setting for modern petrol. Anyway, I don't want to have too much advance so having previously set the timing to 34 degrees BTDC on full advance which on my bike equates to a static timing (measured) of 5 degrees ATDC, I have set the static timing to 0 degrees BTDC and will see how it goes. I think this will give me 39 degrees fully advanced.
By the way Dave I had a pm from another series D guy in British Columbia who had picked up my seat clip tip and he was pleased with the result.

Regards Mac

 

[Ken Tidswell]

Wear in the moving parts of the distributor causes it to over retard, and make starting hard. The tube over the shaft is a good
Provincial field repair,( I like this phrase) and will last for decades, as previously stated . The cams i have measured were, stellited vertical twin modifications and were something like +- 2 deg out. Our Precision man in Hayling Island does them. If you want a new base i have some, very cheap. Ken Tidswell

 

[Deroberson]

Bill

Thanks for the mention of the carbs, I just had these re-sleeved so there may be an initial setting off, but no air leaks.

Mac

The seat clips are still working out great as well! Upon disassembly of my distributor, I notice the springs to be a little weary looking and two sets of holes for tension variation. Do your counter weights have both of these holes.

The base below the cap to which the points affix seem to have some cracking on the underside and around the edges. It was also mentioned to me on another thread that there are modern condensers to be considered vs. leaving in the old ones.

 

[macvette]

Hi Dave, looks the same to me but I can't tel you where the springs go since I haven't looked inside after it was rebuilt. The condenser is new but old style. I'm running 6V and don't have a problem getting a good spark.

Regards Mac

 

[Bill Thomas]

Hello Ken, I could do with a complete Dist' for a Comet if you know of one, But I think you only mean the base plate ?, All The Best Bill.

 

[Ken Tidswell]

Bill all i have are bodies, base plates, and perhaps a cap , The single cylinder cams are expensive to buy, those who have NOS see you coming.
The clockwise shaft and action plates , can be bought from the man who who advertises in MPH . But i expect he would sell you a shaft with the correct advance . Ken

 

[macvette]

Hi
Here's an update. After fiddling around most of yesterday, I set the rear cylinder to fire at TDC. The bike starts now first kick from cold, previously it was two or three which I though was ok. I took it out this morning for a run and it is significantly better altough it didn't feel too bad before. I think another few degrees of advance will improve it although I will not go OTT.

Mac

 

[macvette]

Mac

Interesting that you are going through this, I too am trying to get the timing set correctly on my D. When you say "34 degrees as per the books", just curious which book for reference?

I set mine for 38 degrees but something is still amiss, I have a little kickback at start up and have retarded the distributor fully. The bike will crank and run fairly smoothly but once at speed and under a little load, just is not running quite right.

Measured the points breaking with a ammeter and the distributor shaft, (as being looked at from the left side of the bike) fully advanced or rotated against springs counter clockwise. Does all this sound correct?

Dave

Hi Dave ,
I missed the last part of your question (sorry). The rotor arm should, as you say. be rotated counter clockwise against spring tension until it hits the stops of the advance mechanism. I connected a plug to the HT lead from the coil and taped it to the block so that I could see when it fired as I rotated the dizzy. I found this the easiest way rather than fiddling about with bits of paper or craning my neck to see the ammeter. I also used a small screwdriver in the teeth of the distributor drive to take up the backlash so I could use one hand on the dizzy whilst holding the rotor on full advance with the other hand but be careful, you don't want to damage the teeth.
Mac