still not starting

[Barnsey]

I read the manual with interest.  It said to set the timing at around 1/16" which is close to 1.5mm, but it didn't say anything about advancing the distributor, so, maybe 7mm fully advanced is correct.   I can check that next time. 

The spark looked pretty reasonable to me, I can't say I noticed the colour, (bluish?).  I can try the gap test next time too. 

I set the valve clearances myself after fitting the new kickstart.  I'll put this on the list, but I have access to a compression tester, so I will try this out before anything else. 

 I run out of time for today so expect to see an update on Saturday,

     Thanks!   Ian

[rhyatt]

The valves are quite specific in the places where you asjust 1 valve after positioning the other valve carefully.

The earlier book for the distributor engine  I think indicated setting around 1/16" at the retarded.
Whereas , the other books indicated how to hold the advance retard unit fully advanced.

[scifi]

I think you are spending too much time fiddling with the timing, when it might be that the carb is not set correctly.   Do you use any twist grip rotation when kicking..?   Have you got the idle mixture set correctly..?   
My B40 will only start with zero throttle, and needs to run like that for ten seconds before I twist the grip, or else it stops.   I suppose I could make some adjustments to make it better but have not yet tried, as it runs ok when warmed up to temperature.

[Barnsey]

Well I think that the exercise has shown that the timing is more, or less, correct.  I will measure the compression, as that should be quick and easy, and replace the condenser routinely.  Then I will take a look at adjusting the mixture screw.  I note that the manual says to set the throttle at 1/8th when starting, although this must be a guideline.   After rebuilding the carb I was careful to set the mixture to the same number of turns as it had been before. 

 Is there a procedure for setting the mixture on a non-running bike? 

[JulianS]

No. The adjustments need to be done with a warm running engine.
I have found over the years that setting the air screw 1 1/2 turns open from fully closed is a good place to start. Then follow the Amal tuning hints and tips.

[Barnsey]

I fitted the condenser this morning.  It was fiddly as the new one was slightly longer than the original. It also looks like the alloy edge to the housing, where the points are mounted, is getting eroded. It all looks to be of pretty fragile design and I am surprised that it was at all reliable.  It is tempting to fit electronic ignition, although an old pearl of wisdom is not to modify anything which has never worked until you have it working.  However, out of curiosity, is there an electronic ignition which will work on a 1963 C15 with 6V? 

  As ever I ran out of time (family man), so I'll check the points gap and give it a kick over later this weekend. 

   Ian

[Catz]

However, out of curiosity, is there an electronic ignition which will work on a 1963 C15 with 6V?   

   Ian

Is this any good to you? Says 6 or 12volt. I run a 12v electronic ignition on my A10.  https://www.classicmotorcyclespares.com/index.php/default/electronic-ignition-self-generating-bsa-c15-b25-b44-b50-with-lighting.html

[Barnsey]

I checked the compression.  After several kicks I was achieving between 105 and 125 psi, so a smidge on the low side.  A search online suggested it should be 130 to 175.

 Thanks for the info re electronic ignition. I'll check it out.

[DAVE BRADY]

Hi,

There are Boyer and other EI that just replace the points etc.
A bit cheaper as well.

Dave.

[iansoady]

There are also even cheaper devices - Boyer do one - that keep the points but use them just as a very low current switching mechanism. This does away with the condenser / capacitor.

http://www.boyerbransden.com/IDunits.html

[Barnsey]

Well.... I'll kick it over and see if it starts, now that it has a new condenser, then I'll go from there.  What do people think on the compression. IS 105psi low enough that I should be concerned?

Ian

[rhyatt]

As in an earlier reply, have you correctly positioned the engine to adjust the valves . It's quite precise.
And I have sent you both books with the procedure inside.
A decent , well adjusted set of points will spark a bike or car fine.
The c15s were lowish compressions anyway.
I use a gammatronic 6v kit on another bike.
And that works fine , from memory about 35 quid.
You're correct , get it running 1st on what you have , in the 60s and 70s I did thousands of miles reliably on points and condensers.

[Barnsey]

No probs.  Checking the tappets was going to be my next task anyway (and thanks again for the manuals) .  I just wanted a guide as to whether 105psi is bad, as in, we can fix that by tweeking the tappets, or bad as in new head gasket and piston rings.  All this is new territory for me.

[rhyatt]

ideally , you should have a shade more really. my Son's C15 is quite easy to kick over TDC , but I have never actually measured the psi. i think the C15s were 7:1 CR

conversely, my SS80 is 8.5:1 and is significantly harder to get over TDC

do your tappets carefully , check the spark is a good blue crack (unscrew the HT cap) and lay the end of the ht lead on the head , jam it in the fins to give a good 1/4" gap to jump

[Steve.S]

My goodness me, what a saga. I imagine you will soon need a replacement knee and kickstart quadrant.
This may be nothing to do with your problem, but I'm not clear that you have quite grasped the ignition timing.
Since they started making motorcycles, BSA have recommended setting the timing on full retard, but since you're only interested what is happening on full advance (where the engine will spend most of it's time),what does it matter where full retard is? Once full advance is set, full retard will take care of itself.
I believe you have tried setting it on full advance, so could I ask how you held the cam in the fully advanced position against the springs? Also, how did you determine points opening? Test light or fag paper?
Sorry if this is a bit basic, but it might be worth remembering that the engine turns clockwise when viewed from the right hand side, and anticlockwise when viewed from the left hand side. You're not making the mistake of thinking the engine turns clockwise while you're on the spark plug side are you?
As has been suggested, get a pencil or spoke and with it in gear, rotate the rear wheel with your hand until you can see the piston rise to the top. Do check and double check that it's on the compression stroke and not on one of the other strokes. put the spoke in the plug 'ole and jiggle the back wheel until you can feel the piston is at the top of it's stroke. (This will not be very accurate, but it'll do for now.)
Holding the spoke on the top of the piston, turn the wheel backwards until the piston has PASSED your timing mark on the spoke (7mm up from the TDC mark.) Then turn the wheel forwards until your timing mark lines up with your fixed point. I use the back of the top of the spark plug hole. It's very important for the piston to always come UP to the timing mark and not down. This takes care on any backlash in the 'distributor' drive train. Now without turning the engine, and the cam held in the fully advanced position, use a test light or fag paper to establish the exact points opening position. Hold the 'distributor' and tighten the screw. Recheck the timing to make sure nothing has moved.
You once said it kicked back badly. This usually indicates the timing is too far advanced.
However, bearing in mind that the motorcycle started before you fitted the new wiring loom, assuming nothing else has changed, then either you have fitted the loom incorrectly, or the loom is faulty (which if it arrived into the UK on a ship, is quite likely.)
A few random thoughts. Quite often bad starting can be caused by a worn carburettor. I have never found a new slide makes much difference as it's the body which wears and distorts through overtightening. If you open the throttle a bit, you may be able to squeeze your little finger into the intake and see how much back and forth play there is in the slide. Don't open the throttle too much, as the most wear takes place at small throttle openings. Maybe you could use a bit of bent wire? There shouldn't be much play at all.
You mention it pops sometimes. Do you mean fires? If it does actually pop, this indicates an ignition problem.
Moving on to your Monobloc, you need to make yourself familiar with the Pilot Bypass and the Pilot Outlet. These are the 2 small holes in the inlet tract either side of the slide. The best  way to physically check these are not blocked is with an aerosol and extension tube. A sonic bath may not clear these.
I believe you have disconnected the feed wire to the points and connected a separate wire directly to the battery, not to the headlamp switch? And still it did not start?
Your compression is a tad low, but it should still start.
You said you purchased a Spark Gap Tester, but you have yet to tell us what gap the spark could jump. Or did you mean you bought a neon tester.....not the same thing.
Perhaps you could let us know the answer to these questions, and we can move on to further suggestions.