C15S Cam Timing Mystery

[Daz]

 I believe the C15S had the energy tranfer ignition? It may need the correct type of stator to work properly with the magnets inline with the coils when the points open.
 

[limeyrob]

Yes, I'm thinking that way, magnet, coil and points all have to be timed together.  Putting a battery onto the coil would show if the engine is mechanically OK.

[rhyatt]

You said that you fitted a RM13 alternator.
This has 3 wires
Why did you fit the RM13 ? Was the other stator damaged or not working and how many wires did the old stator have, 3 wires or more wires ?

"I should add that I also install a new Lucas RM13 rotor and stator as well as a new coil.  The output more than exceeds the minimum voltage."
 and the new coil , how did you test the old stator and the new stator??

if it is Energy Transfer system on your bike, then it is a special coil  3ET

have you checked BSA service sheets 813B specific to the ET system (assuming you have this on your bike)

[C15S]

I will try inserting a battery and see how it goes.  This bike was delivered with Energy Transfer System, i.e., no battery.  I have installed a new Lucas RM13 alternator and am getting a solid 6 volts across the B/W wire to the coil and ground.  I turned out all the lights in the garage and see a clear spark at the plug.  Will let you know about the battery.

[rhyatt]

You may find this link useful

https://www.jrcengineering.com/technical-support/electrical-tech/lucas-et-ignition-unraveled/

most - if not all - of the circuit diagrams offered by Lucas or BSA had 4 or 5 wire alternator stators fitted due to the internal variance of the coils and their usage with the ET system - and the Black/white colour scheme you mention only applies to these stators - the standard 3 wire stator has a different colour set up.

hopefully , your temporary lash up hot wire of separate battery direct to coil and cb points (disconnecting everything else to give you a stand alone set up) with get the bike running and thereby disprove the camshafts and other related mechanical things etc

[C15S]

Limeyrob - Tried disconnecting the alternator and inserting a 6v battery directly into the process.  Still no joy.  the tester suggested by rhyatt arrived and shows I have a spark. Points are opening just before TDC per specs.  Sparkplus is wet after multiple kicks.  As suggested by scifi I have gone back and looked at valve timing.  My valves are starting to open at spec points, not fulling opening or closing as suggested.  As much as I hate to do it, I guess I will pull the tranny side cover and verify the cam drive pin pricks are correctly aligned and the key hasn't sheared.

[limeyrob]

You are working hard!  I have to agree, until you get the timing cover off and check you will never know.  Look for the timing marks, the part number on the cam and the condition of the keyway on the drive gear.  Also free movement of the cam followers and that they are in line with the cam lobes.  Its very hard to think what could be wrong but I have personally bought bikes with wrong parts that could clearly not have been running.

[scifi]

I seem to remember that on a C15,  Is it possible to put the wrong pushrod into the wrong cam follower.?  i.e. to get the pushrods crossed.?

It was always a bit of a juggling act to get the rods and shiney tube back in place.

[rhyatt]

yes indeed - the OUTER (ie nearest the camshaft wheel) pushrod must operate the INLET valve.

easy to mix up - I use a blob of grease in the pushrod tube to hold the pushrods where they need to be as I lower the rocker box onto the head - guides the pushrod top cup into the rocker arm
PLUS a blob of red paint on the matching rocker arm/pushrod cup and cam follower to facilitate accurate assembly

[limeyrob]

You could be one to something with the push rods, very easy to do.

[Rupert]

If the pushrods are the wrong way round it won't run at all.
As you've opened the ET ignition can of worms... Your C15S would originally have been fitted with ET ignition.
The specific parts for this comprise -
The alternator stator (5 wire)
The points cam (5 degrees)
The ignition coil (for AC ignition).
None of the above are compatible with a 6v or 12v DC ignition system (Boyer or original points etc).
Would be a good idea to check that whatever system you are running has all the correct bits.