First the timing, My bike is a 1960 350cc Clipper, coil ignition and auto advance mechanism, does anyone know the procedure for setting the ignition timing? I remember reading somewhere that you adjust the timing in the fully retarded position and the points to open when the piston is 1/16" before TDC. any confirmation or otherwise would be appreciated.
Second, is anyone able to measure the Mf of the coil/points capacitor, the bike originally had a 'Car' coil fitted which I have replaced with the correct "lucas"coil but kept the old capacitor.
thanks again for any replies.
Welcome Clipper, and I have two comments:
1. The value of the capacitor with coil ignition is not all that critical, and on bikes it is generally 0.2 to 0.22 uF
2. I prefer to wedge the auto-advance to "full advance", and set the timing that way. Problem with setting timing at "full retard" is that you are susceptible to wear in the advance mechanism giving you too much advance at higher revs. And of course, too much advance can result in engine damage.
Hello Greg, Thanks for your reply with the cap rating, Re the timing: I have managed to locate/borrow a workshop manual where it does stipulate that "For all 350 Clippers the auto-advance mechanism used is of a a different type from that on the 350 bullet up to 1959, and the engine timing must be checked and set in the fully retarded position" This procedure also applies to 350 & 500 bullets from 1960 onwards.
Do you know what the B.T.D C measurement is for the 1960 Clipper when setting the timing in the fully advanced position.
Stuart, the info I have lists the advance is 5/16" - 3/8" BTDC when fully advanced. Mind you, I don't have anything specifically for a 1960 Clipper, but could you please clarify whether your engine is one based on the Bullet design, or the Clipper?
That dimension I quoted above translates to about 34.5 to 37.5 degrees BTDC when checked with a degree wheel. I really see no reason to set timing at full retard, especially when it is much morecritical to an engine's heath to get it correct at full advance.
Hi Greg, The bike is a clipper 350cc This was determined by Hitchcocks UK from the engine number, It is basically the same as the bullet with slight differences, one being the distributer and auto advance and retard mech. The manual does say in bold letters to set fully retarded 1/16" BTDC. and not the fully advanced method.
I originally set at 5/16" BTDC in the fully advanced position and the bike was very hard to start and then when it did start it was very rough and back fired a few times before stopping. In order to get the 5/16" I had to take out the distr. adjusting screw in-order to rotate the dist. sufficient to get the 5/16"adjustment.
When cleaning up the distributer and removing the the two advance springs I did notice they appeared slightly stretched ie: coils were not tight but had a slight gap between each coil, I have 2 new ones on order.
It does start first kick with the 1/16" adjustment but gets uneven when the revs are slightly increased so I will see how it is after fitting the springs.
Thanks for you help.
Stuart, it sounds to me that with only 5/16" of advance, the distributor's fully retarded position had the engine firing after TDC, hence the hard starting.
I suspect the 1/16" BTDC number was the Factory's attempt to ensure the above never happens ... though that leaves open the question of what the actual timing becomes at full advance. Setting up at TDC means that you are exposed to full advance errors caused by wear in the auto advance mechanism, and getting timing right at full advance is pretty critical.
It could be that increasing the advance to 3/8" BTDC (which is still a pretty mild advance setting) would have improved your starting.