Hi all, Apologies in advance for this potentially rambling post, - quite a lot to cram in.
My 'mixed bag' '59 Flash with A10SR engine (DA10R.163 - HC) is still giving me grief. 'Sparks' now sorted thanks to Boyer B replacing dead twin coil.
To recap, bike now has;- *SRM ignition conversion (using some BB bits). *Dyn. belt drive & DVR2. *SRM Oil pump.
I've reset/checked ignition timing and tappets. (can anyone improve on the hit & miss 'red dot-through hole' guesswork (pre-strobing) ?
With all set correctly, the engine only wants to spit back (every 2nd /3rd kick.) When looking at valve timing figures it occurs to me this may be the 'wasted spark'
igniting a 'wet' cylinder while the inlet is opening. ( nonsense ?)
The valve timing issue caused me to wonder if there may be a 'dot misalignment', but not wishing to rush into stripping the 'chest', thought i'd check timing angles since tappet covers and primary were off I refitted the timing disc and got to measuring opening / closing points.
Results initially surprised me (comparing to Haynes R.R.figs.(SR not listed) ). All valves open earlier and close later, but also vary LHS to RHS. as follows;-
*In.O 75 BTDC.LHS, 67 RHS. *In.C 87 ABDC LHS, 105 RHS. *Ex.O 77 BBDC. LHS, 72 RHS. *Ex.C 52 ATDC.LHS, 55 RHS.
There is a 'click' from the valves as they make/break there seats. Compression testing indicated 120/130 psi. with no added oil.
Q's arising are;- 1, Is excessive wear indicated ? 2, Is a 357 cam indicated ? 3, Is 35 deg. ignition appropriate ? 4. What comp.ratio would be expected in DA10R 163 (assuming home mkt.) 4, Is any of the above independently or in combination going to make for difficult starting. 5. What is the common reason for spit-back?
The bike is a recent purchase, not run for years,but was hoping to get some 'running' in before embarking 'blind' on any rebuild work.
Phew !
Happy head scratching guys
Pete