I have just fitted a Boyer Bransden Mk4 EI and static timed the engine. It starts easy but miss fires when running. My engine is a 67 model but it has an earlier primary case without the strobe timing cover. my question is how can I strobe the engine without the primary case marker?
I fitted a new boyer a couple of months ago to my 78 t140, I used the timing marks on the engine, when a mate of mine turned up with his strobe it was spot on. Some say 38 degree is to much for modern fuel you could try 36 degree.
Super rocket
Hi,
The answer is yes, mark the timing marks on the rotor and alternator. Before starting take the necessary precautions and make sure the remaining oil doesn't coat the garage etc.
I have a spare 1966-68 cover part number 68-0837, it needs cleaning up, which I can sort out if you're interested.
Best wishes...
Bess, im very interested in the cover. Let me know what you want for it please.
I can't see a timing mark on the alternator only the rotor.
There are two threaded holes in the alternator, do you thread a pointer into one of those for timing?
Hi,
I just checked the pointer position in relation to the alternator. Mark the alternator lining up the edge of the bolt hole with the centre of the crankshaft, that will be the mark you need to line up with the rotor when fully advanced.
Best wishes...
Hi Chris,
Attached are the A65 primary cover images.
I have checked and can only see a small casting defect on the outside, I polished the inside area and it doesn't extend to the inside so I'm confident its in very good condition. If you are still interested please let me know via personal message system.
Best wishes...
Hi - having timed the ign statically and it just needs fine tuning by strobe, in my experience this would not cause a misfire. If it didn't misfire before fitting it is more likely to be a poor connection or low battery output, coils etc, not the timing being slightly out.
Regards
John.
Interested in thoughts about timing settings. On an A65 the book says 34degrees, but with modern fuels 32degrees is thought to be better. However, I'm assuming with stepped increases in ethanol (not long before E5 is removed off the forecourts), the 32 degrees may not be enough to stop pre-ignition. Which leads to the question whether strobe timing is a waste of time -ie set the timing around the book figure, then alter until any pinking is eliminated (after rounding off any sharp edges on any new pistons installed).
2 thoughts to throw into the discussion.
1 ) use something like castrol valvemaster plus, octane booster and lead replacement, works well., time as book and be prepared to back it off a whisker.
2) use the old trick of timing to the book and then road test with a screwdriver in your pocket to back it off fractionally until any pinking vanishes.
Hi,
I think it is a bit of trial and error as each engine seems to respond differently to E5 and E10.
We use E5 but mostly E10 as this is more widely available. No retarding of the ignition from standard and all seems to go quite well. I would suggest standard timing and try E10 to see what happens and as suggested retard a bit if pinking occurs.
Dave.
Quote from: Chappers1962 on 11 Jul, 2023, 09:21
Interested in thoughts about timing settings. On an A65 the book says 34degrees, but with modern fuels 32degrees is thought to be better. However, I'm assuming with stepped increases in ethanol (not long before E5 is removed off the forecourts), the 32 degrees may not be enough to stop pre-ignition. Which leads to the question whether strobe timing is a waste of time -ie set the timing around the book figure, then alter until any pinking is eliminated (after rounding off any sharp edges on any new pistons installed).
The actual ethanol content is unknown by many. Whether it says E5 or E10, it could still be using the same 4% ethanol which has been used for years by some refineries. Infact some refineries still don't use ethanol in their blend. They don't need to because they have made other efforts to meet the benzene requirement. The E* number is the MOST which any supplier can use from the pump without having to tell you otherwise. Not the exact figure of what is being used.
If you want to be sure, pour 100ml of fuel into a cylinder, add 10ml of water. The ethanol is attracted to the water and should separate after a little while. Take 10 of the separation value and that will be roughly the amount of ethanol in the fuel. You could also add food dye into the water. (You also should seal the top of the cylinder too).
As for the ignition timing, I "finish" my pistons before installing. So that is removing all the sharp edges and putting a radius on them. I set the timing to where the apex on the ground electrode tells me and compare that to where the bike runs it's best, ie best accelerates and top speed. It's usually slightly advance of 34°. It doesn't pink and it runs great.