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Setting ignition timing on Dommi '99' with Electronic Ignition fitted

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1959 Dommi '99'.

The bike has a Boyer electronic ignition system fitted. This was on the bike when I purchased it. Since then I have undertaken a full engine rebuild and I now need to reset the ignition timing. I've been told I need to do this with a Strobe and that the engine needs to be revving at about 4000 rpm when this is done. I also understand that the setting should be 32 deg. BTC.  

My question - how do I set the ignition timing to a point whereby I can actually start the engine ? Obviously I cannot use the Strobe until this has been achieved.

 

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I set up the Boyer on the Atlas using the instructions .Was never able to hold the bike still enough at 5000 rpm to do the strobing. One day I will refit a mag. 

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Hi Mike .........answering your question. Please check out the ignition timing info below.

For 77, 99, 99SS & 99 Nomad   1956 - 1962     32* BTDC or 0.307" or 7.808mm BTDC.

Of course, it is best to hang a timing disc off the crankshaft to get the most accurate readings but a pencil or rod of wood down the plug hole will help get you TDC. Then put the bike in top gear and crank the wheel backwards until the piston has dropped by 0.30" or 7.8mm.....assuming that you have standard compression pistons. It won't matter too much if you have not as these numbers are close enough to get the engine running without damage.

You can then check and reset the ignition timing more accurately using a strobe and marks painted on the rotor and stator. Which generally means pulling off the primary outer cover. However, you don't even need to do that as a quick run down the road will tell you if the engine is pulling well - good timing........pinking - over-advanced......or very stodgy - under-advanced. The Boyer Trigger plate can be easily moved a fraction to correct any wrong settings, though you might need to repeat the process with a few runs.

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I don't know if a Manx is more forgiving than a 99. When I first started it after 23 years sleep, I found it started with timing anywhere between 38 BTD and 12 ATD! If I remember the kill switch.

Phil your idea for finding the ignition timing on the engine is as you say 'near enough' for starters. But you don't mention the critical point of finding the ignition point on the BB pickup. and this is......(this information is on BB web site) but turn the engine slowly so that you can see the rotating magnets through the holes in the BB plate, Yes not easy standing on your head and pearing in above the gearbox...when you find the rotating magnets the ignition point is as a magnet is viewable through the hole BEFORE the pick up coil. If this point is in line with what Phil says then you should be able to start and run up the engine to be able to strobe it.

 


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