Timing a Boyer magneto conversion

Previously wrote:

Recently I acquired a magneto replacement boyer set up. Don't know if any have done this, but I am at a loss as to how to time it? I have timed magnetos quite a few times with degree wheel, dial indicators and such. but the magneto is set with the engine dead. The Boyer is asking to be set at 5000 rpm. as the early engines have no timing mark where does one or rather how does one best achieve this?

Thanks

maybe best to just leave the magneto in... starts good great lighting!

Hi Steve,

Previously wrote:

Peter,

your points understood and appreciated. might i askyour method todetermine thefirst setting?

I have owned tractors (1939 IHC for one) that had aspark retard lever which one sets before hand crank starting.with the engine running it was easy to hear the effect of spark advance on the motor. My 650 with magneto runs the best when i am very diligent in finding exact TDC with a dial indicator in the spark plug hole. I bought the conversion for a friends machine and right now i am not certain that it actuallywill bean improvement over the magneto system. It may end up as a paper weight on my desk.

I agree that some, yourself included, are able to detect the correct settings by ear. It is a very special skill. for myself ishould think i might prefer an exact method which wouldrequire fitting a degree scale with pointerpermanently inside the primary. the timing can thenbe checked as on a Commando. i suppose that will also require another rubber bung and hole as well. If not one has to disturb the seal that keeps the oilin the oil bath and off the floor.

After all that, one has to decide if itis reallyworth the effort.

sincerely,

steven phelps

Hi Steve,

Your comment that the bike is running great with the old magnito set up is a very valid one and at the end of the day you can spend a lot of time and effort trying to find the elusive perfect set up. If it runs well and you are happy with it, leave it until a real problem occurs. I mentioned that there are now some very sophisticated strobes available at reasonable prices, if you want a more scientific method of setting the timing then this is the way to go. The most accurate way of determining TRUE TDC is to put a dial guage on top of the piston and a degree disk on the crank with a good fixed marker usually from one of the cylinder studs. You need to rotate the crank forward to TDC, make a note of the position of the degree disk and then go well beyond TDC, say 30-40 degrees and then rotate the crank back to TDC on the dial guage. You will probebly get a difference of a few degrees beteween the two measurements and if you half the figure it will give you TRUE TDC. The TDC tool through the plug hole is ok but not exactly accurate. Ater you have established where TRUE TDC is you can paint a mark in the primary chaincase and on the rotor so you can know see TDC. Next rotate the engine backwards until you get to 32 degrees BTDC which is where the boyer needs to be set, paint another mark in the chaincase at this point and then you can set the points plate. Put the trigger and fasten loosely, fit the pick up plate and tighten the pillar bolts loosely in the middle of the slots, then turn the trigger with a small screwdriver or similar until it just comes into view in the little hole, make sure you are using the right hole as the commando hole is different as the trigger moves in the opposite direction. Tighten evey thing up and check connections and start your engine. It should start and run well but for spot on timimng use a strobe to see if the marks you have painted stll line up. Some strobes can be programed to flash at any given setting BTDC using only the TDC mark but you will need to read the instructions for that particullar make of strobe in order to set it up properly. As you say, with the standard set up the pimary chaincase has no inspection holes and is full of oil so this has to be done with the outer chaincase removed unless you want to drill a hole and fit a rubber bung. I hope this helps but you might want to wait for when you need a rebuild before fitting the kit.

Regards,

Peter Austin

Hi Steve,

I'm glad if it has helped you.

Just a couple of other items you might want to look at; with some of the electronic ignitions they do require a full 12v (if you are converting to 12v you will need to change coils, bulbs, battery, etc, but 6v systems are available) to operate, often the first signs of problems are when the bike wont fire up, misfires or runs eratic. The first thing is the battery which must be in A1 nick, batteries that slowly loose charge are no good and you are wasting your time recharging them with this set up. Next is the charging systems. On Commando's the standard alternator set up is ok but check the retifier/zenor diode are working correctly. Later models had a bigger output version and you can fit the 180w stators to earlier modles but you need to fit 2 zenor diodes or go over to a solid state rectifier/boyer powerbox arrangement. This type of alternator can be retro fitted to most Dominators but you may need to go over to belt primary drive, Mick Hemmings or RGM or Norvil would be able to advise on this. The output of the standard alternator model Dominator should be ok with electronic ignition if every thing else is spot on and you dont drive with your main lights on (during the day!).

You may find this a bit of a carryon, and I agree it can be a nightmare if you get it wrong. I have done this on a number of bikes, even a triumph (oops! dirty word) but they have always been ground up rebuilds where I've planned to convert to electronic ingnition, belt drive, PW3 Cam, big valve head, quaife 5 speed box, Arrgh! the money I've spent! I try never to think about that if at all avoidable as it makes me ill.

As you are no doubt aware you can through tons of money at a Norton and at the end of the day, the only person who knows if half of it was worth it is you and you don't need all the flash bits to enjoy riding a bike.

Previously wrote:

Recently I acquired a magneto replacement boyer set up. Don't know if any have done this, but I am at a loss as to how to time it? I have timed magnetos quite a few times with degree wheel, dial indicators and such. but the magneto is set with the engine dead. The Boyer is asking to be set at 5000 rpm. as the early engines have no timing mark where does one or rather how does one best achieve this?

Thanks

maybe best to just leave the magneto in... starts good great lighting!

hello the Magneto is the Best BUY far all this messing about And if you battrie Dies Or is nicked or you transistor goes bang you are snookered BIG Time there more things to go wrong on these mag replacement thinges than you can shake a stick at ??? So You can not Beat A trusty old Magneto in good order ??