Anti Vibration Coil Mount for Motoplat

[Timothy Field]

I guess we all know that Motoplat Coils may sometimes suffer damage through the high revs of the engine the mounts can crack or electronic components can fail.

What I’ve done with mine is to try and prevent the damage through mounting the coil on rubber bobbins. I wanted to keep to engine in as original state as possible hence not make anything to permanently change it so for show purposes it can be put back to its original coil fixing points.

I’ve also tried to make sure that I provided the earth strap with good connection points. The pictures below is what I’ve done for a Hewland understanding that it may have to be designed differently for other makes of engine. This modification was made out of 50mm high X 6mm thick aluminium bar and was cut to form a bracket 45mm long.

[JEB]

Hi Tim,
You may recall that at Rowrah on the Saturday when you were there that I had terrible misfiring problems with my K80. I tried just about everything then resorted to using my K88 on the Sunday - and had a superb day. Rather than buy another duff Motoplat off t'internet I opted to buy a brand new Ducatti ignition and coil. This has served me well, however I do not reccommend these to any BHKC members as the stator does not match the three fixing threads in the motor and only two fixing screws can be used. Also, because of this, I cannot retard the ignition as far as I would like to for modern petrol octane rating and I therefore run the risk of putting a hole in the piston. Photos attached.
Garry.

Komet K80 with Ducatti ignition and coil.

[Timothy Field]

Sorry to hear that Garry it's a shame these don't fit as Dartford Karting describes them in the picture as "Stator, rotor and coil assembly to replace Motoplat units with small cone". Do you think it could be modified i.e. slots extended or some sort of adaptor plate could be made to accommodate it better?

[JEB]

Not in my opinion Tim, it has been suggested that the timing problem can be sorted by leaving out the key, but that is not my style
Also. I had to make a special rotor holding tool ......... not a happy chappy - the igniton once fitted works perfectly and has enabled my no.1 one priority for this year i.e. Track Time !!! BIG MEGA THANKS to Retro Racer for being very flexible/accomodating and the key is to keep track days to get future numbers up

[SteveGoodman]

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[peter freeman]

garry i run my tt22 with out a key so far have had no trouble pete.

[Timothy Field]

Would putting another keyway on the magneto work at a point so allowing all 3 holes the match up and enough room for movement the get the timing at the correct position?

[bultaco49]

Gary I'm with Peter on this one. Strictly speaking the key only locates the magneto on the shaft. The magneto and shaft are fixed by the taper. There are some reputable suppliers of magneto kits supplied with no keyway at all, for example Powerdyno of Germany who make very good aftermarket Ignition systems (including an internal rotor Motoplat replacement).
I'm now running my Bultaco with a 1kg external magneto flywheel without a key and no problems. Some of my trials motorcycling friends also run 2kg magneto flywheels without keys.


Tim

[JEB]

Learning all the time, thank you ............. Pete does my 'ed in , with the greatest of respect ...................

[Timothy Field]

Hi Garry,
Sounds like you have a plan thanks to Pete Freeman, Tim Norwood and a few other suggestions a well. Collaboration like this is what we are best at and long may it continue.