Hitchcocks Forum

2007 500 Classic. Hitchcocks 50s pipe. Tea caddy air filter. Mikarb jetted to suit. Boyer Mk 4 ignition.

I’m so utterly fed up with my bike that I’ve thought about cutting my losses and selling it as a non-runner. The bike has been lavished with attention. It’s immaculate having only covered 3500 km, but it’s so difficult to start that I’ve had enough. It’s an utter liability. I can’t use it for fear of being stranded - and yet when it starts, it runs fine. It ticks over slowly and evenly. No pinking.

It’s not that I haven’t got the knack – I’ve owned it from new. Sometimes it starts first kick. Most of the time though, it backfires, usually blowing the carburettor off and running backwards until it chokes itself. I know this will destroy the worm gear if left unchecked.

Tappets are fine. Carb has been off, cleaned and checked. Carb rubber has no leaks and the jubilee clips securing it are fine.

The Boyer Mk IV ignition (from our hosts) was fitted 18 months ago, and was fine. This year, the starting problem has emerged and has gradually got worse. I’ve re-checked the timing as per the instructions – anti-clockwise on the slots at TDC, then moved to mid position (I know that I can find TDC quite precisely). I’ve tried retarding it further - moving it fully clockwise on the slots. This must make static timing about TDC. All wiring is secure. Although I haven’t used a strobe, I do not think my method would put the timing far out. Still it backfires. Most of the time.

I know that battery condition is critical. Mine is about 18 months old. A volt meter tells me that it has a 12.6 volt charge that only drops to 12.4 volts over a period of days. My Optimate assures me with two green lights that things are fine. I’ve connected a ruddy great car battery in parallel, and still it back fires.

There is a degree of end float in the tapered shaft which now secures the rotor, “slop” if you prefer. This amounts to about 5 mm. The magnets and back plate are secure on their taper, but because of this “slop” they had been fouling the blobs of solder on the reverse side of the stator plate. I had thought that the magnets fouling the solder blobs were inducing a mis-timed spark. I've dressed this excess solder with a file, and fitted a cardboard gasket behind the stator to further increase clearance, and so the magnets no longer foul anything. The connections created by the solder have not been compromised by my judicious filing. Now I’ve painted the solder on the reverse of the stator plate thinking that this might insulate them and prevent a spark somehow being induced.

So that’s it. I’m at a loss.

My options as I see them are:

1. Sell it as it stands and buy a (Hinckley) Bonneville.
2. Re-fit the points and condenser. If I can work out the wiring.
3. Fit a new battery despite the positive indicators outlined above.
4. Put it in the shed and let my executors dispose of it in maybe 20 years or so.
5. Torch it.

Any thoughts anyone?

I would bet that if you obtained a strobe you would find the timing out. The fouling of the magnets is a clue, either something isn't fitted correctly or is missing, that shouldn't happen. Have a look on the Boyer website for some FAQs. Where are you located? perhaps one of our 'gurus' can give you their opinion.

I would re fit the Points & Condenser back on as it only takes about half hour then try it again as its the easy way to test If all works well. If it dose then you know its something to do with the electronic ignition.

I struggle to understand why people insist on fitting electronic ignition on these things, leave the things alone, thousands and thousands with points running around beautifully. My thoughts generally are why did you fit the electronic ignition, was there a problem and if there was a problem then fix it , don't try wacking on electronic ignition to mask a problem, fix the problem and all will be good

The standard points set up is fairly basic but is simplicity itself to maintain. It costs very little money to replace any part of the set up if any fault develops and the tool box has plenty of capacity to carry a complete spare system of points, coil and condenser. The standard system alos works surprisingly well. I suspect your fault lays with the electronic system, as a simple change to the exhaust, air filter and the jetting is unlikely to have such dramatic effects.

interesting thoughts why does it always seem that boyer ignitions give problems ? as another poster said anyone who can set an electronic ignition especially a boyer without a strobe must be a genius,remind me if i,m wrong but doesn,t a boyer self advance while the engine is running so how can you check that without a strobe? best advice either refit the points set up which will also entail fitting the advance retard mechanism or get a strobe follow our hosts tech notes on fitting boyers ,i don,t like to repeat myself ased i once had a boyer mk 3 on a gs750 years ago ,i found it to be a load of crap so i returned to the points set up the problem was a flat spot on the advance just before 3000 revs nol good on a four hope this helps paul.

Yes I'm a bit bemused by this desire to install electronic ignition on everything. I've put a mag on mine and that is without question a bit of titivation that I didn't need to do but it does make the bike look older and there is something splendid about making a spark mechanically but unless the battery and coil set up had totally worn out I can't really see the advantage. It's not a performance tool and whilst it possibly compensates for the lack of a vacuum advance/retard through some clever software (or does it?) it would seem to suggest the keeping it simple is best.

Hi Mazeppa. From all that you describe it seems you know what you are doing. There are a few things that need emphasising about setting up the Boyer. First is the actual piston position when positioning the rotor. The timing is set with the engine moved to the full advance position. Then the rotor is loosely fitted and the stator fitted with the locating screws central in their slots. The rotor is turned (Not the engine) until the red dot on the magnet (It doesn't matter which one) lines up with the inspection hole that is to the RIGHT hand side of the lower magnet (NOTE there are 2 holes). The rotor spindle bolt is then tightened. This gives the full advance timing but at low rpm the unit delays/retards the ignition spark slightly more than the centrifugal device so should make kick-back less likely. It could be that if your magnets are running closer to the magnets this will advance the ignition a bit more so end float on the distributor shaft you be addressed.
You can use a strobe to check the action of the rotor to see if the unit is advancing and retarding by shining the strobe at the distributor to see if the red dot appear at the hole when revving the engine, and move away again as the revs drop. If the unit is set up right then it could be just your technique. I’ve said on here loads of times the best way to start any big single is to use no throttle what so ever and just catch it on the throttle when it fires. This will minimise kickback as long as everything is set correctly. You should be able to start any bike this way with no more than 2 kicks. If problems persist phone the Boyer tech help-line, or fit back the contact breaker just to prove it will start OK.

I had a Velocette Venom brought to me with a very similar problem two years ago Boyer system fitted...... What I found was that the two wires from the pick up had been extended to reach the box under the seat, as the leads where extended the owner had crossed the wires over causing the problem,,,, although all appears OK this puts the timing way out.

The Hinckley Bonneville is an infinitely better machine in every respect. That said, there is no reason your Bullet cannot be made to run perfectly.

The problem is indubitably one of timing. Scrap the Boyer along with any associated bodges of your own and reinstate the points.

Every symptom you describe is a textbook timing fault.

Where are you? Is there someone near who might help? Despite being knowledgeable it's difficult to disassociate oneself from a chronic problem in order to view it objectively and dispassionately.