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Boyer Mk3 v's Mk4
Posted: Tue Jul 10, 2012 2:35 pm
by Bullet thrasher
Anyone have any direct experience of the two on a 500 Bullet. I still suffer from under volting from time to time and wonder whether the Mk4 is a worthwhile investment. I picked up an advance and points etc recently, is that my best bet for performance and reliability. If it don't stop raining soon I might just get a submarine instead.
Boyer Mk3 v's Mk4
Posted: Tue Jul 10, 2012 3:00 pm
by Les H
I have a Mk 3 which works OK. The mark 4 is designed to tolerate much lower supply voltages without over advancing the ignition timing. The Mk 4 is very similar electronically as the Pazon Surefire. Note you can buy the mk 4 amplifier unit without needing to buy a complte new kit...save quite a bit of money that way.
Boyer Mk3 v's Mk4
Posted: Tue Jul 10, 2012 3:05 pm
by JOHNNY SINGLES
What is wrong with the old points set up then. Running for cover
Boyer Mk3 v's Mk4
Posted: Tue Jul 10, 2012 4:01 pm
by Les H
In my case Johnny, the Boyer was fitted to the bike (AJS 500 short stroke) when I bought it. My Bullet still has the original points and I agree there is nothing wrong with them and I have no need or desire to change to electronics. What I would say is that the Boyer on the AJS produces excellent strength sparks at slow kick-over speeds and allows it to be started first kick most times hot or cold, which impresses me.... whether retro fitting the points system would cause less consistent starting I am not tempted to find out.
Boyer Mk3 v's Mk4
Posted: Tue Jul 10, 2012 5:33 pm
by marsie
Keep the points. Fit a Boyer Inductive Discharge Unit No KIT00069 Read all about it on there site.All the advantages of electronic ignition and save money
Boyer Mk3 v's Mk4
Posted: Wed Jul 11, 2012 12:47 am
by Bullet thrasher
Thanks. I have never had points on this bike but had them on my 350. If it weren't for the fact that I use my bike every day I'd probably fit and time the ad/re and points, Ihave them in stock for when the time and a strobe come to hand. For now I suppose I was trying to decide whether the time and cost versus the reliability, performance were worth the effort. I realise I can just buy the box and may get a few quid back on the Mk3 box. The inductive discharge system sounds promising. Best of both? I will have a look at that and update you on my progress. Thanks again.
Boyer Mk3 v's Mk4
Posted: Wed Jul 11, 2012 8:21 am
by Les H
If you think about it, the inductive system is not the best of both worlds; it is the worst of both worlds.
By keeping the points you have a mechanical switched system that is subject to wear and slightly variable switching caused by arcing which will always require periodic adjustment. These mechanical aspects compromise the electronics’ advantage of precision accuracy and override the benefit of the fit-and- forget installation. The looking at it the other way, the advantage of long term reliability of the points system is then compromised by the chance that the electronic box might fail at any time (very rare it has to be said). The only real benefit of the inductive system is the ease in which the ignition box can be removed and the ignition switched back to conventional points for a "get you home" fall back. Electronics nowadays are extremely reliable...every petrol powered vehicle manufactured for the last 20 years or more uses electronic ignition with exceptional reliability, so the fear of the Boyer/Pazon failing should be very low. A very punchy spark at cranking speeds really does help starting....how many cars do you hear nowadays, cranking away, and getting slower and slower as the battery drains on a cold morning? Hardly ever I would say and that is mostly to do with the fact they have electronic ignition. The Bullet engine does start and run perfectly ok with points though but it would be nice to hear from anyone who has changed to full electronic ignition from points and get their feedback. BTW. Another advantage of the Boyer is the increased range of advance or looking at it the other way round, if set up perfectly, the static ignition retard is greater at kick over speeds which should result in less chance of a kick back. Having said all this, I can’t see myself changing away from the conventional points at the moment.
Boyer Mk3 v's Mk4
Posted: Wed Jul 11, 2012 9:37 am
by Alan R
Hi Guys------- I'm with LES H on this one. I have two Bullet Classic 500's, both of which had points with the inductive discharge units fitted. And for similar reasons I removed them---fitted a NEW set of points + capacitor, checked the mechanical go-roundy bits'n bobs things and springs. 1,000 miles later all is well ( Ooops, hang on---going to TOWCESTER TON-UP day this Sunday. Best not say too much, eh ??). Also, my reasoning was similar to LES ie I will either have a FULL electronic OR---a FULL mechanical system, but not a "Halfway-House" where more complexity has been added into the "loop" as it were. The mechanical short-falls compromise the electronic improvement. Sorry MARSIE, alas you don't get all the advantages of electronic ignition for this very reason. LES---- it was mostly the Ford Cortina Mk1 down our way that groaned to a stop. My Moggy 1000 Pick-up was a v. good starter all year round.
Boyer Mk3 v's Mk4
Posted: Wed Jul 11, 2012 12:09 pm
by Bullet thrasher
I was under the impression that the inductive system means that the point no longer carry so much current and that the gap is less critical and that contact erosion is greatly reduced. Also due to retaining the mech/advance the curve is constant regardless of supply voltage. On balance I think I may go the Mk4 route as my voltage is variable despite having a powerbox and gel battery and LEDs everywhere except the headlight. Thanks all
Boyer Mk3 v's Mk4
Posted: Wed Jul 11, 2012 12:52 pm
by Les H
The points do carry less current but the fibre heel still wears. Any change in gap whatever the initial setting will change the timing. As regards the stability of the ignition advance curves, once the operating voltage is above the minimum level (Which is lower for the Mk4) the advance curve remains independant and stable. For example if the maximum advance is set at 38 degrees BTDC then this timing figure will be met whether the Boyer is powered anywhere in the range of say 10V - 15V...it is only when the supply voltage drops below the lower figure (around 8 volts for the Mk 4 and Pazon) does the ignition fail to retard as much (In effect more advanced) ...Info from the Boyer tech help. This gives stable and accurate ignition timing when running.