I have a frustrating problem with the (Norton type) Boyer ignition system on my Silk.
When I rev the engine the timing retards rather than advancing. The system has been back to Boyer who have tested it and say it's fine.
I've tried switching the sensor wires and disconnecting the electronic rev counter in case it was causing interference but without success.
I'm still running the Lumention system so have no direct knowledge of the Boyer system. The Boyer has been used successfully so it can be made to work. A couple of observations:
The standard Norton Boyer gives max advance at about 3200 rpm. As it is mounted on the camshaft it actually rotates about 1600 rpm. Mounted on the crankshaft of a Silk it will give full advance at 1600 rpm which is not much more than idle speed. This was brought up with Boyer by Clive Worrall and George Silk and Boyer will make a system with an advance curve suitable for a Silk. If you do a search of this site for Boyer and/or Pazon you will find the threads.
The rotor for the Boyer on a Norton rotates anti clockwise, fitted to a Silk it rotates clockwise. I don't know how the Boyer pickup works but this may be a factor. Have you told Boyer what bike you are fitting their system on and the direction of rotation? May give a clue to the problem and a solution.
I do know about the Silk Boyer version, but I bought this one before it became available.
I checked with Boyer about the change of rotation, but their response is that the system works equally well for either rotation.
I'm thinking about going back to lumenition as I have a used spare I bought from Ebay, but when I trial fitted the sensor assembly the A/R weights fouled the sensor so I've got a bit of head scratching to do to remember how it goes together.
I guess you are strobe timing the ignition on the alternator rotor. If you are, which way does the strobe mark move on increasing engine speed - clockwise or anticlockwise? Got bored with TV last night and looked around Google about Boyer problems. A lot seem to be due to poor electrical connections or suspect batteries. It seems some Boyer systems go to full advance on low volts. Can be a big problem with electric starters - not applicable for Silks! If you can't find anything else wrong have you checked the supply voltage at the Boyer box - it should be the same as the battery if all connections are good.
The Lumenition system was changed in the mid 1980's from the MK16 to the MK17 and not surprisingly the components are not interchangeable. I don't know which model you got from Ebay. Identification of the Lumenition model can be found on their website at:
From a Silk perspective the main difficulty with the later model is that the optical sensor is different and won't fit directly on the mounting plate. I met Tony Donnithorne at Popham a few years ago and we were discussing Silks. He had a Silk and fitted the later type and kindly sent me instruction on how to modify the Lumenition sensor to fit a Silk. If you have the later type let me know if you would like the information from Tony.
The alternator rotor goes anticlockwise and the timing mark also moves anticlockwise on increasing revs so the TDC mark on the rotor moves closer to the TDC mark on the stator. I did know about Boyer's issues with voltage. I have a 6 month old battery, kept well charged and a voltage drop of about 0.1V between the battery terminal and the ignition module connection, so I don't think it's that.
The Lumenition I have is mk12. On the original I had on the bike the optical pick up failed. The new unit (also mk12) has the same type of pick up mounting but the screw holes positions are different so I'll have to modify something. If that's what Tony's instructios cover I'd love a copy please.
Your Boyer really is going backwards! Another boring night on TV so thinking about how the Boyer pick up works. This may be a bit left field but may help understand what is going on. The pick up generates an AC voltage wave in the coil as the magnet passes the coil. If the wave form is positive followed by negative reversing the direction of rotation will produce a negative followed by positive wave form. The Norton Boyer box works for either direction of rotation so the electronics must be able to detect the direction of rotation from the wave form. The system you have seems to be working as the strobe and Boyer testing demonstrates. I understand the rotating magnet has to be modified to fit the Silk. If the magnets are turned over it has the same effect as reversing direction of rotation of the rotor.
I don't have a Boyer rotor to hand to know if this is possible, try turning the magnets over on the rotor and see what happens. This should make the Boyer think it is going the opposite way round and give the correct direction of advance.
I'll send a PM for your email to send you the Lumenition write up. It is for the Mark 17 type but may be of some help.
I'm hurt that you doubted me! LOL
Boyer tell me that the black box is blind to the direction of rotation, it simply applies a variable delay depending upon triggering rate. They did say that incorrect magnet polarity could cause retarding as you suggest but that mine were right. I have tried reversing them on the rotor (which was a pig to do as I'd fixed them on too well) but it didn't make any difference.
I hate being beaten, but Lumenition and a nice mechanical advance calls.
I'm surprised Boyer are not more helpful. They must have some idea what is causing the system to retard. I'm at a loss as to what to do next. I believe some systems are sensitive to RF interference from unsurpressed ignition leads/plugs. Not sure if this applies to Boyer systems. Is it possible to move the Boyer box to get it clear of other electrical equipment to rule out this possibility? Apart from that I can't think of anything else to try.
I tried sending you an email using the messaging system on this site and it got knocked back as undeliverable. You could try to contact me from your end or give me some details.
Here is a picture of my \Boyer as fitted by Clive a couple of years ago. Had hoped to fire up this week but water pipe issues (Mk 1 bike and angles/dimensions all over the place) and just discovered one of the treads on the pump housing is gone and needs helicoiling. Already helicoiled 2 different size holes now ordered a 1/4 UNF kit!
Maybe you can see if your fitment is different to mine?
Personally I prefer Pazon by far for service and item quality. The Boyer wires are always too short and the crimp fittings are just horrid. Wires too short to do an alternative job. A mate had a Boyer on a Vincent pack up mid way across Canada (nice Holiday for a Brit) the replacement too ages to arrive and then if I recollect was faulty.
yes, my Boyer sensor set up is the same as yours.
Boyer don't seem to have a great reputation, although to be fair they have tried to assist but don't seem to be able to work out what's wrong. I went for the Boyer originally as it seemed to be the established modification.
I hope you get your bike running soon.
My silk is now running beautifully (no back brake cable yet so not tried on road) BUT the oil pump housing does not quite fit properly over the Boyer. Not sure what is fouling and its not much about 10 thou but enough to make oil leak from the O ring area
Also have oil weep on crankcase half at front right in middle. Clive says not seen that before...anybody else??
How frustrating for you, but it's great to hear that it's running well.
It is very tight with the Boyer fitted, I remember that I had to do quite a bit of minor fettling to get clearance everywhere. If you've got enough clearance between the rotor and the back of the stator plate you could shave a bit off the thickness of the aluminium ring the stator plate sits on. For a quick bodge while you think about it you could always try a gasket and a thicker O ring!
Regarding your oil pump housing not going right back onto it's mating face, it might be worth checking that the rotor retaining nut is not fouling on the oil pump spindle oil seal. My oil seal was well and truly graunched when I first got the bike. Since I was fitting a Boyer system and had to make a new rotor I was able to adjust this clearance.
Hope it might solve your problem without resorting to more more expensive mods.
Thanks for that , I presume you do not have the retard ignition problem one of teh opther chaps on the Forum is plagued with?
I measured up the gap and it was about 1mm fouling
Used a bit of engineers blue and predictably it was one of the coils so Dremeled (is that a word?) the offending area and its on !! Really did not enjoy doing this so reward tonight is a particularly natty Red Wine after a Hobgoblin IPA
My Silk is still on the workbench having slowly evolved from a pile of bits. It has certainly taxed my patience. I hope that I don't encounter too many more problems if I ever get it to run.
I am nearly there but then I have thought that before and found yet one more problem to overcome. Still hoping it will have been worth all the effort when up and running.
I get frustrated by threads that don't have a proper conclusion so:
I've removed the Boyer and gone back to Lumenition.
Boyer were as helpful as they could be, but couldn't find a solution. They took the system back and it tested all ok, they supplied another black box on sale or return so I could double check whether it made any difference on the bike (it didn't) and they suggested various things to try.
I tried everything I could think of, even borrowing another timing light in case my fancy electronic one was faulty (I was desperate at that stage). Nothing seemed to help so I finally and reluctantly gave up.
Until I try the strobe on my Boyer i dint know whether I have the same symptoms. Will keep you posted
Meanwhile I thought to get my Luminition system out of its box and work out how it goes together (Clive took it off 7 years ago)
My bike is engine 4 and the system is a Mk12 version so as old as the hills, but I cannot work out how the ATD fits. Anybody got any pictures....this would be helpful on this site rather than pictures of Yamaha engined Spondons ( debate!!)