Forum

[Mark B]

My 1999 500 Bullet has a Boyer MkIII system fitted and I've added the powerbox to replace the reg/rec. It runs well but is reluctant to start. I know that the starting issue could be something completely different, but the Boyer website states that you should use a suppressor plug cap otherwise the electronic ignition could be affected, causing poor starting. I've got an un-suppressed plug cap - should I change it? Thanks for any wise thoughts.

[NicoV]

This is what I found in the Boyer Bransden's faq sheet:
MKIII and MKIV do not require suppressed plug caps for operation although we recommend using supressed 5000 ohm plug caps. It is only on the Micro Digital and Micro Power units that it is required to have suppressed caps.
I had starting trouble right after installing the BB electronic ignition. It was due to a poor earth connection.

[Gwilly]

It says the Mk3 and 4 do NOT need suppression only that its recommended, 5000 ohm.

Use copper core HT lead NOT the silicon type which degrades and don't use a resistive cap as well as a resister plug (has an R printed in the type lettering).

May be time to upgrade the original coil to something with a bit more oomph.

Make sure the carb is clean and tuned to perfection or you will just be chasing your tail...

On that note, change or adjust one thing at a time and evaluate results before moving to the next..

[Mark B]

Thanks Nico and Gwilly. I'm trying to focus on one issue at a time; a few months ago I fitted a new coil with copper HT lead which cured the tendency to cough and die after 20 minutes' running (the Bullet, not me...). I recently swapped the Mikcarb for an Amal MkII (because I was given it), rejetted as per Hitchcocks' recommendation, and it goes very well, after it's started - it's been hard to start hot or cold. I'd had the Amal ultrasonically cleaned. The compression has seemed a bit tired so at the weekend I cleaned and lapped the decompressor valve which has made a big difference - once again I can stand on the kickstart without it sighing and drooping, and it started 3rd kick - massive improvement, but maybe a fluke... I've not had the chance to take the Bullet out this week but I hope that the decompressor will have sorted the issue; I just didn't want to compound things by having the ignition affected as well. I've got a 5ohm resistor plug cap which I'll fit anyway, after I've checked that the starting really has improved. Thanks, Mark.

[Valsp]

The most common reason for poor starting with Boyer systems is low voltage. Make sure you have at least 12.5 volts at the battery when the ignition is on

Dave

[Revband]

Valsp is on it. The mk3 goes to full advance on low voltage, if you are using the power box to run without a battery, that is your problem.

[Adrian]

The Mk4 claims to have fixed that problem, prompted I think by the arrival of the Pazon ignitions, which were developed by ex-Boyer people, and claim to work well at lower voltages!



Mark hasn't mentioned running battery-less, for that an alternator upgrade would be a good idea, either a Lucas RM21 or our hosts' Lucas replacement for the 4 wire Indian alternator, 1999 was the year the factory changed to AC headlamps.



A.

[Mark B]

I run a normal battery which is charging well, and the Powerbox is meant to overcome the problem of older Boyer systems going on to full advance when the voltage is low.

[Gwilly]

Yes indeed poor compression at kickover will indeed give lack lustre starting, the decomp may reseat after the motors fired but you would have to really spin the motor like bump starting..

So with luck you've sorted that, you may need to fine tune the timing and carb so keep an eye on the plug colour from 5 mins at tickover to half throttle cruising.

Watch the exhaust header for "blueing" a sign of retarded timing or weak mixture, and listen to the exhaust note, flat or barky

Use high octane premium fuel like Shell/BP for a slower burn, keep clear of supermarket crap, or you might as well be trying to burn Kerosene.

Leave that rubbish for cars with variable valve and ignition timing aided by knock sensors etc...

Anyway i've wittered enough and the dog wants to go out..