Latest topics
» Villers 14A seagul engine HELP
Today at 8:14 am by JonTheBuilder

» pivot tube
Yesterday at 5:54 pm by ernie

» Double lift centre stand
Yesterday at 4:24 pm by FB vincent

» Contact breaker screw
Yesterday at 1:56 pm by jasperbell

Thu Jan 18, 2018 7:44 pm by MR SINBAD

Thu Jan 18, 2018 9:37 am by piston 197

» 8e gear lever
Wed Jan 17, 2018 1:45 pm by kerabo

» help wanted
Tue Jan 16, 2018 8:20 pm by Dickey0-1

» Cruiser 75 Generator Coils
Tue Jan 16, 2018 7:38 pm by peter@dunfordconstruction

F-B Merlin - Road Legal?

View previous topic View next topic Go down

F-B Merlin - Road Legal?

Post  NDHAERO on Sat Aug 01, 2015 7:26 pm

Hi all,

some time ago I bought myself a F-B Merlin. A direct lighting 1950 version.

I now taking my CBT in a weeks time, and want to get my bike ready for the road.

Being a new rider, i don't fancy doing hand signals, so am planning of fitting indicators.

I am also going to have to improve the rear light, and rig it so that the break light works.

I also need a horn.

So, my question really is, is a direct Lighting system going to be suitable? Or should i try and convert to the rectify / battery system?

Is the magneto the same in both types? Looking at the wiring diagrams, they seem to be.

Any advice for anyone who uses a FB Merlin on a daily basis, would be most helpful.

Many thanks, in advance,

Nicholas Hill


Posts : 12
Join date : 2015-02-10

Back to top Go down

updating electrics

Post  piston 197 on Sun Aug 02, 2015 6:26 am

It is doubtful if the rectified lighting system will cope with the indicators, brake light and lighting requirements required of it ? I would suggest leaving as is, and if you want indicators and brake light, fit the biggest 12 volt battery in the toolbox you can, and wire the brake light and indicators to it direct, leave a charging plug accessible . Charge the battery on a trickle charger when the bike is not in use ? You will still have direct lighting for the headlight and tail light and as long as your battery is charged will have decent indicators and brake light .
piston 197

Posts : 3719
Join date : 2008-08-17
Location : ross-on-wye

Back to top Go down

Indicators etc

Post  falcone on Mon Aug 10, 2015 9:39 pm

I agree with John that the best solution is probably a total loss battery for indicators and brake light. A 12V battery will be better than 6V because the current is lower for the same power, and this means fewer losses due to resistance of connections etc. It also gives a wider choice of bulbs. I would run the tail light and horn from the battery as well, because (a) the horn will actually be audible, and (b) it is much easier to have a dual filament (or LED) bulb for tail and stop light (although you would need a separate switch for the tail light.
Using LED bulbs means that the current is very low, so a 5Ah 12V battery would give at least 20 hours of use and probably a lot more. I have in the past used LED indicator bulbs but found that the visible angle was quite small, so I went back to filament bulbs. Since they are only on for a small proportion of the time they don't affect battery life much. I use an M-flash flasher unit which is expensive but works with anything from 5 - 18 Volts and filament or LED bulbs, it is much better than the hot wire type which will slow down when the battery is low or if the bulb power is changed.
Good luck


Posts : 55
Join date : 2013-05-21

Back to top Go down

Re: F-B Merlin - Road Legal?

Post  Sponsored content

Sponsored content

Back to top Go down

View previous topic View next topic Back to top

- Similar topics

Permissions in this forum:
You cannot reply to topics in this forum