Hi Everyone I am new here, and I am looking for some advice with my recently acquired 1972 Bonneville T120v USA import. I am relatively new to bikes but did have a 1996 Trophy 900 that I sold as it was too big for my "local" running about, and bought this Bonneville, that needs work. The bike arrived with no battery and a non standard rectifier. I fitted a new battery and connected it up + positive earth and connected the rectifier. However I can't get anything electrical to work. On further investigation I have found several wires dissconnected either by accident or on purpose!!!!. Plus the wireing diagrams in the manuals don't correspond with what I have in front of me on the bike. I Forgot to mention it is a matching numbers bike. A) Is there any chance the bike could have been changed over to a negative earthed bike? B) Where do I go from here to get any of the electrics working. (I have not tried to start the bike yet). Any advice you can pass my way would be really appreciated. If anyone needs clarification on anything I have said here please do get in touch and I will try to clarify the situation. Thank you very much in anticipation.
Your best option is to disregard your present wiring and buy the correct new loom as they are cheep and available.
Hi darkman, thank you for the sound advice. However I have been working my way through the problems I have and most seem to have be "contact" issues that I have managed to sort out. I may still put in a new loom though for my own peace of mind. However the wiring diagrams in the Haynes manual are different to what is on the bike, as I have said, and they are incomplete as they don't show the indicator / handle bar circuits etc. I have been looking on line but can't find anything that shows the wiring to the left and right handle bar clusters and what their respective wiring should do, go and colours. Is there anyone I can contact within the group that would be able to send me a copy of the complete correct diagrams for my bike. And of the many parts suppliers out there are there some that anyone can recommend that sell good quality parts for these older bikes and are helpful to us new members.
Have you tried here :- https://www.carlsalter.com/triumph-service-manuals.asp for the workshop manual ?
For sources of spares and information about your bike - and many others from the good old days - have a look at magazines such as Classic Bike, Classic Bike Guide and The Classic Motorcycle where many dealers advertise there wares. These people are often willing and happy to give advice. Slater Bros were very helpful when I had problems starting my delinquent Laverda Montjuic many moons ago. Just a thought .... I seem to remember recently reading about a couple of gents in one of the aforementioned mags running a bike shop/garage in Dover (not too far from you - strangely I was a student in Canterbury, Christ Church College as was, when I was a yoof) specialising in old bikes. May be worth a bit of research? This may be them - Road Star Cycles, Victoria Park Mews, Dover CT16 1QP. Seems likely from what I remember. Over to you, Sir!
With the Lucas switches you have the left switch should be head light flasher and m beam n dip switch (middle toggle) and horn (push button) On the right hand switch middle toggle is indicators and push button is kill switch. If you can't make sense of colours then use a meter to test the switches for correct wires
Hi guys. Thank you for your help it is much appreciated. I have got everything working now electrically by using the wiring diagram as suggested which had all the correct colours and locations of all the equipment. I renewed all the Lucas connectors on the loom which helped. I have now freed up the Pistons within the carbs and given the carbs a good clean and polish, adjusted their cables, fitted 2 new petrol taps, adjusted the clutch, adjusted the tappers and points, cleaned the plugs and cleaned out the fuel tank...... I then checked I had oil in all the correct places and ... gave it a kick or twenty. After several coughs and a few pops and bangs..... It fired up. So, I now have a running 1972 T120. A bit more fetling continued....then me and the bike moved under its power up the drive. A bit more fetling and then I tried the bike up a near by private road and have been up to a heady 3 gear and all seems well. If exceptionally noisy with the American exhausts that are on it. We are now booked in for an MOT so watch this space. Thank you for your help again.
As for parts....Roadstar are still in Dover....friendly and helpful guys, also FD motorcycles and Triumph Twin spares, both in Essex
I have a 1972 T120R 650 Bonneville #NG... I haven't had it on the road since 1996 and I can't remember how to take the ignition side cover off. I think it just pops off but I'm afraid to bozo it. I have a Harold Glenn manual and I've looked through the Haynes workshop manual. No help. It's probably easy but ???
