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Motorcycle Discussions => British Bikes => Topic started by: ramwing7 on June 02, 2021, 09:48:26 PM

Title: 1973 Bonneville Ignition Switch
Post by: ramwing7 on June 02, 2021, 09:48:26 PM
I recently purchased a 1973 Triumph Bonneville T140V for restoration.
Guy I bought it from said it didn't have an ignition key, which was ok, but on further examination it doesn't have a ignition lock either.  It has the wrong front fork and some other missing pieces, so my question is; If it had an ignition switch, where was it mounted when it left the factory?
Thanks.
Title: Re: 1973 Bonneville Ignition Switch
Post by: L.A.B. on June 02, 2021, 09:59:40 PM
It has the wrong front fork and some other missing pieces, so my question is; If it had an ignition switch, where was it mounted when it left the factory?

In the left-hand headlamp bracket. The fork being wrong probably explains why it isn't there.
Title: Re: 1973 Bonneville Ignition Switch
Post by: Rex on June 03, 2021, 08:21:27 AM
So what is the current (hoho) method for starting and stopping the engine, or is the whole loom missing?
Title: Re: 1973 Bonneville Ignition Switch
Post by: ramwing7 on June 03, 2021, 06:56:26 PM
Left headlamp bracket?  I don't have one of those, so I guess that explains it.
Not sure how they stopped the poor thing.  Only heard running on starter fluid.  When fluid stopped, engine stopped.   ;D
I suspect I'm gonna have to go the new wiring loom route.  There's some sort of mess there, but it looks like it might be impossible to sort out.
Thanks, folks.
Title: Re: 1973 Bonneville Ignition Switch
Post by: Rex on June 03, 2021, 10:04:16 PM
Yebbut even on starter fluid it still needed a spark, so somewhere the ignition circuit was made before it could run.
Title: Re: 1973 Bonneville Ignition Switch
Post by: oldgoat on September 08, 2021, 04:56:37 AM
My '73 T100R Daytona sat for a year while I was involved in other projects. When I got back to it, I could not start the bike, even with a new battery. But I had spark -- the bike would fire on starter fluid but immediately die. Fuel flow into carbs appeared to be fine. I pulled off both carbs, dismantled them, and did a full cleaning, and noted that in both carbs the pilot jet was severely blocked -- took a lot of soaking in carb cleaner, plus running a #10 guitar string into the air pilot screw hole to remove the blockage (I know some advise against the latter, but it was the only way I could clear the blockage, as revealed by free flow of compressed air through the passages). While i had the carbs apart I replaced the needle jets and the float pins. Upon reassembly, I now have first-kick starting every time.