Hello there Chaps, Here is my story. My old man has this immaculate 1971 Triumph T120 Bonneville that he has slowly built up since the day that he retired. Its the most beautiful bike you've seen and he's spent the best part of his retirement taking back the bike back to its factory floor condition with a few extra bits of chrome here and there.
Just recently my old man had a back operation to fix a old back problem he had, but now he can't kick start his pride and joy anymore. Its terrible that he's pumped so much love into it but can't enjoy his pride and joy in the best years of his life.
I'd really like to put the wind back under his wings again and get some sort of a electric starter for his bike. I must confess that I know next to nothing about this model or if a electric starter was ever an option.
Either ways could some of you experts there point me in the right direction if I could buy somesort of a starter kit or if I could sucessfully retrofit a starter from another bike or another model to his T120 bonneville.
Sorry to hear of your father' predicament- hope the following helps:
There are two possible solutions that I am aware of :
(a) is to buy a T140ES Electro, Executive or Royal Wedding models, TSS or TSX model, all of which fitted an electric starter as standard and parts for which are available. The system cannot be retrofitted on prior models- I think there is a bronze bush fitted in the timing chest of electric start models unlike pre-electro models. It can be fitted onto post-electro Meriden models so afr as I am aware such as the TR7T Tiger Trail and TR65 Thunderbird. The system is far better than the Norton Commando's and works first time every time
(b) I saw in an old issue of Classic Bike Guide that an English gent called Roy Shilling, machine registrar of the Triumph Owners Motorcycle Club (TOMCC)produced a Bendix/Ozzie Oswald-type electric starter for a TR6P and one which can be retro-fitted to earlier models like your father's T120.
Ryan - While I'm sure some owner of a welding shop has taken 5 years and added one in the past, I know of no way to directly connect an electric starter to this model bike. I'm very sorry to say that because I know how much your dad loves his bike. I guess I'll be in the same condition myself in another few years so here are the options I've considered....
- Racers remove the k/s lever from their bikes and crank the bike in the pits with a motorized set of rollers. It's merely a Brigs motor on a small frame. You could easily add this item to the garage. The downside is if he stalls the bike away from the house.
- You can lower the compression way down to 7:1 like a pre-unit. It would be MUCH easier to crank this way. You can do this with new pistons or a double thick base gasket. The power will drop dramaticly, but I take it your dad is past impressing the girls with wheelies anyway.
Don't hide 'em, Ride 'em !!
RF Whatley Cornelia, GA
"Shop Boy" at Rodi British Bikes
Re: Electric Starter for 1971 T120 Bonneville#98350 08/14/0612:23 pm08/14/0612:23 pm
Since it appears that any retro-fit of a starter is going to require a complete strip, a few things (other than Mr. Whatley's apt comment on reducing compression) can be changed to ease manual starting: 1. retarded intake cam will reduce cranking compression without changing the ratio, and will keep some peak power. Less cam timing (6T cams are the easiest choice) will help by increasing low-speed vacuum but remember not to close the intake valve too early or the cylinder pressure will stay up. 2. heaviest crankshaft you can find will make the engine spin through the compression stroke with less effort. There are areas on the existing crank that extra weight can be added but will ruin the balance completely. More work, more $$: add Mallory slugs to flywheel cheeks. 3. solenoid operated compression relief valves are available, installed like 2nd plug. Switch on bars for easy access to close both valves immediately on fire-up. Engine will run with the valves open but will cycle through easier. 4. if you have to balance it anyway, removing material from the piston dome to reduce CR is preferred to adding gaskets because it preserves quench distance.
Re: Electric Starter for 1971 T120 Bonneville#98352 08/14/062:39 pm08/14/062:39 pm
In the Gaylin/Brooke book "Triumph Motorcycles in America", on page 115, there is a picture of actress AnnMargret astride a 1966 T100C. It states that one of her Triumphs was fitted with a Honda electric starter. Does anyone have information on this conversion?
Re: Electric Starter for 1971 T120 Bonneville#98353 08/14/063:00 pm08/14/063:00 pm
IIRC massive welding to the primary, left case, complete retro-fit of fabricated clutch drum for the ring gear, larger battery, wiring for switch, support brackets for the starter, big ground strap, etc.
Re: Electric Starter for 1971 T120 Bonneville#98354 08/14/063:45 pm08/14/063:45 pm
Thanks Panic and RF,that is food for thought, interesting because of a bum knee and the effort it takes to kick through my T140E.My 650s (Triumphs and BSA)are very easy to kick,but the 750s are a *****. Can`t understand why,stock cr is 7 1/2 to 1? I know 100 more cc,but my buddy has a 650 with a MAP big bore kit and high compression pistons that is much easier to kick than the 750s? Thanks...JR
Re: Electric Starter for 1971 T120 Bonneville#98355 08/15/064:26 am08/15/064:26 am
Gents, Its great to hear so many options now available. I just shot a mail to Roy Shilling through his TOMCC link, hopefully he can give some other alternatives if not how he actually did it on his bike.
Anyway, I'll keep you guys updated on what transpires from this.
Re: Electric Starter for 1971 T120 Bonneville#98356 08/15/067:21 am08/15/067:21 am
I bought a 1981 T140ES from a dealer in 1983. Not sure how much work the starter had had before I bought it..But it died within a few weeks. The sprag clutch bearing disintegrated; spreading metal shavings etc right through the oil pathways. ( yep...long job there) Anyway...The only time the starter motor worked effectively prior to this was if the motor was warm and the battery fully charged.
I'm sure that decent bits would be made for them these days to make them work effectively, but thought I'd let you know what to be aware of in case you decide to take that route.
51' Thunderbird project 48 Speed Twin project. 85' BMW K100RT and sidecar.