What are these controls please?
Discussion
The decompressor lever is normally a 'trigger' type lever under the clutch lever. I would have thought a 1962 bike would have had an automatic advance/retard. A choke for each carb on a twin carb bike perhaps? Don't ever recall seeing that, but it does add a symmetry to the handlebar controls.
One is advance/retard, t'other is choke. Can't remember which way way around they were - both needed for cold starting, suspect choke was on the right. Should be easy to determine which is which by following the cables.
Don't forget to tickle the carbs before trying to start from cold, too.
Don't forget to tickle the carbs before trying to start from cold, too.
MartinFC said:
The decompressor lever is normally a 'trigger' type lever under the clutch lever. I would have thought a 1962 bike would have had an automatic advance/retard. A choke for each carb on a twin carb bike perhaps? Don't ever recall seeing that, but it does add a symmetry to the handlebar controls.
A lot of people preferred manual ignition still in the sixties, my 63 Velocette Venom has been converted back to manual ignition at some point. Which I’m pleased about as it makes it easier to make up for crappy modern fuel!But yes, right lever will be choke left hand ignition.
gareth_r said:
Vertical twins never had valve lifters/decompressors (AFAIK)
A potential complication with manual advance/retard is that you need to know whether the magneto is set up for slack-wire advance or tight-wire advance.
The only engines I've actually personally owned with a decompressor were diesel boat engines. single and triple.A potential complication with manual advance/retard is that you need to know whether the magneto is set up for slack-wire advance or tight-wire advance.
Bike wise, AFAIk, it's a 'big single thing', from pre-war Brit bikes to 70s yamahas and beyond.
The advance/retard lever for magneto ignition was sometimes retrofitted, because the centrifugal advance mechanisms were clapped out on 60s bikes in the 80s. With mix'n'match parts anything went. As I recall, magnetos which were removable units could rotate in either direction on various bikes.
gareth_r said:
Vertical twins never had valve lifters/decompressors (AFAIK)
A potential complication with manual advance/retard is that you need to know whether the magneto is set up for slack-wire advance or tight-wire advance.
That’s why I don’t like parallel twins. We briefly had a Rocket Goldstar and with all my (not insignificant) weight on the kick starter when cold I couldn’t get it over compression. My Norton is on the cusp of being able to start easily. Heavy compression plus clip-ons make it really awkward I find. A potential complication with manual advance/retard is that you need to know whether the magneto is set up for slack-wire advance or tight-wire advance.
All my vintage and post-vintage v-twins have valve lifters though so I don’t know why parallel twins never did!
Most old bikes from people who have a few have a badly written A and R in old felt tip marker on the lever
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