BSA A65 tappets in Nortons

jseng1

jseng1

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For anyone using BSA tappets in their Nortons (as introduced in the 1970s on some Commando engined dirt track racers).

New tappets can have a sharp edge that should be polished/rounded off to avoid wearing against the tappet block (not a problem with used tappets).

BSA A65 tappets in Nortons


The outside corners should be chamfered to clear the lifter tunnel.

BSA A65 tappets in Nortons
 
jseng1 said:
For anyone using BSA tappets in their Nortons (as introduced in the 1970s on some Commando engined dirt track racers).

New tappets can have a sharp edge that should be polished/rounded off to avoid wearing against the tappet block (not a problem with used tappets).

BSA A65 tappets in Nortons


The outside corners should be chamfered to clear the lifter tunnel.

BSA A65 tappets in Nortons
Click to expand...
Thought I'd mention....
Your past recomendation/comments for tuning Keihin's and the like are spot on.šŸ‘
Did Dunstall use BSA cam followers in his alloy barrels ?
 
Dunstall had his own version of lifter that was lighter than a stock lifter but not as light as a BSA lifter and it had a flat surface so you could use it with a stock cam instead of a cam designed for radiused lifters.

BSA A65 tappets in Nortons


BSA A65 tappets in Nortons
 
Automotive called them tappets aviation called them cam followers.
 
Iā€™ve always known the adjuster side as the tappet and the cam side as the follower.

The tappet makes the tapping noise and the follower follows the cam.
 
jseng1 said:
For anyone using BSA tappets in their Nortons (as introduced in the 1970s on some Commando engined dirt track racers).

New tappets can have a sharp edge that should be polished/rounded off to avoid wearing against the tappet block (not a problem with used tappets).

BSA A65 tappets in Nortons


The outside corners should be chamfered to clear the lifter tunnel.

BSA A65 tappets in Nortons
Click to expand...
A few months ago I fitted a jsmotorsport cam and follower kit complete with pushrods. The followers look much like those fitted to a BSA A65. The cam I chose was the JS0 that has the BSA Spitfire profile. Jim describes it as a near match to the standard 2S. The first thing I noticed while setting the valve gear up was the reduction in friction in the valve train. I've only covered 250 miles on the conversion the improvement in overall performance and mechanical silence has put a big smile on my face.
 
dictionary.cambridge.org

tappet

1. a part of a machine that causes another part to move by hitting it 2. a partā€¦
dictionary.cambridge.org dictionary.cambridge.org
"a part of a machine that causes another part to move by hitting it"
Norton Commando tappets.
andover-norton.co.uk

Motorcycle parts and spares for Norton motorbikes - Genuine Andover Norton Spare Parts - Andover Norton Motorcycles Parts - Original Andover Norton Parts

Motorcycle parts and spares for Andover Norton motorbikes: Andover Norton manufactures and supplies all Genuine Factory Spare Parts for Norton motorcycles built before 2002.
andover-norton.co.uk
 
L.A.B. said:
dictionary.cambridge.org

tappet

1. a part of a machine that causes another part to move by hitting it 2. a partā€¦
dictionary.cambridge.org dictionary.cambridge.org
"a part of a machine that causes another part to move by hitting it"
Norton Commando tappets.
andover-norton.co.uk

Motorcycle parts and spares for Norton motorbikes - Genuine Andover Norton Spare Parts - Andover Norton Motorcycles Parts - Original Andover Norton Parts

Motorcycle parts and spares for Andover Norton motorbikes: Andover Norton manufactures and supplies all Genuine Factory Spare Parts for Norton motorcycles built before 2002.
andover-norton.co.uk
Click to expand...
I donā€™t really want my cams ā€˜hittingā€™ the followers !

But have to accept my tappets will hit the valves.
 
Fast Eddie said:
I donā€™t really want my cams ā€˜hittingā€™ the followers !
Click to expand...

The tappet is the follower because it: "...converts the rotating motion of the camshaft into linear motion of the valves!"
en.wikipedia.org

Tappet - Wikipedia

en.wikipedia.org en.wikipedia.org

Fast Eddie said:
But have to accept my tappets will hit the valves.
Click to expand...

It's one arm of the rocker that 'hits' the valves in an OHV engine. So one arm of the rocker could loosely be described as a tappet although it doesn't convert rotary motion to linear. :)

Fast Eddie said:
Iā€™ve always known the adjuster side as the tappet and the cam side as the follower.
Click to expand...

In a side-valve engine the adjuster side would normally be the tappet/follower and where the term "setting the tappets" originates but normally referred to as setting valve/rocker clearance in an OHV engine.
 
Been pulling my hair out today.

Try as I might, I simply cannot get the feeler gauges in between the cam and follower in order to set my ā€˜tappetā€˜ clearance'sā€¦ šŸ˜
 
Don't worry Brits - us Americans will eventually rub off on you :D Tappet, Cam Follower, Lifter all the same to many of us. I always call them lifters. I have no idea where tappet came from (the sound?) I suppose cam follower makes sense but I've never heard them called that anywhere but Brit sites.

Then there is: Hydraulic Flat Tappet Lifters
 
marshg246 said:
Don't worry Brits - us Americans will eventually rub off on you :D Tappet, Cam Follower, Lifter all the same to many of us. I always call them lifters. I have no idea where tappet came from (the sound?) I suppose cam follower makes sense but I've never heard them called that anywhere but Brit sites.

Then there is: Hydraulic Flat Tappet Lifters
Click to expand...
So long as we donā€™t mention alooominum ā€¦
 
cash said:
A few months ago I fitted a jsmotorsport cam and follower kit complete with pushrods. The followers look much like those fitted to a BSA A65. The cam I chose was the JS0 that has the BSA Spitfire profile. Jim describes it as a near match to the standard 2S. The first thing I noticed while setting the valve gear up was the reduction in friction in the valve train. I've only covered 250 miles on the conversion the improvement in overall performance and mechanical silence has put a big smile on my face.
Click to expand...
The description on the JSM cam description page says the JS0 is same as a webcam 312 with improved ramps. I have no clue if a webcam 312 is like a 2S cam.

My observation: I've got a JS2 with all the JSM valve train trimmings in 750 and it is not as spicey a hit as the 2S I had in it previously. The JS2 produces better predictable linear power with an impressive high RPM top end. The JS2 is supposed to be a PW3 copy cam with smooth ramps. Mine was really quiet initially but sounds more like a slightly quieter Norton after a few thousand miles. I hope yours remains really quiet.

My kit came with the smaller Triumph lifters, and they needed all the edges polished and rounded off before they got along well with the soft bronze lifter blocks.
 
Fast Eddie said:
I donā€™t really want my cams ā€˜hittingā€™ the followers !

But have to accept my tappets will hit the valves.
Click to expand...
Yes but, the 'tappet' is at the end of the rocker arm, you left that part out!
 
Fast Eddie said:
So long as we donā€™t mention alooominum ā€¦
Click to expand...


One of my old college lecturers used to bang on about this sort of stuff ( including tomatoes ) and he used to put it all down to the long sea voyages that folk made in order to colonise the Americas and other such far flung places.

He used to say it addled their brains just like syphilis would and with the waiting of a few hundred years for the invention of penecillin it made a permanent genetic deformation :eek:

He had lots of other curious snippets about all sorts of others that I'd better not mention, one at a time is plenty !

Gotta say he had us apprentices in stitches most days though I doubt it would be allowed these days.
 
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