This may interest Norton owners as I have seen the use of decompressor buttons on high comp Norton engines.

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mark parker

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This may interest Norton owners as I have seen the use of decompressor buttons on high comp Norton engines. My A65 twin is 441cc per cylinder and 11-1 compression and has always been a bit of a pain to kick start. When hot it started readily 'if' the pedal moved. So, as it's together and running fine I was experimenting on an old head fitting a decompressor button. Wanting to do this on the engine without taking the head off :( That was not going to work. Then a couple of days ago I was thinking what if the kick start was longer?

Not much work to do that, so I had 3 kicks shafts and two bikes. Two of those kick shafts had bad ends, so I cut the ends off and welded the good bits together but making it longer by 34mm. I angle cut it to get more weld area and that took about an hour with using an angle grinder to smooth it a bit, paint and test. That gives about 16% more leverage and it's brilliant. The motor is fairly high in this frame, so it is well clear of the ground, and I wish I did this decades ago. There are probably a few things stressed by this but no longer is this 71yo one of them. Though I can still stand on the pedal, it moves when I kick it with much less effort making decompressors unnecessary.

This may interest Norton owners as I have seen the use of decompressor buttons on high comp Norton engines.

This is with the normal length kick pedal.

This may interest Norton owners as I have seen the use of decompressor buttons on high comp Norton engines.
 
Never had a decompressor/ex-valve lifter until i got my Velocette. It has one on the 500cc single and after learning how best to use it, position piston just past compressiln while holding lifter in. She starts very easily and reliably, more so than my Commando. The Velo has a magneto, no electric shut off switch and the lifter is again deployed in order to stop the engine....so quite a well used component on this bike.

Have heard modern bikes,even the Triumph Thruxton 1200, has a valve lifter that engages automagically when starting.
 
Stephen Hill said:
I recall Comstock looking at installing a decompression release and concluded there wasn't enough room.
Click to expand...
Someone built one like yam xs 650 one acting on the rocker arm from the valve cap
Also there have been posts with the husqvarner button type being used like on some of the big bore Harley's
 
mark parker said:
This may interest Norton owners as I have seen the use of decompressor buttons on high comp Norton engines. My A65 twin is 441cc per cylinder and 11-1 compression and has always been a bit of a pain to kick start. When hot it started readily 'if' the pedal moved. So, as it's together and running fine I was experimenting on an old head fitting a decompressor button. Wanting to do this on the engine without taking the head off :( That was not going to work. Then a couple of days ago I was thinking what if the kick start was longer?

Not much work to do that, so I had 3 kicks shafts and two bikes. Two of those kick shafts had bad ends, so I cut the ends off and welded the good bits together but making it longer by 34mm. I angle cut it to get more weld area and that took about an hour with using an angle grinder to smooth it a bit, paint and test. That gives about 16% more leverage and it's brilliant. The motor is fairly high in this frame, so it is well clear of the ground, and I wish I did this decades ago. There are probably a few things stressed by this but no longer is this 71yo one of them. Though I can still stand on the pedal, it moves when I kick it with much less effort making decompressors unnecessary.

This may interest Norton owners as I have seen the use of decompressor buttons on high comp Norton engines.

This is with the normal length kick pedal.

This may interest Norton owners as I have seen the use of decompressor buttons on high comp Norton engines.
Click to expand...
I ended up with around 80mm added to my commando kickstart when my knee went
 
I had a '87 Honda XL600R one time that the Kickstarter mechanically engaged the valve lifter via a cable setup. It also had the lever release on the handlebars.
 
It's been done to a commando too... I made 2 banana shaped kick levers into a one that's about 1-3/8" longer than the standard one. Once you get used to it, you forget if the shorter one was much harder to kick or just a bit harder, and then you wonder if it was any harder at all... but of course the physics say it was.. 🤣

long kickstart lever1.jpg
 
o0norton0o said:
It's been done to a commando too... I made 2 banana shaped kick levers into a one that's about 1-3/8" longer than the standard one. Once you get used to it, you forget if the shorter one was much harder to kick or just a bit harder, and then you wonder if it was any harder at all... but of course the physics say it was.. 🤣

View attachment 114846
Click to expand...
It's been my experience that bike would be much easier to kick if the lever were moved back a spline or two so the pawl in gauges at about or very slightly above the 9:oo O'clock position. For me moving it back made more difference than the longer lever.
 
It can engage at any angle you like. You just maneuver the pistons where you want them with the lever, then squeeze the clutch lever when you push on the kicker, and release it when you are a bit above your favorite 9 o'clock position. Now you have the pistons positioned and the lever where you want it...

The thing about having the lever straight up and slightly forward is to get it out of the way. There's a few bikes that have their resting kickstarter in the straight back 9 o'clock position. I think vincent's are that way... I've seen nortons that way too, but the banana kicker seemed more out of the way in the standard position..
 
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