Magneto impulse coupling

The rotor’s differ, that’s for sure now, the sr2 has symmetric cut outs, the sr1 ia a-symmetric.
 
The newer Joe hunt magnetos have neodymium magnets and plenty of hot spark at kickstart RPM. Easy one kick starting. Here it is at only 100 RPM.

 
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I had several Lucas KF magnetos give up. I found a new SR4, and ran the two diagonally opposite plug leads to each of the plugs on my Triumph. The SR2 and the SR4 both have geared rotors which run off the end of the armature. The cam in the SR4 had four lobes. I did not bother to buy the 2 lobe cam and the different cap with 2 leads. I just used spade fittings on the four leads and screwed 2 to each spark plug.
The impulse start was on the SR4 when I bought it, but I think it was removable. I would never have used it. Rotating magnet magnetos are far superior.
 
jseng1 said:
The newer Joe hunt magnetos have neodymium magnets and plenty of hot spark at kickstart RPM. Easy one kick starting. Here it is at only 100 RPM.

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And they will fire up on one kick without even retarding them.
 
I have never retarded the spark on a bike in order to start it. Even with a kick start, if your foot is not firmly on the lever, you are likely to get bitten. If the motor kicks back, you should always be able to hold it. A lot of things have to do with mindset - who is in control ? My motorcycle is commanded by me, it does not have a mind of its own. Subordination is out of the question.
 
acotrel said:
I have never retarded the spark on a bike in order to start it. Even with a kick start, if your foot is not firmly on the lever, you are likely to get bitten. If the motor kicks back, you should always be able to hold it. A lot of things have to do with mindset - who is in control ? My motorcycle is commanded by me, it does not have a mind of its own. Subordination is out of the question.
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I thought you hadn't ridden on the road since you were 27 years old ?
Do your race bikes have kickstarters fitted?
 
Richard Tool said:
Wow ! ( and ouch !)
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Bullshit. I have kick-started a Vincent which was on 16 to 1 compression. The only I ever really came undone, was when I tried to kick-start my mate's Bonneville when I had a piece of bone broken-off inside my knee joint. I had fallen-off a mini-bike when I was not wearing a helmet, and my toe caught the road. I ended up in hospital and had to learn to walk again. When you use a motorcycle, YOU are responsible for what happens, if you get sloppy.
I am 83, for me - riding my Seeley 850 is easier than driving my car. My wife does not understand that. She does not want me to race again.
If you are kick-starting a 500cc single cylinder 4-stroke motor and bounce it off compression, you are likely to get bitten, so always push piston well up the bore before you flick it past the top. It is NOT rocket science. I always stand astride the bike when kick-starting - I never do it from the side.
 
A lot of guys probably do not know how to bump-start a bike, and ride it full-blast while sitting side-saddle. I am an expert at it. Unfortunately, most races these days are clutch starts. I cannot remember when it was, but I was in an Allpowers race somewhere with Z1 and H2 Kawasakis. I had lowered the gearing on my 500cc Triton. A lot of bikes had electric start, and I still blitzed them all off the start, and led them all for almost a full lap. I got passed by a couple of guys towards the end of the longest straight and entered the next corner miles too hot behind them, and ran-off to miss them. I did not usually race with the gearing lowered.
 
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acotrel said:
Bullshit. I have kick-started a Vincent which was on 16 to 1 compression. The only I ever really came undone, was when I tried to kick-start my mate's Bonneville when I had a piece of bone broken-off inside my knee joint. I had fallen-off a mini-bike when I was not wearing a helmet, and my toe caught the road. I ended up in hospital and had to learn to walk again. When you use a motorcycle, YOU are responsible for what happens, if you get sloppy.
I am 83, for me - riding my Seeley 850 is easier than driving my car. My wife does not understand that. She does not want me to race again.
If you are kick-starting a 500cc single cylinder 4-stroke motor and bounce it off compression, you are likely to get bitten, so always push piston well up the bore before you flick it past the top. It is NOT rocket science. I always stand astride the bike when kick-starting - I never do it from the side.
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The bullshitter cries bullshit …
 
acotrel said:
Bullshit. I have kick-started a Vincent which was on 16 to 1 compression. The only I ever really came undone, was when I tried to kick-start my mate's Bonneville when I had a piece of bone broken-off inside my knee joint. I had fallen-off a mini-bike when I was not wearing a helmet, and my toe caught the road. I ended up in hospital and had to learn to walk again. When you use a motorcycle, YOU are responsible for what happens, if you get sloppy.
I am 83, for me - riding my Seeley 850 is easier than driving my car. My wife does not understand that. She does not want me to race again.
If you are kick-starting a 500cc single cylinder 4-stroke motor and bounce it off compression, you are likely to get bitten, so always push piston well up the bore before you flick it past the top. It is NOT rocket science. I always stand astride the bike when kick-starting - I never do it from the side.
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I'd love to see you or anyone come to that
Start my old b50 by bringing it up too tdc and flicking it past😂😂😂😂
It ain't gonna happen
 
Al it's been so long since you even been on your bike as well you have told us you have a roller starter with a hand grinder to spin it up and how long ago did you kickstart a bike, as for push starting a bike, I got real good at it when a scumbag stole my kicker off my Norton, for 4 months of push starting and found it easy to do when in 4th gear but had to be real quick on the clutch when it fired up, you might have been an expert with it way back when.
My 850 has lots of compression but with it all set up and with the Joe Hunt magneto I can kick it to life first kick every time no matter where the piston is, it's the first kick for the day when its stone cold is when it needs a full kick, other time after its fired up for the day it usually starts on 1/2 a swing on the kicker.
Each British bikes are different some start easy and some not so easy, some have more compression than others, big singles can be a pain to kick over, not all but some are, and how long ago did you kick that Vincent to life, at 83 years old you might have lots of troubles now, maybe not if you been kicking a British bike to life all your life of riding and doing it regularly, all my mates have trouble kicking my Norton to life and they all own and ride British bikes but for me it's easy because I know my own bike, 49+ years of kicking it I have the knack, the JH and Amals carbs work so well together.
You seem to be a nice person Al but you need to get out on your bike instead of talking about what you have done, who listens to the wife when it comes to bikes and riding, my wife would never do that, she knows where she stand where my bikes are involved and she knows when I need to get out, the good thing about riding on the road you can go out on your bike anytime you like, I don't need to ride flat out to beat my mates in the ranges/tight twisties or they beat me lol.
Maybe it's time you got off YouTube and do more on your bike instead, even if you never ride it again or maybe give it to someone who will take it on as you said your family aren't interested, age catches up with us all and time to just throw in the towel when it involves your bike, sad when that day comes but we all will go through it at some stage, but hopefully I be still riding till I am 105, well that's the plan.

Ashley
 
Both magnetos on my plane have impulse couplings. The puts the spark at just about TDC. Remember that most airplane engines were certified decades ago and certifying anything new is costly. That said there are now electronic ignitions for aircraft that generally replace one mag and have an actual advance curve rather than the fixed timing of a magneto. The remaining mag provides the redundancy in case of electric failure. There are also replacement systems now that also run on ships power but have PMAs, Permanent Magnet Alternators built in for backup. An actual advance curve makes for more efficient cruise flight instead of the compromise fixed advance magnetos that are set for max takeoff power.

Interestingly PMAs are also on the Falcon 7X I fly. Each engine has one for the FADEC or Full Authority Digital Engine Control plus two of the three engines have PMAs as backup power for the Fly By Wire systems.
 
Finally got the sr2 magneto fitted on the commando. Needed to make a new flange since the fairbanks morse has a 4 bolt mounting, the lucas a three bolt mounting. Made a flange from tufnol to isolate is from heat, but should be no problem for the alnico magnets. Build a buzz box from an old tube amp output transformer, a buzzer and a neon light. Adjustment is super easy. Runs beautifully and, what it was all about, starts easier. So single fire magneto works and a lower resistance coil does help, more current! Great!

The impulse coupling idea for now is not needed.
 
The magneto on my 500cc Triton was an SR4 with the geared rotor button. I ran two leads to each spark plug with spade connectors on the plugs. It worked really well - the motor would run to 11,000 RPM without missing. I think the SR2 also has the geared rotor button which runs at half armature speed.
 
Erik said:
Finally got the sr2 magneto fitted on the commando. Needed to make a new flange since the fairbanks morse has a 4 bolt mounting, the lucas a three bolt mounting. Made a flange from tufnol to isolate is from heat, but should be no problem for the alnico magnets. Build a buzz box from an old tube amp output transformer, a buzzer and a neon light. Adjustment is super easy. Runs beautifully and, what it was all about, starts easier. So single fire magneto works and a lower resistance coil does help, more current! Great!

The impulse coupling idea for now is not needed.
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Could you post some photos of your setup please?
 
I am fairly certain that I removed the impulse thing from my SR4. I would not have had anything which could possibly change the timing at high revs. From memory, I think it was part of the drive, and could simply be removed. That was in about 1970 - 55 years ago.
 
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