180 sprag clutch

You have sucksesfully decifered my criptic measage. Yep, Howdy Spag. Fantastic looking gadget, shame it was a handgrinaded.Mr Howdy came to a Sydney meeting years ago and showed us.
 
yea well unfortunately i have one in my lav .it does work quite well even when it is falling apart. the engineering is sound except the sprag itself which comes from a gm 4 speed auto trans that goes into commodores( i don't like commodores anymore for reasons i wont go into here) is what lets it down.its made up of about 24 s shaped pins in a circular cage. when the pins breaks apart the magnets in the flywheel pick up the bits & fuck the alternator. so i have replaced a few  alternators which is a bitch .

now is there anybody out there who has found a better sprag  to replace the one that keeps on fucking up, apparently they were originally made for ducati's. maybe some of those guys may have an answer will keep searching as i think it is a better idea except the sprag isn't strong enough which is a shame because you can pick up the sprag at almost any auto trans shop.  marty you may know of an alternative?
 
levo said:
yea well unfortunately i have one in my lav .it does work quite well even when it is falling apart. the engineering is sound except the sprag itself which comes from a gm 4 speed auto trans that goes into commodores( i don't like commodores anymore for reasons i wont go into here) is what lets it down.its made up of about 24 s shaped pins in a circular cage. when the pins breaks apart the magnets in the flywheel pick up the bits & fuck the alternator. so i have replaced a few  alternators which is a bitch .

now is there anybody out there who has found a better sprag  to replace the one that keeps on fucking up, apparently they were originally made for ducati's. maybe some of those guys may have an answer will keep searching as i think it is a better idea except the sprag isn't strong enough which is a shame because you can pick up the sprag at almost any auto trans shop.  marty you may know of an alternative?
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Went down that road many moons ago at Moto Witt.  Lasted all of 5 start attempts before self-destructing.  Still got the un-used second prototype, quite pretty to look at... :D

Seems the OE design is still the best in this case!

piet
 
Not sure what a 180 sprag looks like but in my search for 750 Starter alternatives I?ve seen bikes like Goldwings that have similar roller designs. Even chain drive on early models, very reminiscent of the SF
 
I think Honda were using this type of design in 1959 or earlier. I should imagine it's part of the CB77 influence on the Laverda 750.
 
When Red rebuilt the engine for my RGS Mongrel track bike, he found that it has a non-original starter clutch. No idea where it came from. Red couldn't identify it and the previous two owners of the bike couldn't shed any light on it either. So it it pre-dates the bike's known history. It's a bit of a mystery. The bloody thing has apparently been there for a long time and still works perfectly. I'd love to know its origin, but will probably never find out unless the new owner of the bike has more luck with detective work than me.
 
Dellortoman said:
When Red rebuilt the engine for my RGS Mongrel track bike, he found that it has a non-original starter clutch. No idea where it came from. Red couldn't identify it and the previous two owners of the bike couldn't shed any light on it either. So it it pre-dates the bike's known history. It's a bit of a mystery. The bloody thing has apparently been there for a long time and still works perfectly. I'd love to know its origin, but will probably never find out unless the new owner of the bike has more luck with detective work than me.
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Next time you have it exposed, grab a pic and post it. I see more jap starter clutches than I'd like.
 
That might take telling who the new owner is and whether it's going racing in the future? Cam won't tell and the new owner hasn't commented YET
 
link=topic=98231.msg410532#msg410532 date=1533174747]
I was wondering the same thing Quentin - whether centrifugal force from the plungers and rollers would compress the springs when the clutch assembly gets up to normal running speed. It would be interesting to spin one up on a test rig and take some photos with a high speed camera.
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I am willing to be shot down in flames Cam, but I thought that the sprag clutch only spins up when the starter is engaged! Then stops when the engine is up to speed, oherwise the starter motor would turn all the time and we know what happens then.

The rollers or 'S' shape thingies slide in one relative direction and grip in the other surely? If the engine is up to speed they just slide?
 
GregT said:
Next time you have it exposed, grab a pic and post it. I see more jap starter clutches than I'd like.
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Vince is right. It's not likely to happen in my ownership. Bike is going to a new owner in a couple of weeks, but I'll pass the message on.
 
SimonR501 said:
link=topic=98231.msg410532#msg410532 date=1533174747]
I am willing to be shot down in flames Cam, but I thought that the sprag clutch only spins up when the starter is engaged! Then stops when the engine is up to speed, oherwise the starter motor would turn all the time and we know what happens then.
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You're probably right. It's been years since I looked at one, and I've never actually disassembled led one. I can't remember which bit is connected to the starter and which bit spins with the engine.
 
Vince said:
Those in the tent know, those outside the tent sit and wonder
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Welcome to the tent Al, when you comin back over to build those train links ?

Hey Vince, hope that race bike
Has a nice pre heated garage  :LOL:
Bloody nippy in Canberra  :P
 
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