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I was reading this about sprag clutches- especially slipping

I

ian11

Joined Apr 2012
190 Posts | 0+
I've never heard of a sprag clutch only "ordinary"....seemingly they're a right pita and cost a bastard fortune, mine cut out twice the other when putting into first, and forgot mention that I was sure I felt it slip at one point too (I'll try it again) and thought of fk it maybe I need a new clutch or bled, adjusted ect (as I mentioned in another post). But this slipping is seemingly caused by the spring in the rollers, is this the right thing I'm looking at.

And can the sprag be converted to a conventional one ie barnet ect with proper plates ect.....just wondered


Meant to say though, if it's needing bled ect or starting to get fkd, it'll go back to the shop and they can do it, do see why I should start buggering about with it as I've still got 3 weeks warranty
 
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The rotax motor has two clutches
There is the normal one for the transmission
and
The sprag is there to engage & disengage the starter motor. The sprag is pretty reliable, not too difficult to change if need be, but it can't be converted to a conventional arrangement.
Keep on top of your battery maintenance & the sprag will virtually last forever.
 
ian1 said:
I've never heard of a sprag clutch only "ordinary"....seemingly they're a right pita and cost a bastard fortune, mine cut out twice the other when putting into first, and forgot mention that I was sure I felt it slip at one point too (I'll try it again) and thought of fk it maybe I need a new clutch or bled, adjusted ect (as I mentioned in another post). But this slipping is seemingly caused by the spring in the rollers, is this the right thing I'm looking at.

And can the sprag be converted to a conventional one ie barnet ect with proper plates ect.....just wondered


Meant to say though, if it's needing bled ect or starting to get fkd, it'll go back to the shop and they can do it, do see why I should start buggering about with it as I've still got 3 weeks warranty
Click to expand...

Ian

Don't get confused between the two. Although they have some similarities in basic function (they allow 2 parts of the bike to engage and disengage as required) they are mechanically quite different. http://en.wikipedia.org/wiki/Sprag_clutch

Specifically this part of that link...

Motorcycle applications
Starters
A sprag clutch is used in the electric starter motors of modern motorcycle engines to replace the Bendix gear common to automobile starters.

They are really quite unrelated in terms of problems.

Rob :)
 
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Ah ok.....I thought this sprag WAS the clutch, I understand now, it's do with starting, so if it doesnt start ie spins ect ect it's the sprag and if it slips it's the "ordinary" one
 
ian1 said:
Ah ok.....I thought this sprag WAS the clutch, I understand now, it's do with starting, so if it doesnt start ie spins ect ect it's the sprag and if it slips it's the "ordinary" one
Click to expand...

Ian

You've got it. The sprag allows the starter motor (as it starts to spin) to engage automatically with the engine so it will turn over. Then when the engine starts the sprag disengages the starter from the engine automatically and allows (once you take your finger off the start button) the starter motor to stop.

Rob :)
 
one thing I was told when my sprag went (a month after buying my bike) that its important to use the starter throttle (whatever its called :p) looks like a choke, instead of the normal throttle for starting...so much torque with the mille that it can cause unnecessary damage,.... look after ur sprag and itl look after you :p
 
Thebees said:
one thing I was told when my sprag went (a month after buying my bike) that its important to use the starter throttle (whatever its called :p) looks like a choke, instead of the normal throttle for starting...so much torque with the mille that it can cause unnecessary damage,.... look after ur sprag and itl look after you :p
Click to expand...

Official term for 'starter throttle' is 'cold start lever' I think.

Rob :)
 
apostrophe said:
Ian

Not sure technically why but it's not a 'choke'. I think only carb engines can have a choke not injected engines.

Perhaps someone here can explain?

Rob :)
Click to expand...

i thought that becasue its fuel injected that it has a automatic choke, im sure it is only ment to take the torque from starting....could be bollox lol :p
 
I think the 'choke' restricts (or chokes) the amount of air passing through a carb to enable the engine to start. It does not make any difference if it's a manual or auto choke, it still works in the same basic way. The cold start on the RSV is a device that temporarily increases the idle speed to assist in starting. It does not restrict the air flow so therefore it is not a choke.

Is that right?

Rob :)
 
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