Starter clutch SF750

SF750-72

SF750-72

Junior member
Location
Norway
Hi, my starter clutch has given up on me. As the weather is warming I would like to use my trusty SF.
Which spares do I need? Just the springs or plungers and rollers as well?
 
You'll need to pull it off and inspect it - sometimes you can get away with just springs, but if plungers are stuck, rollers deformed and/or the roller contact surface on the starter sprocket then you'd be wise to give it a more thorough reco. There will be two opinions on here as to whether to lubricate the system. I never have and have had years without probs. Others will say they grease and make the same claim.
 
The parts are cheap.
Change the lot.
As for lubrication, the last series of freewheels are drilled with 6 holes from the outside into the plunger locations to squirt some oil in from time to time. Must be a reason.

Paul
 
Paul Marx said:
The parts are cheap.
Change the lot.
As for lubrication, the last series of freewheels are drilled with 6 holes from the outside into the plunger locations to squirt some oil in from time to time. Must be a reason.

Paul
Click to expand...
And the lube escapes just as quickly as soon as the engine starts spinning...

piet
 
sfcpiet said:
And the lube escapes just as quickly as soon as the engine starts spinning...

piet
Click to expand...
I don't think so.
No obvious trace of it inside the dynamo cover but then I don't take them off every other week. Maybe twice a year, which is a few hundred starts.

Paul
 
My take is that those holes are to enable removal of the plungers once they're stuck - because getting them out when they are is a major drama. I drilled the used one that I was given for that very reason. It made tapping out the stuck plungers an absolute breeze.
 
piranha-bro2 said:
My take is that those holes are to enable removal of the plungers once they're stuck - because getting them out when they are is a major drama. I drilled the used one that I was given for that very reason. It made tapping out the stuck plungers an absolute breeze.
Click to expand...
Yep. They do double as a means of introducing oil, that is but a short-lived measure.

piet
 
If the freewheel is properly maintained, you don't get stuck plungers. And if you use those drillings to squirt a bit of oil in from time to time, you don't get stuck plungers.
Chicken or egg?

Paul
 
why not dribble a bit of oil in the drilled holes and plug them with tight fitting plastic plugs, available in many sizes for air con small bore copper tubing., that would save the centrifugal forces and when the clutch is stationary the higher ones will drain the oil down again.Flick the starter and the other (might) be at the top.
CLEM
 
Whats really important is that the Back Plate is not loose or warped. They were originally riveted in and prone to loosen causing the starter clutch to rattle.

You may have to remove the Back Plate, straighten it out and Tac-Mig it back in place.

After removing the rivets, rather then Tac-Mig, you can tap the holes and use small bolts to hold the back plate on.

It's critical that the starter clutch back plate is firmly attached to the Flywheel to prevent the Dogs from rattling.

Do not be afraid to use a sharp file to smooth out the bruises on the crank snout..

This is a common issue with Breganzies it you neglect to clean the starter clutch every 2 years or so.
 
Last edited:
Well butter fixed the Mad Hatter's watch so I guess margarine does it for Paul :cool:

I reiterate, jury's out on the lube - never used it and probably rebuilt my starter clutch once every 3-5 years and ave 20,000 k's a year in the good ol days. Each to their own.
 
Two thoughts from my side:

1. The life of your freewheel clutch also depends on how you use your bike. Long haul or permanent start / stop on short haul.
The load is low if you only drive in good weather and high if you are out in the rain or on dusty roads.
These points may explain the different experiences.

2. I have worked with one-way clutches a lot in the printing industry.
Every manufacturer, whether SKF, FAG or machine manufacturers like Heidelberger, have always pointed out that grease must not be used, only thin, non-resinous oil.
This is logical for me, because the rollers have to grip and block as quickly as possible.
Grease on which metal debris and dust get stuck is suboptimal in terms of low static friction.

Thomas aus LAU
 
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