Starter free wheel inner cracked 750

[Tree Hugger]

Discovered this crack on the 750 I am hoping to rescue. Looks like a replacement will cost an arm and a leg. Is it too big a risk to leave it

 

[Exmoor beast]

Yes.

 

[chrisk]

I'm no mechanic, engineer or metallurgist ..... but that looks ready to go bang, and possibly at the most inopportune time.
(if you're luck is anything like mine)

 

[piranha-bro2]

Not a huge expense, TH. I replaced that inner ramp insert on mine with an excellent repro sent to me by Piet (SFC Piet on this forum) from Germany to Oz. He even supplies the pressed metal cover and the rivets. Send him a PM. Replace the springs and rollers at the same time - plungers are often OK; my 50yo originals are still in there - repro ones I bought were brittle and I tossed them after a couple broke.

When pressing the rivets (whoever does it) care should be taken not to compress any further than JUST home, as it will distort the assembly and plungers can bind in the hole/s ... DAMHIK! Fortunately I was able to punch the rivet back out ever so slightly.

 

[martymoose]

Ramp piece not going anywhere. Crack is not where the roller goes, I would put it back together and keep riding

 

[chrisk]

Ramp piece not going anywhere. Crack is not where the roller goes, I would put it back together and keep riding

That proves it ............... I'm not a mechanic, nor an engineers arsehole.

 

[piranha-bro2]

If it's cracked I'd be VERY surprised if it isn't harbouring other nasty dodges. Mine looked perfect but just wouldn't grip. Worn out.

 

[sfc vintage]

Hi.
I have one for sale .
Br
Peder

 

[piranha-bro2]

Having said that it might be compromised, I think Marty's suggestion to fit it and see how it goes is a good one. It's a part that is only ever under duress while the starter button is pressed. If it starts the bike consistently, that's all you need to worry about. Mine was misbehaving whether it had new springs, rollers or plungers. the new ramp from Piet was a game changer. No way would I fit a used part when Piet's offering is new and very well made.

 

[martymoose]

The face on the cog is the area that wears out, where the rollers run. We did make a batch of oversized rollers for the NSW club a few years ago

 

[piranha-bro2]

The face on the cog is the area that wears out, where the rollers run. We did make a batch of oversized rollers for the NSW club a few years ago

Mine is providing excellent service in concert with the new ramps ... so not always the face of the sprocket.

 

[sfcpiet]

The face on the cog is the area that wears out, where the rollers run. We did make a batch of oversized rollers for the NSW club a few years ago

Mine is providing excellent service in concert with the new ramps ... so not always the face of the sprocket.

Both parts can wear considerably. Admittedly, the driven spigot is more affected.

The big game changer is the accuracy with which the repro part is made, it (theoretically!) allows all 6 rollers to engage perfectly whereas the original stamped part is quite rough on the ramps and often only allows a fraction of the rollers to fully engage the spigot of the sprocket and places high loads on the needle bearing/crank journal through eccentricity and taper.

As long as the ramp thingy is cracked only once and is still a tight fit within the housing, it should be good for quite some time. Regular maintenance should be adhered to, if only to check if further cracks develop.

piet

piet

 

[Tree Hugger]

Thanks for all the excellent input as always, exactly what I needed.
I will stick with the existing ramp. When I get it all buttoned up and hopefully started I’ll feed back.
I will, when finances permit, buy a new ramp as back up. The cracked bit looks to be associated with the rivet hole, all is tight, but another reason to keep a close eye on it.

David