Is the sprag bearing for a CNW starter the same as the one Andover sell for the Mk3?

Hopefully a simple question with a simple answer. I have tried to go through all the recent sprag clutch threads but can't find the answer to this question.

I had my clutch fail in my CNW starter about 6 years ago and the replacement Matt sent came in this box. Photos attached. A Renold bearing.

Recently a friend in the UK had the sprage in his CNW clutch fail. So I sent him these photos and part noes to buy a bearing in the UK.

Turns out he went to Andover Norton and they sold him a sprag bearing with a Norton part no which seems to be the Mk3 bearing. They told him it was the same bearing.

I'm surprised but have never owned a Mk3 so have no idea.

I read all the threads about 18 bearing and 14 bearings and Alibabah ones etc etc but given the replacement Matt sent in the photos attached has lasted 6 years I just recomended one of those.

So in summary.

Are the CNW sprag clutch bearings as in the photo the same as the Andover Mk3 bearing?

Does anyone know before my friend tries to fit it? The Commando in question is actually the runabout bike for the NZ Velo team in the IOM.

The CNW kit uses the same size sprag as the Mk3. You have seen my post here https://www.accessnorton.com/NortonCommando/cnw-e-start-conversion-sprag-failures.41767/

I supply Holland Norton Works with these sprags and Constant (HNW owner) modifies them to fit into the CNW kit (HNW pt number #H15ESC) These sprags are 'tuned' to work in the CNW kit (the spring tension that holds the roller cams in contact with the engine sprocket snout has its tension adjusted so the 'heel dragging' that the CNW kit sprag has, is lessened) These are the only sprags that this can be done to.
That Renold sprag is probably a reboxed chinese sprag with a price premium.

dobba99 said:

The CNW kit uses the same size sprag as the Mk3. You have seen my post here https://www.accessnorton.com/NortonCommando/cnw-e-start-conversion-sprag-failures.41767/

I supply Holland Norton Works with these sprags and Constant (HNW owner) modifies them to fit into the CNW kit (HNW pt number #H15ESC) These sprags are 'tuned' to work in the CNW kit (the spring tension that holds the roller cams in contact with the engine sprocket snout has its tension adjusted so the 'heel dragging' that the CNW kit sprag has, is lessened) These are the only sprags that this can be done to.
That Renold sprag is probably a reboxed chinese sprag with a price premium.

Click to expand...

Thankyou for this answer. I now recall had read your original post but honestly forgot your information after reading the 200 plus follow-up posts.

That Renold sprag came direct from Matt at CNW as a no cost replacement for the original that failed after a few starts. It has lasted for 5 years now but I shall certainly remember your information about the Holland Norton works mod shoukd I have any problem in future.

Regards

John

johnm said:

Thankyou for this answer. I now recall had read your original post but honestly forgot your information after reading the 200 plus follow-up posts.

That Renold sprag came direct from Matt at CNW as a no cost replacement for the original that failed after a few starts. It has lasted for 5 years now but I shall certainly remember your information about the Holland Norton works mod shoukd I have any problem in future.

Regards

John

Click to expand...

Hi John - mine is the original that came in Matt's kit and has been running for the last 5 years. Only 3 hiccup spinning starts now. Solved by either pulling in the clutch or rocking the bike.

I ordered one of the HNW sprags a week or so ago. PostNL says it has crossed the border, so who knows where it is now.

PM me your email and I will send you an update what it arrives.

gortnipper said:

Hi John - mine is the original that came in Matt's kit and has been running for the last 5 years. Only 3 hiccup spinning starts now. Solved by either pulling in the clutch or rocking the bike.

I ordered one of the HNW sprags a week or so ago. PostNL says it has crossed the border, so who knows where it is now.

PM me your email and I will send you an update what it arrives.

Click to expand...

My CNW sprag has lasted a long time with thousands of starts , 20 W 50 in chaincase . Recently it has slipped , freerolling twice . 14 sprags . Rocked the bike to get it going , instantly . Hardened internal gear . Removing the kicker again to make wife happy again after complaints about it in way of her foot .

Torontonian said:

My CNW sprag has lasted a long time with thousands of starts , 20 W 50 in chaincase . Recently it has slipped , freerolling twice . 14 sprags . Rocked the bike to get it going , instantly . Hardened internal gear . Removing the kicker again to make wife happy again after complaints about it in way of her foot .

Click to expand...

Time to replace.

dobba99 said:

The CNW kit uses the same size sprag as the Mk3. You have seen my post here https://www.accessnorton.com/NortonCommando/cnw-e-start-conversion-sprag-failures.41767/

I supply Holland Norton Works with these sprags and Constant (HNW owner) modifies them to fit into the CNW kit (HNW pt number #H15ESC) These sprags are 'tuned' to work in the CNW kit (the spring tension that holds the roller cams in contact with the engine sprocket snout has its tension adjusted so the 'heel dragging' that the CNW kit sprag has, is lessened) These are the only sprags that this can be done to.
That Renold sprag is probably a reboxed chinese sprag with a price premium.

Click to expand...

My HNW sprag arrived today and I have 2 questions of you (since you supplied these to Constant):
1. Did you or HNW put the arrows on? I'm sure it will be obvious when I have mine apart - but what do the arrows denote? The locking or freewheeling direction? (no instructions with it)
2. Those external "ears" around the periphery appear be uneven, that is, randomly bent to some degree. Should I be concerned about this and attempt to correct the worst bends? Most obvious in top of third photo.
EDIT I see those in your post show some of that strange bending too https://www.accessnorton.com/NortonCommando/cnw-e-start-conversion-sprag-failures.41767/post-717284

You'll also notice some slight corrosion on the sides of the cage (most obvious in the second photo) - not a good sign for a brand new bearing. Any comment?
I would have PM'd you on this but you're not a full member.

robs ss said:

My HNW sprag arrived today and I have 2 questions of you (since you supplied these to Constant):
1. Did you or HNW put the arrows on? I'm sure it will be obvious when I have mine apart - but what do the arrows denote? The locking or freewheeling direction? (no instructions with it)
2. Those external "ears" around the periphery appear be uneven, that is, randomly bent to some degree. Should I be concerned about this and attempt to correct the worst bends? Most obvious in top of third photo.
EDIT I see those in your post show some of that strange bending too https://www.accessnorton.com/NortonCommando/cnw-e-start-conversion-sprag-failures.41767/post-717284

You'll also notice some slight corrosion on one side of the cage (most obvious in the second photo) - not a good sign for a brand new bearing. Any comment?
I would have PM'd you on this but you're not a full member.

View attachment 126021
View attachment 126023View attachment 126024

Click to expand...

Mine does not look like this .

Torontonian said:

Mine does not look like this .

Click to expand...

You have a Dobba or HNW sprag?

Rob
Answer to your questions:-
1. The arrows denote the direction the sprag revolves in a Mk3, I draw them on the side plates after i reassemble it.
2. The bent ears around the outside are done to centralise and more importantly, hold the sprag into the engine sprocket (Mk3) or drive gear (CNW estart kit). The sprag has to revolve with the sprocket in the Mk3 for it to operate correctly. They are not bent at random, I test fit every sprag into a sprocket and drive gear to make sure it is even and operates correctly.
If you look at a dogbone type of sprag, it has three thin square shaped clips around the outside, these hold the sprag cage into the engine sprocket. Some old sprags had a split cage that did the same thing.
As for the slight like marking, i didn't supply it looking like that. It won't affect its operation in any way though.
HNW modifies the sprags i supply. You will have to ask Constant if the arrows match the direction of rotation in the CNW estart, The tension spring will have been removed and replaced to adjust its tension and lessen the heel dragging the CNW estart kit suffers from. The marking could originate from that operation. I cannot tell from your photos which way the roller cams are facing compared to the arrows on the side plates. Any chance you can take another, at an angle, showing the roller cams and sideplate.

You can PM me, everybody else has done.
Regards
Peter

dobba99 said:

You can PM me, everybody else has done.
Regards
Peter

Click to expand...

Will do Peter - I understood that Jerry had changed it so only VIP (= Full Member?) could use PMs.
Maybe something has changed again?
Cheers

robs ss said:

Will do Peter - I understood that Jerry had changed it so only VIP (= Full Member?) could use PMs.
Maybe something has changed again?
Cheers

Click to expand...

Just sent you a PM

That sure does look like a stronger design and will be very interested in hearing how it goes. Nat I’d expect bugger all difference if the existing sprag works well and so will be some time before we get any useful data.

One question though, does it greasing also?

Café au Lait said:

That sure does look like a stronger design and will be very interested in hearing how it goes. Nat I’d expect bugger all difference if the existing sprag works well and so will be some time before we get any useful data.

One question though, does it greasing also?

Click to expand...

I think all sprags need the right grease if running dry