CNW e start conversion, sprag failures

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Sprag and sprocket jobs done and Arnie rides again!

First impression of Chinese sprag ? I don’t know if it’s because it’s an 18 rather than a 14 dog bone sprag but the starting is far more immediate than my old one ever was, bodes well I guess but only time will tell if it can go the distance; watch this space
 
Café au Lait said:
Definitely 2 pads. Mine is a 2013 build. Double checking I have at least 2-3 mm left so not as urgent as I thought but at least I know what to order. What I may also do is replace the disc which has a fair amount of wear but worse is pulses very slightly at low speed. Again in my last email to Matt I enquired as to the part # but still no response 😢 Anyone know?
Click to expand...
I think that is a proprietary part for CNW.
 
robs ss said:
Yep - on my build #134
Click to expand...
You have the dual disc front end, right? So, you must have the calipers that were the same ones on the Duc 996, 999 etc - they also have a four pad per caliper setup.

If you look at the standard CNW single disc setups you can see that the setup for the pad retaining pin and the floating spring is different - these are meant for single disc front ends I think.

CNW e start conversion, sprag failures
 
Having finally made contact with Matt he explained that up until recently he’d run the sprag dry with great success but now that he’s changed supplier of that part they recommend this grease, to be lightly speared all over. He did stress that this was more about lubricating the dog bones movement rather than their contact with the shaft.
 
Café au Lait said:
Having finally made contact with Matt he explained that up until recently he’d run the sprag dry with great success but now that he’s changed supplier of that part they recommend this grease, to be lightly speared all over. He did stress that this was more about lubricating the dog bones movement rather than their contact with the shaft.
Click to expand...
How did you determine how much grease to repack into those 2 roller bearings beside the sprag?
I'm aware that too much grease can also be a bad thing.
Cheers
 
robs ss said:
How did you determine how much grease to repack into those 2 roller bearings beside the sprag?
I'm aware that too much grease can also be a bad thing.
Cheers
Click to expand...
Every day’s a school day🤣

Tbh they’re so cheap I’ll be replacing them when I grease the sprag come winter
 
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cliffa said:
I was just browsing the Holland Norton works site, and spotted this...


View attachment 125673

exclusive Commando parts | Holland Norton Works

www.hollandnortonworks.eu www.hollandnortonworks.eu
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Yep, that is my kitchen table, its now famous!
Constant asked me to supply him with the roller cam sprags and he has adapted them to fit into the cnw estart kit. The beauty of the roller cam sprag (apart from its robustness) is that you can 'tune' the engagement of the roller cams by altering the spring tension. No other sprag design will allow this to be done easily.
 
dobba99 said:
Yep, that is my kitchen table, its now famous!
Constant asked me to supply him with the roller cam sprags and he has adapted them to fit into the cnw estart kit. The beauty of the roller cam sprag (apart from its robustness) is that you can 'tune' the engagement of the roller cams by altering the spring tension. No other sprag design will allow this to be done easily.
Click to expand...
Dobba,
What adjustment would one make to the spring tension? I would think that one would just install it and re-assemble the system along with new or greased bearings on either side of the sprag.Am I missing something?
Thanks,Mike
 
Is there any solution to this sprag issue for the cNw e-start installed in a '72 Combat other than replacing it periodically, hopefully before it fails? Mine failed after less than 1,000 miles and maybe 50 starts--just started making a loud clicking noise without turning over the engine. Everything that I've read here suggests that high mileage will cause the failure due to the dog bones dragging while the engine is running, so not sure what my problem was other than maybe a defective sprag.
 
YING said:
Dobba,
What adjustment would one make to the spring tension? I would think that one would just install it and re-assemble the system along with new or greased bearings on either side of the sprag.Am I missing something?
Thanks,Mike
Click to expand...
The roller cam sprags i supplied to HNW were to fit the Mk3 commando. Constant (HNW owner) told me that the cnw estart kit uses the same size sprag and wanted them to also fit the kit. I suggested he altered (lessen) the tension of the spring (holding the roller cams onto the engine sprocket) so that the 'heel dragging' is reduced to a minimum. This he did and told me it works. Important to bear in mind this doesn't get around the heel dragging problem, but hopefully lessens its impact.
 
HouTexNorton said:
Is there any solution to this sprag issue for the cNw e-start installed in a '72 Combat other than replacing it periodically, hopefully before it fails? Mine failed after less than 1,000 miles and maybe 50 starts--just started making a loud clicking noise without turning over the engine. Everything that I've read here suggests that high mileage will cause the failure due to the dog bones dragging while the engine is running, so not sure what my problem was other than maybe a defective sprag.
Click to expand...
That could have been a failing battery or loose battery lead/s. was it the solenoid clicking?
Until Matt at CNW or somebody else comes up with a redesign of the sprocket/sprag/drive gear you are stuck with the heel dragging problem with these kits.
 
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dobba99 said:
Yep, that is my kitchen table, its now famous!
Constant asked me to supply him with the roller cam sprags and he has adapted them to fit into the cnw estart kit. The beauty of the roller cam sprag (apart from its robustness) is that you can 'tune' the engagement of the roller cams by altering the spring tension. No other sprag design will allow this to be done easily.
Click to expand...
I didn't know you made them (or had them made?)
I have a Mk2A 850 "restored" by Matt with an e-start. Will it fit that?
...and, would you consider selling to members here?
Cheers
 
robs ss said:
I didn't know you made them (or had them made?)
I have a Mk2A 850 "restored" by Matt with an e-start. Will it fit that?
...and, would you consider selling to members here?
Cheers
Click to expand...
This was my original post on the roller cam sprag.
D

Post in thread 'Mk3 Sprags, a new design'

Number of starts now into triple figures (102 so far) on the new roller cam sprag. I have a bunch already modified. PM if interested
  • Like

Constant bought some from me and did the work on the retensioning of the spring to reduce the 'heel dragging' (i think he went through a few springs doing so) so if you want a roller cam sprag to fit the cnw estart kit you need to contact HNW. I can supply you with a RC sprag with the standard supplied spring but it will need the spring tension reducing to reduce the 'heel dragging' pressure.
 
dobba99 said:
This was my original post on the roller cam sprag.
D

Post in thread 'Mk3 Sprags, a new design'

Number of starts now into triple figures (102 so far) on the new roller cam sprag. I have a bunch already modified. PM if interested
  • Like

Constant bought some from me and did the work on the retensioning of the spring to reduce the 'heel dragging' (i think he went through a few springs doing so) so if you want a roller cam sprag to fit the cnw estart kit you need to contact HNW. I can supply you with a RC sprag with the standard supplied spring but it will need the spring tension reducing to reduce the 'heel dragging' pressure.
Click to expand...

Just placed an order with Constant. 👍
So, when I service mine, I'll have 4 choices:
1. Stay with the existing (if its good, that's what I'll do!)
2. Cheap-arse Ali-Express 18 bone
3. Ringspann - as posted by @slimslowslider in post #90, and
4. HNW spring-modified @dobba99 roller cam.
Can't say I'll be short of choice! 🤣
Cheers
 
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robs ss said:
Just placed an order with Constant. 👍
So, when I service mine, I'll have 4 choices:
1. Stay with the existing (if its good, that's what I'll do!)
2. Cheap-arse Ali-Express 18 bone
3. Ringspann - as posted by @slimslowslider in post #90, and
4. HNW spring-modified @dobba99 roller cam.
Can't say I'll be short of choice! 🤣
Cheers
Click to expand...
Let us know how you get on.
 
robs ss said:
Just placed an order with Constant. 👍
So, when I service mine, I'll have 4 choices:
1. Stay with the existing (if its good, that's what I'll do!)
2. Cheap-arse Ali-Express 18 bone
3. Ringspann - as posted by @slimslowslider in post #90, and
4. HNW spring-modified @dobba99 roller cam.
Can't say I'll be short of choice! 🤣
Cheers
Click to expand...

I expect the sprag Im got from from Peter (Dobba 99) will last a long time, I still kick the Mk 3 into life from cold and will continue to do so. I always make sure the battery is in really good shape.
 
trident sam said:
I expect the sprag Im got from from Peter (Dobba 99) will last a long time, I still kick the Mk 3 into life from cold and will continue to do so. I always make sure the battery is in really good shape.
Click to expand...
Afternoon Sam
I take it you installed the RC sprag in your Mk3? If so, how many starts have you got on her now?
I got to over 150 odd starts and then a conrod let got on the M1. Smashed the crankcases to bits, snapped the cam, broke a tappet , smashed the plates either side of the isolastic housing and put a dint in the exhaust pipe! I,ve spent the last 6 weeks getting Mitzi back together.
 
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