why is the norton atlas clutch such a bear?"

any idea how to cut the 19 degrees exactly the same in the basket? This sounds like a really good idea but very labor intensive. If there was a special cutting tool for a milling machine along with a custom fixture it could be done with a lot of accuracy. I picture using a cut off wheel in a disc grinder (carefully) to get the rough dimensions cut out then a lot of time filing to get the tangs to hit all at the same time.
 
seattle##gs said:
any idea how to cut the 19 degrees exactly the same in the basket? This sounds like a really good idea but very labor intensive. If there was a special cutting tool for a milling machine along with a custom fixture it could be done with a lot of accuracy. I picture using a cut off wheel in a disc grinder (carefully) to get the rough dimensions cut out then a lot of time filing to get the tangs to hit all at the same time.
Click to expand...
I would start with a new plate if doing it that way.Needs to be right or plates will tip and drag on each other.
 
To:John Ebert
‎Dec‎ ‎23 at ‎4‎:‎17‎ ‎PM

John,
Actually I machined the clutch basket and the plates. I had a rotary table and Heinz didn't. I have attached a slightly better picture of the clutch. The slots are not widened, but the one edge is milled at 19 degrees. The reason we picked 19 is that the one Heinz made when he worked in the Norton race shop was the opposite. He used the inner spines of the plates. He was able to get a un- machined center hub and machine it himself. He experimented and came up with 19 degrees worked the best. We just used the same, but did it on the outer basket. I also machined the plates with a matting edge. I played with mine, unscrewing the spring tension until I had to safety wire the screws. It still didn't slip. I now just put them in where I have a reasonable clutch tension. Heinz said that when he showed it to the Norton managers, what they wanted to know was if they did it could they eliminate a clutch plate or two! They really didn't care about the effort to pull the clutch, just the cost. Cheers Brian

  • why is the norton atlas clutch such a bear?"

    19 degree clutch1.JPG
    823
 
Last night I replaced the clutch operating lever in the gearbox with the later Commando version and it was a noticeable improvement. Holding them side by side there was quite a bit of difference.
 
I have drilled the oil tank support and made a better route for the cable ,I also use a nylon lined cable lubed with thin silicon fluid and oversize rollers in the drum race . My clutch has never been better.
 
No mods needed, just check the clearance between roller and track ,I found 3 thou so a set of 1 thou oversize rollers took out 2 thou, Rollers bought from a bearing supply co. Drum wobbles much less ,plates dont drag or rub the inside of the drum. Also check the outside faces of the spring tubes for ridges that will catch against the hub front plate bores as the clutch lifts.
 
Thanks Bob, good info. This will be the first Atlas clutch I have done up, it seems as if it may be lighter than the Commando. If I could ask another question, two bearing cages came in the boxes of parts one steel broken one and a new looking one made out of aluminum. Which would be better? I could just buy another steel one if it's better.
 
I don't know the answer to that one, I would give the ally one a try as long as the rollers are free to revolve,sometimes dissimilar metals work better ,big end cages are often alloy. I remember I had to scratch around to find a bearing supply that worked (bought 50!) .
 
In case you think that drum slop can be cured with a new cage ,race plate and rollers ,think again, I tried that and finished up with more slack that I had with 58year old parts.
 
seattle##gs said:
I just don't see how it improves clutch pull, it is the same three springs either way.
Click to expand...

Take note of the spring tensioning nuts on the modified clutch. The book calls for them to be flush with the stud top end. In the pic, the nuts are way off the stud top!

I have to admit, I am interested in this mod.

Slick
 
Bernhard said:
With my tongue in cheek, you were not doing something right!:)
Click to expand...
What I did wrong was buy new parts from those who should have checked that the tolerances were to the drawings. They were undersize according to my mike. With the new race plate I would need 2 thou oversize rollers . Might go that way with my other Norton. Too much hassle to send stuff back and endure the ignorant argument from someone who is not interested or capable of doing simple checks.
 
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