You built a work of art that 50 years ago many hams could do for high power RF amps. But today, the modern ham buys his dipole antenna premade and has someone put it up for him. Serious dumbed down hobby today, mostly due to the ARRL.
There was a successful Norton-Race-Team years-back in NZ , they had some engine and gearbox-failures until they went full-synthetic-oil . This makes-me want to fit a cooler on my old 82 XV1000 (TR1-Roadster ) and maybe some cooling-fins on the external cam-oil-feed-lines . People think I'm mad to change my-oil as-frequently as I do....I think They are-mad to leave-it 5-7-thousand between services . I also change-it scalding-hot immediately-after a good-ride , while all the clutch 'fines' etc are still in-suspension . Since I started doing it this-way , my oil now looks-clean (not like-new obviously ) when I drain-it and nothing-like it used-to look . I think it was FortNine who had lab-analysis done on a bunch of motorcycle Brands @ their first-service , some very-interesting-results . Dave nz
Wondering why the same oil in my bikes got black and stiff in so different intervals I came down to the conclusion its because of the more or less rich mixture causing more or none soot......
Yes, this is the original "Superblend", made and named by Ransom, Hoffmann, and Pollard (recently amalgamated from the the Ransom and Myles company, which had supplied Norton main roller bearings for years). It is a Type NF roller bearing which is characterized by only a single lip on the outside bearing race. The inner race, which is pressed onto the crankshaft stubs, for this type of bearing has double lips; therefore, when the crankcases are split, the rollers stay on the crankshaft and slide out of the outer race. Many of us believe that this played a great part in the tendency of the bearings to fail in the "Combat" engine. The non-Superblend type bearing -- used on the drive side of the Norton twin engine from the late '40s, with a roller bearing on the timing side which prevented end float of the crankshaft -- was an NF-type bearings and was simply substituted on the timing side of the crankshaft when the strengthened-type crankcases were introduced on the Commando from the first week of January, 1972. The only way that they could be installed was with the non-lipped side of the outer bearing race facing the crankshaft and the new, thicker crankcases tended to crush the bearing race down slightly. This problem was observed on the assembly line in early 1972 and a service release put out, advising dealers of the possibility of this warping occurring and advising a revised inner crankcase bore dimension which, when machined into the crankcases, would result in less clamping force on the outer race with the unintended effect of the outer race being less firmly held in position in the case. The worst of the examples seen on the assembly line could were so tight that the crankcases could not be assembled together. A slightly less dramatic condition would result in no free end float on the crankshaft and could result in the crankshaft being hard to turn or, even, stuck completely. Since these earlier-type bearings had the less-relieved contour on the end of the rollers, a "clamped down" bearing would have all the load on the bearing carried by a thin strip of the inner race because the inner end (in relation to the crankcases) of the rollers were crimped inwards toward the inner race and a very thin strip of the inner race was forced to carry all the load subjected onto the bearing. It's no wonder that they failed. Add to this the flexibility of the Commando crankshaft and the timing-side rollers could be pushed out of line -- and thus tipping the edge of the roller into the inner race even further -- resulting in an even worse condition of only a small corner of the roller carrying the entire load of the bearing. (The first examples of failed bearings being returned to the factory were from the timing side of the engine although later, pretty much an even number of failed bearings were identified as both timing and drive side.) I was in John Nelson's office (John was International Service Manager for Norton VIlliers at the Wolverhampton) when he turned from the first consultation with RPH engineers regarding the early bearing failures. I remember his exact words "they have a new bearing with a blended taper on the end of the rollers - making them barrel-shaped - and they call the bearings with these tapered rollers in them 'SuperBlends'". From that day, that's how they were known in the Norton factory but the term "SuperBlend" was not a term derived by Norton. It was a term used by RHP and the description of the rollers as being "barrel-shaped" was also from RHP. The issue of the single-lipped bearing race having less resistance to being "crimped down" onto the rollers was recognized early. Thus, as the problem in service became more common, RHP introduced a Type-NJ "SuperBlend" bearing; these bearings have the double lip on the outer race and, when disassembled, the rollers and the cage remain in the outer half of the bearing. The fact that the race pressed onto the crankshaft has only a single lip is much less of a problem as the force imposed upon them by installation on the crankshaft is parallel to the race's bearing surface. As Jim notes here, the rollers used in the RHP Superblend bearings were shorter that those used in the much more common and better-accepted FAG "SuperBlends" -- please note that the term was NOT used by FAG although their rollers have a more tapered or relieved shape than the RHP type. The real secret with the FAG bearings is that the longer rollers are more resistant to the "crimping" effect and also provide a great dynamic load rating. In fact, the FAG bearing has a dynamic load rating almost twice a high was the original RHP roller. So, that's the real story of the SuperBlend bearing in Nortons and how they ended (for all practical purposes) the problems of main bearing failures in Commando engines. (We'll leave the issues of oil scavenging and return, crankcase breathing, and the fact that the 10W-30 Castrol multi-grade oil, specified as the Norton factory fill and recommended service replacement, would test in the laboratory as being a straight-weight 8-grade oil after about 250 kilometers of running at top speed on the Autobahns in German alone for now and go back to them on another day.)
Hi Jim - your video showed up and I watched it again. You do beautiful work. I hope all is well. I have completed a grounded grid, class-C, plate modulated 3-400Z that I run on 40M AM. I load it to 500 watts of carrier and plate modulate it with a pair of 3-400Z in class-B. Hope to hear you on the air, 20 or 40M. Bob, KE0SSP and Byron, WA4GEG still get on 20M around 14.156, Wednesday at 1 PM Mountain time so maybe you can join us some time.
My 750 Norton , just recently slipped out of second gear a couple of times under load , my kick start shaft has .050 to .060 end float at a guess , i have bought some new springs as i heard they can get rusty and weak , also detent plunger , looks like i should address the end float while i am in there , i have spare new Iso shims 🙂 .
So the inserts don't seem to add significant load to stock spec torque for those studs (360 in-lbs). On your earlier video you showed stock thread pull out at 590 in-lbs. How can we explain that?
Performed this repair as described but subdivided the 48" by 6 so that the 5 screws were evenly spaced 8" apart so the screws were at 8", 16", 24", 32", 40" (had to offset the middle screw down slightly to not hit another screw that is in the center of the vertical span). The screws, drills, and other process I kept the same. After putting in the screws and tightening them just so they were flush with the side that by itself almost completely removed the buzz and with just a little more tightening (half turn maybe) the first AL-III plus had no distortion and for the 2nd unit I didn't have to tighten it any further than simply screwing the screws flush with the metal. No more distortion or buzzing. Thank you so much for making this!
Great Video James! Do you think it is possible to over tighten the screws? My pair has a buzz at medium high listening levels. I performed your modification exactly and while tightening the screws I would find the buzz getting worse as I tightened so I loosened them fearing that I am doing more harm than good. Am I stopping shy? Have you encountered anything similar? Just thought I would ask as you have modified several sets. Thank you, W
Next level R&D for what I’m assuming is a home builder??? What are you using to capture these images? Some kinda stroboscopic light synced to a high speed video camera/boroscope going thru spark plug hole or a hole you milled in the head at the proper angle to view valves? Running on a spintron! There are big name shops that don’t do R&D on this level and prolly wouldn’t know how to interpret this and gain any value able insight from it. So cool!
Exactly as I do them on my Bridgeport Interact 4, thread milling is the way to go! ive done Ducati, Morini and even a small 2 stroke Suzuki as well as Nortons
Thank you so much. Was about to spend almost 1500 for a 60" replacement tweeter. I mean the buzz was really bad..... This solved it completely. The whole time I was thinking oh boy I must have drilled through some magnets, but no. Works flawlessly now, thanks!!!
Pretty impressive. A Norton guru and, a connoiseur of thermionic valves. Love the idea of high power and the fact that you put this beast of an amp into service because you can. Pretty impresive. Oh did I say that already? Well, probably because It's pretty impressive.
Jim - It's a little hard to see (perspective, mostly, I think) but are the lifter faces flat like stock or are they radiused? Is the cam in the spintron a WebCam 213A and does that require a radiused or flat lifter? Thanks Bb
The new followers are radiused. They can be cut with a 3 or 4 inch radius and used with the 312a cam. The 312a cam is suitable for a flat to 3 inch radius follower. I also have custom cams to use with the same follower ground with a 1 inch radius. They are available in 4 grinds from stock to full race. The hardweld material is not compatible with any cam other than a Webcam.
The conclusion is that all the MK3 cams measure softer than the earlier cams - they are made using a different process. But the fact that they are soft is not a condemnation as I have seen many MK3 cams that lasted over 100,000 miles.
I know this has been some years past, but as I'm new here :-) I always felt the problem with motorcycle engine design/implementation is that there is so much heat at the exhaust side (at the front of the airflow, which your room temperature mimics), along with the undirected airflow causing the front to get more active temperature exchange, makes for an inefficient cooling system. You have me thinking... :-)
