Would it be easier just to use an Atlas dual timing chain/gear setup and just hog out a hole and drill and tap for the mount bolts in the back of the 850 case?
It's been so long, but it seems like the chain tensioning was like the primary, so super-precise location of the mag mounting hardware shouldn't be necessary as there has to be some play to tension the chain properly? Like the bottom stud was the pivot and the other two had elongated holes in the mag base.
the problem ,though not insurmountable, that I see is that of a heat shield. not much of a problem with the ktf , but Jim in an earlier post made clear that modern magnets are liable to failure. The answer is a thick tufnol gasket between the magneto body and the engine case. but then that will throw the chains out of alignmentNot on my Atlas! The tensioning is as I describe above. The holes in the K2F flange are not elongated, but are of diameter to go over the 5/16" studs. There is not much lateral adjustment, but enough to loosen for removal of the AAU, and enough to tighten beyond "too tight". The magneto drive chain is lightly loaded and well lubricated, so adjustment for wear is not a factor.
Re: Your next post.
I do not know for sure, but it stands to reason, from the standpoint of mass production machine tooling, that the layout of the three holes in early Commandos, would have been the same as pre-Commando models.
Slick
the problem ,though not insurmountable, that I see is that of a heat shield. not much of a problem with the ktf , but Jim in an earlier post made clear that modern magnets are liable to failure. The answer is a thick tufnol gasket between the magneto body and the engine case. but then that will throw the chains out of alignment
Do we have any old "replies" that show with pictures the necessary machining to the 850 cases to fit a mag behind the cylinders? Also, can you machine a right side Atlas case to fit an 850 commando engine in order to more easily mount a mag the old way? Or was so much changed it's 'apples to oranges'?
yes he did but the heat path will be through the case of the magneto which is bolted to the timing chest... the oil temp , will go through the armature and bearings to the points... Certainly my Alton starter does not get especially hot and it is exposed to the same barrel temp, but then there is no heat conductive connection between it and the crankcases or timing cover... What Europeans like me tend to forget is just how hot it gets in parts of the states, maybe supermagnet magnetos would be ok in the UK. scoops would be simple and if they picked up cool air worth while, but what about when stuck in trafficI think Jim's comments were more directed to heat coming off the barrels, which might be 300 deg. F or more.
The timing chest is well bathed in oil, and therefore should not exceed the oil temperature, which is about 200 deg F max. (Except in short burst of power) Therefore, heat conduction from the timing chest should not be a factor.
As I noted in a previous post, a small air scoop, or one on each side of the barrell base, might mitigate the heat problem with the super magnet magnetos.
Slick
yes he did but the heat path will be through the case of the magneto which is bolted to the timing chest... the oil temp , will go through the armature and bearings to the points... Certainly my Alton starter does not get especially hot and it is exposed to the same barrel temp, but then there is no heat conductive connection between it and the crankcases or timing cover... What Europeans like me tend to forget is just how hot it gets in parts of the states, maybe supermagnet magnetos would be ok in the UK. scoops would be simple and if they picked up cool air worth while, but what about when stuck in traffic
When you fit the nice brand-new fairing to a race bike or do the lovely paint-job, you are certain to crash almost immediately. A Joe Hunt Magneto might be similar - what happens if it gets ripped off the timing case ?