75 Mark III refurb/mod project

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I have never had any sort of catastrophic failue on any bike I've owed or built for a client with 2 exceptions:

1. my little Kawasaki 90 Bushmaster trashing a piston and taking the cylinder and rotary valve with it, due to improper 2-stroke mix with straight 30W crankcase oil, mixing "by eye" at the gas pump.

2. Failure to fully seat the sludge tube in a Triumph crank sludge trap, resulting in blockage of the main oil gallery at the neck; final results were a complete teardown and replacement of rod bearings (no core component damage).

As these rods got severely nicked by the stray washer, they had to be replaced. Since we're warming up the engine with pistons & cams, it's just extra insurance.
 
Crank & rods all done-

75 Mark III refurb/mod project
 
Obvious! Well maybe, just maybe it's all a ghost-story about these inferior D-type rods after all?!
 
Didn't the story originate from a Norton Villiers technical bulletin? I would take heed. It could be that the run was ok for a while but problems developed during manufacturing, bad alloy or what ever. I couldn't find the original bulletin for review but if the Norton factory acted on it there likely was a real problem of some sort.
 
nortonspeed said:
Obvious! Well maybe, just maybe it's all a ghost-story about these inferior D-type rods after all?!
Click to expand...

I doubt that all D rods are flawed.
However there does appear to be some evidence to suggest the D rods are likely to fail prematurely, possibly there was a faulty batch, I don't know, but if that is the case, then there appears to be no way to determine which ones will break and which ones won't, therefore I think it would only be prudent to avoid the use of D rods wherever possible, just in case?

http://www.norvilmotorcycle.co.uk/techtalk35.htm
 
Paul, I recall reading that the Norton racing shop and some of the subsequent Norton gurus, solder the circlip on the early model drain plug with the filter attached, once it is locked into it's slot. Given what you have found inside this engine this seems like a good idea to me as one seldom has to remove the filter anyway and if you do a quick heat up with a small torch should release everything.
 
http://www.norvilmotorcycle.co.uk/techtalk35.htm
Click to expand...

Thanks L.A.B. this is just the information I needed to be sure not to reuse my D-rods.
 
Cylinders ready to bolt on, just need the cam & radiused cam followers from Megacycle...

75 Mark III refurb/mod project


75 Mark III refurb/mod project
 
Great progress. I am curious as to what size cam is going in? And why are you using the Rowe valves and not the Kibblewhite valves?
 
No big reason to use the black diamonds over the Rowes, this isn't a race bike (althought the spring kit is required by the cam)

the head isn't ported, so it isn't anywhere near critical on the differences in the valves.
 
Just received the floating rotors, they match up to the Dreer hub perfectly with the bearing caps, perfect center-to-center spacing on the setup.

75 Mark III refurb/mod project


Also got in the Megacycle cam and radiused cam followers-

75 Mark III refurb/mod project
 
Managed to find this very nice remote reservoir shock, I'm patterning the mounting lugs now...

75 Mark III refurb/mod project
 
Removing the primary side main bearing was easier than ever. I pre-heated the oven, set the case in there and made myself a sandwich; I'm nearly finished and I hear a "plop" in the oven, there's the old bearing sitting on the bottom of the oven...

New ones dropped straight in from the freezer with zero effort.

75 Mark III refurb/mod project


Installed the Megacycle cam with thrust washer and red goo they provided-

75 Mark III refurb/mod project


So that's it, the bottom end is done.
 
Paul - the superblends in the cases look like one is facing one direction and one is facing the other. Is this correct? The reason I ask is that I have never installed these and I installed mine both with the smooth side up with the inner race facing the crank. This is the way that the races came out of the bearings so I installed them into the cases accordingly.

Do I need to change mine to look exactly like yours?
 
It's half a dozen of one and six of the other. These are the double lipped outer races, so only the inner race stays on the crank. They have a "loose lip" on the opposite side of the inner race that functions as the bearing shoulder. Same technical spec, just a bit different arrangement of bits.

No need to change yours.
 
byrdman76 said:
Paul - the superblends in the cases look like one is facing one direction and one is facing the other. Is this correct? The reason I ask is that I have never installed these and I installed mine both with the smooth side up with the inner race facing the crank. This is the way that the races came out of the bearings so I installed them into the cases accordingly.
Click to expand...

As I understand it, it is generally considered good practice to fit the races the same way around as they come out of their packaging? Which would normally be with the bearing inner and outer race markings on the same side of the bearing, so if that's the way you have fitted them, then I would say it was correct.
 
Really good info guys. I had just gotten done shimming the crank, so I'm glad that I do not need to change anything.

Thanks again,

Byrd
 
New chamchain and cleaned up oil pump-

75 Mark III refurb/mod project


New timing cover seals (including a new rubber on the oil pump nipple); the cam seal is a bugger to remove, I tore the old one up-

75 Mark III refurb/mod project


Timing side all nipped up-

75 Mark III refurb/mod project
 
byrdman76 said:
Paul - the superblends in the cases look like one is facing one direction and one is facing the other. Is this correct? The reason I ask is that I have never installed these and I installed mine both with the smooth side up with the inner race facing the crank. This is the way that the races came out of the bearings so I installed them into the cases accordingly. Do I need to change mine to look exactly like yours?
Click to expand...

Remember that what you want on installation is for the loose inner race lips to fit up to the crank, so the crank can be removed without struggling. Simply use a bearing splitter to remove them from the crank in the future.

I have pulled apart cases where one or both bearings were installed backwards and it was a major pain to free the crank from the cases after splitting them (also with much effort)
 
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