1971 Single sided swingarm fastback (2011)

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Time for pistons then,

ring gap checks out

1971 Single sided swingarm fastback (2011)



These are not OEM pistons, this is the marking , Its been so long since I got these I dont remember :?

1971 Single sided swingarm fastback (2011)

1971 Single sided swingarm fastback (2011)



And Wa-LA I have pistons installed...and i even got the circlips in with out one shooting across the garage


1971 Single sided swingarm fastback (2011)
 
Gotta love the Maiden bench stool! I was so close to getting the aces high artwork airbrushed somewhere on my tank. Die with your boots on brotha!
 
quote="Snorton74"]Gotta love the Maiden bench stool! I was so close to getting the aces high artwork airbrushed somewhere on my tank. Die with your boots on brotha![/quote]

Yeah, maiden has always been one of those bands ill always go see....hard to believe the youngest member of that band is in his mid 50s. And they still put on a show that shames any of these retarded bands of today.

Just jump to :35 and see if you can ID the bike

http://m.youtube.com/#/watch?v=DdpMx0-A ... dpMx0-AlDs
 
Are those pistons slotted under the oil ring? or do they just have the tear drop expansion slots, either way not the strongest choice, if fully slotted I would seriously consider not useing them
 
splatt said:
Are those pistons slotted under the oil ring? or do they just have the tear drop expansion slots, either way not the strongest choice, if fully slotted I would seriously consider not useing them
Click to expand...

hmm, as far i can tell its just the slots on the upper skirt of piston. im not sure if understand --- grove under the oil ring?
you mean under as hidden by the rings with them installed..or as in a forth row?
 
Yep good observation, the comma shaped oil holes are known taboo stress risers of ancient Norton issue and had one tear up an other wise perfectly good Combat engine on 3rd week of timid use while cruising on very light throttle level road going about 50 mph, tinkle tinkle CLANK locked rear, but clutch released to pull over upright. That one set me back almost 3 yrs to recover. I don't know if your pistons are same risk or not.
 
motoalchemist said:
splatt said:
Are those pistons slotted under the oil ring? or do they just have the tear drop expansion slots, either way not the strongest choice, if fully slotted I would seriously consider not useing them
Click to expand...

hmm, as far i can tell its just the slots on the upper skirt of piston. im not sure if understand --- grove under the oil ring?
you mean under as hidden by the rings with them installed..or as in a forth row?
Click to expand...

http://www.norvilmotorcycle.co.uk/techtalk34.htm
 
If I was fitting aluminium barre ls to a commando, I would leave them silver, the same colour as the original cast iron ones that were painted silver to look like aluminium. I think that if your road bike is f ull of hot parts , you should not advertise the fact. I still have cast iron barre ls on my racer and painted black to lose heat better even though I use methanol fuel. I wish I had aluminium barrels, but it would present a minor problem when warming the bike up be fore a race .
I'm interested in your single s ided swing arm. Do you till use isolastics - how do you stop the engine plates from flexing ?
 
splatt said:
Are those pistons slotted under the oil ring? or do they just have the tear drop expansion slots, either way not the strongest choice, if fully slotted I would seriously consider not using them
Click to expand...

I dont think these are the "dangerous" pistons, based on the references from Andover Norton and L.A.B. But here is
a close up of the piston for your scrutiny.

1971 Single sided swingarm fastback (2011)
 
acotrel said:
I'm interested in your single s ided swing arm. Do you till use isolastics - how do you stop the engine plates from flexing ?
Click to expand...

Yes I am still using the isos...as a matter of fact I have added another Iso on the engine plates which also act a a reinforcement
Check back on page four or so for the pics. Also, here is a pic of the carrier in mock-up. notice the extra iso and the tube that its contain in which is also added structure......Im not saying this is going to work. wont know til the bike is together.

1971 Single sided swingarm fastback (2011)




And just or fun and sheer enjoyment o custom parts, this is my buddys Norton projects' engine plates....hes sticking to tradition style swing arm.

1971 Single sided swingarm fastback (2011)

1971 Single sided swingarm fastback (2011)


A true piece of art....wait til you see the whole bike
 
What do you mean by 'traditional style' swing arm ? My feeling is that extra plates should be fitted to the frame to carry two silentbloc bushes at the ends of the swing arm spindle, so that the isolastics are restricted in the lateral direction and all vibration damping is in the vertical direction. That would greatly minimnise the hinge effect.
 
That's a very nice looking alloy cradle your buddy is making. Sometimes it's worth doing things like that just for the pleasure of making something a little different (and cool), whether or not it makes any performance improvement. I like the approach of using thicker than stock plates to get strength at the engine mounting points, and then machining relieved areas to reduce weight at other locations. Besides, it's visually appealing. I've seen several aluminum cradles where the builder used either the same thickness plates as the stock steel, or maybe slightly thicker, and I've always worried about the fact that they were now weaker than the steel plates at the right side engine mounting locations, where the steel cradles normally break. That area is a known problem area, and is frequently reinforced by Commando racers, usually after it has broken. The other issue I worry about is wear at the swingarm spindle in the softer alloy material. I assume you could prevent that with a good clamping design, like the tapered locks in the MKIII, or maybe steel inserts at the ends of the tube. In any case, please do post pics of the rest of the bike when you can. It's sure to be interesting.

Ken
 
lcrken said:
The other issue I worry about is wear at the swingarm spindle in the softer alloy material. I assume you could prevent that with a good clamping design, like the tapered locks in the MKIII, or maybe steel inserts at the ends of the tube. In any case, please do post pics of the rest of the bike when you can. It's sure to be interesting.
Ken
Click to expand...
I was thinking the same thing. There has to be some kind of insert at the end because you can't have the bushing riding against aluminum. Maybe some kind of steel top hat insert. Didn't Hobot do something like that?
 
After looking at the pictures of the alloy cradle, I'm guessing he's not planning to use the normal Commando swing arm spindle mounting method. When I built my box section swing arm I used two tapered rollers on each side, with preload spacers betwee, and the inner races were clamped solidly to the cradle by bolts that screwed into an insert in place of the spindle. This located the swing arm side-to-side, so there was no rubbing between the cradle and the swing arm. Maybe he's doing something similar.

Ken
 
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