1971 Single sided swingarm fastback (2011)

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Gottcha. The odds of him using a standard issue swingarm are slim and the odds of him overlooking something like that are slimmer.
 
I'd say if he traps the spindle firm enough in that fairly thick cradle tube then good to go to point swing arms flex as much as cradle and frame. Peel's race grade 606TS 5/16" cradle passes the over size spindle straight though on the bare Al tube is nice almost tight fit but is trapped-fixed by two 3/8" allen screws from above down in robust blocks of threaded Al butt welded to cradle walls. Its got SS top hat bushes installed for center stand pivots though.

Ya can see the tops of the bolt blocks beyond swing arm blackness here. These blocks also tend to back up the tube to cradle load junction,
1971 Single sided swingarm fastback (2011)
 
Hobot, my friends commando rear end has some similarities. I dont know all of what hes done with his...but the swing arm going on his alloy cradle is also a hand built titanium unit. I will try and see if I can get more pictures of his project. Its pretty amazing. I just happen to be passing by when he showed me this cradle, it just got back from the welder. And it was on its way to being heat treated, (Its T6 and after welding it goes to "O" so it needs to be brought back to T6 hardness.)
My friend does this kind of stuff because he is a fantastic machinist, and engineer, Im pretty sure his work will improve the bike....unlike my project, lot of my mods are not really proven yet.
Any who, back to my bike, :D , I will pull the oil scraper rings to verify and make sure I dont see a groove behind them, On the advice of this forum and Andover I definitely don't want gernadable pistons.
 
hobot said:
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.
Click to expand...

Thanks, as mentioned, i am going to check and make sure I dont have "risky" pistons
 
bwolfie said:
Don't pill the rings, they might break. Just look from the inside for a long groove.
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Oh, ok gotcha. yeah I didnt like the prospect of pulling off the rings for that very reason.

Tyler
 
You should be able to see the slot with a mirror and torch, or through the oil ring, if you can break that type of oil ring you probably shouldn't be there to start with.
A couple of points
You have checked the ring gaps ?
It was taught to me to position the oil ring expander end on the opposite side to the rail ends and space the rails appart, make sure the expander ends butt and not over lap.
The slots in the pistons are a older form of expansion control, neither type really likes high revs, high comp or detonation, probably be reliable if you ran 8.5-1 comp and didn't rev past 5000rpm, but I don't think thats your intention.
 
hey kids, just thought id update everyone on the project. As usual everything takes twice as long as planned.

anyway just a few pic with text
here is the dunstall style lifters and retainers

1971 Single sided swingarm fastback (2011)

1971 Single sided swingarm fastback (2011)


cylinderhead done
1971 Single sided swingarm fastback (2011)


bottom end ready for top end
1971 Single sided swingarm fastback (2011)


A freshly build Commando powerplant ready to serve
1971 Single sided swingarm fastback (2011)
 
I bought a new set of Dunlop Qualifiers and got the rear wheel mounted and balanced

1971 Single sided swingarm fastback (2011)


engine installed
1971 Single sided swingarm fastback (2011)


mooved bike up to workstand, no more bending over
1971 Single sided swingarm fastback (2011)


close-up of headsteady
1971 Single sided swingarm fastback (2011)


of course theres always a setback with productive weekends, somehow i forgot this lower casebolt, the only way to get this in is the raise engine up, the frame is in the way of the bolts, bummer
1971 Single sided swingarm fastback (2011)
 
Gorgeous, absolutely gorgeous !!! Glad I stumbled on this thread again, your bike is a work of art. :D Thank you so much for sharing, and the many kewl pics 8)
 
Those Dunstall lifters really don't look right. Maybe I'm missing something here, but they look like you have them paired wrong. Is that how you put it together?

Ken
 
Ken,

Shit! ....see, this is what Im talking about, I cant get anything done without being interrupted at my home. Not that its a problem most of the time. but during delicate processes (like engine assembly) i need to focus, and I remember that I got stopped several time that weekend I was working on this

so to answer your question....I assume I did put it together this way because of the retainers already installed.......and yes, after staring at that picture something does seem askew....Crap!

Ken, you may have just saved my engine....Thank you

time for 2 steps back
 
nortriubuell said:
Gorgeous, absolutely gorgeous !!! Glad I stumbled on this thread again, your bike is a work of art. :D Thank you so much for sharing, and the many kewl pics 8)
Click to expand...


Your welcome and Thank you for the kind words....as you may have noticed from the previous post i may be disassembling the top end. :( :!:
 
That Is one slick, tricked out Norton........keep up the good work.......what am I missing with regards to the lifters ...both pictures seem to show them oriented the same way?
 
No, the cam following surfaces are 1/4" askew (front to rear) on both pairs.

They should be aligned with each mate.
 
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