Front Vernier Isolastic too tight

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Drummer99

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The front vernier isolastic mount for my 74 Commando can not be adjusted tight enough to fit between the 2 mounting holes on the frame It appears that the front mount is the culprit as I cannot tighten the 2 collars any tighter against the front mounting tube cap. If I remove the 2 washers it will fit so it is about 1/32 of an inch too tight.According to the Norvil spec sheet I have the right vernier 66130 and 66131 to fit the standard motor mounts. The rear fit with no problem! It appears the only solution is to take about 1/32 off of the motor mount but this doesn't make any sense to me. has any one else run into this problem and any suggestions. The frame spec calls for 152.27 mm between the mounting holes mine appears to be about 151 mm which makes the problem worse. Thanks Drummer99
 
Never had the problem, but I think I'd shave the outer surfaces of the collars before I did anything to the frame.
 
Drummer99 said:
The frame spec calls for 152.27 mm between the mounting holes mine appears to be about 151 mm which makes the problem worse.

The frame downtubes occasionally need to be sprung apart slightly to allow the front Isolastic to fit between the frame lugs.
 
When I added the Vernier Adj Iso mount on my 72, I had to remove the head steady and other motor mounting bolts to teeter the motor up as far as possible to get this bastard in place. After that is was clear sailing.
 
I ran into this on Trixie putting in past Peels adjustable iso and found absolutely could not spread front tabs enough to matter, even about shearing off threads of 1/2 inch all-thread rod though tabs eyes and sledge hammering wood blocks between front down tubes, so trial-error 3xs machined off some the iso tube till snug clearance that still allowed some gap adjusting in normal range. Do suggest while easy access to 45* bevel front cushions down to ~1/4 inch wide contact rim for sweet isolation w/o much or any lost of Commandos innate sloppy handling control.
 
I seem to remember that on earlier models, the ISO tube needed to be shortened (read machined) 1/4" shorter, to suit the ISO mod. But I did a lot of drugs back in the day
 
I had this same issue in 2010 when restoring my '71. The frame specs were spot-on but the mount was 0.035 too wide. I shaved down the vernier nut just a hair.
 
L.A.B. said:
Drummer99 said:
The frame spec calls for 152.27 mm between the mounting holes mine appears to be about 151 mm which makes the problem worse.

The frame downtubes occasionally need to be sprung apart slightly to allow the front Isolastic to fit between the frame lugs.

+1
I used a 2x2 cut to length and fit it between the frame down tubes and then drove it up to spread the frame just enough, It did not take much. mine was so close, but just would not fit.

If you think it would over stress the frame or you have too much to go then machine the ISO

Dennis
 
L.A.B. said:
jug said:
I seem to remember that on earlier models, the ISO tube needed to be shortened (read machined) 1/4" shorter, to suit the ISO mod. But I did a lot of drugs back in the day

Yes, early vernier kits did.

http://www.norvilmotorcycle.co.uk/techtalk03.htm


Later kits do not.

http://www.norvilmotorcycle.co.uk/techtalk04.htm

As Drummer99's Iso. was 1/32"too wide to fit then the tube being over-length by 1/4" (6.35mm) doesn't seem likely.
Yep that's it. The tubes needed to be cut back to 1/4 each side. All coming back now. lol
 
jug said:
L.A.B. said:
jug said:
I seem to remember that on earlier models, the ISO tube needed to be shortened (read machined) 1/4" shorter, to suit the ISO mod. But I did a lot of drugs back in the day

Yes, early vernier kits did.

http://www.norvilmotorcycle.co.uk/techtalk03.htm


Later kits do not.

http://www.norvilmotorcycle.co.uk/techtalk04.htm

As Drummer99's Iso. was 1/32"too wide to fit then the tube being over-length by 1/4" (6.35mm) doesn't seem likely.
Yep that's it. The tubes needed to be cut back to 1/4 each side. All coming back now. lol

Just off one side of the tube an only if you are using normal width adjuster not the thinner type made specifically to save having to cut down the tube.
 
"If we ignore the theory it should be quite good" Joe Craig


toppy

that is a great quote, do you have a source for Joe Craig saying that and what was he referring to?
 
1up3down said:
"If we ignore the theory it should be quite good" Joe Craig


toppy

that is a great quote, do you have a source for Joe Craig saying that and what was he referring to?

I can't remember exactly if it was a book or magazine possible even this site. But he was reported as giving that answer when asked about the continuing success of Manx Norton in the face of far more modern competition as i recall.
 
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