Author Topic: Primary drive alignment  (Read 354 times)

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cdsdorset

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Primary drive alignment
« on: 24 November, 2021, 17:40:58 »
Bit of an oddity. Working on an A65 (appears to be 1969 cases). Normally would check clutch /crank sprocket and add shims to crank sprocket if needed. This one the crank sprocket is actually proud of the clutch. Not much but a few thousand.
Anyone  had this before? Could it be mismatched year parts iecrank/sprocket spacer

Bess

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Re: Primary drive alignment
« Reply #1 on: 24 November, 2021, 19:02:16 »
Hi,
    My thoughts are:


What thickness is your 68-0688 spacer? (0.295")
Is the spacer installed with the internal chamfer to the flywheel?
Any burrs on the sprocket face?

Best wishes...
   
« Last Edit: 24 November, 2021, 19:05:03 by Bess »

cdsdorset

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Re: Primary drive alignment
« Reply #2 on: 24 November, 2021, 22:13:13 »
Think I have had a DOH moment. I'm checking it without fitting the timing side crank gear and tightening it!

Bess

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Re: Primary drive alignment
« Reply #3 on: 25 November, 2021, 15:17:44 »
Hi,
    That wont make any difference, the end float is obtained by the difference between the crank and casings, shimming to get the desired 2 thou float.

Once that is set adding the timing side crank gear and tightening it will not alter the end float.

Best wishes...
« Last Edit: 25 November, 2021, 15:20:15 by Bess »

cdsdorset

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Re: Primary drive alignment
« Reply #4 on: 25 November, 2021, 16:59:25 »
I think I need to step away from the bench for a bit  :)
You are right,  for some reason the spacer is too thick.

DAVE BRADY

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Re: Primary drive alignment
« Reply #5 on: 25 November, 2021, 17:43:48 »
Hi,

When you say a few thou, how many exactly? 

Dave.

TTJOHN

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Re: Primary drive alignment
« Reply #6 on: 26 November, 2021, 10:03:48 »
Dave

My end float is about 1/16"I recon but I don't mind that, when it gets to 1/4" I start to worry, not much  ;) ;)

TTJohn

Mike Farmer

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Re: Primary drive alignment
« Reply #7 on: 26 November, 2021, 17:23:35 »
 :) :) :) :)
 
Had this problem last year mine with the correct spacers etc was almost 2mm proud. Therefore the primary chain was tracking wildly out of line So we machined the inner flange on the front sprocket. All seems OK.

Strangely at that time someone else on here had the same problem and used the same method/cure.

Right or wrong====pass, but it works, I have no answer to the why of it. maybe I should have stripped the whole thing down but the bottom had just come back from SRM (not the bearing mod) having had the bottom sortied.

Mike 8) 8) 8) 8)