Author Topic: cam shaft slop  (Read 1396 times)

Offline coater87

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cam shaft slop
« on: 12.09. 2009 00:21 »
 Guys,

 I am moving along here and have come to the cam shaft. I have given thought to new bushes, but I am just not positive that with the tools I own I can pull off a decent line reaming. The cam shows slight wear, and I believe is quite serviceable with a little attention.

 Now I have not been able to find a definitive word on tolerance for the cam bushes. I need to know how major of a deal it is to run with slightly sloppy cam bushes on an a10 motor- as I believe I have between 6 and 8 thousandths.

 Lee

Central Wisconsin in the U.S.

Offline A10Boy

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Re: cam shaft slop
« Reply #1 on: 12.09. 2009 11:20 »
In my opinion 6 - 8 thou is too much play to have and will probably wear quickly. I assume you have the engine cases apart at the moment so I would recommend replacement of the bushes now while its apart.

BSA had a special tool for removing the blind camshaft bush and as you know, new ones need to be line reamed properly so if you have doubts have it done by your local engineering shop.

Good luck
Regards

Andy

1960 A10 - Black Golden Flash
Plus
1974 Kawasaki Z1a
Yam XJR 1300

Offline Josh Cox

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Re: cam shaft slop
« Reply #2 on: 12.09. 2009 15:31 »
Coater,

If you read the Haynes and Bacon books, they make a sweeping statement regarding the CAM bushes, something along the lines of " these will not require replacing unless your mahine has done a very large amount of miles".

Are you talking end play or differences in ID/OD ?.
Black 1953 Golden Flash Plunger

Offline coater87

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Re: cam shaft slop
« Reply #3 on: 12.09. 2009 16:10 »
 Hi Josh,

 Yup, the haynes and Bacon are what are throwing me. I have no idea the miles this bike has done, some parts look almost new, and then there are others....

 I am indeed talking about inside diameter. I am just not sure what "exceptable" is on a BSA a10 motor. For all I know, mine are at factory spec (but I doubt it!). It would be great if someone could say "this is factory spec, this is exceptable, and this is re-bush time"!

 Lee
Central Wisconsin in the U.S.

Online Triton Thrasher

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Re: cam shaft slop
« Reply #4 on: 12.09. 2009 17:04 »
If it's any help, I think Triumph specify 2 thou as maximum bush clearance, but that's on new parts.  What's satisfactory in a used engine may be different.

Offline beezalex

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Re: cam shaft slop
« Reply #5 on: 14.09. 2009 17:10 »
Yes, worn cam bushes are a PITA.  .0015-.002" running clearance is required.  After many failed attempts to align ream and or bore the bushes and binning several sets, I finally got a proper adjustable full-length adjustable hone from Sunnen.  Pricey but it's the only thing I've found that works.
Alex

Too many BSA's