Author Topic: Camshaft and idler bush diameter?  (Read 911 times)

Online KiwiGF

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Camshaft and idler bush diameter?
« on: 30.08. 2011 11:37 »
I've just noticed the camshaft and idler bushes in the timing side case have all rotated so the oil holes do not line up, so I need new bushes as they are too loose in the case

But before I order some replacements I was wondering if anyone knows the correct outside diameter of these bushes so I can check new bushes will be a tight fit in the case and whether the root of the problem is with the case and not the bushes

The part number of the bushes is 67-686

thanks!
New Zealand

1956 A10 Golden Flash (1st finished project)

1949 B31 rigid “400cc hot rod” (2nd finished project, + favourite bike)

GL1800 Goldwing, well, the wife likes it

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Online bsa-bill

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Re: Camshaft and idler bush diameter?
« Reply #1 on: 30.08. 2011 11:47 »
I have a new one , comes out at  0.940

Friend of mine sorted his with loctite, he reckons it's cured.

If you try Loctite I would use the old bush as a new one would probably be tighter on the shafts and more inclined to turn
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Online KiwiGF

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Re: Camshaft and idler bush diameter?
« Reply #2 on: 31.08. 2011 11:03 »
Thanks bsabill the bushes are 0.939 one end and 0.941 the other ie conical but I reckon it's mostly the case at fault and worn which gives me a problem to solve

The bushes are 0.753 on the I.d so fairly worn out

Ill have to decide on whether to get some special bushes made up and reamed or bodge what I've got! I'll prob fix it properly though
New Zealand

1956 A10 Golden Flash (1st finished project)

1949 B31 rigid “400cc hot rod” (2nd finished project, + favourite bike)

GL1800 Goldwing, well, the wife likes it

KTM 950 ADV, cos it’s 100% nuts

1952 Armstrong Siddeley Whitley for rainy days (with wife)

Online KiwiGF

  • Last had an A10 in 1976, in 2011 it was time for my 2nd one. It was the project from HELL (but I learned a lot....)
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Re: Camshaft and idler bush diameter?
« Reply #3 on: 10.09. 2011 02:32 »
I've measured the 3 cams and idler pinion shaft I have (the spare 357 won't be fitted as im going for a cooking engine with flat top pistons but i might try to get a 356 instead of using one of the 334's) and I'm wondering how to tell if the bearing part of the cams are worn
They measure between 0.746/0.748 dia which could be the cams are a worn 0.750 or clearance for a 0.750 bush.

Anyone know what would be the STD  dia and tolerance of the cams?

The bushes I guess could be reamed to suit the cams if they are worn, provided they come from Draganfly a bit undersized

I've got a quote from Newman cams uk for 175gbp delivered nz for a new CNC 356 cam which is en40b nitrided but I'm not sure how that would last compared to an oem cam
I should really refurb the followers to suit a new cam as well which is all getting a bit expensive!


New Zealand

1956 A10 Golden Flash (1st finished project)

1949 B31 rigid “400cc hot rod” (2nd finished project, + favourite bike)

GL1800 Goldwing, well, the wife likes it

KTM 950 ADV, cos it’s 100% nuts

1952 Armstrong Siddeley Whitley for rainy days (with wife)

Online muskrat

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Re: Camshaft and idler bush diameter?
« Reply #4 on: 11.09. 2011 04:45 »
G'day Kiwi,
              Do the followers. Just ordered a 357 (112 quid landed AU) from SRM, and a set of followers (75 quid landed AU) from Resurrection Scooters Ltd on ebay. So will be a few weeks to measure a new one, all my old ones are worn.
 Cheers
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
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Online KiwiGF

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Re: Camshaft and idler bush diameter?
« Reply #5 on: 11.09. 2011 09:24 »
Thanks muskrat it looks like I could save a few quid buying from the suppliers you are using.
New Zealand

1956 A10 Golden Flash (1st finished project)

1949 B31 rigid “400cc hot rod” (2nd finished project, + favourite bike)

GL1800 Goldwing, well, the wife likes it

KTM 950 ADV, cos it’s 100% nuts

1952 Armstrong Siddeley Whitley for rainy days (with wife)