Author Topic: Conrods A7  (Read 283 times)

Online Ratchet Richard

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Conrods A7
« on: 18.11. 2020 10:15 »
On taking my 1958 A7 apart to set the endfloat I have found that I have a pair of matching conrods. The trouble is they are exactly the same, ie no oil hole in the left rod.  I have read a few of the conrod debates on our forum and am thinking of getting the correct conrod for the left side with the hole. 
My question is around the marked numbers on the current rods.  They are both marked 67-391 but they both have a further number R1R1R which is the same on both rods. Anyone know what this number refers to. Thanks

Online KiwiGF

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Re: Conrods A7
« Reply #1 on: 18.11. 2020 10:46 »
On taking my 1958 A7 apart to set the endfloat I have found that I have a pair of matching conrods. The trouble is they are exactly the same, ie no oil hole in the left rod.  I have read a few of the conrod debates on our forum and am thinking of getting the correct conrod for the left side with the hole. 
My question is around the marked numbers on the current rods.  They are both marked 67-391 but they both have a further number R1R1R which is the same on both rods. Anyone know what this number refers to. Thanks

Have you got the tools to drill the hole? (Might be easier than finding a good rod)
New Zealand

1956 A10 Golden Flash (1st finished project)
1949 B31 rigid “400cc” (2nd finished project)
1968 B44 Victor Special (3rd project,in progress)
2001 GL1800 Goldwing, well, the wife likes it
2007 KTM 950 Adventure, cos it’s 100% nuts

Online Ratchet Richard

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Re: Conrods A7
« Reply #2 on: 18.11. 2020 12:10 »
Hi Kiwi, that sounds interesting, tell me more.  I might not have the tools but I know a man who might.

Offline Swarfcut

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Re: Conrods A7
« Reply #3 on: 18.11. 2020 13:38 »
  Richard. 67 391 is the part number for the bare forging This does not appear in parts list as only a loaded rod complete with small end bush and big end bolts and nuts is listed. Rest assured its the correct length rod for the engine. The other number is a manufacturers' forging identification.

 More important is that the numbers on the rod eye and big end cap are the same.

  The drive side rod has the drilled hole facing to the flywheel, big end tabs face to the front of the engine. From memory the hole is 1/64", but confirm this if you decide to proceed. Getting another rod or a matched pair of rods are alternatives.

 Swarfy.

Online RichardL

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Re: Conrods A7
« Reply #4 on: 18.11. 2020 13:43 »
Probably way too many mentions by me of having drilled my own. In looking for a good one to share, found this, which might be as good as anything.

https://www.a7a10.net/forum/index.php?topic=12113.msg98449#msg98449

(Julian S. does it again.)

Richard L.
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020. This year it's a solo or pillion ride in dapper attire. Watch website at https://www.gentlemansride.com for details.


Online bikerbob

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Re: Conrods A7
« Reply #5 on: 18.11. 2020 15:08 »
I have a 1956 A7 and the left hand conrod does not have the oil hole in it I have ridden it without problems for about 4 years. My 1963 A65 does have the oil hole in the left conrod but it does no good because the big end shells do not have the hole in them to allow the oil through that bike has been ridden for about 8 years again no problems. But I do not ride either bike like I did in my youth now I am in my late seventies I cruise both bikers at 50-55mph and neither bike has been over 60-65 mph. This oil hole buisness has been debated many times with no real definitive answer some think it is essential others that it is not needed, personally I think that if you are like me and take your time then no problem but if you are contstantly ridng using high revs then maybe it is needed.  My A65 is still on standard barrels and the crankshaft is still standard big ends and main bearing the pistons  are the original ones that were fitted by BSA wen it left the factory in October 1962 it was not first registered until June 1963.

Online Ratchet Richard

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Re: Conrods A7
« Reply #6 on: 18.11. 2020 15:24 »
Thanks for all the replies, decision made, I will save mayself some cash and sick with the  conrods I have.  I will not be thrashing this bike and I could do with spending the money on other areas of the engine like pistons rings relining etc.

Online Black Sheep

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Re: Conrods A7
« Reply #7 on: 18.11. 2020 15:25 »
I had no idea A7s had drilled drive side con rods. Mine does not, nor has any A7 I have dealt with over the last 50 years. You can interchange the rods from Norton 88s and 99s, and thay don't have drillings either.
So, am I just ignorant or were drillings produced at some point?
P.S. My A7 has been thrashed to within an inch of its life for the last 60,000 miles and is still going strong.   
2 twins, 2 singles, lots of sheep

Online RichardL

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Re: Conrods A7
« Reply #8 on: 18.11. 2020 15:39 »
Bikerbob,

Julian is about to post another service sheet saying A7s can go 49 months without the hole and A65's, 97 months.  *smile*

Looking at the service sheet (from Julian) that I just shared, I hadn't even noticed that it was about A65s and when they started shipping with the hole.

Richard L
Plan on signing up for the world-wide 2020 DISTINGUISHED GENTLEMAN'S RIDEon September 27, 2020. This year it's a solo or pillion ride in dapper attire. Watch website at https://www.gentlemansride.com for details.


Online bikerbob

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Re: Conrods A7
« Reply #9 on: 19.11. 2020 14:00 »
Well Richard you have me really worried now (I tnink I am getting dandruff with the stress) not sure of the exact date when A7 was on the road but can accurately state that the A65 has been on the road for 9 years 5 months and 12 days since restoration.