Author Topic: A10 Rocker box differences (solved)  (Read 421 times)

Online Bsalloyd

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A10 Rocker box differences (solved)
« on: 13.11. 2018 04:18 »
 I am just starting to assemble my 1962 RGS engine. The bike came with a lot of spare parts including five rocker boxes. I went to the parts books and found that there are numerous iterations of this part. I am assuming that the difference may be in the distance between the rocker spindles and possibly the height from the center line to the base. Can anyone advise which box would fit my bike?
coastal Texas

Offline Billybream

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Re: A10 Rocker box differences
« Reply #1 on: 13.11. 2018 04:54 »
I think you will find that the difference is mainly to provide clearance for larger valve springs associated with alloy heads.
I purchased  one recently of Ebay and was just lucky it suited my bike.
Best check with dry assembly and pay attention to all threads as they have history of stripping.
1960 Super Rocket, owned since 1966, back on the road 2012 after being laid up for 29yrs.

Online JulianS

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Re: A10 Rocker box differences
« Reply #2 on: 13.11. 2018 09:16 »
Three basic rocker boxes;

First A7 A10 iron head basic box with short fixing studs.

Second A7 Shooting Star basic box with long fixig studs.

Last A10 Rocket engines, long studs but as Billybream says extra machining on the inlet side to basic box clear wider rocket valve springs.  You can see the extra machining in the photo.

Despite the extra machining the same gasket was specified.

Online duTch

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Re: A10 Rocker box differences
« Reply #3 on: 13.11. 2018 09:54 »

 Hiya lloyd - my phone died earlier when I read this.....what they already said, mainly the spring cutaways, but I fitted a Plunger model cover onto a later big valve head/sprigs no probs...(using the obvious 'other' bits).....

 Ps; just between you and me, you better sneak over to the 'introduction page' before yo're sprung... *shh* (I won't tell)
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
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Offline Seabee

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Re: A10 Rocker box differences
« Reply #4 on: 13.11. 2018 13:09 »
I think you will find that the difference is mainly to provide clearance for larger valve springs associated with alloy heads.
I purchased  one recently of Ebay and was just lucky it suited my bike.
Best check with dry assembly and pay attention to all threads as they have history of stripping.
[/q
I love learning something new!uote]
1961 Super Rocket
1957 Road Rocket
2009 Harley Electra Glide Classic
1993 Harley Springer Softtail
1970 Harley Sportster Chopper
1982 Yamaha XT550
2001 KTM EXC 400
1970 Honda CT70
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Online Bsalloyd

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Re: A10 Rocker box differences
« Reply #5 on: 13.11. 2018 21:15 »
Thanks everyone for the great information. From your comments I believe I can use any of them with the correct studs installed. I had the head rebuilt with the beehive springs so it is very small at the top end. Lloyd
coastal Texas

Offline Swarfcut

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Re: A10 Rocker box differences
« Reply #6 on: 14.11. 2018 10:47 »
Hi Lloyd,  I  find it a whole lot easier to replace the rocker box with no vertical studs fitted. This gives a bit more lateral movement to get the box round the valve caps and springs, plus makes pushrod location easier. Trick here is to make sure the studs go in nice and easy with finger pressure beforehand. Also to have some gynaecological skill working in confined spaces.

Swarfy.

Online Bsalloyd

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Re: A10 Rocker box differences
« Reply #7 on: 14.11. 2018 19:18 »
Hi, Swarfy. I kind of got that idea from the comments. Thanks for confirming it. I could have used this hint when installing a rocker box on an Ariel Huntmaster last year. What a job! Lloyd
coastal Texas