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gREgg-K
gREgg-K
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Rocker boxes
#715010 11/14/17 11:51 am
Joined: Jan 2006
Posts: 2,130
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Thinking about upgrading the rocker boxes on the race bike to 750 style. The 71 boxes with their multiple holes, plugs and the necessary safety wiring are a pain to deal with. Question is will I need to upgrade to T140 head bolts as well or will the 650 bolts work with the new RB's?
Thanks, Mike

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Re: Rocker boxes
Mike Baker #715014 11/14/17 12:47 pm
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You'll have to use the later style head bolts. These bolts clamp down on the head itself instead of the rocker box, the rocker box doesn't have an inner boss to support the pressure from a one piece long head bolt.


'68 Bonnie, '70 TR6r
'74 CL360
trail 70's and minitrails
Re: Rocker boxes
Mike Baker #715119 11/14/17 10:25 pm
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Just to be clear, I'm wondering if I need to use the later T140 head bolts or are the 71 style bolts ok?
The early dry frame type rocker boxes and their through the RB bolts don't enter into this equation, thanks.

Re: Rocker boxes
Mike Baker #715151 11/15/17 1:52 am
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Ahh, sorry Mike, I get it now. And I'm not familiar with t140 bits (thought the boxes were the same as '71), hopefully JH or another of the gurus will chime in.


'68 Bonnie, '70 TR6r
'74 CL360
trail 70's and minitrails
Re: Rocker boxes
Mike Baker #715160 11/15/17 4:05 am
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...Im thinking about that and I do not think all will fit because: 71 rocker bolts are 7/16 I think, then the 72 are 5/16 and 73 on are 3/8s so the boxes of the 750s seem to have different holes for those bolts, but you can made the right ones in a lathe.

Re: Rocker boxes
Mike Baker #715175 11/15/17 9:07 am
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Hi Mike, my 72 TR6 had the same rocker boxes as yours so I fitted the four hole inspection cover type rocker boxes from the later 650 TR6 with the same bolts and push rod tubes no problem. It works fine, cheers Steve.


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