81 CB650 Custom Cylinder head bolts

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81 CB650 Custom Cylinder head bolts

Postby pavehog » Sat Apr 23, 2016 6:31 pm

Greetings, First post. I am in the process of a total rebuild of the above listed bike. Tore the engine down to cases. Its been sitting unassembled for a few years. I have both Clymer and Haynes manuals and have referenced the House of Honda OEM parts diagrams. Am reinstalling the cylinder head and the manuals all call for 12 bolts. The diagrams call for 10 x (8x120) flange bolts and an unspecified number of (8x145) flange bolt(s). I have 9 x (8x120mm) bolts, 1 x (8x126) and 2 x (8x145). I don't know if the previous owner threw the 8x126 bolt in as a replacement, and I don't know where the 8x145's go. I do have the tightening pattern and Tq spec's but the picture in the manuals do not show where the longer bolts go. So basically 2 questions, 1. Is the 8x126 an extraneous bolt? and 2. Where do the 2 8x145mm bolts go?
Thank you for any assistance with this.

Dave Dubuque

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Re: 81 CB650 Custom Cylinder head bolts

Postby Folsoml » Sun Apr 24, 2016 8:08 am

Hmmm. I just checked all the manuals and fiches I have at my disposal and find it odd that none of them say where the two longer bolts go. That being said, I do not see where there should be an 8X126 anywhere on the cylinder head. There should be (as you already said) 10 of the 8X120 bolts, so I guess the PO substituted it for one of those.
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Re: 81 CB650 Custom Cylinder head bolts

Postby themaddrebel » Thu Apr 28, 2016 12:46 pm

Use a depth gauge to measure the holes for the head bolts,go from there

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Re: 81 CB650 Custom Cylinder head bolts

Postby cb650 » Thu Apr 28, 2016 3:24 pm

If I remember right the longer ones are the inner rear.
Did you clean the tank out?!?!?!?!

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