Honda-SOHC

SOHC.co.uk Forums => CB350/400 => Topic started by: simco1964 on June 26, 2017, 12:48:32 PM

Title: M8 x 125mm Bolt
Post by: simco1964 on June 26, 2017, 12:48:32 PM: Hi All,
Have been rebuilding bike (CB400/4) for the last 9 mths or so and I must admit there was alot of make do and mend from the previous owners, I now seem to have an M8x 125mm bolt spare and have no idea where it has come from? have look at the schematics on the CSMNL website and again no luck on finding where it goes? it may well have been used instead of the correct bolt? but I would like to have some clarification before continuing.
Hopefully someone out there can give me some piece of mind!!!
Cheers in advance
Simon
Title: Re: M8 x 125mm Bolt
Post by: andut on June 26, 2017, 01:46:46 PM: Simon,

Just checked the length of the M8 bolts that join the crankcases top to bottom around the main brgs, and they're about 10mm shy of your measurement - not wishing to teach egg sucking, but I assume that you're measuring from under the bolt head to bolt end ?

Only other place that I can recall using M8 is engine mounts, but 125 is still too long - longest bolts go into the lower crankcase from either side, but they're critical on length to avoid damaging the casting.
Title: Re: M8 x 125mm Bolt
Post by: hairygit on June 26, 2017, 01:52:17 PM: Andut could well be right about engine mounting bolts, but if it had engine/crash bars fitted it would indeed use 10mm longer bolts to account for thickness of the attaching bracket of the engine bars.
Title: Re: M8 x 125mm Bolt
Post by: simco1964 on June 27, 2017, 12:44:41 PM: Hi,
My first thought was crankcase bolt as I did have to source one due to me possibly mislaying one or not!! but then its rather long to go there?
The bolt was measured from underneath bolt head. Also no crash bars fitted.
Well it may be the case of waiting for something to fall off or fail?

I hope neither
Simon
Title: Re: M8 x 125mm Bolt
Post by: royhall on June 28, 2017, 08:11:31 AM: If all the holes have bolts in them your good to go. If not put it in the empty hole. Or did I miss something here?
Title: Re: M8 x 125mm Bolt
Post by: simco1964 on June 28, 2017, 10:25:25 PM: HI,
Bolt not flanged and no vacate holes!! well not anymore!
Going to have to bite the bullet and go with it, if it starts and runs that will be good enough!!
Simon
Title: Re: M8 x 125mm Bolt
Post by: mike the bike on June 28, 2017, 11:14:45 PM: If it isn't flanged then it ain't a crankcase bolt. It's probably a stray one put there to wind you up.
Title: Re: M8 x 125mm Bolt
Post by: mike the bike on June 29, 2017, 11:40:46 AM: I'm referring to 400s, not 500s. Having reassembled the engine about 40 miles ago, I'd remember a bolt like that.