Cylinder head bolts (again)

Joined
Aug 24, 2025
Total Posts
16
Total likes
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Location
Southern England
Hello all,

I was wondering whether anyone could advise on replacement head bolts for my CB400NB. I’m in need of the inner 4...2 at 212mm and 2 at 222mm. I’m building a spare engine from parts I acquired when I purchased the bike, but the spares appear to be modified, so for instance, they have ground them down less than 212. I don’t have any extra 222mm bolts that are usable, only odds and ends, 2 at 206mm and 3 at 216mm, again all ground to the wrong lengths – unless I use the bolts from the running engine. Trouble is, I don’t know the condition of them… Does anyone know of alternative bolts I could use from a generic supplier? I’ve tries Wemoto, David Silver, CMSNL, Fowlers and John Oldfield in the UK, but all are out of stock and apparently NLA. Also checked Partzilla, but I can’t get to the checkout section, to see what the postage is....just out of curiosity.
 
In the eBay listing...I notice there are 206mm and 216mm length bolts....similar to ones I have. What's the reason behind the different lengths if any? Was there a difference in thread depth in early or late model casings?
 
In the eBay listing...I notice there are 206mm and 216mm length bolts....similar to ones I have. What's the reason behind the different lengths if any? Was there a difference in thread depth in early or late model casings?
Not to my knowledge. I've only seen the 212 and 222 bolts. Possibly they measured from the copper washer instead of the bolt head.
 
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