ralph
New Member
Posts: 16
|
Post by ralph on Dec 8, 2018 15:40:49 GMT
The head bolts are all out now, and frankly not what I'd hoped to find. Here they are, with their length and position of each one indicated (R, L = right, left, as seen from the front, I,O = inside, outside) It looks like some of the bolts belong to a CB400 (eg the 222mm bolts) Two (only) of the eight have built in seals. One of them is only 204mm long. It's what my mum would call a "bugger's muddle". Any suggestions most welcome...  |
|
|
|
Post by buster on Dec 8, 2018 15:48:57 GMT
there was a thread on here not so long ago about this (cant find it at the mo and not quite sure how to post the link even if I could I'll give it a go though) and I think it will answer most if not all your questions.
|
|
|
|
Post by buster on Dec 8, 2018 16:09:31 GMT
|
|
|
|
Post by na44superdream on Dec 8, 2018 16:09:48 GMT
,250N, all fronts should be 216mm and rears 206mm, bolts with seals are inner left cylinder. Surprised that the 400 bolts would tighten up.
(do the case threads look good at those positions with the longer bolts?) All inner bolts have copper washers, so they got that correct...
|
|
|
|
Post by buster on Dec 9, 2018 9:42:15 GMT
|
|
|
|
Post by na44superdream on Dec 9, 2018 13:42:58 GMT
There not for a 250 though...but interesting...
|
|
|
|
Post by buster on Dec 9, 2018 14:02:36 GMT
There not for a 250 though...but interesting... I agree john but it mentions something about modifying them for a 250 it wouldnt be my first choice but if the bolts are hard to get it could be worth a look |
|
|
|
Post by na44superdream on Dec 9, 2018 14:59:12 GMT
Sorry missed that suggestion, would be a bit of a boj.
3 in stock of each 400 bolts 90087-413-010 & 90088-413-010 ...at davidsilverspares for about £22 delivered, for one of each.
90088414010 is the bolt that is needed with the seal for the forward left inner, rare I admit!
|
|
|
|
Post by JonnyHonda on Dec 9, 2018 15:15:37 GMT
Here's a thought, and I'll be honest I've not read the whole post and I've not got me glasses on but..
has stretch been considered, if it has. sorry I'll shut up.
if not, I have experienced bolt stretch in the past, where an over zelouse PO, has just tighted them up as hard as possible
you'll get studs that a few mm over length, scrap them, they'll never reliable torque up.
|
|
rickntheo
Full Member
The older I get the faster I was.
Posts: 215
|
Post by rickntheo on Dec 9, 2018 16:46:29 GMT
I'm definitely going to use the phrase "a buggers muddle" from now on. Brilliant.
|
|
|
|
Post by wazzbo on Dec 9, 2018 20:27:37 GMT
The rear 206mm and the front 216m sleeved bolts are as rare as hens teeth. CMS have only one 216mm unsleeved bolt left but have the 206mm unsleeved bolts available www.cmsnl.com/honda-cb250n-1980-a-england_model15816/partslist/E01.html#.XA11NOLLfDeIf it`s had the longer bolts fitted, have a good look down the crankcase bolt holes as you can easily crack the bottom of the holes and force the broken bits into the engine. when you rebuild it make sure there`s no oil or anything in them as the clearance between the bolt and the bottom of the hole is minimal and can can cause the same problem due to hydraulic pressure. |
|
|
|
Post by wazzbo on Dec 9, 2018 20:55:12 GMT
If the rubber sleeves are u/s you can get round the oil leaking problem by filling the two slots on the bottom of the barrel in the pic, to stop the oil running down the bolt holes.
The earlier engines didn`t have them so don`t need the sleeved bolts. a few people have successfully blocked them off with no problems.
this pic is my `79 250n barrel without the slots
 |
|
ian
Member Of The Year 2019 
Isle of Man
Posts: 5,401 
mini-profile background: {"image":"","color":"29908d"}
|
Post by ian on Dec 9, 2018 21:25:20 GMT
The 400 sleeved bolts were similarly rare a few years back when I rebuilt my 400NA engine, so I filled those slots above with gasket seal which lasted 3 years or more, but then the 400 sleeved bolts came available again & I've since replaced them. I daresay a decent epoxy would last indefinitely, but for my 250 rebuild I decided to be done with the problem & had the slots welded up & machined.
|
|
|
|
Post by buster on Dec 10, 2018 0:04:23 GMT
The 400 sleeved bolts were similarly rare a few years back when I rebuilt my 400NA engine, so I filled those slots above with gasket seal which lasted 3 years or more, but then the 400 sleeved bolts came available again & I've since replaced them. I daresay a decent epoxy would last indefinitely, but for my 250 rebuild I decided to be done with the problem & had the slots welded up & machined. right with you ian on the idea of weld up and machine, but epoxy has a tendency to melt (like most off the shelf glues) around 100 degrees c, unless somethings come onto the market in recent years that I dont know about |
|
|
|
Post by na44superdream on Dec 10, 2018 11:59:36 GMT
|
|
