SOHC.co.uk Forums > CB500/550
cylinderhead overhaul
andy_c101:
Firstly to Pete:
Looks like you did a great job on yours 750(?) head.
Where did you buy the cutter?
For BryanJ:
some photos of the camshaft, No4 Ex valve lobe.
To the outside edge of the lobe is an unworn ridge; I tried to phot the profile, inthe second shot you can see the raised edge.
the Lobe/cam height measures: 34.32mm (1.352") versus nominal 1.360" and bottom service limit of 1.356".
Then the No4 Ex valve rocker follower:
you can see a slight 'flat' across the centre portion of the follower; that's probably lost a thou or so (?);
so in total that's say 5-6 thou' lost valve lift (bottom limit case; nearly ten thou' on nominals.
- I guess it could be much much worse?
but I'd welcome your opinion on my options.
AndyC
UK Pete:
Hi Andy, i bought the neway cutters, they come up on ebay here and there or send of and buy them from USA , the head i did in that post was a Kawaski Gpz550 head, as this is the bike i am restoring at the moment, but they will also do my cb750 heads when i get round to it
Pete
Bryanj:
That Cam is shot due to lack of oil, look at the bearing surface on the end.
Also check wether the rocker spindles that are in the cover have worn the cover oval, this can happen although I've only seen one.
Still reckon your cheapest repair is a replacement head as guides and machining will be well over £100 plus £80 for pattern valves.
Camshafts and covers do come up on ebay---don't forhet the USA BUT remember there is only airmail now---Unless you plan on a holiday or know somebody who is
matthewmosse:
California Connection / AP incorporated inport US bikes and often have engines, last time I needed one it was £150 for a unknwn quantity engine or £300 for a tested one plus £60 for pallett delivery so I had 2 unknowns to make the best of the deal - one was mint to look at but kept eating tensioners so wound up with bent valves - never did find out why. Other is in my 500. Given ebay prices at the moment I'd look at a complete engine from them if available and if the price is still in that ballpark.
andy_c101:
I'm hoping to pick up a camshaft off of fleaBay.
& I've ordered valves n guides off CMSNL (D/Silver didnt have the full sets)
I managed to extract the valve guides (I pre-heated the head in the oven at "60" for ten minutes - like we do to 'warm the dinner plates'; .... shhh don't tell you-know-who!)
I have a question (request advice) regarding cylinder/bores.
- I've used a bore dial gauge to measure each bore, tdc/bdc/mid-stroke, in a couple of places (each cylinder), and all measure within 58.50-58.52/.53mm (within service limit of 58.60mm);
piston ring gaps (side & end) all measure within service limits;
So my question: What would folks on here do/recommend? - just rebuild as-is? or renew rings and/or more?
Andy C
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version