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CB250RS info please

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Oggers:
Folks

Thinking about  buying a 1981 (kisckstart only) CB250RS to recapture those heady days of my youth when I had one for a while. At the time, I thought it was a very good bike, but I never really took it apart to any great extent. The one I now have in mind has about 30K on the clock so I wouldn't mind delving into the innards of the engine to check things out. With that in mind, a few Qs if I may

How easy - or difficult! - is it to start exploring the innards of the engine. Is there anything in particular I need to be aware of?
What would you recommond replacing given the mileage - main bearings? crankshaft bearings? piston rings? cam chain? valve guides?
Anything else on the bike I should be mindful of?
   
Many thanks

Mark

K2-K6:
One of the forum has extensive experience on here (threads worth searching) of this bike that'll give you insight.

A beautiful rebuild to stunning condition along with trials and tribulations of engine work, I'm sure he'll contribute to help you soon.

Laverda Dave:
Hi Mark.

Here's a link to my CB250RSA restoration.
Considering the mileage of yours the items worth checking are the cam lobes and rockers, the cam bearings in the head and rocker cover (lack of oil changes or dirty oil will toast these leaving the head and rocker cover as scrap). The cam and rockers can be repaired by Newman Cams if they are not in bad condition. The rocker spindle pins can be a royal pia to remove, use plenty of heat and luck!
Renew the balance chain, CMSNL were charging £280 for a genuine Honda item but you can get a far better quality DID Go-Kart racing chain for £20, Andy the Chainman (he's always at Kempton Park Autojumble and has a website) got one for me and cut it to the correct length with a soft link.
If you need a rebore make sure the engineer doing the work is aware of the very tight clearance, don't do as I did and take it to an engineer used to old brit bikes and will overbore the barrel. I use SRS in Sutton for my engineering work or use Trigger on here as he's top notch and is used by forum members.
Good luck, post photos and there's  lots of advice on here.

http://www.sohc.co.uk/index.php/topic,11929.msg91265.html#msg91265

Laverda Dave:
Another thread when the oil seal split resulting in engine strip to replace! Buy genuine seals if you can.

Laverda Dave:
http://www.sohc.co.uk/index.php/topic,15771.msg132065.html#msg132065

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