Hello (again)

[cbradley400/4]

I used to be a member of this forum back in 2008 when I owned a 400/4.
For many years I've been a fan of the CB250 RS and have owned quite s few of these .
My current one is a 1981 A model which I've owned for the last 10 years.
I bought it as an abandoned cafe racer conversion and returned it to standard.
I cover about 1000 miles a year on it as i have other bikes too.
It's been pretty reliable.
I'm just wondering how much interest there is on this forum for these models?

[McCabe-Thiele (Ted)]

If you use the search facility a fair bit.

[Laverda Dave]

Lots of love on here for the mighty CB250RSA . Congratulations on running a great bike, they deserve classic status imho, they are that good but seriously underrated.👍
I owned mine for over 20 years and used it as my everyday hack, it was a great little bike, fast, light, handled really well and full of character.
I restored it a few years ago and started a thread on here covering it's restoration, link is here:

https://www.sohc.co.uk/index.php/topic,11929.0.html

I am still kicking myself for selling it last year, why did I do it .

If you have a fuel tank with the original colour you could help a member on here who is rebuilding a CB250RSA. His name is Ash (Ashimoto on here). He needs the measurements of the central band that runs down the fuel tank as they were painted on and were not a decal. I'll post a link to the post Ash put up a couple of weeks ago, if you can help him out with some measurements he'll be greatful.

[Laverda Dave]

Here's the post Ash put up a couple of weeks ago asking if anyone could help with the tank decal measurements:

https://www.sohc.co.uk/index.php/topic,31353.msg302457.html#msg302457

[AshimotoK0]

Plenty of interest on here... you must have left just after I joined. So welcome back !

I bought a basket case 250RSA last year ... trying to make it one of the best around. Managed to get a full top end NOS apart from the camshaft.

As Laverda Dave says .. I am doing my paintwork (Nassau Blue) at the moment and stuck for the dark blue centre area dimensions on the fuel tank.

[Athame57]

Welcome back!  I owned four (five?) CB250 RSs in the 1980s, I used all of them for dispatch riding. The one you see in the pics was my last, I got 77,000 miles out of her, with a couple of camshaft changes mind. I loved them and the sound they made especially. They weren't without their issues and the stress of dispatch riding would bring them out too. Even so on my short list of options when I returned to biking six years ago, I ended up with a 400/4 though, an RS seemed a bit too small for my purposes now.

[cbradley400/4]

Thanks for replies.....

Yes they are very underrated and great very light weight and unintimidating bikes-perfect for an every day hack or despatching back in the day-well as long as the distances are not too great.

I always think they could do with a bit more urge and have always admired the 500 conversions but that would be way above my skill set-Allen Millyard I most definitely am not!

As to the tank dimensions I've done my best but can't guarantee the accuracy : A = about 45mm, B = about 35mm, C = about 25mm, D = about 20mm. The others I can't do at the moment as the seat is a bit of a pain to remove as you will know but if they are still needed let me know and when I have time I'll remove the seat and try again.

Mine has always suffered with most Un Honda like oil leaks presumably from the head and I'm going to search on this forum but I don't suppose there are any easy answers to this problem?

Another problem I had with mine in the past was corrosion of the frame which only became apparent when the kick start lever began to foul the right footrest hanger. My mate had to investigate and weld up the frame behing IIRC where it bolts to the frame.

[cbradley400/4]

I've just read Laverda Dave's rebuild thread and you have my total sympathy regarding the engine trouble.
In fact my 400/4 which was the reason I originally joined this forum suffered from engine trouble and had to be re-bored. 4 times the number of components in many instances and very expensive IIRC. Luckily I have a good friend who's a very competent  bike and car mechanic and he did the work for me without any issues. I seem to recall the re-bore was done by Grampian Motors.
Those engine problems you encountered sound like an absolute nightmare and you did very well to persevere and complete the bike after all those problems.
I've had running problems with my 750 Ducati Monster ever since I bought it 4 years ago and I know how expensive and frustrating these problem bikes can be.

[Laverda Dave]

The strange thing about the 250RSA is some will leak oil whilst others don’t!

Leaks are normally confined to the rocker box with the oil seeping from the ends of the two rocker shafts on the left hand side. The design isn’t very good in this area as it relies on two very thin O-rings on the end of the rocker shafts to seal between the rocker shaft and rocker box casting. The O-rings become damaged when installing the rocker shafts simply because they need to be placed in the grove on the rocker shafts and then pushed into the rocker box casting. As they are pushed in they tend to tear and will then leak. I tried to avoid this by applying red rubber grease on the o-ring to help things along, it worked but I still had a very, very slight weep from the exhaust rocker shaft, it never dripped or ran over the motor but I could see a tell-tale mark around the rocker shaft. Triumph twin engines have the same problems (but normally a lot worse due to very slack tolerances ) but with Triumphs you can buy a special tool that helps with fitting the rocker shafts and protects the o-ring (in theory anyway).

If you do have a leak from the rocker shaft on the RSA the cost of the two O-rings to fix it will be about £5, getting the rocker shafts out though to replace the O-rings is a different issue and often painful and expensive. In their wisdom Honda used a hardened metal dowel to locate the rocker shafts in the rocker box. These dowels are really, really difficult to remove. I tried heat (lots of it), parallel pliers, penetrating oil and swearing at them but they would not budge. In the end I tried to remove them using the Haynes manual method, slot the end of the dowel and twist it out. The dowel broke off flush with the rocker box casting, game over as it was too hard to drill out . As a last resort I managed to find an aircraft engineering company close to Heathrow Airport who took pity on me and one of the engineers used a spark eroder to remove both dowels during his lunch breaks.

I have heard from others of these dowels being really easy to remove so maybe someone else had already removed them at some point and in the process had made the locating hole a bit bigger, you may be lucky with yours, it’s very straightforward to remove the rocker box to check and is one of the best things about the RSA, so easy to work on .

[cbradley400/4]

Thank you...
I think I'll just have to live with this-the bike has always done it.
My mate did fit new O rings and sealed them but it hasn't worked clearly. This was done a few years ago. It's very irritating as I've owned over 100 Jap bikes and they rarely leak oil in my experience. I did use to own a Kawasaki W650 which looks more like a Triumph and that bike actually did leak oil just like the real thing!!

[Nurse Julie]

Great to see you back Chris