Cracked head (the bike too).

[Dick Scratcher]

One of my CB250RSAs has a crack between the valve seat and the spark plug hole. After asking a couple of knowledgeable sources it would appear that this is not as uncommon as it might be on Honda 4-valve singles, 500s especially and I assume 250s too. Whilst I gather that this could be repaired (SEP,Kegworth/Head Techniques, Telford) it usually entails the removal and replacing with new, Valve seats and valve guides in order to provide a guarantee-able repair. I doubt that this would  be inexpensive though I am prepared to go ahead if necessary. I have also been told that owing to the frequency of this problem that many riders solve it with the admitted expediency of "F**k it, I'll ignore it, rebuild the motor and see what happens" and nothing does and the bike bashes on as if there was no crack at all and go good-timin' it over the horizon never again to worry about it.
                  Anyone got any experience, thoughts, prejudices, bad jokes, stupid ideas etc etc on this matter ?.

                                                                   Regards to all...............Dick S.

[SteveC#222]

Many many XBR's have the same problem and run absolutely fine with the crack. I have spoken to people who enthusiastically had the head welded and had more problems afterwards. Assuming the RS is much like the XBR, if it isn't obviously causing problems I would leave it - if it ain't broke don't fix it! ( just  keep an eye on it).

[johnr]

my 16v 1170cc suzuki katana had just this problem when i was building the motor in about 1995. crack from the plug thread to the exhaust valve seat. on 2 cylinders. if worried me at the time, but it has been round the uk, done countless drag strip miles, been round europe and its still not gone pop. so i reccon i just about got away with it these last 17 odd years!!

[Dick Scratcher]

my 16v 1170cc suzuki katana had just this problem when i was building the motor in about 1995. crack from the plug thread to the exhaust valve seat. on 2 cylinders. if worried me at the time, but it has been round the uk, done countless drag strip miles, been round europe and its still not gone pop. so i reccon i just about got away with it these last 17 odd years!!

It sounds like you just about 'scraped by' there Johnr. I've spoken to one or two folk plus I've had the responses on this site so I've decided just to lap the valves in, stick a set of rings in (or get a new standard size piston complete), a new output shaft seal in, new gaskets etc then swap the motor into my 'other' RS for a month or two and see how it goes before I spend more dosh on doing the frame and other parts up. Thanks for yours and the other replies.