ajs 14

[Bill2181]

Hi All, I have recently acquired a 1959 model 14 250cc. the exhaust valve insert is very slightly loose in the head. Also the insert is too big in outer diameter and has a flat ground on it to accomodate the cylinder. Is this normal or is it a scrapper?
I would like to attach photograph, but don't know how.

[SPRIDDLER]

I'm reading that it's the valve guide which is loose in the head. Also that the o.d. of the guide has been reduced so that it will enter the head.
Correct valve guides with an oversize o.d. have been available. Russell Motors may still have some. You'll have to phone as they don't use email.
http://www.russellmotors.co.uk/

There's info on attaching photos in the FAQ section of this website.

Here it is:

http://www.jampot.com/forum/viewtopic.php?f=8&t=8894

[Bill2181]

Hi All, Its not the valve guide but the valve seat insert that is a bit loose. I gather that it is not uncommon, and have bought a replacement head, hoping it is a better one.

[alanengineer]

I have a lightweight head and the valve seat has heavy peaning around the seat. Its off to the skip sometime

[g80csp11]

dont every scrap a head , T&L will replace the insert for £55 + VAT the replacement will be a interference fit in the head
Although ive not done a lightweight head this way , its a common repair on heads

[SPRIDDLER]

Hi All, Its not the valve guide but the valve seat insert that is a bit loose. I gather that it is not uncommon, and have bought a replacement head, hoping it is a better one.

Of course. My confusion. Probably due to lack of oxygen to the brain with this mask on.

It's not unusual for a valve seat to loosen. A new secure seat can be fitted.

[56G80S]

Alan

Give it away rather than scrap it!

Johnny B

[Duncan]

I had an inlet seat come loose in a G3 head, the engineering company I took it to removed the original insert which has a sort of hour glass shape going into the head. That meant the replacement would have been large and could have overlapped the spark plug hole, they advised me that I would do better to find a second hand head rather than get it repaired due to the cost. The next month I picked one up at Shepton Mallet.

They also mentioned that the majority of lead free seats are let into the existing steel insert so there is still the potential for the original insert to work loose.