Yep thanks Grumpy, it does have the split cotters on the exhaust valve only.
When I flexed the spring with my screw driver I didn't see them as they where stuck inside.
I got the valve out using an 18mm open end spanner as a fork and tapped the valve head until the cotters where visible, then using a small flat tip screwdriver was able to get them out.
I can move forward now, many thanks.
Another question: why are Briggs rings so expensive? You can pick Honda parts up at a more reasonable price.
