Thanks Fontyyy. Don't worry about patronising - I am a total NSR newbie and any advice is good info for me. I think I'm pushing them home fully, but I'll give 'em an extra shove next time I try it. I'll have another, closer look at the manifold too I'm secretly hoping it is the manifold as I'd much rather buy a new one of them than have to try new crank seals on the off-chance. Anyone know if the 28 and 21 use the same manifold?

Cheers

Wb