Britbike forum Forums British Motorcycle specific Brands Triumph bulletin board Thick or thin head gasket?

I note both are listed for the 350 3TA I'm building (very slowly). How do I know which is required?

Many thanks

What are you using the bike for?

What pistons?

On my 350 race bike, I'm using a .017" thick head gaskets with T90 pistons, no piston to valve issues at all

You can use thick or thin without problems on both the T21/3TA head and T90 head

Thin = more compression

This engine is a bit of a mongrel but the pistons I have for it have a fairly low dome so I assume are 3TA / T21. I was just wondering why two different thicknesses are offered - I would probably go for the slightly higher compression if there are no other issues, however the top face of my barrels are somewhat corroded so may need a light skim therefore needing the thicker gaskets.

Whatever you do, make sure to dry assemble and check your rocker geometry. Getting that right will tell you what you need to use...........or modify your rocker gaskets and/or pushrod length to suit.

I assume that the rocker should be in line with the valve stem at half lift?

Yes, you got it.