classic motorcycle forum

Motorcycle Discussions => British Bikes => Topic started by: enfield49 on July 20, 2010, 11:14:35 PM

Title: Unit 500 triumph heads
Post by: enfield49 on July 20, 2010, 11:14:35 PM

The Head on my T100ss of 1968 is badly cracked I have been offered a replacement but the year is unknown . Are early and late heads interchangeable? what differences are there? Graham

Title: Re: Unit 500 triumph heads
Post by: Rex on July 21, 2010, 11:13:06 PM

1967 they went from the earlier squish-band head with slightly domed pistons to the later hemi-heads and high top pistons,so the earlier heads won't work on the later engines unless you fit the relevant pistons too. They changed in more subtle ways (pushrod tubes, rocker boxes etc) too  over the years but you can get around those problems easy enough.
By the way, there were no T100SS' in 1968 as they stopped in 1966, so maybe you mean the entry-level T100S model?

Title: Re: Unit 500 triumph heads
Post by: enfield49 on July 22, 2010, 03:13:45 PM

Thanks for that , It may be a t100 s, it has the end fed crank like the daytona but a single carb. The head offered is the early type (e3991) so I think I will try to source a late head. Graham