t25t trail blaizer
 

Ive been having a blast with my little 250... It has come time, however, to put some new rings and re-hone the cylinder. No problem. There is a problem with my valve guides, they need to be replaced. Any suggestions with getting new ones? i have been having great luck with e-bay finding parts but no luck with the guides. Are there any other bikes, other than BSA's b25, that might have similar parts that i could use (guides and other engine parts.)?

top end parts
 

I have no idea where in the world you are but will assume the Uk,
Try "the cylinder head shop" who I think are in London,they offer a full cylinder head restoration service for a price, also unleaded seats if they are needed.
I also use Brit bits in Christchurch who might be able to help but am not sure if they do parts for B25s.
Mark

Stick it in the oven, knock out the old ones and find an engineering workshop. Give them your valves as well and they'll make a set.

Google "Brit bike parts " , you'll find there's dozens of dealers selling later Triumph bits .