herbz,
I can't say this is your situation, but they clunk in 1st gear till they warm up. Switching to Amsoil helped eliminate a lot of that noise on my '03 TA, but it is still a nature of the beast. If your noise is prevalent after warm up or in other gear changes, I would suspect a misalignment between the front and rear sprocket, possibly caused by your rear wheel being crooked. An improper adjustment of the chain could also be a cause.
Stay tuned, more learned minds than mine will be along with their opinions....
