Has anyone tried a Boysen Reed on a TY175 I beleive one from a YZ80 makes a big change to the power band?

I'm running the Boysen reeds in my TY175 along with a 1/4" aluminum spacer. I also removed some material on the reed cage to clean up the air flow. My primary reason for the Boysen reeds was not performance related. I was very concerned about the integrity of 30 year old stainless reeds, and having one get ingested by the engine. I bought mine through B&J Racing and the fit was spot on. I can't tell you whether reeds from a TY80 would fit the 175, but the Boysen reeds have served me well.

Even though you didn't buy them for performance, have you noticed any differences? Thinking about them for my 250.

It's really hard to say, when I bought the bike the engine was overdue for a total overhaul. Bearings, seals and con rod were all shot. I installed the reeds before having the engine rebuilt. Now that the engine has been done, it runs great. Bear in mind I ride the easy sections with the old men, but the bike has yet to come up short of power. A young expert rider in our club took the 175 for a spin on some rather difficult terrain and it handled some steep climbs just fine. Boysen enjoys an excellent reputation throughout the industry, I really don't think you can go wrong.