Hi you guys,

Last summer I ran Doris (RVF400) in a dyno. She was total stock, except for a Tyga end can. Here's the dynograph from the session. I was told she was running lean, so since then I've changed the main jets from stock 108 to 112 all round. I'll run her in the dyno again as soon as the winter ends, to see if I need to mount even larger jets.

What I'm wondering now is - should I consider mounting carb springs? The curve doesn't look too bad in the midrange for all I can see. But as always, a second opinion is never wrong.

Would you do something, and what?

That is a bit lean, I think you'll be right with the 112 mains.

I fitted a set of Rick Oliver's replica hrc springs to my rvf carbs, was much happier with the increased midrange torque. It might help your situation also, you could always fit them then get it dynoed to check, they're fairly inexpensive.