Honda CB400 Hyper VTEC Questions & Answers

Hi. I am owning a cb400sf spec 1. Unfortunately the original CDI unit got blown. I couldn’t find a spec 1 CDI unit. So, I replaced with a non vtec CDI unit until I find a spec 1 cdi unit. Does it harm for the valves or piston or any other parts inside engine for using the non vtec cdi unit. Because when I rev more than 6500 rpm, still two valves only gonna work for each cylinder. So those two valves only bear the pressure inside the cylinder when it runs in a high rpm. Please someone advise me on this matter. Thanks in advance

Valve clearance range?

what is the production year?