Hey guys, I have a 1976 RD400, and I have a problem.

I'll be gunning it along, and always, when I hit 7000, the bike seems to choke up and splutter., and refuse to rev more.

Is it retarded timing or is it needing a carb readjust?

Or is there anything else that you would suggest is wrong with it?

Advice/knowledge is kindly accepted, haha.

Is the bike standard or modded? Check the air filter is good also the fuel tank is venting ok.

I brought it and it had been rebuilt etc etc. So I'm not sure as to how well it's set up. Its got stock carbs, expansion chambers etc. The pistons are apparently a little oversize. I think the tank is venting okay, but I'll take the bike for a run tomorrow with the lid popped up to see if it is the problem. I'll check the airfilter too....