My XJ stumbles right after startup. What's wrong?

[radare]

My XJ600 Seca II stumbles when riding right after startup. What's wrong?

If this occurs during the first start of the day when the engine is cold and goes away after a few minutes, this is normal and typical of a Seca II. The Seca II is jetted lean on the pilot-circuit, from the factory, and thus has to warm-up before being rideable. The stock jets are #17.5 and are lean until the bike warms up. If this drives you nuts, you can remedy the situation by installing #20 pilot jets which will improve cold-startup ride-ability and will also help with general ride-ability even when warm.

If this occurs even when warm, it's likely your pilot jets are dirty or partially clogged. Clean the carburetors and, after cleaning, upgrade to #20 pilot jets.