How can I get more power from my XJ?

[radare]

How can I get more power from my XJ600 Seca II?

Refer to the Articles section of The Wall for references.

In the early days of the XJ600 (Seca II/Diversion), many aftermarket manufacturers tried to squeeze more power from it to make their products desirable for the Seca II Challenge series. After spending a small fortune on a new exhaust, a jet kit and a series of dyno tuning, Cycle World could only squeeze one more horsepower from the XJ and at a major hit to low-end performance (see Yamaha Seca II: Bargain Blaster Made Better by Matthew Miles, taken from Cycle World, December 1993, pp 58:61:).

No aftermarket manufacturer could honestly do a better job than Yamaha did with the bike from the factory. A stock Seca II makes as much power as it possibly can.

The question is, is yours in a good state of tune and does yours make what it did when new? Since these bikes are 20 years old and often not well cared for, they are typically not running at peak performance. Spending time and money to finely tune the bike and reclaim some of that lost power is a much better decision than chasing horsepower that doesn't exist by spending a fortune on bolt-ons and aftermarket gizmos.