I sent a message to tri spark, here is the reply:
Q: Hi, can you share the advance curve vs rpm for the Yamaha XS650 system (not rephased)?
Also, do you offer a Firebox equivalent for XS650?
A:
Thanks for your inquiry.
Our Compass system for the Yamaha XS650 (not rephased) follows the same advance range as the original factory system, but with more subtle transitions. The advance begins at approximately 1400 RPM and reaches full advance by 3500 RPM, with most of the advance occurring before 3000 RPM. Half advance is achieved at 2000 RPM. This design provides excellent low-end throttle response, a stable idle, and reduced risk of pinging or knocking.
While I don't have a specific drawing to share, I hope this description gives you a clear idea of the advance curve.
Unfortunately, we do not offer a Firebox equivalent system for the Yamaha XS650.
How much for postage to the US?

