Front circuit will be pushing a bit more fluid
25% more. I would definitely want to upgrade to SS brake lines to minimize line expansion.
The Gen 2 FJR linked brake system also incorporates a metering valve and a proportioning valve. The metering valve prevents operation of the front piston from the rear master at low pedal force -- IE there is no front braking from the rear pedal when gently dragging a brake in a corner or manouvering at low speed.
The proportioning valve reduces rear brake application rate under hard braking, reducing the likelihood of lockup as the weight transfers forward to the front wheel by transferring more of the rear brake pedal force to the front caliper where it is needed.
I wanted nothing to do with the linked brake system when Yamaha first added it. I wrongly assumed it was just as primitive as other manufacturer's systems of the era that I was familiar with. Having studied the system and put it through it's paces, I now find it quite livable. And while the front brake suffers from the loss of one caliper piston, it is at least partially offset by the increase in rotor diameter on the Gen2 compared to my original 2003 Gen1 (2004 and 2005 Gen1's also have the bigger rotor, so best of both worlds?).
I've not done a side-by-side stopping distance test. All I can say is the 03 was more inclined to do a stoppie, lifting the rear off the ground. But I'm not certain that is attributable to stronger front braking or more because the Gen2 is heavier with a longer wheelbase.
I'm less enamored with the ABS. Unlike modern motorcycle ABS systems that utilize accelerometers to at least estimate the effect of cornering on total available traction, the Gen2 is strictly based on rotational speed. As such, I think it errs on the side of caution under straight line conditions and cannot offer sufficient prevention while cornering.
Tests conducted "back in the day" by one of the motorcycle magazines revealed that skilled riders without ABS could consistently out-brake ABS equipped bikes, even in low traction conditions such as wet pavement. However, the average rider performed as well or better on an ABS equipped machine. The difference was attributed to confidence -- skilled riders hung on the ragged edge of lock-up, but average riders tended to caution and underestimated the amount of braking force they could apply before the front would lock up and wash out. ABS gave them the confidence to mash the front lever all the way to the bar and let the computer sort it out.
One difference between the two unrelated to braking: the Gen1 are quicker (not faster, but quicker). Side-by-side, a Gen1 will outpull a Gen2 gear for gear. Partially due to weight, but mostly due to the extra tooth in the final drive (2.698:1 vs 2.773:1). A Gen1 is more inclined to wheelie for the same reasons, plus the shorter wheelbase. The Gen2 wheelbase can also be felt in the corners.
