Rear Brake Problem developing Mechanical or my riding style?

[dmccu11ough]

I've recently modified my bike for highway commuting.  Increased front sprocket to 17 tooth from stock 16 tooth and countered the side effect of decreased bottom end with ignition advancer (Thank your Bob B.!!).  
The end result is I'm getting more comfortable in the higher rpms and faster speeds to the point the rear brake seems increasingly soft and squishy.  I've started  pulling sideways the last few times I've hit the brakes hard.  I believe its just me working the bike harder, but I'm not sure.  I've had visions of a highside and don't want to go there.  Help!

I've been thinking about hitting the track soon for a critique of my riding.  I will be taking the MSF course this weekend and hope to pick some info from the class.

[TheGoodGuy]

make sure your rear wheel is "aligned" straight.. not the axle alighment but the wheel alignment..

im having it too.. it started after i adjusted the chain and axle alignment.

I suggest you check your rear wheel alignment to the front wheel and swing arm. Scratch can describe how to do it, he was telling me how to do it on mine this weekend.

[xaindagger]

With the ignition advance do u think it compensates for the 1 tooth in the front. I am thinking of doing the exact same thing, bumping up a tooth in the front and prbly rejetting the carb.

[Blueknyt]

check rear wheelalignment, check swingarm bearings too, 17toothfront? whats onthe rear? stock gearing has a hard enough time pulling in 6th, it just barly maintains your speed, god forbid heavy head winds

[scratch]

I'm not too sure how to address your squishy rear brake prob, but maybe the alignment will help. I've been taught that the tick marks on swingarms are not to be trusted, but if you align the wheel and note the difference of the two, you'll have a pretty good idea after that. I have found it easiest to line up the rear wheel with the frame or swingarm. Loosen everything and then sit behind your bike. Grab the ends of the axle and push/pull the wheel. Sight past the edges of the tire and line them up with a location on the frame or swingarm, like a bolt, the inside edge of the swingarm, or for our bikes the rubber chainguard on top of the swingarm. Find an equadistant (double word score) point to sight the other side of the wheel (I use the tang for the rear brake hose). Note: Every bike is different. Different tires, frame, swingarm, axle not manufatured to spec or bent.