Grabby brakes

Got a 6-yr-old Sym Wolf/Legend. The problem is when I use the front brake, it feels hard and doesn’t do much up to a certain point, then grabs really hard. Dumped it once because of this in a low speed situation. (Yeah, that was embarrassing, right in an intersection.) I’ve had the brake fluid changed a number of times, most recently when I got a braided SS front brake line put on. Every time the fluid gets changed, the brake feels good for a few weeks, then goes back to this passive aggressive thing. Got an oversize front disk put on a while back; I’m wondering if it’s heating the fluid up more than the pitiful little master cylinder can handle? Maybe using DOT 4 with its higher temp rating would sort the problem out? Or should I just chuck the master cylinder/lever and get a new one?

Sounds like it is your mastercyinder. How old is your mastercylinder? They do go bad sometimes. If you have a SS brake line, and upraded to a bigger disk, might as well upgrade the mastercylinder, and even the caliper. I’ll bet a new mastercylinder will solve your problems. It for sure isn’t the brake oil.

The sliding pins the caliper body moves on could be worn out and or bone dry. Have the caliper dismantled and inspected. If there’s a lot of wear on the pins you will have to replace the caliper. If not, clean and lube with proper high-temp brake grease.
Master cylinders and the slot the lever pivots in often get worn to point where they stick. Replacement is the only solution.

yea for a bike that old, just replace both mastercylinder and caliper. especially if it already caused a crash. you could even ungrade to a RPM unit which would be a bit better than stock and sometimes cheaper. but total for both shouldnt be more than $4000.

Beast, would the average hop-up shop/scooterpunk hangout have the RPM master cyl/calipers?

Yeah probably, considering RPM is a Taiwanese brand. The worse that could happen is you would have to order it, but I think they would carry it.

yea most TUNER shops would have them, or as RK said, they can easily be delivered to your shop in about a day. What city you live in?