03-26-2020, 01:32 PM
FYI, this is the content from a post I made over on the Hawk GT Forum many years ago...
I picked up my Hawk a couple of years ago. It's an '88 model, all stock, and about as clean as can be, just beautiful to look at. I was pretty happy to find it.
However, like yours, my Hawk had been sitting for an extended period of time and the brakes needed some attention. My front brakes ended up locking up - fortunately I could tell something was up and had slowed down to a crawl, the bike and I were both unharmed.
In my case, it turns out that the front master cylinder needed to be cleaned out really good. The fluid had started to turn to crud and the tiny return hole had clogged up. In addition the cylinder surface needed to be polished (I used some really fine steel wool attached to a short length of plastic tubing attached to a drill). I would have never suspected it when first looking the bike over. I've read of others here having the same problem as well. Just be sure to look everything over well before you really start racking up the miles. I know that I'll be sure to dig through things more thoroughly should I buy another used bike.
What is interesting is that when I first got home from Seattle where I had bought the Hawk, my buddy (who had a truck and drove) had backed into our driveway so I could just roll the bike out of the bed, down the ramp, and then into the garage. Of course it was a beautiful warm June day and a number of my neighbors were outside and watching everything. After loosening and removing the tie-downs, the bike would not budge — at all. The front wheel was completely locked up. Since my neighbors were watching I couldn't throw my normal pissy-fit. Realizing it might take me a while to figure out what was going on, I went inside to get a couple of cold beers for my buddies who had travelled to Seattle and back with me that weekend. I figured it was the least I could do, especially as I wasn't exactly sure how long it would take me to come up with a solution that would not make me look like a bigger idiot than I already did — or one that would risk eventually dumping the bike over. By the time I got back up in the bed of the truck to check things over again, the front wheel rolled just like normal again, easy peasy.
The eventual front brake lock-up event made for a good story as well. I had been working to get everything working just right on the bike and had already rebuilt the carbs. The front brake issue was the next big thing that I was trying to take care of. I had had the bike out for a few short test rides when I was working on the carbs and I could feel pressure building up in the front brake lever if I rode far enough (and I was not going far at all). On that day when I started looking into the brake issue I cold feel the lever had almost no travel at all so I slowed the bike to a crawl. I mean really slow.
What was funny was that one of the other projects I had on my list was to replace the tires as those that came with the bike were pretty old. So when the front brake locked up completely I was not exactly aware that it had happened until the bike itself got super squirrely. By the time I had figured it out it was too late, the bike was already starting to fall to the left (fortunately I was almost hugging the curb on the right side of the street by then). Since I knew the bike (my brand new to me dream Hawk!) was going down, I ended up sacrificing myself and brought it down sort on top of my like one of those rodeo cowboys bringing down a calf by it's horns (although I was much more gentle with my motorcycle). The bike ended up fine, without a singe scratch on it. I nicked my helmet up just a tiny bit as I ended up doing a full roll like a kid in gymnastics class. It all happened in super-slow motion. My leather jacket didn't even have a mark on it.
I looked around to see if any of my neighbors had seen me and no one appeared to be outside. I managed to get the Hawk upright and the kickstand down. Then I walked back around the block to my house to get a wrench so that I could crack the bleeder valve open just enough free some pressure on the calipers. Then I pushed the bike back home. I figured out in my case that it did not take much heat at all to cause the brake fluid to expand. With the tiny return orifice closed off, the only place the fluid had to go upon expanding was into the caliper's piston cylinders. Eventually things would get bad enough that the front wheel would lock up.
It was a very good lesson learned, and as it turns out, my experience has proved to be helpful more than once in helping people diagnose braking problem where they ended up in the same situation as 2017EX (and myself of course).
I picked up my Hawk a couple of years ago. It's an '88 model, all stock, and about as clean as can be, just beautiful to look at. I was pretty happy to find it.
However, like yours, my Hawk had been sitting for an extended period of time and the brakes needed some attention. My front brakes ended up locking up - fortunately I could tell something was up and had slowed down to a crawl, the bike and I were both unharmed.
In my case, it turns out that the front master cylinder needed to be cleaned out really good. The fluid had started to turn to crud and the tiny return hole had clogged up. In addition the cylinder surface needed to be polished (I used some really fine steel wool attached to a short length of plastic tubing attached to a drill). I would have never suspected it when first looking the bike over. I've read of others here having the same problem as well. Just be sure to look everything over well before you really start racking up the miles. I know that I'll be sure to dig through things more thoroughly should I buy another used bike.
What is interesting is that when I first got home from Seattle where I had bought the Hawk, my buddy (who had a truck and drove) had backed into our driveway so I could just roll the bike out of the bed, down the ramp, and then into the garage. Of course it was a beautiful warm June day and a number of my neighbors were outside and watching everything. After loosening and removing the tie-downs, the bike would not budge — at all. The front wheel was completely locked up. Since my neighbors were watching I couldn't throw my normal pissy-fit. Realizing it might take me a while to figure out what was going on, I went inside to get a couple of cold beers for my buddies who had travelled to Seattle and back with me that weekend. I figured it was the least I could do, especially as I wasn't exactly sure how long it would take me to come up with a solution that would not make me look like a bigger idiot than I already did — or one that would risk eventually dumping the bike over. By the time I got back up in the bed of the truck to check things over again, the front wheel rolled just like normal again, easy peasy.
The eventual front brake lock-up event made for a good story as well. I had been working to get everything working just right on the bike and had already rebuilt the carbs. The front brake issue was the next big thing that I was trying to take care of. I had had the bike out for a few short test rides when I was working on the carbs and I could feel pressure building up in the front brake lever if I rode far enough (and I was not going far at all). On that day when I started looking into the brake issue I cold feel the lever had almost no travel at all so I slowed the bike to a crawl. I mean really slow.
What was funny was that one of the other projects I had on my list was to replace the tires as those that came with the bike were pretty old. So when the front brake locked up completely I was not exactly aware that it had happened until the bike itself got super squirrely. By the time I had figured it out it was too late, the bike was already starting to fall to the left (fortunately I was almost hugging the curb on the right side of the street by then). Since I knew the bike (my brand new to me dream Hawk!) was going down, I ended up sacrificing myself and brought it down sort on top of my like one of those rodeo cowboys bringing down a calf by it's horns (although I was much more gentle with my motorcycle). The bike ended up fine, without a singe scratch on it. I nicked my helmet up just a tiny bit as I ended up doing a full roll like a kid in gymnastics class. It all happened in super-slow motion. My leather jacket didn't even have a mark on it.
I looked around to see if any of my neighbors had seen me and no one appeared to be outside. I managed to get the Hawk upright and the kickstand down. Then I walked back around the block to my house to get a wrench so that I could crack the bleeder valve open just enough free some pressure on the calipers. Then I pushed the bike back home. I figured out in my case that it did not take much heat at all to cause the brake fluid to expand. With the tiny return orifice closed off, the only place the fluid had to go upon expanding was into the caliper's piston cylinders. Eventually things would get bad enough that the front wheel would lock up.
It was a very good lesson learned, and as it turns out, my experience has proved to be helpful more than once in helping people diagnose braking problem where they ended up in the same situation as 2017EX (and myself of course).