Rear brake middle piston dragging
- Thread starter Jonnyboy750
- Start date
Terry,I have to applauded you. Still haven’t bled it yet but believe me I know when someone is knowledgeable @nd is Actualy on your side. I have been reading up on all the other comments.well your comments are certainly appreciated. When I got as deep as the blue clip the heavens opened up and I knew your every word is gospel.without your guidance I might have not gone in so deep. At least now I feel good about it. I wonder if I could get your opinion on fuel gauges? I fill mine up and watch the fuel 
bars go down till I get to reserve. Flashing one bar. I take note of the fuel mileage left. If I pull over and take knots how many miles left turn it off,come back switch it on the remaining mileage is not the same as it was before I turned it off. So I perciveer and ride and it says I have more mileage left then run out of gas.I replaced the fuel gauge in the tank.still the s@me.
bars go down till I get to reserve. Flashing one bar. I take note of the fuel mileage left. If I pull over and take knots how many miles left turn it off,come back switch it on the remaining mileage is not the same as it was before I turned it off. So I perciveer and ride and it says I have more mileage left then run out of gas.I replaced the fuel gauge in the tank.still the s@me.
I should point out that I am far from a perfessional mechanic, just an enthusiastic amateur. Actually I do know lots about wood preservation, and get involved in fault finding and process improvement often!
The low level fuel thermistor is actually separate to the float gauge, and is attached to the fuel pump bracket in the lower tank. I've not seen the 1300 sensor but on my 1100 it was a small vertical cylinder about 1cm diameter, I believe it senses the cooling effect when immersed in fuel and triggers the flashing last bar when it is exposed, at which point you should have something like 5L remaining. The sensor is connected to the brown/black wire. Thinking about the separation between the first 7 segments and the last, that probably explains why the 2nd to last bar either lasts longer or much shorter that you may expect. My bike certainly sits on the 2nd bar for longer than I expect it to, based on the rate of the previous bars.
Each time the low sensor is triggered, the ECU calculates mileage remaining based on your average consumption over the last 20 minutes. I assume that the system resets whenever the ignition is cycled on/off, so the ECU is assuming you've just hit reserve when you re-start, even though you've used up part of the reserve already, and recalculates the remaining mileage assuming you have the full reserve. What you describe sounds like the system doing its normal thing. So a feature, not a bug.
Morale of the story: treat the remaining mileage when you first hit reserve as a good guide, but if you don't fill up before the next re-start, don't trust it.
The service manual does point out that:
The low level fuel thermistor is actually separate to the float gauge, and is attached to the fuel pump bracket in the lower tank. I've not seen the 1300 sensor but on my 1100 it was a small vertical cylinder about 1cm diameter, I believe it senses the cooling effect when immersed in fuel and triggers the flashing last bar when it is exposed, at which point you should have something like 5L remaining. The sensor is connected to the brown/black wire. Thinking about the separation between the first 7 segments and the last, that probably explains why the 2nd to last bar either lasts longer or much shorter that you may expect. My bike certainly sits on the 2nd bar for longer than I expect it to, based on the rate of the previous bars.
Each time the low sensor is triggered, the ECU calculates mileage remaining based on your average consumption over the last 20 minutes. I assume that the system resets whenever the ignition is cycled on/off, so the ECU is assuming you've just hit reserve when you re-start, even though you've used up part of the reserve already, and recalculates the remaining mileage assuming you have the full reserve. What you describe sounds like the system doing its normal thing. So a feature, not a bug.
Morale of the story: treat the remaining mileage when you first hit reserve as a good guide, but if you don't fill up before the next re-start, don't trust it.
The service manual does point out that:
I have put her all back together,she seems fine. I took it for a test ride,she seems to do what she is supposed to. I decided to Realy hammer the a.b.s. Leaving long black lines up the road. Just jamming them on full from fifty k.p.h. No issues at all. The brakes heated up Realy hot. I rode home and they cooled off on the highway. All seems fine. Checking her over I believe the rear brake is no longer dragging. Thank you. However could you put my mind to rest. I put her on the centre stand and applied the rear she stoped spinning. Spun the rear tyre and applied the front brake solid but no stoping the tyre.not what I expected. Is this normal?
Kevcules
Site Supporter
The rear tire brakes are activated if the front tire is turning (while riding) while pulling the front brake lever, or while on the center stand, if you lift up on the SMC (front left caliper) while your rear tire is turning. The SMC activates the rear brakes.
It does not sound like you understand the brake system, which concerns some of us, since you’ve already opened up the system in ways that you should not have done per Honda.
I direct you to read John Heaths article on avoiding the pitfalls, as this may held you understand.
The front brake lever will only activate the SMC when the vehicle is in motion.
As far as you jamming on the brakes, even then, the rotors should not have gotten as hot as your description, and it would have cooled down quickly, without having to ride it for a ways etc.
I suspect you have more issues going on than you realize.
Be careful riding your bike till you sort things out correctly and/or replace damaged parts.
I direct you to read John Heaths article on avoiding the pitfalls, as this may held you understand.
The front brake lever will only activate the SMC when the vehicle is in motion.
As far as you jamming on the brakes, even then, the rotors should not have gotten as hot as your description, and it would have cooled down quickly, without having to ride it for a ways etc.
I suspect you have more issues going on than you realize.
Be careful riding your bike till you sort things out correctly and/or replace damaged parts.
Hey I don’t appreciate your opinion.I never asked you to scare me to death! I have learned such a lot from this forum all good knowledge.why don’t you reply just what I asked? Forget the rhetoric try hammering your own a.b.s. And be aware just how inspiring it is.It impressed me sure it got hot stoping over and over again never locked up and yet hovering on the border of traction was inspiring. Now I have apsolute confidence in stoping ,No I never abused her this way before but knowing what’s possible is inspiring. All I asked was for you to reply THATS NORMAL or not I never asked you to insult me .
I should point out that I am far from a perfessional mechanic, just an enthusiastic amateur. Actually I do know lots about wood preservation, and get involved in fault finding and process improvement often!
The low level fuel thermistor is actually separate to the float gauge, and is attached to the fuel pump bracket in the lower tank. I've not seen the 1300 sensor but on my 1100 it was a small vertical cylinder about 1cm diameter, I believe it senses the cooling effect when immersed in fuel and triggers the flashing last bar when it is exposed, at which point you should have something like 5L remaining. The sensor is connected to the brown/black wire. Thinking about the separation between the first 7 segments and the last, that probably explains why the 2nd to last bar either lasts longer or much shorter that you may expect. My bike certainly sits on the 2nd bar for longer than I expect it to, based on the rate of the previous bars.
Each time the low sensor is triggered, the ECU calculates mileage remaining based on your average consumption over the last 20 minutes. I assume that the system resets whenever the ignition is cycled on/off, so the ECU is assuming you've just hit reserve when you re-start, even though you've used up part of the reserve already, and recalculates the remaining mileage assuming you have the full reserve. What you describe sounds like the system doing its normal thing. So a feature, not a bug.
Morale of the story: treat the remaining mileage when you first hit reserve as a good guide, but if you don't fill up before the next re-start, don't trust it.
The service manual does point out that:
Terry,could you please check your bike for me? With her on the centre stand ,spinning the rear wheel and applying the front brake lever it surprised me that although solid it never slowed the rear wheel.a simple yes it’s normal or that’s not right will do it for me. I trust your reply. I doubt you will lambaste me for not understanding how the system works.Thanks
Wow....I don't even have any words for your reply.
I'm sure nobody meant to offend or scare you, and I'm sorry you feel that way.
With no disrespect to Terry, for him offering HIS advice, (sharing our experiences is how we learn and help each other) however, by his own statement (far from a professional mechanic, just an enthusiastic amateur ) he suggested to NOT follow the correct method(s) as suggested by Honda as outlined in Their service manual, and even went against some warnings in the service manual. He even stated how some of his methods/attempts damaged things etc. While results may/could vary with following instructions as such, it sounds like in your eyes that he was a Hero, and his advice was Gospel (your words) because he was suggesting/or agreeing with something that you wanted to try.
I would think that you would probably be safer off following the Service manual's advice and instructions, over anyone's suggestions/advice on any forum (mine included). And if you don't understand how the system works, and why the front lever would not have any affect on the rear wheel, when the bike was not in motion, perhaps you should consider taking it to a dealership or someone with experience in this bike's brake system.
I guess my comments/suggestion to you were out of concern for safety, and not meant to scare you, or disagreeing with what you thought.
A brake system failure can cause serious damage or worse, I always try to err on the side of safety, and not cut corners or take short cuts.
Sorry you didn't like what I had to say. Don't believe everything you think. It was just MY opinion and nothing more.
Ride safe.
I'm sure nobody meant to offend or scare you, and I'm sorry you feel that way.
With no disrespect to Terry, for him offering HIS advice, (sharing our experiences is how we learn and help each other) however, by his own statement (far from a professional mechanic, just an enthusiastic amateur ) he suggested to NOT follow the correct method(s) as suggested by Honda as outlined in Their service manual, and even went against some warnings in the service manual. He even stated how some of his methods/attempts damaged things etc. While results may/could vary with following instructions as such, it sounds like in your eyes that he was a Hero, and his advice was Gospel (your words) because he was suggesting/or agreeing with something that you wanted to try.
I would think that you would probably be safer off following the Service manual's advice and instructions, over anyone's suggestions/advice on any forum (mine included). And if you don't understand how the system works, and why the front lever would not have any affect on the rear wheel, when the bike was not in motion, perhaps you should consider taking it to a dealership or someone with experience in this bike's brake system.
I guess my comments/suggestion to you were out of concern for safety, and not meant to scare you, or disagreeing with what you thought.
A brake system failure can cause serious damage or worse, I always try to err on the side of safety, and not cut corners or take short cuts.
Sorry you didn't like what I had to say. Don't believe everything you think. It was just MY opinion and nothing more.
Ride safe.
Last edited:
You probably won't appreciate my opinion either but I'll give it anyway. People like Igofar are trying to help you resolve the issues with your bike - free of charge. He's arguably one of the most qualified people to give you advice on this forum. And from personal experience, far more qualified than your average Honda dealer mechanic.
You don't have to like or accept anyone's advice here...and that's perfectly ok if you don't. Just skip past those posts if you feel that way. No need to call anyone out because you don't like their opinion.
The front lever has no effect on the back brake at a standstill. The reason that it does when rolling is that the calliper is pulled forward by the moving disc, and that compresses the SMC piston and activates the back brake. So your experience is normal.
- Joined
- May 27, 2021
- Messages
- 1,027
- Age
- 63
- Location
- Coquitlam British Columbia Canada
- Bike
- 2009 ST1300
no good deed goes unpunished; I think someone's just trying to save you from a bad outcome. There's potential for serious problems with these systems and I think the point is they need to be understood, obviously you're satisfied enough but in some instances lives have been spared by some of the guys on this site expressing their opinions.
You can lead a horse to water 
Sad thing is, a couple months ago, I had the same conversation with an ST owner, who purchased a garage queen with low miles, that had been sitting (Covid bike) and he was having the same issues with his brakes, and just like our friend here. He didn't want to spend the time or money to do the job correctly, and decided to take apart the SMC and clean it out. He watched a couple Youtube Certified Mechanics, and their videos, opened things up, tore a hole in the screen, damaged some parts, put it back together wrong, and tried to bleed the system without fully understanding what he was doing.
Well I get a call about a month after our conversation, explaining that his brake system completely locked up without warning while on a cross country trip.
It cost him over $300 dollars for a tow bill, motel bills, and had to cancel his trip. It completely destroyed his rear rotor, rear caliper, rear brake line(s), rear caliper bracket, pads, secondary master cylinder, and almost cost him a pretty serious accident since he was exiting the highway when his bike decided it wanted to lock up and stop right then and there without warning etc.
It was a very costly lesson.
He ended up spending more than he purchased the bike for in parts/labor/bills, but considered himself very lucky that he didn't go down and get run over by a truck.
If this guy thinks I was trying to scare him, perhaps I should have had this other guy contact him
Some folks you can teach to slip a punch, while others will just get smacked in the face eventually, then be completely surprised and wonder why that happened.
I hope his brakes never fail him.
Sad thing is, a couple months ago, I had the same conversation with an ST owner, who purchased a garage queen with low miles, that had been sitting (Covid bike) and he was having the same issues with his brakes, and just like our friend here. He didn't want to spend the time or money to do the job correctly, and decided to take apart the SMC and clean it out. He watched a couple Youtube Certified Mechanics, and their videos, opened things up, tore a hole in the screen, damaged some parts, put it back together wrong, and tried to bleed the system without fully understanding what he was doing.
Well I get a call about a month after our conversation, explaining that his brake system completely locked up without warning while on a cross country trip.
It cost him over $300 dollars for a tow bill, motel bills, and had to cancel his trip. It completely destroyed his rear rotor, rear caliper, rear brake line(s), rear caliper bracket, pads, secondary master cylinder, and almost cost him a pretty serious accident since he was exiting the highway when his bike decided it wanted to lock up and stop right then and there without warning etc.
It was a very costly lesson.
He ended up spending more than he purchased the bike for in parts/labor/bills, but considered himself very lucky that he didn't go down and get run over by a truck.
If this guy thinks I was trying to scare him, perhaps I should have had this other guy contact him
Some folks you can teach to slip a punch, while others will just get smacked in the face eventually, then be completely surprised and wonder why that happened.
I hope his brakes never fail him.
- Joined
- May 27, 2021
- Messages
- 1,027
- Age
- 63
- Location
- Coquitlam British Columbia Canada
- Bike
- 2009 ST1300
The bike is some eight hundred pounds, cresting a hill, decelerating only a bit, doing over 80 miles an hour, the center of gravitity rolls from the lower rear, over the middle toward the front, while the rear caliper fails to disengage cleanly. That can be a problem, glad you mentioned it, if for no one else but me, at least I was told.