Drivetrain lock-up?

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May 2, 2022
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2006 ST1300
Well it seems it was a short honeymoon with my new-to-me 2006 ST1300A-6 that has 45k on it and a clean pass in February with the MOT. Today, my bike broke down, and it did so so comprehensively I was worried I'd need a crane to get it onto the flat bed breakdown truck. It has me greatly puzzled and not a little worried. It might also have been signalled by some misbehaving a couple of weeks ago.

The initial symptom was as though the brakes were binding, but like, really really binding. Today I was rolling along at 30 or 40mph and the engine braking was much higher than usual: when I let go of the throttle, the bike slowed down very abruptly. I presume, and actually I'm pretty sure, it will have been doing it while on the throttle too, but the engine has enough power and torque to mask some of that. But in the space of a mile or so, it got worse and worse and when I slowed for a junction and dropped to 1st gear, the engine cut out. I could barely get the bike to move once I'd reselected 1st gear. It needed a lot of throttle and a lot of slipping of the clutch to get the bike moving at all, and the noise was awful, a sort of loud clattery noise, and it felt like I was riding through treacle. It took four or five goes of throttle-shuffle-stall-restart to move it a couple of metres at a time, and in the end it was all I could do to get it off the road. Then the engine cut out, and the bike was stuck in 1st gear and wouldn't go into neutral. Even with the clutch pulled in I could barely move the bike, and it took me, plus the less-than-friendly owner of the driveway I was now blocking, to get the bike clear to await the breakdown truck.

With a lot of huffing and blowing and hoiking the bike fore and aft I managed eventually to get it back into neutral. Once on the centre stand, the front wheel spun freely, so it wasn't the front brake binding. And the back wheel spun freely too, so it wasn't the back brake.

What gives? It feels like it's not the clutch that's at fault, but something in the final drive perhaps. I'm concerned the UJ has died an early death, or something has jammed something deep inside the gearbox. Because gosh darn it, the thing really wasn't for moving at all. I had the horrifying thought that perhaps the engine had drained half its oil, but the oil warning light was fine and the engine temperature seemed normal (though I've noticed the fan tends to run a lot of the time in town).

The misbehaving a fortnight ago was that I'd done about 50 miles no problem at all, some motorway riding, quite a bit of smaller roads and traffic. I stopped and parked for a few minutes, and I could hardly push the bike backwards out of the space. I thought first the slope of the ground was just enough to make it difficult, but it really looked level. Then I thought it must be the brakes that were binding, but if they were, they seemed to loosen off after a mile or two.

The bike is now at the Honda garage in town, but it'll be several days before they can investigate and diagnose the damage to my purse. The bike's been - I presume - fairly faultless up until now. It's had a tendency to bog down at idle before it's warmed up, and the revs drop from 1000 to 500 then a bit more and the engine stalls. It's done that a few times and I was going to tinker with the idle adjustment. And though I've yet to fill the tank from empty, the fuel consumption so far has seemed a bit on the high side. Edit: I just remembered that the bike has a tendency, too, to jolt forwards when engaging 1st when the engine's cold. My Africa Twin does it, and my old VFR did it too, though neither perhaps quite as much as the Pan. This afternoon though it really jolted when I was leaving work. Goodness knows it probably broke something.

All of these shenanigans meant that I wasn't able to get to the vet in time to pick up the meds my cat needs. :mad:
 
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Sadlsor

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First thought was an SMC failure, but as I read more of the symptoms I dismissed that idea.
Standing by for the White Courtesy Phone diagnosis... or you could preemptively call Larry / @Igofar .
 
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check the above article out, that is most likely the problem.
 

Mellow

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Yeah SMC would be a high probability.
 
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Arellcat
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If the SMC was all it was, I'd've had them bring the bike back to my house. :confused: But I'm too new to the bike to know it intimately yet. I can take my AT apart in my sleep, almost.
 

Igofar

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Absolutely your SMC has given up the ghost!
You can't remove the rear wheel from being suspect, just because you can turn it after it cools down etc.
If/When your rear wheel locks up, and your unable to move it, take a 8mm spanner and crack open the rearmost bleeder on the rear caliper, this will release pressure in the system, and at least allow you to roll/move the bike off the road or out of harms way.
With a lock up that bad, you should also inspect the rear brake caliper bracket for damage.
The Honda shop may want to start selling you calipers/lines/service etc. however until you inspect/test the SMC, I'd hang on to your money till you find the cause, and not throw solutions at a problem that they may not understand.
Search the Articles, and find John's write up on avoiding the pitfalls, and others with info about the SMC issues.
I'm sure Mr. Heath will be along shortly.
I'll be available to assist you via emails/pictures if you need help, but alas, my white courtesy phone does not reach your side of the pond.
Good luck, keep us posted.
Ring.....Ring...."calling Mr. Heath...
:WCP1:
 

Igofar

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If the SMC was all it was, I'd've had them bring the bike back to my house. :confused: But I'm too new to the bike to know it intimately yet. I can take my AT apart in my sleep, almost.
Rescue your bike, take it back to your house, Mr. Heath and/or myself can describe what needs to be done/inspected etc.
 
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Arellcat
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Wow, you guys are on top of your subject!

"Rescue" is easier said than done; I don't have a car, let alone a trailer. The dealer is only six or seven miles away, but the machine might not make it all the way home before it happens again if I were to try riding it.

Y'know, I did half-suspect the brakes. I stomped on the rear brake pedal several times, and pulled the front brake lever several times, as though I thought something wasn't retracting. I'll swing by the Honda place tomorrow and give them a couple of suggestions about what to check first.
 
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Igofar

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Do you guys have rental cars or vans over there?
Or Home improvement type stores that rent trucks and/or trailers?
I would suggest NOT trying to ride it, as they will/do lock up without any warning, and could cause serious injury or worse.
Figure out how to get it home, and reach out and send a message to Mr. Heath or myself.
We got your back mate.
:thumb:
 

dduelin

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There’s a rear brake dragging thread showing about once a week. It might take a few new parts and two or three pints of brake fluid but it’s easy to set right.
 

jfheath

John Heath
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You say that the back wheel spins OK now - I don't think that it would do that if it was the drive train that was broken. That leaves a locked up brake. A tell tale sign should have been the very distinctive smell of hot metal, possibly accompanied with some smoke. But the quick diagnosis would be to do as Larry suggested and release the fluid pressure in the rear most bleed valve on the rear caliper. If that frees up the wheel, then you have found the cause of the problem. There's more work to do to find the solution that is required though.

You're in the UK. I can send you my phone number if you want to talk things through. In the meantime here are the links to articles that have been mentioned. Unfortunately I am about 4 and a half hours drive away from you - in West Yorkshire. But phone calls are cheap enough. Send me a PM. Response may be slow over the next 3 days - I'm out and about during the days.

Avoiding the pitfalls.




Getting air out of the braking system. You don't need this for the purpose for which it is intended (yet), but it has some nice coloured diagrams which break down (sic) the different sections of the brake system and make it easier to understand.



SMC stuff - again, unnecessary for what you want at the moment - but these two links show you the problems with a poorly maintained Secondary Master Cylinder (SMC)

When the brake lever / pedal is released, the fluid that applied pressure to the brakes has to retreat - and for the rear caliper it has to retreat through the Secondary Master Cylinder and also through the main master cylinder for the rear pedal. And if it has not been cared for, the SMC is the chief culprit in preventing fluid from escaping back to the reservoir - resulting in locked brakes. The photos will make you see why. It doesn't have to be like this - all it needs is a bit of care, time and know-how.



-------------

The jolting when setting off is possibly the same reason that you have rear wheel drag. My guess is that the previous owner shied away from all things hydraulic. The first thing to do would be to flush and bleed the clutch line, and check the clutch lever for correct installation and operation.
 

Gus1300

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Following with interest...I have a new SMC on the shelf but haven't replaced my '04's original yet. I do give it the 'spin the rear wheel with your foot while activating the SMC' ops test occasionally to see if it's still working. These two lines:

Even with the clutch pulled in I could barely move the bike
the fuel consumption so far has seemed a bit on the high side
led my by no means expert mind to think that it was in fact something associated with the wheels (brakes...SMC) rather than the drive train. I'll be watching and eating popcorn while waiting on the diagnosis. Don't be afraid to wrench on your bike! The gang here is more than helpful, and while your local dealer may be well intentioned, I doubt they have the depth of knowledge this forum does!
 
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The ST Brake and Company is on the mark with all the suggestions on here Becky.
Get your bike home or hand over the articles that describe your problem to your favorite Honda guy.
Igofar and Mr. Heath are your top notch brake specialist's on here, heck in the world.
Great response from you guys.
 
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Arellcat
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Just to come back to this thread for a moment, I am rapidly losing faith in the general safety of the bike. A machine that is so intolerant of maintenance is not just highly strung, it's a liability. I don't say this as a motorbike rider, I say this as a mechanical engineer.

I'm also increasingly frustrated with my Honda garage. They had to replace the clutch because the plates were burned during the lock-up and it wouldn't disengage. Fair do's, but that was money I didn't expect to spend. They also noted the SMC was airlocked with far more than the expected movement, so they did a full re-bleed of the system, test rode it and pronounced the bike good. The dragging rear brake continues. It somehow didn't manifest during their test ride, but did a couple of times during my fairly short ride home. I had them take the bike back for another look and they gave me a story of how the fluid "isn't returning properly and maybe it's the rear master cylinder or the SMC or it could be a blockage in the pipes or maybe it's the PCV and, y'know that's not a servicable part and £££ and we weren't asked to look deeper into any faults..." I shan't name the garage but I was prepared to give them the benefit of the doubt, and I'm now running out of goodwill.

I'm going to take the bike home, armed with my 8mm spanner, as I have better things to spend my money on right now, and better things to do with my annual leave. After it taking six hours to change the oil and filter on my AT the other day because the sump plug and the old filter had been put on by a gorilla, and the filter wrench Halfords sold me only punched a hole in it, I have currently had enough of motorbikes!
 
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Louisiana
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Just to come back to this thread for a moment, I am rapidly losing faith in the general safety of the bike. A machine that is so intolerant of maintenance is not just highly strung, it's a liability. I don't say this as a motorbike rider, I say this as a mechanical engineer.

I'm also increasingly frustrated with my Honda garage. They had to replace the clutch because the plates were burned during the lock-up and it wouldn't disengage. Fair do's, but that was money I didn't expect to spend. They also noted the SMC was airlocked with far more than the expected movement, so they did a full re-bleed of the system, test rode it and pronounced the bike good. The dragging rear brake continues. It somehow didn't manifest during their test ride, but did a couple of times during my fairly short ride home. I had them take the bike back for another look and they gave me a story of how the fluid "isn't returning properly and maybe it's the rear master cylinder or the SMC or it could be a blockage in the pipes or maybe it's the PCV and, y'know that's not a servicable part and £££ and we weren't asked to look deeper into any faults..." I shan't name the garage but I was prepared to give them the benefit of the doubt, and I'm now running out of goodwill.

I'm going to take the bike home, armed with my 8mm spanner, as I have better things to spend my money on right now, and better things to do with my annual leave. After it taking six hours to change the oil and filter on my AT the other day because the sump plug and the old filter had been put on by a gorilla, and the filter wrench Halfords sold me only punched a hole in it, I have currently had enough of motorbikes!
 

Sadlsor

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You make the case for doing the work yourself.
I DO understand not everyone has the tools,the space, the time or even the confidence to do this, but the rewards for many of us is much more than worthwhile. Safety? If that's a real concern then do it yourself (with our help!) so it won't be a worry for you.
It's been pointed out many times here, that many our most Honda techs today have never seen a live ST in the flesh.
But nearly ALL of us here have.
And do not forget these same bikes have racked up literally millions of miles over a roughly 20yr span, including being the perennial darling of the Iron Butt crowd, even after it was discontinued.
So, yea some may have problems, and no they don't take kindly to neglect, particularly the clutch slave and your (and my own) SMC.
None of this discounts the longevity nor dependability of this model.
I'm not alone - obviously! - in this sentiment.
Sorry for your troubles, but they CAN be fixed. Maybe not at a Honda dealer, though, ironically.
 

V4 Rider

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If you mean a Honda dealership in the same city as your home location I personally would not trust them to do any mechanical work.

They have even got fitting tyres to loose wheels wrong.

Re filter on AT the ones Honda supply as a filter and tool set (search David Silvers) has never let me down.
 
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Just to come back to this thread for a moment, I am rapidly losing faith in the general safety of the bike. A machine that is so intolerant of maintenance is not just highly strung, it's a liability. I don't say this as a motorbike rider, I say this as a mechanical engineer.

I'm also increasingly frustrated with my Honda garage.
The SMC has very small passages that are easily blocked, and gradual or intermittent lockups have been discussed here. ST's are quite reliable and few see the dealerships for service. The consequence is very few mechanics ever have more than a passing acquaintance with them and cannot diagnose problems quickly and correctly. It is very possible, if not probable that you have some damage to the rear disk/caliper as @Igofar mentioned.

As far as ST's being intolerant of maintenance, how many 16 year old machines tolerate neglect and infrequent maintenance and exhibit no problems? The guys here who do regular maintenance have experienced few problems with their SMC's, however ignoring basic procedures will shorten virtually any component's life.

Your best bet is to get the bike home (you can take apart your AT in your sleep so you are well acquainted with tools) and phone @jfheath to discuss your problem.

Have a drink of your choice, relax, and then come back to bikes.
 
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Arellcat
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Postscript. The workshop manager had checked the caliper and found it was OK, though I think he said the outer pistons retracted together, or not together, or something. I didn't quite follow him. He suggested I avoid using the back brake while I rode home, but otherwise it'd probably be ok. So I did. I babied it, and the bike ran fine for about two miles, then the rear brake dragged again, then all but locked up again, exactly the same behaviour as what led to the whole situation a month and more ago, so I pulled over straight away. The caliper and disc were smoking hot, as I suspected. I was glad for my 8mm spanner – thanks, Igofar – and a nice little squirt of fluid out of the caliper freed it up temporarily. Somewhat remarkably I was able to ride the rest of the way home almost without touching even the front brake.

I know things will improve once I have wrapped my head around the braking circuit. I appreciate the knowledge in this forum, and I fear that it rather exceeds my vacillatory enthusiasm.
 
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