Subject: weird click when slow speed braking Sat Jun 03, 2023 10:38 am
I've been noticing this during city riding, as I bring the brakes to maximum effect and the bike weight moves forward I can hear a loud click and feel it in my palms as well...
No other handling issues. Bearings were re-packed with grease about 2 years ago.
I'll get it on the ramp when I have time and check for any play with the front wheel raised when I can find some time. Just thought I'd check here if there's anything model specific to look out for
just thought, I also have adjustable Jota handlebars, maybe they're flexing a bit?
Pete Roper GRiSO Capo
Posts : 10711 Join date : 2013-05-29 Age : 67
Subject: Re: weird click when slow speed braking Sat Jun 03, 2023 3:42 pm
Discs moving on the bobbins? Head bearings loose?
Lazlokovacs Don Abbondio
Posts : 310 Join date : 2015-08-20
Subject: Re: weird click when slow speed braking Sat Jun 03, 2023 4:28 pm
I freewheeled down a big hill and compressed the front forks a few times while braking with one hand on the frame neck, (I was wearing full PPE honest!) and yes, I think it's loose head bearings. the nut might have slackened off when I dropped the bike a few months ago?
I've been putting off a fork oil change for a while, so I guess I'll do it all in one go.
Got a big trip coming up so would like everything to be sorted.
Pete Roper GRiSO Capo
Posts : 10711 Join date : 2013-05-29 Age : 67
Subject: Re: weird click when slow speed braking Sat Jun 03, 2023 5:42 pm
Get the front wheel off the ground and hold the forks straight by their bottoms and pull them fore and aft in line with the axis of the bike. Watch the bottom yoke carefully in relation to the frame, any discernible movement is too much!
If there is play the bearings will probably need replacing but you can try just tightening them down to remove the float. You need to remove the handlebars and top yoke which is a bit of a palaver but not difficult and that will give you access to the two head stem nuts which are locked together with a tab washer in between. Bend down the tabs to the upper nut and loosen it off and then tighten the bottom nut until all the free play is out of the stem bearings. At that point you can rock the forks from lock to lock and feel for notches or tight spots. If there are any then the bearings need replacing and the whole front end has to come out. Chances are by now the bearings will be fairly crusty anyway so I'd bank on changing them.
If you're lucky and they're OK you can just tighten down the upper lock nut and bend up the locking tabs on the washer. Problem is the washer only has four tabs so it's often impossible to do this! It's a weirdly inadequate system! If that is the case a drop of Loctite 'Super wick-in' dripped onto the top of the threads will assist but what really keeps the nuts from moving is the top yoke being pressed down firmly on it by the decorative stem nut at the top. This is why it's important not to tighten the upper yoke pinch bolts on the fork tubes before you have tightened down the stem nut. If you do that the yoke can't compress down onto the locknuts and prevent them from moving and the bearings will loosen off again.
lcjohnny likes this post
Lazlokovacs Don Abbondio
Posts : 310 Join date : 2015-08-20
Subject: Re: weird click when slow speed braking Sun Jun 04, 2023 2:00 am
thank you so much for that post.
sounds like there's enough model specific weirdness in there that things could've gone quite wrong.
looking at the parts book right now, looks like the tedious bit is removing the handlebars etc
Nobleswood GRiSO Capo
Posts : 583 Join date : 2016-12-20
Subject: Re: weird click when slow speed braking Sun Jun 04, 2023 4:33 am
After last year having a slide on fine gravel, I had noticed the bike not being as stable & confidence inspiring as before. Slowly I worked through what I should be checking & came to check the head bearings.
As Pete said getting the handlebars & dash loose are awkward but doable. In my shed I could arrange a way to undo the bars & keep them pulled up & out of the way which helped, with an overhead beam & cord.
In my case, the bearings were still good & greased from the last service but releasing the top yoke & re-aligning the forks, as everything was put back together, solved the stability issue.
The most difficult part of the work was getting the bike up, braced & getting to the bearings. Worth doing
Lazlokovacs Don Abbondio
Posts : 310 Join date : 2015-08-20
Subject: Re: weird click when slow speed braking Tue Jun 06, 2023 2:41 am
the plot thickens... no discernable play with the front wheel up. All feels very nice in fact...
however, If I get someone to apply the front brake and move the wheel, I get a huge clicking from the discs. Is this normal? Is it possible that the floating discs are floating too much or too far???
wheel bearings seem good
Pete Roper GRiSO Capo
Posts : 10711 Join date : 2013-05-29 Age : 67
Subject: Re: weird click when slow speed braking Tue Jun 06, 2023 2:44 am
Yup, as I mentioned before, the disc bobbins and discs are rooted.
Lazlokovacs Don Abbondio
Posts : 310 Join date : 2015-08-20
Subject: Re: weird click when slow speed braking Tue Jun 06, 2023 5:44 am
well, that's kind of good news, 26000kms is that normal life expectancy? Its a heavy bike I guess
Pete Roper GRiSO Capo
Posts : 10711 Join date : 2013-05-29 Age : 67
Subject: Re: weird click when slow speed braking Tue Jun 06, 2023 10:19 am
It really depends on how you ride and how much and how hard you use the brakes. I see and have replaced a lot of discs on many bikes but have never had to do so on one of my own. The only thing I can put this down to is my riding style where I use the brakes very little and rarely hard unless it's an emergency situation.
Lazlokovacs Don Abbondio
Posts : 310 Join date : 2015-08-20
Subject: Re: weird click when slow speed braking Tue Jun 06, 2023 10:43 am
I will plead guilty to the charge of grossly over using my front brake as it's just such a pleasure to do so with the brembo radial MC and the maxton front forks!!!
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Oz1200Guzzi Don Abbondio
Posts : 6086 Join date : 2014-03-13 Age : 69
Subject: Re: weird click when slow speed braking Tue Jun 06, 2023 4:24 pm
This is a known issue with the brakes on the CARC bikes. My theory is that the bobbins are way too tight to start with and don't float properly, leading to pad material buildup on the rotors. This causes vibrations.
A common fix was to put a bolt through the bobbin and rotate it with an electric drill and lubricated by some brake cleaner. As others (and myself) have done, too much of this is not a good thing and leads to sloppy bobbins. This starts off with a rattle/click and will eventually lead to the bobbin wearing out the aluminium spider works that house the bobbins. Once this happens, the disks will deteriorate very quickly.
I think this is more common in the wave type disks, rather than the round type - this may be my pure conjecture too!