Saturday, October 4, 2025

Index - of sorts anyway. Think of it as a guide. 04/10/2025

 Bikes



Clutch


Electrical


Engines and Dyno runs


Exhaust


Maintenance


Suspension



Tuning - Carby

Tuning - Fuel Injection


Moto Guzzi


Cagiva


MV Agusta


Stuff


.
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Ducati 1098 Rear brake disc screws coming out and making a mess

Earlier this year I had a 1098 in for a 12,000km service - it was a bit early, with 9,400 on the speedo - and when I went for the after work road test, just up the road I got a really odd clunk from the rear wheel area.  Figuring I'd better stop and have a looksee, I found one of the rear disc screws come out and making a mess.






On closer inspection, the big circlip that holds the rear brake caliper bracket onto the rear hub snout wasn’t there.  Not even a hint of it.  There’s only one way to get that clip on and off, which involves removing the axle.  If it was going to force its way out otherwise, it’d be leaving some trace for sure.

 Possibly, my work at the service – unbolting the caliper to flush and bleed fluid and refitting it with the pads pushed back – caused the big flat washer to move around as it hadn’t previously, and that brought it into the path of the screw which had wound itself out.  Not sure.  But all the better for finding it out.

When I removed the caliper I could see some damage on the inner side, and the inner pad material just fell off.

So I ordered a new disc screw, big flat washer and circlip, and removed the axle to fit it all up.  Loctited and torqued all the screws in to 25Nm, and fitted it all back up with a new set of pads.

Recently, I had another, with 11,500km on the odo.  Nothing like the previous mess, but it just looked to me like the screws weren't tight enough.

The main issue here is the lack of access. I did manage to get my cut off 5mm hex key in there to at least feel that yes, it was loose. But with no access to tighten properly, let alone remove, re-loctite and refit with torque, the only option is pulling the axle out and sticking it in the vice. Which is really not that hard to do, although you can say that in hindsight when you haven't had to wail the living crap out of the axle to get it out. Certainly had to do that with a few MV over the years.

I did put some black texta marks on 3 of the 4 screws (didn't think of it at first) just to see how much movement I was getting. They are a fine thread M8 torqued to 25Nm, but they were all tighter run by hand than they had been. Looks like a good 30 - 45 degrees, so well worth taking the time to do.




The white paint pen marks should be durable enough longer term to show any future loosening. Not that I expect it to.

Something to be checked for sure.

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Friday, October 3, 2025

Ducati 749 999 fluid bleeders inside the front brake and clutch fluid reservoirs.

If you're servicing a Ducati 749 or 999, there are bleeders inside the front brake and clutch fluid reservoirs to bleed the radial master cylinder. Being radials, they angle up from the fluid entry to the fluid exit, and so trap air at the top.

Just don't open them with the lever pulled in - you'll get wet.
As below. The 6mm black hex in the middle.

Often, the clutch fluid coming out will be quite manky. I fill the reservoir up, then push a few lever pulls of dirty fluid out, stopping once the dirty fluid gets down toward the fluid inlet. Suck all the fluid out, start again. After a few cycles, the fluid being pumped out should clean up nicely.

On the brake side, I push the pads back to force the fluid back through the system into the reservoir. Cracking the bleeder while pushing the pads back will force any air in there straight out into the reservoir.



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