General Bearing Condition Question

[gregwils]

The bearings on the clutch basket feel pretty gritty, not the buttery smooth feeling of a new bearing. My question is do these bearing wear or get dirtier faster than other bearings in the motor or would it be reasonable to conclude all the bearings in the motor are in similar condition - i.e. gritty or worn feeling? I think I know the answer, but before tearing the entire motor down, thought I would ask. Thanks.

[Dave450]

do these bearing wear or get dirtier faster than other bearings in the motor or would it be reasonable to conclude all the bearings in the motor are in similar condition - i.e. gritty or worn feeling?

In my experience, they don't necessarily reflect the condition of all the bearings in the motor, and I have seldom had to replace them in all the years I have had mine. The cam support bearing in the cam cap seems to last a long time, and the same with the self aligning bearings in the bevel train. In my teardowns, the gearbox bearings seemed to wear more than the main bearings. Since you have the primary cover off, how does the crank outrigger bearing feel? I only once heard a main bearing on its way out on a single, and it was a distinct whine.

If you are disinclined to strip the motor just because you suspect the other bearings, change the oil frequently and run a magnet through the oil. Look for bright, shiny, magnetic particles which could indicate a bearing breaking up. You can also have a look inside the cambox covers to inspect the cam lobes. The big end is the most vulnerable bearing in the engine. I have once removed the plug for the centrifugal filter in the crank with the crankcase undisturbed, and used a vacuum cleaner to suck out the debris, but I generally wouldn't recommend this without a strip down, in case you missed a bit of sludge and it blocked an oilway.

How long was it since the last major rebuild? And did you replace all the bearings the last time?

Dave

[Nick]

There used to be someone out there making magnetic drain plugs for the singles. You could also fab your own by drilling a recess in the stock plug and epoxying in a small magnet.

If you just got the bike and don't know how it was cared for it's always a good idea to do a few quick oil changes to flush things out.

[ducwiz]

The bearings inside the clutch basket are uncritical, as they are going to spin only when you pull the clutch lever. For me, it was allways sufficient to flush them thoroughly. After that, the gritty feelin was mostly gone.

cheers

[gregwils]

Thanks. I actually have two 160 motors, one that came with the bike and one purchased recently. I was hoping to put the original motor back in the bike without the rebuild and ride it next summer, then rebuild the newly purchased motor, then swap them while I rebuild the original. The rebuilds are just for fun.

I think I will flush the motor to the best of my ability and proceed with my plan. I like the idea of pulling the head and p/c, then removing the sludge traps. I have a few questions. I attached a photo from the 2nd engine that I purchased showing the bottom of the crank. Should the smaller opening have some for of plug or should it be open as shown? Should I be able to unscrew the plug in the larger opening with a screw driver and some leverage? Does anyone know the direction of the oil flow through the crank? Thanks for thoughts and sharing your knowledge.

[ducwiz]

Greg,

the smaller "opening" is nothing but a drill hole. It was applied to take some mass off the flywheel, for counterbalancing purposes.
The threaded plug for the sludge trap in principle can be opened as you described. Prior to any attempt one has to remove the two dents which block the plug against loosening, i. e. with a drill bit or Dremel grinder. My experience: you will fail using a screw driver and a wrench. An impact screw driver with a snugly fitting bit - and a hammer - will do the job. But in this case, it's better to have the crankshaft apart from the crankcase lying on the bench. Otherwise, your hammering forces will be applied to the main bearings!
The circulation of the oil is explained in a nice figure, on page 19 in the 160 user manual, http://ducatimeccanica.com/160_monza_jr/pages/pg19.htm.

..

[gregwils]

Okay, well I guess the thought of a quick and easy crank flush were wishful thinking. Thanks for the info on the dents, I did not look closely enough to look at them. If I ever get them out, I am going to replace with the hex nut type from Lacey. Thanks again.

http://www.laceyducati.com/ducati-parts/sludge-trap-p-314.html

[Dave450]

Greg - if you decide to remove the plug for the sludge trap, I would just get the largest, widest screwdriver you can muster and grind the tip if necessary so it's a nice tight fit in the slot. A vice grips around the handle or shank of the screwdriver should shift it, without hammering. The Lacey plug looks the business. If/when you refit the plug, don't use Loctite. Temporarily fit the primary gears and lock them with something to stop the crank rotating as you loosen the plug.

The way I cleaned my sludge trap was to tape a smaller tube to the vacuum hose and then loosen the crud inside the trap with a thin screwdriver or a bicycle spoke and it should get sucked out. If any bits fall down to the bottom of the trap, you can carefully pick them out with a small screwdriver with a bit of grease on the end. You should see a jet or restrictor at the bottom of the sludge trap. To make sure this is clean and unblocked, you would flush with oil from the primary drive side with an oil can, with your finger over the hole of the sludge trap. You will of course have to remove the grub screw in the primary side of the crank end. Flushing in this direction avoids contaminating the big end bearing. You would also have to remove the timing cover and flush until the oil runs clean as it exits from the oilway in the timing side of the crank.

I have to admit all this sounds a bit Heath Robinson, but it can be done if you don't want to split the motor.

Dave