Geoff's 3AJ rebuilds....

[Spike]

see the pics now. interesting my retaining screws are Philips head. I've tried heat to no avail, next was drill them out and re tap

[jibber]

They are cross head (assume JIS ) as standard, try an impact driver.

[cadno]

how did you keep the clutch bearing clean when you had it vapour blasted, or probably more likely how did you clean it after vapour blasting?

[scottieh]

Hi Geoff, can't see any of the pics? but my question is how did you go about getting those 3 screws out ? L have the same problem

I had moderate success removing those screws using an old style impact driver, the kind you hit with a hammer and hope it doesn’t crack the aluminum casing. On average i got out half of the screws and the other half were drilled out.

[cadno]

Make sure you put a towel or something soft underneath the casing when giving it some grief with a impact driver. They usually have Loctite on from the factory.

[GeoffD]

Hi Geoff, can't see any of the pics? but my question is how did you go about getting those 3 screws out ? L have the same problem

I had moderate success removing those screws using an old style impact driver, the kind you hit with a hammer and hope it doesn’t crack the aluminum casing. On average i got out half of the screws and the other half were drilled out.

I've removed those screws probably 6 or 7 times in the past on different engines, I always use an impact driver & I always supports underneath with a piece of wood, I NEVER hit the impact driver hard and I always heat the cases first.
These 3 little bastards had already been hit with an impact driver, with the wrong cross head end on I think ( its really important to use the correct driver).
These screws had also been mullied (army word) by some ham fisted twat with a centre punch.
I used my very sharp 10mm snap on chisel to open a groove on one side of each screw, then I ground the chisel to a blunt edge of around 2 mm... a sharp tap with the chisel on the previous created groove in an anti clockwise direction & they came out really easy.
It's very important not to try to undo the screws with a sharp chisel otherwise you'll just chop the screws.
I'm replacing them with Allen heads rather than Phillips type...

[GeoffD]

how did you keep the clutch bearing clean when you had it vapour blasted, or probably more likely how did you clean it after vapour blasting?

I left the clutch arm & the seal in Dan & told the bloke doing the blasting where not to blast.... I also filled the recess where the shaft fits with grease... when I got the casing back I took the pivot shaft out, put the case in the parts washer I left it running all night with the nozzle pointed at the bearings... seems fine mate.

I also left all the old bearings in to remove afterwards... so no chance of damage to the bearing recesses...
This is the first time I've had a set of inner casings vapour blasted, I didn't want to, to be honest but I had no choice...

[cadno]

A friend has a powder coating and vapour blasting business so I'm spoilt really.
I vapour blast almost all alloy components. It's surprising what you see asked for, carbs that haven't been disassembled is real common. How on earth they get the media out of the carbs is beyond me.
There's only one way with vapour blasting, total disassembly, and a thorough wash afterwards ideally with an ultrasonic if you have one big enough.

[Mezo]

This is the first time I've had a set of inner casings vapour blasted, I didn't want to, to be honest but I had no choice...

Not sure if you've been following the guy rebuilding his 900SS on the Two Valve group? he had his cases vapour blasted the other day & one of the comments from another Ducatista said never blast the inside of your cases as he reckoned that the sand in beds itself in to the alloy, and once the engine has warmed up & the oil flowing again the fine sand releases itself & buggers the bearings, what you say Geoff?

Mezo.

[GeoffD]

Not sure if you've been following the guy rebuilding his 900SS on the Two Valve group? he had his cases vapour blasted the other day & one of the comments from another Ducatista said never blast the inside of your cases as he reckoned that the sand in beds itself in to the alloy, and once the engine has warmed up & the oil flowing again the fine sand releases itself & buggers the bearings, what you say Geoff?

Mezo.

When I got these casings, a long time ago.... can't remember when, they were covered in oil, crap, etc... so in my wisdom I filled a plastic box with diesel & submerged the casings thinking that when I come to use them it will be an easy job to clean them... I was wrong.

When I took the casings out of the diesel last week, they were covered in some sort of sticky tar stuff that was impossible to clean off in my parts washer... it took an hour to clean the bastard stuff off my hands.

So that's why I had them vapour blasted.

They don't use sand when vapour blasting Mez, they use fine particles of glass & obviously water, I don't think it will embed in the casings, my biggest worry was leaving some in the galleries... I've thoroughly cleaned all the nooks and crannies, sure it'll be fine.
I'll also run the bike for 100 miles or so on 5w30 oil, then change it and the filter.... back to my normal 15w40.

I've had tons of stuff vapour blasted, heads, outer casings, barrels, etc... never had a problem to be honest, and the guy who blasted these rebuilds old 2 stroke motocross engines & he always blasts the casings...