Hi,
been trying to find more info on my non original engine setup.
Its a mixture of bits but the block has 12H694AA number so I guess its a 1275?

It only has a breather from timing cover but none on crankcase???
Should I get it drilled for a breather and is this a major (expensive) hassle?

A mini motor cant have too many breathers. They stir up a fair bit of air.

You can drill and tap the clutch cover for a breather there but a couple of things.

If you drill it while the whole assembly is on the motor you are going to get metal swaff don into the engine. The second thing is don't drill one big hole. Drill lots of small holes so the nothing can fall through.

Murphy's law says that if you make a big hole a bolt or a nut will fall through the hole and find its way into the motor.

Mike

So can it be drilled without the whole engine out?

as mike said, no, because you get metal swarf (drill gunk) falling into the engine. Just get a rocker cover with a breather built in

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did I tell you that I won a trophy?

So rocker cover with breather will be enough? The vented cap won't cut it?
Do I need to plumb this back to the carb (hif44) or can I just put a hose and filter on it?

Make sure the one on the timing cover isn't blocked with crud, if it's clear one good breather is enough for a roady 1275.
If it's blocked, hook the crappy `mesh' out of it and replace with a S/S scouring pad (the woven type)- they are a perfect fit.

Cooper S only had one breather, on the side cover.
Our 1293A+ only has one (on the flywheel housing), so does my 1360.
Never had a problem. No oil leaks at all, or oil coming out the dipstick hole.

If it needs more than 1 breather for road use, the rings are shot and it needs a rebuild.

<edit> the vented cap is to let air in, not out.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

good point that...... I could use about 12 breathers at the moment, it's fooked

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did I tell you that I won a trophy?

Cleaned the filter with some k&n filter cleaner. Noticed that vented rocker cap has made a little brown oil stain above it on bonnet but no oil around.

Have found this, I have electrical fuel pump so this crazy adaptor might
be the ideal solution!

http://www.minimania.com/web/Item/C-2A2 ... Detail.cfm

any comments on that idea?

I made one for the fuel pump flange 8 or so years ago, from a Cooper S breather. All was fine during running in, below 4500rpm.
Once I went over that rpm the crank threw heaps of oil up it, and it looked like the Exxon Valdez on fire. Bad news
So I re-engineered it to fit on the flywheel housing, no more problems.

The MiniMania one may be better IF it has a baffle in it, I'd not buy it otherwise.

If your engine is in good condition I'd try it with the one you have on the timing cover, and add another to the rocker cover only if you have to. This should not be necessary for road use, My rebuilt 1360 spins to 8000, and it's fine with 1 breather. So is the 1412 stroker I just had dynoed, and we ran it to 7000.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

I would hook the breather up to the carby via a PCV valve and ditch the K&N.

What he said...^^^ it makes for a non-smelly cabin.
For track days I block off the PCV and run the breather (and another off the rocker cover) into a catch tank.
Those K&N etc things on breathers are useless for all purposes except Bling. They get blocked...

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Only investigated as I noticed oil stain from oil cap. And noticed that my mechanical fuel pump is still attached but not in use. Am planning to run mine on dyno this week hopefully.

How can I tell if it has a baffle?

Yeah it's got something in there, mine just had a flange on the breather that bolted onto the block.
If you buy one, let us all know how it goes.
I know people race with them in US, maybe they do work.

Other people in Oz like me who made our own all had the same result- NFG.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Well I should really take of the unused fuel pump anyway.
Undoing 2 bolts vs tearing out half the engine sounds a little more achievable for a noob like me.