it looks like it is coming from the front bearing becuase the flywheel is spraying it onto the carby.
if it was leaking at the carby then you would see a thick build up of oil around the leak.
this can also happen sometimes if you over prime and flood the engine on start up.

Ok guys motor re-build time

im rebuilding my evo3sti i cant get the center bearing out of the crank case is there a special tool or trick to do this with any help would be greatly appreciated.

Cheers
Chris

ps. i have had this motor for almost a year now and this is its first re-build and has never missed a beat.

This is actually very easy to do. Dissassemble the motor so that only the block is left. Grab a pair of channel lock pliers and grasp the bottom of the block around the area of the carburetor. If you have a gas stove at home this becomes even easier. Turn on the burner and heat the block very gradually and slowly. Once you begin to see just a wisp of smoke come out of the block(the oil and water burning off from inside the block) tap the block on the counter top lightly. The bearing should just fall out. The trick is to heat the block just enough so that the bearing just falls out. When heating the block try and keep the flame away from inside the block and heating directly on the front bearing.

To reinstall the new bearing, place the bearing on the crankshaft as it would go inside then engine. Reheat the block as before and slide the crank and bearing assembly into the motor. This is abit of a juggling act, but putting the bearing in as an assembly helps to line it up easily with the front bearing.

I have an electric cooktop so my method is slightly different (my new house will have gas so I'll have to try this way ).

First of all , put the new bearing in it's packet in the freezer.


Second, I strip the engine as in the above post and when all I have left is the block (even wthout the carb retaining bolt or anything else except the block and the two bearings), I set the oven to 250 degrees C and put the block in as soon as I turn on the oven. I monitor the oven so I know when it clicks off meaning it has reached 250C.

At this point I remove the bearing from the freezer and put it on the crank.

Keep in mind the block is now rocket hot so wear an oven mit!!

Take the block from the oven with the mit and knock it on the bench (I use an old wooden cutting board to keep the missus happy) and the bearing will fall out. Keep a pair of longnose pliers handy as it may not fall all the way out and you will need to grab it.

Next, while you still have the hot block in your hand, drop in the crank and new bearing. Use the sharp end of a wooden spoon to seat the new bearing, and you're done.

If anything doesn't seem like it's seated right, just heat the block again and remove the bearing or push the crank in further.

Hope this helps.

yap...i suspect that too as when i change the O-ring... seems dry inside the area. Inwhich, if its leak from the high end needle O-ring, it should be bit oily once you took off the O-ring. My 2cents worth....

but again, I had change the front Bearing but not the centre bearing, is it the cause of it to leak ? But again, if it too rich , the excess oil should more or less came out from the exshast pipe instead, isn't it ?
Damn.... make me keep thinking the cause of it even in bed-time...

try leaning it off first.
what temperature is it running at?

ard 105deg.
to clear my benefit of doubt, isnt it that even when running rich, engine shouldn't be any leaking ?? My Evo2 didn't had this problem before even when running rich or is it only apply to Sti ?

Ive got a question regarding the Sirio .12 engines.

Im considering this three engines at the moment:-

Evo 2 S12TRP 1 3 ports

Evo 2 S12TUP 5ports

Evo 2 S12TUP 5 ports (Factory Modified)

I have no idea which is a better engine.

Thanks.

Sirio onroad front bearings always leak oil even after 1 start on a brand new bearing I have not realy noiced any bad efects only a small pool of oil after i after run an engine. If people are worried that its realy bad or just dont like the thought change it to a rubber sealed front bearing somthing like a tko front bearing here is there web site. http://tkocompetitiondev.com/shop/index.php?cPath=38_41. they are very good bearings ceramic bearings rb concepts also make a ceramic rear bearing to fit a sirio 21 engine size is ("25.3mm outside dia 14.2mm inside dia and 6mm wide") ive never tryed them but if some one is keen or has tryed one let us know what they last and paform like. Regards Jeremy.

anouther good tip to stop carby leaks in a sirio is use some super glue remove the carby ball and boot clean with some metholated sprits clean inside the carby boot and use a small flat screw driver put a tiny bit of super glue on it and wipe it in the grove on the craby main body ware the boot sits in the grove. dont go over boared just a thin even layer on it then replace the boot and ball link. I have found super glue works much better than rvt silcone sealent. Regards Jeremy.

I would be very worried if your not leakiing at least a little from the front bearing. That bearing needs a little oil to keep from locking up.

This is what Dennis Richey said about leaking front bearings:

agreed with that but the leaking isn't it too much for the engine ??
Today i had try leaning it and out thruout my track day...damn... no matter what matter i used , used up 2sets of tires.... and its still wet/oily as my first post picture shown....
perhap i'm lucky to purchase a faulty one ?

hey guys,

im updating my nitro chassis and wondering what engine to get. im tossing up between sirio or a mediocre novarossi of $400 retail value like the sirio. just wondering on your thoughts and tips on the preformance of both engines.

im loosing sleep over this matter
please help!!!!

can anyone help me with somewhere to buy parts for an SP 21 PR Pro ? I would also like an exploded diagram with part numbers . Also would anyone know if the S 21 PR Pro is the new version of this motor and therefore parts are interchangeable ? Thanks