Smoke from valve cover  By  rcq92130 (Read 4,169 times)

looks like blow by , if the engine is running well let it slide . That is a tell tale sign that a top end rebuild is nearing .

John

rcq92130 How did you break this top end in? If you ran it for short periods in cold weather you could have created condensation in the valve cover. Even running mine, it spits a lil water from that hose when it first fires up. By not allowing the motor to run long enough to evaporate this condensation, it could have built up.. And now it's actually blowing steam and water from the vent.

Put the bike up on the stand, point a fan at the cooling fan on the stator and adjust the idle screw to bring the motor up to around 3k rpms. Now let it run until it burns off that water. Worse case is you loose the top end. If that is really smoke coming out of that vent, it's gone anyways. Still double check your oil to ensure water isn't in the crank case. 

Edit: I was just wondering...when you rebuilt your top end, did you take a paper towel and dowse it in oil then wipe out your cylinder jug? There is usually a good bit of machining dust left on the surface of a new cylinder. Mine took 5 wipes with fresh paper towels before it was clean. I was actually surprised at just how much I removed. The first couple of wipes made my paper towel absolutely filthy. If you don't do this, that dust can wipe out your rings before the motor is even broken in.

Synthetic in our motors isn't a good idea. From what I understand the heat of an air cooled engine breaks synthetic oil down.

Ya I hope your reading is low because of the way you had to test it. A stock motor should read around 150, Ours should be higher. I haven't tested mine yet because my gauge is MIA, so I have to wait until I can order a new one.

You are not going to break in an engine in 400 miles. My scooter took about 2000 miles to fully breakin. I know this because it wasn't until the 2500 mile oil change, that the filter screen came out absolutely clean and free on any tiny bits of anything. The 5 oil changes prior to that one, all had a little crap caught by the screen.

Your profile doesn't include your location.....but as mentioned above, crankcase gases do contain a lot more condensation as the outside air temps drop....this could be part of your problem, also, as rpm's go higher, blow by gases increase.

I have a catch can installed in my vent hose, so I can monitor amount and contents of gases being expelled. Last time removed for empting, it contained .45 ounces, after 1200 miles. Three or four drops of oil, and a lot of watery stuff.....looked a lot like yours. That was at 3750 miles, now at 5650, and time to check it again.

Might suggest easy rather than semi-easy first few hundred miles, and no synthetics, just a name brand 10w/40 or my choice, a 15w/40. This is all just an old fart's opinion, but I bought my first new engine in 1965.....I own and maintain 10 engines at the present time, gas and diesel.....none of which have any issues..... hillbillybob

rcq92130 Just an FYI, maybe there is an old mechanic trick I don't know about, to tell if your rings are gone or not, but if you pull the jug off of your piston, scrap the rings. They will never seat properly again. Good thing these things are relatively cheap.

For your break in, a trick I learned wile breaking mine in is to do like I posted earlier. Put your scoot up on it's center stand, point a fan at your cooling fan, and adjust the idle to 3k RPMS, let it run for about an hour wile bliping the throttle every so often. Every time the rings seat better your RPMS will go up and you will have to readjust the throttle screw. Once your done, you should be broken in enough to drive it and not have to baby it. Just avoid running it WOT for long stretches. I did mine like this and it worked freakin awesome.

Yeah, what I ordered is a new jug, piston, rings, gudgeon pin.  Whole thing (from Taiwan) is only $70, so it didn't make sense to see if new rings would solve it, or if maybe the liner was gouged, etc

RE:  break in:  Most seem to think the main commandment is to vary throttle at first.  So wen the current (now gone bad) BBK was first in I spent a while going up and down local hills, over and over .... till I became worried someone would call the locals on me.  Still something went bad obviously.