Topic: yesterday's drama

[hymodyne]

after a series of decent rides on the bike I took her out yesterday prior to my going back to Mass for the weekend. The only difference between this trip and others was that I got on her a little bit on a very open stretch of road, slowly creeping the speed up from 60 to about 85+ mph and that i had overfilled the crankcase (dipstick read at the top line when the bike was centered)  . no weird noises or vibrations, but after i decelerated, There was my trail of oil smoke. I had got to the point that until I get the ring work done that the bike needs, I would just gently ease the throttle up and back to prevent the smoking on startup and throttle down. this run I noticed the bike laboring and hot after I slowed down and when I got back home I saw some oil under the tank, on the RH side carbs and  R side cover. there wasn't much, about enough to cover a single paper towel. I took the tank off when i got home and could only find a few of the tapper covers that were only slightly loose, and no bolts on the breather cover or the tappet cover that were loose. the breather hose is connected to a small filter and exits the bike below with the carb overflow and other tubes. While I was checking the lowercase for sources of oil (I found none), I did notice that the filter/breather I put on was wet with oil

so,
apart from overfilling, was what I experienced an example of blowback/blowby of excess oil?

I'm working with bwaller to hopefully fix the ring issue I have with this 605 overbore kit and get her up to 100%.

hym

[bryanj]

You got the "soft" washer under the steel bracket that the end cap bolts to?

[TwoTired]

It sounds like more ring issues.

If rings don't seal well to the cylinders and pistons, combustion gases "blow by" the rings and pressurize the crankcase.  Any oil splash near the breather exit gets pushed out with the pressure.  Piston ring blow by generally gets far worse with higher RPM.

A high oil level can contribute to this, particularly if the level gets close to the whirring crankshaft, as the mini tornado it creates can suck up oil from the sump, and make it froth/atomize.

Have your rings had a chance to seat yet?

What happens when you run oil below fill line and rev to redline?  Is your tach accurate?

Cheers,

[hymodyne]

Back from out of town...

Yup, I'm over filled, or at least thats what my dipstick and plumes of white smoke said on my way to work this morning.

I'll remove some of the overfill oil after my I'm done teaching and check things out from there.

TT, you might remember a thread I started last year on this bike right after I had the overbore kit installed. Low idle and little variance in rpms over a number of miles meant that I probably didn't break in the rings properly; add to that a teardown to flip middle scraper rings around so she'd stop dripping oil, and I'd guess that the rings have not and will probably not ever "seat' properly.

hym

[JLeather]

Are you relying only on the factory venting?  Some people who've installed large big-bore kits have found the factory didn't provide enough venting and have had to add a vent at the middle rear tappet covers.  If you've got a few spare tappet covers, try drilling a fairly large hole in one and installing a little hose (temporarily) to keep the oil away from the engine.

Even in high performance car engines it is sometimes necessary to add additional crankcase vents to offset the larger volume of displaced air from the new/larger pistons.  It might be that your ring problem isn't as bad as you think, but rather the engine is building too much pressure in the crankcase and forcing oil past the rings.

[eurban]

My experience with the Wiseco 836 big bore in my 750 was that small amounts of oil was seeping from a number of spots such as at the valve cover and some spots along the crankcase upper to lower mating.   I had the valve cover breather going to the stock (78 750k) separator with a hose running uphill to a breather filter.  The filter would emit noticeable fumes at idle and tended to get oily (inspite of the separator) but I never experienced any noticeable smoking underway.  I would guess that his issue is with the rings but who knows.  Certainly the oilier the filter gets the less it's going to be able to vent pressure so I would consider taking steps to help keep it dry. . .A month or two ago I installed two modified intake side tappet covers on the 2-3 cylinders that had hose barbs on them.  Now I have three 3/8" vent hoses running back to an aftermarket breather separator that has three inputs, a drain and a large opening for the vent filter to attach to.  So far I have seen no new seeping from the crankcase seams and the valve cover to head seam is dry.  Filter is staying dry too.  I would surmise from this "experiment" that the stock venting is not quite up to the task of venting the Wiesco 836 big bore.  Someone on this board once suggested that the non aerodynamic shape of the back of the Wiseco pistons made things even worse but I certainly would agree with JLeather that any increased diplacement would likely create increased crankcase pressure.  It would probably help some to keep the vent hose plumbed into the stock air box but with pod filters this isn't an option.  Good luck!

Here's a pic of the breather/separator I used.  I did add an additonal input fitting to it and enlarged the hole going to the filter.  Its installed centered above the swing arm pivot. . . .

[hymodyne]

all this information is helpful. After draining out about 1 pint of overfill, I took off, only to find the bike sluggish and hesitating after less than a mile. steady pufs of white smoke chugged out from the crankcase breather with each Idle turn. in less than a half mile, it started to run like it was overheating and finally stopped running at all; although when it quit and I tried to re-start it, it acted and smelled like it was running rich or was flooded. Once I've recovered from pushing it back to my apartment, I'll look more closely.

I did notice that after last weeks oil leakage at the top of the engine, that this time when it quit there were droplets of oil on the upper right side of the tappet cover.I did use the copper washers on the tappet cover and side fasteners. I suspect that it might be the o-ring on the tach drive cover, although it was replaced recently.

if I did (and I did) have too much oil in the case, what would that have to do with overheating and running rich after the oil has been drained?

hym

[JLeather]

If the overfill and the crankcase pressure issues were forcing oil past the rings into the cylinders it's quite likely you've oil-fouled your plugs.  That's where I'd start.

[hymodyne]

Here's the #1 plug. all the rest are light brown, no heavy deposits.

hym

[hymodyne]

I'm going to drain and measure the oil. It's been about 500 miles.

I started with about 3.1 quarts, usually a little more to account for the oil cooler routing.

will draining the sump help me purge the excess oil from the head?

hym

[JLeather]

There would have to be WAY too much oil in that engine for oil to stay in the head.  If there's a lot of oil in the head still it means your drain passages are clogged.  BTW, if you had plugged oil returns in your head it would also cause unreasonable oil consumption.

That plug is certainly well-fouled.