Water in crankcase of Honda BF100

Thanks for the quick response.

Thanks for the quick response.

Do you think I will be able to tell once the head is off if it was the culprit by close examination of the gasket and surfaces.

"Considering that you were abl

"Considering that you were able to run over 40 hours with no increase in oil level, I would say; perhaps not.

You would also want to carefully check for any cracks or corrosion voids as a possible cause.

A good check before the head gasket, would be the intake/exhaust manifold as it has cooling water through it as well (two gaskets for it).

You could also confirm thermostat operation (located in the manifold) and if it were stuck open, you might get some water contamination build-up just from running too cool."

"Ditto on Pilotart's last

"Ditto on Pilotart's last comment. A thermostat stuck open will produce condensation in the oil on many types of 4-stroke engines simply because it is running too cool. Before removing heads I would first remove and carefully test the thermostat. If any doubt, replace it. Then run it for a couple of days and see if the problem goes away."

"I like the idea of the thermo

"I like the idea of the thermostat stuck open. It makes sense, with the oil level not rising, at least not a noticeable amount.

It looks like it would be easy to get at. I guess the only way to confirm its operation is to remove it and visually inspect it.

I think I will start with that, I will post back when I learn anything new.

Thanks for taking the time.

Cheers"

"If you have the manual, it te

"If you have the manual, it tells you how to check the t-stat - temp to begin opening, and temp at full open. However, if it is stuck open, you'll see it when you remove it. It doesn't open much - maybe 3 mm - so look carefully."

"Clean and then place the ther

"Clean and then place the thermostat in a pan of water on the stove with a candy thermometer.

There were four different thermostats (low, medium and high temperature and serial numbers below or above 1600000 and above 1700000.

The Valve Lift should be 2-3 mm above 70° Centigrade and completely closed below 60° and those specs vary by s/n and L, M or H."

Today I started trying to get

Today I started trying to get at the thermostat. I removed all the cap nuts. The intake manifold is stuck on though. I have been spraying WD40 on the studs and have got a couple of screwdrivers tapped in between the plate and the block. Nothing has moved yet. Anyone have some advice on how to break it loose.

Thanks

"I had noticed those cap nuts

"I had noticed those cap nuts in your photo posted on another thread:



Mine has bolts instead of studs.

I have never been a big fan of WD40 and don't know how well it works as a penetrating oil; PB Blaster or other dedicated penetrating oil ('Weasel Piss' was the term I have heard most ) might do a better job, but give it time.

As a last resort, you could weld nuts on the studs and back the studs out."

"I am with pilotart on the PB

"I am with pilotart on the PB Blaster. I have not seen one as rusted as yours. I usually just grab the carburator and use it a leverage and it breaks loose. From the block out there is a heavy (I'll call it asbestos) type of gasket; then a stainless plate; then a paper gasket; then the outside cover.

Make sure you have taken all the caps off. If I remember right, there is a cap partially hidden by the CDI pack.

You may have to apply some heat with a torch to get the cover to budge."

"After my difficulty with tryi

"After my difficulty with trying to get it apart I had decided to just leave it, I put the cap nuts back on and used it on the weekend.

The cover plate is now leaking, I guess I disturbed the gasket enough to make it leak. Not a surprise, I had a screw driver jambed into it. The repair is back on.

I have now taken it apart. I used some wedges and a hammer and lots of penetrating fluid. I would soak it two or three times a day. I also applied some heat.

I have not cleaned the cover up yet, hopefully I have not damaged it beyond repair. When I used the heat it must have melted what ever glue they use to hold the little pipes in. Anyone have advise on how to re-attach the pipe that came out?

There are two of them, I think I will need to redo the other one for the tell tale as well.

Honda BF100 manifold removed"">

Intake manifold and thermostat