Oil Checkball Valve

[who_gives_a6]

So I've searched through old posts and this and seen a bit about it but is there a definitive cure to the checkball allowing oil on the cylinder?

Lately I've been traveling from CA to AZ and back a lot and I guess it's the big elevation changes, but the cylinder fills with oil and cannot turn over as soon as I arrive to either location. Has to be torn down, plug removed, and excess oil pushed out. When it's at home it'll also do it but it takes a week or so of sitting. If I start it every few days it doesn't do it just sitting. Only with elevation changes. I can start it now, drive out of state, then immediately try to start it and it's filled with oil.

I put in 1.5 quarts plus a small amount of Eastwood zddp additive and also have a high capacity oil line system on this one. My other quads never have this issue, nor did the two bikes I used to own. Just this one.

[who_gives_a6]

Off topic here but who rebuilds the moto Ohlins steering dampers? Mine is due and curious if anyone here does it.

[wistech]

The rubber ball might be deformed or have a piece of debris in it. When rebuilding an engine they need to be cleaned out. Both the epoxied and snap ring oil pump blocks can be rebuilt and replace the rubber check ball if needed.. I have never personally had a quad with 1.5 quarts of oil ever make its way into the cyllinder. I can only guess your not able to get all the oil out of the system when doing oil changes. If you take the starter clutch and cover off you can see the oil level in the crank case. Even if there are 1.5 quarts in the crank it is still lower than the piston. What line is this high capacity in.

[who_gives_a6]

OK. Makes sense. Was hoping there was some easy way. I think excess oil may be the issue. I only remove the rear screen filter every couple changes and have never had oil in it. Just changed oil and this time oil came out of the area; a decent amount. Ended up being a little under 2 quarts total.

I'm using a kit I got in a package buy on here. Believe it's one of boomers' kits. It has larger fittings and hoses on the T part near steering stem as well as the hoses going to engine and larger T fitting there as well.

Still seems really weird that elevation causes so much of a difference.

[rayspeed]

This probably happens to allot more engines then not... its just most people dont know it because they did not put in too much by just enough.
I set my oil level by looking down the dipstick hole with it running and there should be about a quarter inch indentation of the oil rushing down that hole the dipstick goes into. If the oil is above that to where you cant really see the oil going down that hole you have too much and if the oil kind of vanishes way down that hole by a half inch or more then you dont have enough. Then after you shut if off check the dipstick it should be real close to the full mark.
If it still gives you trouble maybe make a quick easy way to drain some out of the sump and pour it back in before you start it if you are concerned about somewhat dry starts. Like using the original banjo fitting in the drain and some sort of small stiff valve or a pipe barb and cap.

[polyesterpig]

Some of the check valve assemblies were machined incorrectly. On some of them, and I have seen a few, we're drilled too deep from the factory. The hole I am talking about is the one that the spring and ball goes into. If it was drilled too deep, not enough or NO tension is on the spring. I have even seen a few that the ball rolled back and forth, thus the check valve worthless. Only easiest fix is just to replace it. Not what you want to here, but Cannondale reality!

[Canniboomer]

Congrats on being able to run over 2 total quarts in your machine, and not notice any oil puking out -- that is because you are using the Hi-Capacity Venting Kit, which certainly DOES make a big difference on how much oil can be used without puking. Here is a pic of over 2 qts drained from a higher compression 460... For doing a race or running the Baja?, I would certainly use 2 quarts,.. BUT that is risky to leave 2 qts in the machine when parked... WHY?... Not because of the checkball problem, but because every stock Cannondale on the planet will leak out of the frame when parked, and it is just a matter of clearances between the balance shaft and oil pump, the balance shaft and filter housing, the wear over time at those surfaces, the oil viscosity, and the temperature -- they all leak, at some rate -- they have to, which really becomes apparent after you study the issue. Here are comparison pics of 2 crankplates, and I've tested many others.
Perfectly fine checkballs no leakage via that route... I think we can quit blaming the checkballs all the time, since that is really not such a common problem by comparison IMO, and cannot even be diagnosed until the other leakage pathways are fixed.

One plate pictured is the stock, normal machine with a good stock oilpump and checkball. The other tested pic, is a same setup after sealing both the oilpump block, AND the filter housing. The results?.. no more creeping leakage of oil into the lower end, and nearly doubled oil pressure at idle and at revs.. yeah I should have posted a long time ago, but still running behind.. more later after you guys chew on these pictures.

Note, about half of the leakage happens along the outside of the balance shaft tube.. and half creeps inside of the balance shaft tube. All of the leakage is not even filtered, since it does not even reach the filter (past the checkball).

Since our pump pushes oil out anywhere it will go, this is happening in operation -- some oil is evading the filter completely and moving straight into the sump or via the 1-way bearing -- all unfiltered. That is proven, which is why the oil pressure suddenly jumps up when those unfiltered pathways are closed.

That machine in question has more trouble than others from more wear, and your using more oil than 1.5 qt has aggravated the oil-locking problem.
As a fix, I would suggest you send me your crankplate, oilpump and filter housing at the next motor job. In the meantime, I'll try to work up more send-out fix kits for this issue. So far, I have not been able to catch up on the demand from regular customers on this... and had not yet posted the findings.

Total cost is less than $100 after core swaps, and includes a quality new Balshaft ballbearing, pump gerotor, and new slight oversized drive pin etc... And the ballbearing still gets a left-to-right feed with oil....but after the fix?.... it is filtered oil. More next week...

[Canniboomer]

To drain out excess oil SO quick and easy... I have Quickie Drains for both the right and left side of the ATV.. just a 1/4 turn into a bottle, or for a quickie 1-quart oil freshening drain-n-fill during a long weekend.... I only post it here since more convenient draining was mentioned above... for problem machines.

[Canniboomer]

Note each crankplate had a new oil filter installed, just for comparison sake. I set up each overhead bottle with the same amount of new 10w-40 oil. The leakage shown for the stock setup was overnight, at an average temp of about 70 degrees. But that seepage never went through the oil filter anyway. Neither setup had any leakage past the oil filter (via checkball). The oil bridges remained dry. For any leakage past the oil filter, that would first go to the oil bridge which feeds the crank, which is the lowest outlet past the oil filter. But before any seepage can reach that high, it instead wicks directly into the sump via the balance shaft clearances -- again, about half of the unfiltered leakage goes internally via the hollow feed to the one-way bearing (collected in bag), and about half into the sump along the outside of that shaft and over the ball bearing. Note one picture shows that telltale drip under the ball bearing (and sopped into the paper towels).