Friday, April 12, 2013

Another Age Old Problem & Another Cheap Tool To Fix It

Spring is in the air.  The birds are chirping, the breeze is finally warm, and you can hardly wait to get your Harley out for its maiden voyage of the season after its long winter rest.  You went and bought a new battery in anticipation of this day, since you once again left it go all winter without any preventive maintenance.  But what's the price of a new battery when you will soon be back in the saddle, enjoying the wind in your face?

You kick the engine through once ....twice, ....(what is that gurgling noise?).  On the sixth kick, Old Reliable catches, and with some quick finessing of the throttle, comes fully awake.  But, now what?  Suddenly you realize that your garage floor is rapidly being covered by a pool of oil.  You quickly shut the engine down.  Dead silence, except that the gurgling noise which nearly caught your attention before is still emanating from the bowels of your beloved steed.

A seeping oil pump check ball has struck again.

It is pretty much inevitable that if you own Harleys for long enough, you will become accustomed to this scenario, though you may never get to the point of actually remembering to plan for it in advance via a pan to catch the oil. 

What has happened, of course, is that the spring and check ball in your oil pump has failed in its duty to keep oil from gravity feeding from the tank, through the pump, and into the lower end of the engine while the bike was at rest.  With the return side of the pump unable to scavenge the excess oil quickly enough, it takes the path of least resistance and exits through the breather. The longer the bike is at rest, the more likely this will happen.  I would go so far as to say that for it to happen over the course of a whole winter may not even be a sign of anything amiss to the point of worrying about, anything except how to clean up the mess that is. 

On the other hand, if you get a similar result after giving your ride a two week vacation, then it may be time to address the situation.  The Motor Company used to tell us that the fix was to remove the check ball and spring and then take the bike for a good ride so that the oil flow could "flush" out anything that may have gotten between the ball and its seat.  That's fine as far as it goes, but if this is a re-occurring condition, you may have to do more.  A new ball and spring may be in order, especially if they are original equipment - I don't put a lot of faith in springs in their old age.  But, assuming you have tried these simple fixes with no success, now what?

As you might expect, any shop dealing with rebuilds on older Harley motors has to address this issue.  The older the engines you rebuild, the more often it will be an issue.  For years and years, I have lapped the check ball seats in oil pumps as a matter of course during a rebuild.  What I did was take a new check ball and braze it onto the end of a screwdriver, dip the ball in lapping compound and lap away.  One problem though.  The heat from brazing took the hardness out of the check ball, causing it to "wear" away from the lapping rather quickly, especially on cast iron pumps.  Frankly, it has been one of those little annoyances that has bothered me for years (like each time I need to replace the ball). 

Bug, a fellow long time HD mechanic mentioned to me that he uses JB Weld to attach the ball to a screwdriver and it works fine.  And here I though JB Weld was only good for gluing broken crankshafts back together (do they still use testimonials like that in their advertising?).  But just as I was prepping my cheap screwdriver to glue, rather than braze, a check ball to it, I had a thought.  As any good mechanic with hoarding tendencies, I have a whole bunch of stock Evo pushrods gathering dust on a shelf in my shop.  The ball end on them is 3/8" just like the check ball.  Hmmm....

So, out came the torch one more time, but this time only to heat the shaft of the screwdriver enough so that it would pull out of the handle.  Then a quick trip to the lathe to bore the hole in the handle to the proper diameter, and for good measure to put a little taper on the recently cut-in-two pushrod, and oh boy howdy ....another cheap special tool.  Best of all, not only does it make for quick replacement even if the ball does wear rapidly (which I don't think it will), but finally a good use for some of those worthless parts that were cluttering up my shelves!


B.C. said...

Great idea Lee,long time back an old friend suggested taking a new check ball,putting it in the hole,and give it a medium hard bap with brass punch.Then throw said ball away and replace with a new one,in theory reforming the seat. Sounds to violent,lapping seems better suited for the job. Nice blog sight.

St. Lee said...

Thanks BC. The tapping a ball with a hammer to re-seat is another valid method, and probably worth a try if you can't or don't want to pull the pump. I would not lap one unless the pump was removed so it can be thoroughly cleaned. The "tap" method should be OK on-the-bike as long as you make sure that there is nothing ON the seat to be driven INTO the seat. I also suspect the "tap" method is more suitable for an aluminum pump body.

There has been talk on the Flatheadpower BB about burnishing the seat. That takes a special tool that uses the cap threads to put pressure on the seat, forming it back into shape. That would perhaps be the best method, except someone pointed out that the cap threads are not always concentric with the seat.

jim said...

Hi Lee, love the blog, covers 2 of my passions in life (well the most important one, God, AND bikes) Got a mate here in the UK with a 2000 Evo Sporty that's sat all winter and suddenly developed a BIG oil leak. Does this check ball problem happen on the new ones as well?

St. Lee said...

The Evo Sporty is not quite the same, having a check ball in the oil filter housing instead of the pump. Sounds suspiciously like the same type problem though. I would not get too concerned if it clears up after some running time though (making sure you keep some feed oil in the tank of course).