Oil leak mystery.

After doing a bunch of repairs over the past few months, close to 12,

 

I took the bike out for a spin today. Ran OK-ish considering how long it was laid up. Unfortunately, when I parked in the driveway it appeared someone had traded my Venture for a Harley when I wasn't looking. Couple of good sized drops of oil splattered down by the kick stand. A closer look revealed the whole engine was covered in oil with a little puddle right next to the twinkie.

 

Cleaned it all up then ran the engine on the centre stand for 15 min at 3000 RPM. Not a drop showed up anywhere. My maintenance included changing the stator and setting the valves, both of which could result in a leak. Paid close attention to both those areas. Also looked in the air filtre to see if there was an overabundance of oil but there was next to none.

 

It's a mystery.

 

Will be riding the Venture to work tomorrow so will see what happens then.

 

Anyone have a guess, I'll even accept first hand knowledge , as to how a significant amount of oil could leak out when the bike is running on the road but not when running in the driveway?

First off do a complete wash of the engine so that you can more closely determine where the leak came from. Then let it sit at idle for 30 minutes. Check. If nothing shows take it for a short ride. Check. If nothing shows, go for a longer ride. Report back.

If you have the oil level higher than 1/2 way up the sight glass it will spew the extra when you wind it out. So on the highway you may have gotten higher rpms than in the driveway.. Have a look INSIDE the air breather.. for oil.

Rode the VR to work today. Oil was visibly leaking on both sides of the engine in the middle between the cylinders so it seems fairly certain the leak is coming from the Twinkie. That's where the crankcase is vented isn't it? Perhaps the reason there is no leak at lower RPMS is due to only a partial blockage of the vent to the air box. No oil made its way into the air box. Does this make sense?

 

In any event I stopped off at Yamaha and ordered a new o-ring for it.

Is there anything in particular that I might need to know to R-n-R the Twinkie?

Look closely for oil higher up running down cylinders.

Now for the controversy.

 

If you are leaking from the top of the cylinders you have two choices around the bolt rubber or the top gaskets, 1) buy all new rubber gaskets and the rubber o-ring things that the bolts go through. They are expensive.

 

Or you can do what I did..that is go to a nut & bolt supplier and buy very ( read VERY) thin washers that match the top shoulder bolts. Now remember..these bolts are shoulder bolts..they do not continue to tighten down..they break... Ask me how I learned that pain in the @&& lesson. But, if you put a very ( read VERY) thin washer between the bolt and the head and carefully tighten it down, it will give just enough of an extra pressure to stop the oil leak.

 

Now, in case I forgot to mention..you need to get a VERY THIN washer.

 

ALSO, invest in a 10MM ratchet box end to remove those head bolts. It will make your life a thousands times easier in removing the head bolts.

 

 

Now you can read the posts about why not to use the washer routine.....

Now for the controversy.

 

If you are leaking from the top of the cylinders you have two choices around the bolt rubber or the top gaskets, 1) buy all new rubber gaskets and the rubber o-ring things that the bolts go through. They are expensive.

 

Or you can do what I did..that is go to a nut & bolt supplier and buy very ( read VERY) thin washers that match the top shoulder bolts. Now remember..these bolts are shoulder bolts..they do not continue to tighten down..they break... Ask me how I learned that pain in the @&& lesson. But, if you put a very ( read VERY) thin washer between the bolt and the head and carefully tighten it down, it will give just enough of an extra pressure to stop the oil leak.

 

Now, in case I forgot to mention..you need to get a VERY THIN washer.

 

ALSO, invest in a 10MM ratchet box end to remove those head bolts. It will make your life a thousands times easier in removing the head bolts.

 

 

Now you can read the posts about why not to use the washer routine.....

Look closely for oil higher up running down cylinders.

Thanks guys. As mentioned earlier, part of the maintenance I did just before this issue arose was to adjust the valves. Replaced the cover gaskets and the rubbers at that time. The valve covers were the first place I checked when I found the oil leak.

 

When I got to work this morning it really looked like the oil was coming from the Twinkie area. Although I will have another look at it when I get to work again in the morning.

Another possibility are the oil supply tubing lines from breather cover up to cylinder heads...either leaking or transporting a drip down to breather cover.

Thanks guys. As mentioned earlier, part of the maintenance I did just before this issue arose was to adjust the valves. Replaced the cover gaskets and the rubbers at that time. The valve covers were the first place I checked when I found the oil leak.

 

When I got to work this morning it really looked like the oil was coming from the Twinkie area. Although I will have another look at it when I get to work again in the morning.

 

Did you used OEM gaskets or Athena? I once used Athena gaskets and after one month I had to use instant silicone gasket to glue the valve covers and stop the oil leaking.

Another possibility are the oil supply tubing lines from breather cover up to cylinder heads...either leaking or transporting a drip down to breather cover.

Oil supply tubing lines, not sure what you are referring to and the same for the breather cover. Is that the Twinkie thingy between the cylinders?

Did you used OEM gaskets or Athena? I once used Athena gaskets and after one month I had to use instant silicone gasket to glue the valve covers and stop the oil leaking.

I used Yamaha OEM gaskets for the 2Gen. There is no indication of any oil coming from those valve cover gaskets.