After overhaul, oil leaking on right side

[cmyoch]

I'm sure there are more posts out there like mine, I haven't seen much to help so I'm going to post the questions again. I just put on 20 initial miles since my top end overhaul. My plan was to warm it up really well, let her cool down tonight, then retorque the head nuts. I noticed at the stop signs that I was smelling oil burning off the block. I brought it home and saw that my entire right side was pretty wet with oil. The valve covers looked pretty clean around them but the advance unit had oil droplets below them. The engine was too hot for me to remove the cover to inspect. I have the fresh gasket set from MMM on my bike and I know I put fresh seals on the cam covers. I'll pull the advance unit and inspect around the rubber seal to see if that may be the culprit. I read somewhere someone suggested taking a scotch brite pad or some steel wool to the advance end of the advance rod to smooth any imperfections. Hopefully that will be an easy fix. It seemed like a fair amount of oil that was on the block. Other than the leak, my break in ride was fantastic. I kept the rpms at and below 3k the entire ride and there was plenty of power. I think I'm going to be pretty pleased once I solve the oil leak issue and get my carbs synced and dialed in.

 

[deadchef]

if you don't get the cam bearings on all the way you won't get a good seal at the cam covers. the bearings need to be pushed in as far as they can go. i would start there.

 

[cmyoch]

I pulled the unit off tonight and made sure the brass and labrynth seals were seated, which they were. I reinstalled the cam cover with a little bit of rtv on the green gasket this time. I plan on a test run tonight when my boys go to bed. Wish me luck!

 

[deadchef]

cmyoch- just to be clear, i was referring to the cam bearings, not the advance rod bushings in the cam. the bearings need to slide on as far as possible towards the lobes. if they aren't on far enough the seals won't do their job. you shouldn't need any rtv sealant.

the #2's on this parts diagram.

 

[5twins]

When you assemble and install the cam, the bearings need to be pushed on as far as they'll go .....

I know it looks wrong because they actually hang off the inside of the casting a little bit, but this is how they have to be. The points and advance housings may not seat in deep enough to seal if you don't have the bearings in enough.

Another possible leak point is the seal in the housing. It has to be pushed in right to the back of the housing or the seal lips may not ride on the cam stub .....

 

[cmyoch]

I know the bearings are correct. I pulled the advance cover to inspect the rubber seal that goes around the cam. I reinstalled and torqued the screws down a bit. I recall them coming loose fairly easy so it may have just been that I didn't have them screwed down too well. I put on another 20 miles tonight and no oil leaking from there. I noticed a little oil on my base gasket on the left side, I do not know if this was residual oil from the right side leak or if it was fresh. Regardless, I wiped it clean and will see if it reappears. I am going to pull my tank tomorrow and retorque the head bolts since I'm now 50 miles on a fresh rebuild. The right side cover is leaking fairly well and I assume that has to do with the green gasket and reusing the copper washers. Next oil change will get a fresh black gasket and of course the washers will be replaced with new ones.

I must say though that the bike runs outstanding. I've kept my wrist out of the throttle until I get through the break in period but I know she is going to run strong. So far, I'm pretty impressed!

 

[ANLAF]

cmyoch, the fellers are right, it will be the bearings - I have had the same oil leak as you following top-end rebuild. I took a socket and gently tapped the bearings in a smidgeon (0.5 mm) and tried again, and again until no oil leak. I moved the bearings in both sides by about 1 mm - problem solved, oil leak gone.

Caution - gently does it. It might look as if the housing, seals, gasket, etc is seated, but try telling that to hot oil, which can find a way through the tiniest of gaps.

Anlaf

 

[ANLAF]

By the way, cmyoch, if your three retaining (counter-sunk) screws are failed (head a mess) try replacing with hexhead bolts. I have electronic ignition so there is clearance for the hex heads - its a solid fit.

Anlaf

 

[5twins]

The three screws that retain the points and advance housings are M6's. That means a torque of about 7 ft/lbs. Being that they're a multiple fastener pattern on an oil retaining cover, equal torque on all the fasteners will give the best chance of a good seal. You can and should use a torque wrench on these screws to achieve this. Fit a #3 Phillips tip into a socket and put that on your torque wrench. I use the 5/16" hex bits from my hand impact (in a 5/16" socket) but a 1/4" insert bit (in a 1/4" socket) will work as well.

 

[cmyoch]

Very good advice. As of last night, I did not see a leak. After a ride, the bike was hot so I wasn't about to mess with removing a hot cover. I plan on retorquing the head nuts tonight so I'll pull the cover to see if it's clean inside as well as behind the cover.