Oil leak after Stud Repair: R100rt

[Banzaibob]

After replacing the cylinder base o-rings on the right cylinder, the top right stud pulled out. Not having the proper tools to do the repair accurately, I took it to my local dealer which has a stellar reputation. They installed a time-sert type. I bolted it all back together, new o-rings around the studs and sealed the base with a very light coating of Three Bond 1104. I spun the engine with the starter to make sure that the top end was getting oil and noticed a pretty healthy leak coming from around the top right stud.

I should also mention that the large o-ring around the cylinder (98mm) that came off originally appears to be the 2mm o-ring. The dealer tells me that the 2.2mm o-ring should work but it appears to be a poor fit and when removed is obviously frayed from not being the right size (also see photo, new and old o-ring)

To me, the problem is pretty obvious, the pictures should illustrate. It appears that the notch for the oil feed exceeds the dimensions of the o-ring as it sits in the recess. The very thin layer of Three Bond does not seem to be an adequate seal. The measurements in that area are; the distance between the recessed area for the o-ring and the edge of the cylinder is 2.5mm. The oil passage notch is not quite 1mm taller than the O.D. of the 0-ring as it rests on the stud. Obviously the first fix that comes to mind for this problem is to use a larger o-ring and slightly more Three Bond in that area.

The test of whether this will work is if it will seal oil as the starter motor turns it over. However with only 1mm or so of sealing area, I would think that it would be a problem that MAY keep coming back.

What do YOU think? Any better fixes or suggestions?

[Banzaibob]

More pics.

[SteveD]

Welcommen bob.

Big pix! 600 wide is usually a good size.

Are they oem o-rings, or something off the shelf?
What torque did you use?

Three stage retorque to 27-28ft lbs. Many will do the torque a tad less in fear of pulling a stud. Two of us did that earlier this year, but it leaked from the base, right top front.
Removal, clean and reapplication of the sealant using a tad more then retorque to 28ft.lbs solved it.

[George Ryals]

It looks like the wrong o-ring. The o-ring od should be the same as the id of the o-ring recess.

[George Ryals]

AND, You should grind a notch in the Timecert aligned with the oil hole in the block. Otherwise no oil will flow along the stud screwed in the Timecert. Without the notch, the o-ring will seal between the timecert face and the cylinder base, isolating the oil passage from the stud and putting full oil pressure on the joint between the block and cylinder.

[ME 109]

AND, You should grind a notch in the Timecert aligned with the oil hole in the block. Otherwise no oil will flow along the stud screwed in the Timecert. Without the notch, the o-ring will seal between the timecert face and the cylinder base, isolating the oil passage from the stud and putting full oil pressure on the joint between the block and cylinder.

But they ground the case and not the timesert?

[George Ryals]

I stole this from a post on ADV. Note the reference to a drill for the oil passage in the last two sentences. I don't know if Timesert still makes the kit for airheads.

I can say from personal experince the tinesert works better than anything i've ever used.A few years back the top left stud on the left side stripped.After we opened it up I found 2 heli coils already in there.Not good.A friend ofmine and probally one the best Airhead mechanic I know bought a tinesert kit for Airheads.It wasn't cheap,but was one of the best kits i've ever seen.The kit has a jig.spacers.and both drill bits needed.The jig slid on the other 3 studs slide spacers over the other studs used the nuts provided locks the jig in.We drilled & tapped out the old slot pulled the jig out.Screwed in the Tinesert with High strengh Locktite & went to lunch.When we came back we reinstalled the jig.The second drill bit is for the oil passage the second hole on the jig is for that purpsose only.This kit was fantastic.The 92 RT/EML is still on the road running great.I will never look at using Heli coils agin.

http://www.hpd-online.com/stud-tool.php Try this link for a kit to repair airhead stud pull out

[Banzaibob]

I placed a metric 13mm x 1.5mm o-ring in the recessed area at the bottom of the cylinder. It fits in the recess firmly but does not exceed the diameter. It does stick out past the recess though by maybe 0.7mm. There appears plenty of outside diameter to cover that "notch" while still maintaining plenty of inside diameter clearance for oil to pass around the stud (provided that 0.7mm does not compress inward too much). I re-assembled with a smidgen more 1104 and spun the starter. It appeared as if the front rocker was getting a decent supply of oil and as of yet I see no oil around the base.
I got the bike running yesterday. I let it get to operating temperature, synced the carbs. Let it cool and then ran it back up to operating temperatures again. Came out this morning and re-torqued the heads and re-adjusted the valves. I took it out for an hour at speeds ranging from two-lane country roads to interstate highways.

No leaks. When I re-torqued the heads this morning I made sure that oil was flowing to the exhaust rocker arm on the right cylinder. It appears to flow with no restriction and when I removed the valve cover the same quantity of oil came out of the front compartment as the rear.

Tomorrow I'm going to re-check head torque, valve clearance again. If I see no oil on the base of the cylinder, I'm going to assume that the larger 13mm x1.5mm o-ring did the trick.

[Major Softie]

Tomorrow I'm going to re-check head torque, valve clearance again. If I see no oil on the base of the cylinder, I'm going to assume that the larger 13mm x1.5mm o-ring did the trick.

Sounds like it.

Grats.