Ideas to fix this oil leak

[mlew]

I have a oil leak on the right rear cylinder head where the carb boot ataches to the head. Aperently the bolt hole for the boot goes through to a oil gallery and the oil is leaking around the threads and running down the side of my engine.

I have tried thread sealer on the bolt and pipe sealer but it still leaks. Even tried gasket cement with no luck. My next thought is to epoxy a set screw in the bottom of the hole but I am a little concerned about blocking the oil gallery.

Any other suggestions on what to do?

[Squeeze]

Put a shiny Bolt in it instead of a green Bolt, this should solve the Issue

[mlew]

I got shiny stainless bolts, they are just covered with oil now.

[dingy]

I learned about this problem from the VMax site last week.

 

Over there they thought the official Yamaha bolt had a ring of RTV around it.

 

There are two socket head screws in the intakes that go into the oil galley. One shorter on each head! cylinder number 2 (left front) and cylinder number 3 (right rear). upper outboard holes. 20mm long for 6 of the socket head screws and 16mm long for the 2 shorter ones.

 

These socket head screws protrude into the pocket that the special nut for the cylinder head stud sets into.

 

It was mentioned to clean the screw and hole as good as you can to get a clean surface for the RTV or a tiny dab of ultra black to adhere to.

 

When I removed my heads this week, I found I had put 20mm screws where the 16mm one should have been and the head nut caught on the longer screws when I was removing them.

 

Gary

[bongobobny]

Yah! #2 and #3 cylinders have a longer bolt where they pass into the oil cavity. What you may want to do is draqin your oil, wick/blow out the threads and clean them, then clean the bolts and put NON hardening gasket goop on the threads. Maybe you aren't torquing the screws tight enough...

Edited February 26, 2011 by bongobobny

[Condor]

Crush washer??

[dingy]

Crush washer??

 

 

Between a crush washer on top & RTV between the intake manifold head & cylinder head it might seal.

 

If you didn't seal between the head & intake though it might weep through there. The intake O-Ring is inside of the screws.

 

Gary

[Squeeze]

I got shiny stainless bolts, they are just covered with oil now.

 

 

On the Vmax, the shiny Bolts go on the outside of each Manifold, which can be seen from outside, the green ones go onto the inside. The shiny ones are longer than the green ones.

 

It's great if you have shiny stainless Bolts, but they need to have the right Lenght also.

 

Dingy already stated what's the standard Procedure.

[dingy]

My next thought is to epoxy a set screw in the bottom of the hole but I am a little concerned about blocking the oil gallery.

 

 

This isn't an oil galley that has been broken through. It is just a head nut pocket. Yes, oil is in there, but it is not a flow path.

 

My concern about putting a set screw in the bottom of the hole would be the length that it would take up. If this were to be done, the already shorter bolt that go in these two holes would then be quite a bit shorter. You might run the risk of not having enough engagement length and stripping out threads in the head.

 

Gary

[mlew]

I'll pull the bolt out tonight and check the length, I don't remember what it was. I did clean the hole and bolt real good the first time I put it together..no luck. I do remenber the new bolts are a bit longer than the ones I took out. I did not want old rusty bolts in a fresh engine. The firts try I used Permatex #80019 sealer on the bolt, should I try again with a longer bolt?

[dingy]

I'll pull the bolt out tonight and check the length, I don't remember what it was. I did clean the hole and bolt real good the first time I put it together..no luck. I do remenber the new bolts are a bit longer than the ones I took out. I did not want old rusty bolts in a fresh engine. The firts try I used Permatex #80019 sealer on the bolt, should I try again with a longer bolt?

 

 

I don't think a 20mm bolt will effect the sealing much if any. It looked like the 20mm screws where sticking into hole about 2mm when I pulled head, so screw would be set back about 2mm if a 16mm where used.

 

I don't have a good product spec to suggest, but I would want something that has a thick consistency, rather than an RTV. There is a black gasket sealer, I think it might be called Permatex, but not sure. I would be generous with the amount used. A little sealer coming out of hole once is better than constantly weeping oil leak. Also, I would only coat threads of screw with sealer and not force any into hole. This might cause excess to be forced inside head.

 

Gary

[mlew]

I just pulled the bolt out, its 20mm long. I think a 25 mm will fit without any interference. I'm in the process of cleaning all the oil from the hole, watch a movie then try to reassamble.

[dingy]

I just pulled the bolt out, its 20mm long. I think a 25 mm will fit without any interference. I'm in the process of cleaning all the oil from the hole, watch a movie then try to reassamble.

 

Just my opinion here but...

 

Putting a 25mm in the hole will not help, in fact may not work at all. I have attached a few pictures below.

 

The bolt penetrates the cylinder nut pocket just above the shoulder on the nut. It is off center with the center line of the head stud. The 20mm already is overlapping the shoulder of the nut. I think that a 25mm will actually hit the O.D. of the nut, thus not allowing it to clamp down on the intake manifold.

 

The 1st picture shows hole in question, upper left on intake boss. And to the top of the picture you can see the head stud pocket going through the bottom of the left cam journal.

 

The 2nd picture has a red arrow pointing to where this hole enters the stud cavity.

 

The third picture shows a head retaining nut setting on head. Imagine this nut setting down in the pocket in picture #2.

 

The 16mm bolt is adequate, it is just a matter of sealing it.

 

Gary

[mlew]

I see your point Dingy, I'll stick with the 20mm bolt. Thanks for the pics, now I understand what I'm dealing with. I got the hole cleaned with no oil, I'll try again with some prematex to seal it.

[mlew]

Sucess

Thanks for the help everyone. I kept the 20mm bolt and cleaned the hole real good. It was not easy, I rigged my vacuum brake bleeder with a small tube to suck out the oil then clean with brake cleaner. Kept at it until a paper towell came out clean and dry. Reassambled with a coating of Permatex and let it sit overnight. Went on several 20 mile trips to the store and home, still no signs of oil. I love it, no more wet spots under the bike.

[jasonm.]

Yes, I also used my brake vacuum bleeder w/small hose when I had the same issue. I used Permatex ULTRA GREY. which any excess blended into the stock head color just fine. No leaks since the work 2k ago.