goirish

I have a magnum 52 4 stroke that is leaking (a very little) around the valve cover. At a idle you can see some bubbling between the cover and head. Question #1 how do I seal it and question #2 do I need to seal it. The motor runs great-starts easy, idles good and had a good transition from idle to WOT.

Ed Smith

It could be that the crankcase drain is blocked, if there is one. Leaking around the valve cover will not affect performance. It will make a bit of a mess. I made a paper gasket up for one of mine.

Ed S

goirish

The leak appears to be very small--just tiny bubbles (hummm sounds like Don Hoe) I have a fuel line from the crankcase vent connected to the landing gear strut. Thanks for the comment.

aerowoof

do the bubbles come out all the time or do the pulse while the engine is running,low throttle would be more noticeable.

goirish

Gee, I think they kind of bubble fairly constant. You have to look close to see them. More like a small leak on both sides of the cover. I tried some gasket tach and that seemed to help. Maybe a little of the gasket maker for automotive--you know the red stuff. What ya think

DelRay

Goirish,

You might want to remove the rocker cover and check the sealing surface for any scratches or roughness. You mentioned you did use some gasket maker, I was surprised to hear it was still leaking any at all after that. You could also use some 400 wet/dry sandpaper and some oil on a flat, hard surface, and run the sealing part of the valve cover on it to possibly remove a slight warp in the casting. Bottom line is the leak is more of a mess than a real problem.

goirish

What I used was Permatex High Tack Gasket Sealant, I don't think it is a gasket maker. Just something to hold a gasket in place.

Insanemoondoggie

Good stuff, wrong application. Go to your Yamaha dealer and pick up some YamaBond. Best sealant I`ve found , after 35 yrs. in the trades.

goirish

Thanks Insanemoondoggie (gosh what a handle) I have a Yamaha dealer close by, so will do. Thansk again.

Insanemoondoggie

LOL! Got my handle many moons ago , was called InsanePuppy then.
Make sure you clean the surfaces good and use sparingly. Follow directions on the tube. It`s also handles high temps well.

goirish

Great will get some tomorrow. Thanks again

MinnFlyer

My Feedback: (4)

If you think his handle's bad, you should see his spout!

But I know him well enough to take his word for an item like this.

Personally, I have used match book covers to make valve cover gaskets and they work fine

Flypaper 2

I use the automotive hi temp gasket maker. Works great on mufflers too.

WMB

My Feedback: (1)

Thanks for the reminder. I have used the Yamabond a lot when repairing motor bikes. I used to wonder why everyone used RTV when this stuff was available. Good stuff!