Ideas for reparing bolt boss

[daf1668]

While trying to remove the broken screw from the front center of valve cover the boss on the head broke off. Looking for what has been do in the past if this has happened to anybody else. Thank you for the help.

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[Rickrod3]

I would look into a replacement but:

You could look into this product.

http://www.youtube.com/watch?v=843jj...eature=related

I'm considering it to repair some fins but; haven't as yet got around to it.
Andreas Wiess may have a replacement.

Good Luck
Rick

[cywelchjr]

That is really nasty looking. I think you may be looking at replacing the head there. I'm not sure that's something that can be repaired, not and stay repaired anyways.

[crazy steve]

You could look into this product.

http://www.youtube.com/watch?v=843jj...eature=related

Most of these 'home fix' aluminum welding products have one major drawback; they melt at too low a tempature. A cylinder head can get pretty close to that hot in normal use. Not much point if the first time you ride it that stuff all runs off...

Best bet? Find somebody that can TIG-weld the piece back on, or just get another head. You might also try gooping it real good with silicon and forget the bolt..

[bikerphil]

Might be able to grind the bottom of the boss somewhat flat, then use a nut and a bolt to fasten the valve cover down. Maybe using a flat piece of steel as a washer on the bottom. Then use RTV around that area. JAT

[ManagerMike]

Ouch!!!

You already know what the only permanent repair is... remove from bike, strip it to bare casting, send to qualified aluminum welder, then to machine shop for re-finishing....mega fundage!!

That being said, there are a number of less invasive options, as it appears that the failure did not extend into the oil side of the casting and is confined only to the gasket clamp load boss alone.

The simplest option is to ignore it and use a gasket material that requires no clamp "load" per se, such as yamabond or permatex anerobic sealer using the remaining screws to "make" the gasket, then use jb weld or jb quik weld to 'bondo' the screw and missing boss in place for cosmetic purposes.
If you want to return to a cut gasket and need the clamp load to seal it, the best option (short of the permanent fix) is to use a product made by 3M called DURAMIX. It is an epoxy like material that has a working time of 20 seconds, is "machineable" in 5 minutes and fully cured in one hour resulting in a polypropalene like end product.
The starter kit comes with the applicator gun, two 4 0z packets and 6 'mixer' tips for about 100 bucks and available at NAPA. You can form it in place around a screw, let it harden, then remove the screw leaving re-usable threads behind, and this stuff has hundreds of other uses as well. I use it at work as a temporary patch for rusted through and leaking oil pans among many other things. I used it to recreate the broken thread boss on my cam chain tensioner and ran it a full season until cowboybob hooked me up with an undamaged used replacement. Thanx again Bob

[skids]

Might be able to grind the bottom of the boss somewhat flat, then use a nut and a bolt to fasten the valve cover down. Maybe using a flat piece of steel as a washer on the bottom. Then use RTV around that area. JAT

I would probably give that a try. You might be able to find a flanged nut and grind off the portion that would be next to the head. Maybe the remaining flange portion could help keep it in place with the ground-flat surface of the boss bottom...

[daf1668]

Thanks for all the great ideas. I do agree a new head or tig is the best answer. Just trying to get thru this riding season is all. Probably will go with the nut and bolt idea with rtv sealant and do a permanent repair or replacement head this winter.

[b.walker5]

Ouch!!!

You already know what the only permanent repair is... remove from bike, strip it to bare casting, send to qualified aluminum welder, then to machine shop for re-finishing....mega fundage!!

Had to do it to mine a while back, but then we have alloy welders at work and the machining was done by me with a file, sandpaper and a thread tap. All up it cost me 40 bucks, and part of that was for the tap.

I realise that many dont have access to things quite that easily but it illustrates the point that these things dont always have to be difficult, or terminal. I bet if you look round your circle of friends you'll likely find someone that knows someone that can sort it for you at minimal cost.

[yamahaluke]

get a wire cup for your drill, clean the site real good, then load the bike in a pick up and find a descent welding shop in the area. Look for the kind of place where most the guys look a lil disheveled and hung over. show it to them and I bet they can build up the area with tig welder then you get home and grind close to flat, file completely flat and drill and tap. I had the same thing happen, total repair cost assuming you have the tools to do the grinding, filing, drilling and tapping. . . ten bucks and a six pack for a tip!