That is pretty much what I was going to do with a tapered aluminum fitting, thread the fitting in then die grind around it to clean it up then run a few beads of filler rod around it one tack at a time so I don't put much heat into it. Hoping there isn't to much to fry in there o ring or seal wise with the heat as I haven't had much to do with top breather motors.Have seen where some have attempted to weld in that area without success.
I have repaired one before with a different method.
First find something you can plug the oil passage and can get back out later.
Take a die grinder with a carbide burr and cut the top surface flat and square to the drilled hole.
Be sure to get deeper than any cracks or defects.
You will most likely have a few remaining threads, enough to start and guide an 1/8"X27 taper pipe thread tap, the hole will already be the proper diameter.
Yes, you will end up with a step in that area but it will be repaired without a chance of heat induced damage from welding.
The only concern is keeping chips from falling into that hole.
Some very good tips and will be the best way to go for sure I was going to pull the back lifter block and use a 90deg rubber elbow on a vacuum and some molly tac grease on the tap lay the motor on the back cylinder, but what you said makes a lot a sense did you guys have any issues tig welding the case ?The chips are the issue - we did a few only way i see to try and not loose the engine was we had an evo lifter block that the bottom was cracked - machined it for a fitting for air pressure - removed the other lifter block used a shovel solid lifter gasket so the air stops - then removed the cone and the oil pump - connected a adjustable lever tap and gage
fed the holes drilled by the factory for oil with air then we did the drilling and tapping - as far as we could tell the chips blew out the drill sides and the tap flanks bike is still a customer 3 or 4 years ago we did that one
i would remove cam cover and remove the plastic breather**you are better off welding a whole motor all assembled & torqued, * the internals are a great heat sink to get heat away faster than when disassembled, plus when assembled things are far less liable to warp & fuck up, seen it happen many times,
As a general rule yes, assembled cases will help control warpage. Two case halves bolted together will be a good thing for something such as but not limited to a broken/damaged motor mount.**you are better off welding a whole motor all assembled & torqued, * the internals are a great heat sink to get heat away faster than when disassembled, plus when assembled things are far less liable to warp & fuck up, seen it happen many times,
I don't think there is enough Meat left on the left hand side/ low side of the thread maybe an eighth of an inch and the only reason I was contemplating welding the thing while assembled was for the reasons Magnum Pete put foward, I figured that I would take it easy and not buzz to much heat into it. If I had to spilt it id definitely run a new or 2nd hand case for sure.Again---> Have seen where some have attempted to weld in that area without success. <---
Contamination while welding WILL be an issue, your welding a die casting around an oil pressure passage...
Plug all openings, ports, oil line fittings... Do not remove the tappet block as you will be opening up much more of the engine = larger chance of contamination inside your engine.
Fill the passage with thick grease, as much as you can get in.
Die grind the surface as needed to get it clean and free of defects and square to the hole.
Yes the case surface will be lower in that small area, that's not a problem past cosmetic.
Who cares if the pressure sending unit ends up a 1/4" lower.
Grease up a tap and twist it in just deep enough, it's tapered remember...
Once it's all ground to shape and tapped, poke a wire into the greased up passage to dig out the chips stuck in the grease.
Once all the chips are gone, flush it with brake cleaner from a spray can.
Jam the spray cans straw deep (roughly 2-3 inches) into the grease to force the grease up and out.
Watch out for flying grease and maybe a chip or two when using the brake cleaner spray.
Your chance of a leak free repair is a lot greater if you don't attempt any welding on a crankcase with the engine assembled.
Thanks for that, never had a top breather apart before and not up with what they do and don't have, best thing about asking get the heads up(guess that's an Aussie term for the right way) before I get into the thing.i would remove cam cover and remove the plastic breather
Yeah Richbob I am going to spilt the thing i have decided, I know the Tec that built it and it is a really good thing, I've decided to do it right due to porosity of cast Aluminum and so on, I know this year was back to being cast in the USA if I am correct and thought it may have been as easy as knocking the oil pump and lifter boar off and a few hits with a filler rod. Even good Evo's are getting thin on the ground.wind your fitting back in and JB weld the area back to its original shape bit of black paint and jobs a good un.
Or strip the motor and do the job properly.
I'd think about it for awhile, do some research. Aluminum repair adhesives have come a long way. There is some amazing stuff out there for repairing threads. I watched a Loctite rep break a bolt off in a thread repaired hole it was so strong. There's really no pressure on a repair like yours. It's not really holding anything other than a sensor or oil pressure gage.Yeah Richbob I am going to spilt the thing i have decided, I know the Tec that built it and it is a really good thing, I've decided to do it right due to porosity of cast Aluminum and so on, I know this year was back to being cast in the USA if I am correct and thought it may have been as easy as knocking the oil pump and lifter boar off and a few hits with a filler rod. Even good Evo's are getting thin on the ground.
It is a very nice strong running motor and fresh top and bottom, just the guy i bought if from over tightened the oil pressure fitting. You may be on the money, i just picked up a real nice set of cases but i might as well try a compound first, nothing really to loose and may get a long run out of it with a compound repair.I'd think about it for awhile, do some research. Aluminum repair adhesives have come a long way. There is some amazing stuff out there for repairing threads. I watched a Loctite rep break a bolt off in a thread repaired hole it was so strong. There's really no pressure on a repair like yours. It's not really holding anything other than a sensor or oil pressure gage.
I would think, if you cleaned real well and your repair held you could continue to use the machine until it really needed to come apart and be rebuilt. You could revisit it then.
If it doesn't work.....you can begin the tear down.
In our old shop one of the guys is a Boilermaker, certified pipeline welder and a wizz on the Tig. I watched as the repaired a case from the sand cast 88 Evo that i believe were made in the regions of Asia, the thing was so porous that you could visibly see black impurity's seeping out of the belly machined gasket surface, always have that in the back of my mind and maybe a chemical fix would be the way to go until next rebuild, Thanks for the comments and advice.Modern structural adhesives are used to install heavily loaded bushings and are more than up to the job. I enjoy welding but there are all sorts of advanced products out there. You don't even have to guess because the makers websites have tech support lines not enough people use. LOCTITE® is an example and Henkel make far more than Loctite. https://www.classccomponents.com/wp-content/uploads/2017/06/Loctite-Fixmaster-Metal-Rebuilding.pdf Harley cases aren't that great (they are not "premium" motorcycles and have no exceptional characteristics while cases went through multiple revisions because the company cared more about saving metal than strength) so adhesive may be a better solution than welding for some repairs as it won't distort adjacent structure.
The Guy at Loctite said epoxy weld in the same process as you described except for the JB part, I will give it a go see how it works.Id wind it in gently with the correct loctite product and then repair area with JB weld using a blade or small spatula(making a small fillet around fitting r2mm or something using a machine coffee stirrer)
Im a big fan of JB weld
And like the other guys say weld or replace at a later date