Tachometer take-off, welding repair?

[Guest]

The previous owner of my GS850G, 1982, shouldn't have been permitted to use pliers. Lots of fasteners have been replaced by incorrect ones.

Refer to

http://www.alpha-sports.com/suzuki_parts.htm
See "cylinder head"
Items 19, sleeve
23, plate
24, screw

The tachometer cable attachment to the head was leaking, and the PO tried to fix it by gobbing it up with epoxy. He replaced the stock screw, item 24, with a huge sheet metal screw, that munged up the threads tapped into the cylinder head. It looked as if he had tried to drill a hole in the pad, and drilled it off-center.

I bought the correct repair parts and installed them. A 5 mm screw didn't catch any threads to hold the lock plate down, so I tried a 6 mm screw. Putting this in cracked the pad on the cylinder head. There is nothing to put a screw in. So now I have two problems:

Short term: I don't know how to hold the sleeve in the cylinder head. Does anyone have any ideas on how to do this? My only idea at this point is to
a) attach a small plate to the frame tubes, directly in front of the sleeve. The plate needs a hole large enough for the tach cable. (b) Put long screws on that plate, on either side of the sleeve. (c) use jam nuts to adjust the screws so that they press against the sleeve.

Long term: It seems to me that the only good long term solution is to rebuild the pad that the screw goes in. So my questions are directed at people who weld. Can this be done? Would it require removing the cylinder head to take it into a shop? Or would a good welder by able to lay down new metal with the engine in the bike? Would it be difficult to find the right composition of rod to build up a new pad? What would the heat do to the head, both if it is on the engine, and if it is removed?

http://i104.photobucket.com/albums/m186/themess_2006/tachoutputdamage.jpg

 

[SqDancerLynn1]

You might try some QuickSteel (two part epoxie) like puddy Use a stud instead of bolt. Otherwise guessing they will want you to remove the head.

 

[Steve]

I had success many years ago when I broke a header mounting hole on the aluminum head on my Toyota Corolla. I did remove the head and take it to a welding shop where they built up the area with heli-arc welding. They then machined the surface to match the rest of the exhaust ports and, at my request, installed heli-coils in all the header mount holes and intake manifold mount holes.

My opinion would be to take the head to a shop where they can position it as necessary to fit their machines and do a good job for you.


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[Guest]

Thanks for the suggestions. I'm guessing that there isn't a whole lot of pressure trying to push out the sleeve. So, Lynn's suggestion might work short term. I really don't want to pull the head right now. But any machine shop would be able to get rid of Quick Steel in a jiffy. It'll be a b1tch to get the area clean enough for anything to adhere to, but that would still be faster than pulling the head. Can the head even be removed without pulling the engine?

 

[SPARKSS]

Thanks for the suggestions. I'm guessing that there isn't a whole lot of pressure trying to push out the sleeve. So, Lynn's suggestion might work short term. I really don't want to pull the head right now. But any machine shop would be able to get rid of Quick Steel in a jiffy. It'll be a b1tch to get the area clean enough for anything to adhere to, but that would still be faster than pulling the head. Can the head even be removed without pulling the engine?

Get that area oil free and dry. Use an alcohol based cleaner - SOME brake cleaner aerosol solutions are good for this (they should evaporate completely when sprayed onto a surface and then blown off with compressed air). Use a small wire brush (miniature "paintbrush" style is available through many auto or welding supply sources) and clean any aluminum oxide and hard matter - reclean with the brake cleaner. I'd recommend something like J-B Weld over the Quick Steel type of epoxy (leaving it to cure for 24 hours) for a stronger less-brittle result.

 

[Guest]

Thanks for the suggestion. I've been trying to figure how to clean the area properly, and your ideas sound better than what I've come up with so far. The only area that is clean now is where the metal fractured while I put the 6 mm bolt in, and that isn't enough to hold it. I'll probably try your method. I already have JB Weld, the slow curing version.

 

[Steve]

I already have JB Weld, the slow curing version.

Besides the obvious factor of curing time, the only other difference I have noted in the two types of JB is operating temperature. I forget the actual numbers, but the slow-cure will tolerate temps about 100 degrees higher than the fast-cure.
Clean it well, as suggested above, good luck.


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[SqDancerLynn1]

QuickSteel -- continuious Operating temp 500 deg F