Larger coil pin in steering arm - narrrow frame
 

On my 125, I'm thinking of drilling and insert a larger 3/8" diameter coil pin in the upper steering arm and spindle to get rid of the slop there. The larger pin will replace the original 5/16" diameter pin. I had inserted a new 5/16 " coil pin but it did not help as much as I hoped. Good idea? Or will I weaken the spindle too much? Everything else in the steering system is in good shape.

5/16 pin is 7.9375MM.. I would try a 8MM metric pin first. I think Grainger has them.

It is not the pin but the hole is over easy....

This is how I fixed a couple of mine. They worked out well, and I have had no problems.
In this case, someone had welded the arm to the spindle by drilling out the top of the arm and weldingthrough the hole, so the top of this spindle was really booger'd up. Pictures follow in this order:

#1. These are 3/8" set screws. Don't remember the length. You can get them in square or allen head.

#2 and #3. Drill and tap the arm for the allen screws.

#4. Counter sink the pin hole in the spindle, on both sides, at a size and depth just enough for the tips of the set screws to get a good bite.

#5. Install the spindle and arm. Tighten down the set screws and lock in place with jam nuts.

#6. Finished. Ihavn't had any come loose. I theorize that if they do I can just re-tighten the set screws. Just something that has worked for me.

Brilliant fix!

I fixed mine with a tapered pin, #7 if I recall correctly. I ran a tapered reamer through the hole, tapped the pin in, and cut off the excess length of the pin.