Valve Adjustment Locknut size on 550ED

[Anonymous]

I was wondering does anyone know the size of the head on the Screw that is in the center on a 550ED valve locknut. I need to adjust my valve clearences and I tryed a 4mm wrench and it was still to big for the screw part.

[Anonymous]

Do you mean the square adjuster, IIRC it is 4mm across the flats, I ended up fabricating a tool of my own to do job. Basically it consisted of a length of metal tube that I had lying round the garage. I forced it over the end of a spare adjuster that I had on a head I use for spares so that it assumed the square shape.

Aluminium or even plastic tube will do as you're not using any great force to adjust the gap.

Plus it also allows you to drop a ring spanner onto the lock nut once you set the gap so you tighten it up whilst holding onto the the "tool" which means you don't disturb the gap!

[lhanscom]

Not only is it small, but it's also square, not a hex. They make special tools that have a 10mm wrench, and the square drive as 1, so it's nice and easy. I've always found that once I loosen the lock nut, I can turn the adjuster with my fingers, the trick is getting it to not move when you tighten the nut again.

BTW, I'm assuming your adjusters are the same as the ones on a 700 and 1150, as those are the only ones I've done.

[Anonymous]

Just remeasured and they are actually a shade over 3mm across the flats!

[Jethro]

I went to Sears to buy a 3mm spanner for that purpose. The smallest they had was a 4mm in a set of tiny ignition wrenches in a little pouch. They had a 4.5mm, 5.5mm and other strange sizes. I took the 4.5mm, figured I'd never use it, heated it up cherry hot, then crushed it in the vise. Presto! A perfect 3mm wrench for adjusting the valve stops! Only $10 and I have a really funny set of the other microscopic wrenches.

[Joe Nardy]

There is an official Suzuki tool for the job. It looks like a stubby screwdriver with a very short handle, more like a knob. It has a cylindrical shaft with the appropriate size square cut into the end. You loosen the locknut, adjust the clearance by turning the tool with thumb and forefinger, then tighten the locknut. A guy I work with gave me one that he had laying around in his garage from years ago. It is one of those simple little tools that really makes the job easier.

Joe