Question for motorcycle techs or diy'ers.

[Professor Gascan]

My motorcycle has screw type valve adjusters that use a 3mm square to set clearance and a 9mm nut to lock it down.

I'm currently using a tool from Motion Pro that uses a small, knurled wheel for the 3mm square and I have real trouble holding it still while trying to tighten the locknut. Even if I stop to clean the tool and my hands really well, I can't hold that little wheel tight enough to have it not turn when I try to lock it down.

Does anyone know if any tool company makes a 1/4 drive, 3mm square socket? It's not the end of the world, but I always end up having to do it 3 or 4 times before I get it where I want it. I just wish they had made the knurled knob a little thicker and put a 1/4 inch receptacle in it or gave it a handle like the lock nut tool.

 

[ericm]

Even with tools I sometimes find it difficult to hold the adjuster in place while tightening the lock nut. When that happend I back the adjustment off slightly and let it turn with the lock nut. It takes a couple times to find where to set the adjuster so it will come out with the correct clearance.

 

[General Geoff]

YehVeh 2 Pack Valve Tappet Adjusting Tool Engine Valve Wrench Mini 3-Way 3mm/3.5mm/4mm Spanner for ATV Screw-Type Valve Adjuster Motorcycle Scooter Dirt Bike Motorbike Lawn Mower Gas Cart - Amazon.com

YehVeh 2 Pack Valve Tappet Adjusting Tool Engine Valve Wrench Mini 3-Way 3mm/3.5mm/4mm Spanner for ATV Screw-Type Valve Adjuster Motorcycle Scooter Dirt Bike Motorbike Lawn Mower Gas Cart - Amazon.com

www.amazon.com

T-handle 3mm for more leverage

 

[Mandres]

Even with tools I sometimes find it difficult to hold the adjuster in place while tightening the lock nut. When that happend I back the adjustment off slightly and let it turn with the lock nut. It takes a couple times to find where to set the adjuster so it will come out with the correct clearance.

Same here, the clearance always seems to tighten up a little bit even if you hold it in place with a wrench. I leave them just slightly loose then double check again after locking it down.

 

[RoninB4]

-Use an open end wrench for this. When it's time to tighten the locknut you rotate the 3mm wrench CCW ever so slightly to just make contact with the square. As you tighten the locknut any rotation of the 3mm square will be stopped by contact with the 3mm wrench.

-You can try the T-handle suggested above by @General Geoff but it will still allow some rotation due to the play between the male square and the female drive. Everybody has different preferences so pick one you prefer but you're still going to have to develop a technique for blocking rotation. It's a common thing you have to develop a sense of feel/touch for doing. Sometimes I'll only tighten the locknut halfway, check the gap, and then tighten all the way. Mechanical contraptions sometimes require more than just the tools to do the job, the techniques of using them can be just as important. If you can sit while doing the adjustment it's a bit easier to concentrate on feeling with your hands.

-Either that or get a bike that uses shim-under-bucket valve adjustment (just kidding). I have had bikes and cars that used the screw/locknut configuration for decades, My XR 650L uses screw/locknut IIRC.

 

[dscheidt]

Same here, the clearance always seems to tighten up a little bit even if you hold it in place with a wrench. I leave them just slightly loose then double check again after locking it down.

This is one those knacks that gifted mechanics who actually mechanic -- you know, work on real mechanisms -- have. mechanisms that will shift as the fastening is done up are all over machinesof all sorts, and the really good techs know how much to allow for, and which way. Sometimes that's experience, but there are some people who know, never having seen the particular device in question. The rest of us get to do it a couple times.

 

[Sangant]

My motorcycle has screw type valve adjusters that use a 3mm square to set clearance and a 9mm nut to lock it down.

I'm currently using a tool from Motion Pro that uses a small, knurled wheel for the 3mm square and I have real trouble holding it still while trying to tighten the locknut. Even if I stop to clean the tool and my hands really well, I can't hold that little wheel tight enough to have it not turn when I try to lock it down.

Does anyone know if any tool company makes a 1/4 drive, 3mm square socket? It's not the end of the world, but I always end up having to do it 3 or 4 times before I get it where I want it. I just wish they had made the knurled knob a little thicker and put a 1/4 inch receptacle in it or gave it a handle like the lock nut tool.

I have some feeler gauges that are "loose" that I, um, cut/snapped off the stack. I put one of those in between the rocker and valve, then tighten it down. If you're not being too heavy with it, the feeler should pull out, and preserve your adjustment.

 

[lbhsbz]

Make one...couple minutes on the grinder to "convert" a 1/4 drive hex key socket

 

[Phang]

Even with tools I sometimes find it difficult to hold the adjuster in place while tightening the lock nut. When that happend I back the adjustment off slightly and let it turn with the lock nut. It takes a couple times to find where to set the adjuster so it will come out with the correct clearance.

this is what I do too

very similar to shooting during a windy day

then you do windage compensation

will take a few trials before hitting the bullseye

 

[RTM]

Make one like this, scale it down substantially?

https://www.garagejournal.com/forum/threads/no-idea-what-this-tool-is-for.549126

 

[F-22]

When that happend I back the adjustment off slightly and let it turn with the lock nut. It takes a couple times to find where to set the adjuster so it will come out with the correct clearance.

I do this too. I have lots of bikes, some of those lock screws have proper hex heads or allen keys or slots on top you can hold with a proper tool. Despite that, I still do it this way. The slack in the tool always makes it move slightly, and the threads are typically not fine enough and that small difference already tightens up the gap.

In my opinion it is better to just get used to it this way, because you end up using the same amount of time with a dedicated tool.

I remember some old probably Italian bike (I think Gilera) had adjusters that were "clamped" by the nut (sideways screw on the threaded portion of the rocker). That was a neat design as nothing moves when you tighten it down (but I assume it gives issues if overtightened and is more costly to make than using a simple locknut).

 

[Professor Gascan]

Even with tools I sometimes find it difficult to hold the adjuster in place while tightening the lock nut. When that happend I back the adjustment off slightly and let it turn with the lock nut. It takes a couple times to find where to set the adjuster so it will come out with the correct clearance.

This is also what I end up doing as well, and according to most of the other replies to my question I'm not the only one.

I don't know why I didn't think of it before, but the 3mm adjuster fits in a pair of 5 inch vise grips and holds it tight enough to do what I need to without having to clamp it super tight.

I was actually thinking of grinding two flats into it for grabbing with a wrench, but the vise grips hold it tight enough to get the leverage I need to hold it where I want the first time.

I appreciate the suggestions though... cheers all.

 

[Rusted Nut]

Agree with ericm. Also, check your clearance specs whether they are hot or cold clearances. If they’re hot specs, and you have an aluminum cylinders and head; the clearances will really tighten up if you adjust them cold. You can adjust them cold, but add at least .005 or more, then check hot. Probably a forum for your particular bike where someone has figured this out already.

 

[seber]

3mm is the same size as dedicated acetylene valve control. You might check a welding shop.

 

[bwringer]

Many of you seem to be misunderstanding the problem; the thing to be turned and held is a 3mm MALE square. Not much torque is needed; it turns freely to set the clearance once the locknut (8mm or 10mm hex, usually) is loosened, and only needs to be held in place while the locknut is tightened

I've never seen a socket for this (there are, of course, dedicated valve clearance tools), but a Robertson screw head fits very nicely with no slop thanks to the taper. Most mechanics make something based on a Robertson screw in a dowel or handle of some sort. Get creative. Release your inner Martha Stewart. Deploy epoxy or JB Weld as needed.

The valve clearance tools available all seem to have a bit of slop in the "socket", and honestly aren't worth farting around with for adjustments this fine.

As noted above, whatever you're using, the real solution is that you to develop the right technique and feel for backing off a little clearance to end up at the correct clearance when the locknut is tight.

One example of a commercial tool. Honestly, I find these things to be fairly useless.

Tappet Adjuster 3mm Sq., w/10mm Socket Wrench - Motion Pro

Motion Pro - High quality cables, tools and controls for motorcycles, ATVs, snowmobiles and personal watercraft.

www.motionpro.com

 

[drmarkr]

Even with the tool your desiring you still have to use the art of compensating for thread pitch movement when you tighten the lock nut. Practice makes perfect.