Is a micrometer always required for valve adjustment? Are installed shim sizes reliable?

Even easier to do if you use the zip-tie method or the wire method

I can usually have a few valves done in the same amount of time takes to do one valve with 'the tool'

Yes compression is lost when the valves are not close.... exhaust valves can get too hot and burn the edges, especially if it's coupled with a lean charge.

These are MUCH easier to adjust.... check the clearance, check the chart, swap the shim, close up up, go ride.

The "singer sewing machine sound" is a GOOD sound. Chatty valves are HAPPY valves

 

Good idea Hogfiddles, I might try that next time they need done. Loose valve clearances must open late and close early then I assume. Clearly the parameters Yamaha use are to allow the engine to breathe properly that is why valve clearances are critical to good engine power output and longevity. I was always fascinated how reciprocating engines work, it is amazing how they stay together.

 

With the old Honda I got to the stage when I removed the adjuster caps I did not bother trying to get a feeler gauge in between the valve stem and adjuster screw. I just slackened them off put the feeler gauge in and tightened the screw till the gauge was a good sliding fit then tightened the locknut and finally rechecked. Yes the shims on the XJ are much easier and I with fewer moving parts I assume shims engines will stay in spec longer than engines with screw type adjusters and rocker arms.

 

They may or may not......that why there is a 5000 mile regular checkup. If they are in, the shims stay....if they are out, you swap, some will change a few times, others won't. As the mileage gets higher, the amount of changes gets less. Kind of like the seats slowly get hardened as they "compress"
The nice thing is, that you don't have to worry About the valves hitting the Pistons, though, as they go out of spec. That can't happen that way.

Dave

 

Yes true they are great engines and easy to service.

 

Why not get a measurement caliper anyway from Harbor Freight? A plastic variety is available for around 10 bucks. It measures inches and mm and
has a digital display. I keep one in my tool box and use it all the time.

 

Calipers will only measure the edge thickness. Since the cam does not run on the edge of the shim any wear will show up toward the middle of the shim. A micrometer is the correct tool for that type of measurement.

 

That is true but the HF digital caliper has parallel jaws that are 1 1/2" long. They reach almost all the way across a shim. If one
can't see light under the caliper at the middle of the shim wouldn't that be an accurate measurement. I also use one to measure
clearances, diameters, thicknesses etc. They are well worth the price. Yes micrometers are more exact especially for cylinders and
crankshafts etc. I'm going to check out a set of xj650 jugs tomorrow and will see if I can rent a micrometer from Autozone

 

I'm not really understanding how a micrometer could help this process if the current shim size is still readable. Even it has wear, will it really wear enough to be the next shim size down.

For example, I doubt a 270 shim will wear down below a 265? I would think that much wear would be visible with a straight edge across the shim?

In this case, if the current shim is labelled 270, and the specs are less than .005 out of the bottom of the range tight, then a 265 should bring in the spec range, even if the original was slightly worn.

I may be wrong.

 

I'm just clarifying what the different measurement tools are intended to be used for.
It is highly unlikely that you'll ever come across a worn shim, and even less likely that the wear will be enough to make the shim unusable.

People have been known to grind shims instead of buying new, and even that is an uncommon thing for the larger diameter shims the XJ uses. In that case I would want to know exactly what the measurement is of the daylight between the shim face and the caliper (though if the work is done correctly there will be none). Eyeballing .05mm takes a lot of practice.

 

Maybe, maybe not. All I see in this thread is a lot of time overthinking things where these people could be out riding

 

If it is worn, just flip it over

 

Right on if the top is dished the bottom with the numbers would still be intact

 

OP here.

Thanks for all the post.

I went ahead and purchased a micrometer.

Turns out that at 12k miles, the used shims were still exactly the same thickness as they were labelled. Hooray for hardened metals.

 

Great idea.

 

I, ve always checked the shims with a micrometer , as I use a combination of genuine and aftermarket shims . The genuine are pretty reliable , but I've found that the AM can vary up to .02 of a mm I've found that some times if the clearance is borderline , just replacing an AM with a genuine of the same stamped value can bring it in . It's worthwhile having a range of good quality micrometers in the tool kit