Checking Valve Clearances: Near Disaster?

[Steve]

If you hook the coat hanger to it before it falls, it's a LOT easier to keep track of it.

Ekabil, I think you are making it harder for yourself if you don't remove the cams. Just lift the chain, take out the cams, hang the chain from the coat hanger, work your way around more easily to clean things up. When you are ready to re-install, you will need to have the ignition cover off the right end of the crank so you can see the timing marks, then follow the procedure in the manual to re-install the cams. It's really not all that hard.

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[Allie]

You can just insert a long socket extension under the chain in place of the cams. Do NOT put the extension in the lower bearings, don't even breathe on them. Thinking don't rotate the engine another smidge, just get the cams out. Thy should have less tension on them with so many shims out, no?

[ekabil]

well thanks guys, I think I'll pick up a magnet and a torch today on my way home and then get to work getting those bolts off or cleaning up what I can, putting shims in, and rotating the cams so I can get the covers off and then the cams off. its like light at the end of a tunnel (or a carb jet in my case)

[ekabil]

Sorry guys and gals, no pictures today. It rained earlier and it's cloudy out there and I don't want to get caught with my pants half down. I'll work on these carbs today and hopefully it will be sunny tomorrow

[Allie]

One thing, you'll be using a magnet in there to get metal out, but I've read cautions to avoid using magnets by the shims as there could be a risk of a cam lobe sucking a shim out at high revs and throwing it. I don't know how true that is, after feeling the seal that the oil creates between the shim and the bucket, but to be safe at least have alllll the shims out and away from the head when you cut loose with that magnet. I'd avoid using it by the cams too.

[Steve]

... and I don't want to get caught with my pants half down.

Maybe THIS will help. It was posted just a few days ago.

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[Allie]

It's one of those wives tales myths some people like to perpetuate as the truth because someone told them so, or they know someone who really had this happen BS, you can look in the XS1100 Yamaha manuals and they even suggest using a magnet to get the shims out, takes more than a little contact to magnetise something of that size, especially for any length of time.

I'm pretty sure I read that caution in the Clymer manual /shrug.

[Nessism]

I've used a magnet before to remove shims. Seems low risk to me.

[7981GS]

I've used a magnet before to remove shims.

Eric

[Steve]

One thing, you'll be using a magnet in there to get metal out, but I've read cautions to avoid using magnets by the shims as there could be a risk of a cam lobe sucking a shim out at high revs and throwing it.

You would have to be WAAAYYY over-revving the engine and getting into some SERIOUS valve float to have that happen. I don't have have a valve bucket handy to measure the depth of the rim, but I know it's WAY more than the .03-.08mm valve clearance. You would have to have valves floating at least as much as that depth before there is any danger of spitting shims.

It's one of those wives tales myths some people like to perpetuate as the truth because someone told them so, ...

I have seen that caution a few times on this forum, but have never seen it in an official publication.

I've used a magnet before to remove shims. Seems low risk to me.

Me, too. I actually do it quite often, especially on the smaller engines, there is not as much room to get hemostats in there to grab the shims.

It takes more than a simple contact and release to magnetize the shim. You need to stroke it several times, and that is not my 'thing'.

I think a larger concern about magnetizing the shims is that it might attract any metal shavings, which would then score the cam. Sorry, but any shavings that might be attracted to a magnetized shim would go to the outer edge, where the magnetism would be the strongest. Guess where the cam lobe does NOT hit?

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[Allie]

You fellows only think that way because you don't have your tin foil hats on. I wear mine 24/7 so I am unaffected by the evil magnetism.

Seriously I believe your explanations and as I said I myself had some doubt as to the true danger. I could swear I read that caution (to be exact it cautioned against using magnetic screwdrivers) in the manual -which doesn't automatically make it true- but I'm going to double check it when I'm home today. If it's not in there it means I got it from a less reputable source, ie here. My point is I'm not in the habit of promulgating something as truth just 'because someone told me so' and believe me I pay attention to such things. I'm not immune to error and oversight though, so we'll see.

[Agemax]

if anyone has any doubt about using a magnet to remove shims etc, then there is one easy answer.
use a magnet to fish the shims out then run them through a demagnetiser before refitting

[mpencegs]

I read the do not use a magnet warning as well in the clymer manual.

[mpencegs]

Thanks for clearing that up. It is good to remember that these are not manufacturer manuals (Clymer and so forth) and therefore are not always correct.. *Also a little sad you have to add a disclaimer like that..

[shwaz]

damn you, pot-stirrer!


my feelings have been hurt reading this thread. going to cry in a corner.