Valve clearances, please hold my hand....

[TravisZack]

digging this one up but I could do with some hand holding myself... here are my numbers



I guess I need to adjust 1, 4, 5, 7 and 8. I'm just getting confused as to the process, working on one cylinder at a time would be easiest but I'll have to wait for shims to turn up before rebuilding, checking, dismantling the other side and then ordering and waiting again for more shims. If I take both sides apart I'll have to really check the sprockets and timing marks all line up when I put it back together, which is fine, but is it even ok to keep turning the engine over by hand?

These things are a right pain compared to lock-nut adjusters.

[Jamoi]

Looks like your 0.13 clearances could do with 0.05 shims which will get you to 0.18mm.

And your 0.23 & 0.24 clearances would need 0.10 shims to get to 0.33 & 0.34.

I'm not sure if shims come in 0.10mm increments? Or if you can use x2 0.05 shims?

I just about scraped through this myself, so might be worth shooting a PM to Tony for properly sound advise on your clearances.

[tony.mon]

Jamoi, I think your post might be misleading- you don't fit stacks of shims, only one in each bucket.

If the gap is too big, then you need to swap the shim you have for one that is thicker.
If the gap is too small, then go for a thinner shim.

As to how much, just work out how much of a difference is needed and deduct/add that thickness to the shim you have fitted.

For example:
You have a 180 shim fitted, and the gap is .05 smaller than your ideal size, (let's say it's an inlet, so the ideal gap is .16mm) the acceptable range for an inlet is from .13 to .19mm.
Your gap measured .11mm.

A 180 shim measures 1.80mm.
You need to make the gap bigger, so need a thinner shim.
It needs to be .05mm thinner, and so you need to remove the 180 shim and fit a 175.

Actually the Haynes isn't so bad; they give a calculation that works fine, but it depends on how your maths is.

You have to remove each cam and refit it after the shim has been changed, and check the gap once more. Then move on to the next one.
But this is easier for a novice that trying to change them all and then check them afterwards- it's too easy to mix them up, especially if several need to be changed.

[Jamoi]

Ahh yep, I've slept since I did this job

Told you The prophet .Mon was the man

[TravisZack]

Ok... so front cylinder

In - 0.13mm – Shim size - Barely visible but looked like 207? I don't think that's a size they come in but I've no way of accurately measuring.

Ex. - 0.23mm – Shim size - 1.2 - this will need a 1.12, right?

[tony.mon]

Ok... so front cylinder

In - 0.13mm – Shim size - Barely visible but looked like 207? I don't think that's a size they come in but I've no way of accurately measuring.

Ex. - 0.23mm – Shim size - 1.2 - this will need a 1.12, right?

No point taking a chance on the markings being correct, so buy a cheap digital vernier and measure them.
They're cheap, honest, about the price of two shims.
Tenner in the UK.

But broadly you're right if your sizes are correct.
By Jove, i think he's got it!

Almost always the shim range is 172 to 187 or so as standard.
If the shim is much smaller than this then it may be that the valve seat has been cut into the head after a seat re-cut. i don't think this is very likely, and hence my suggestion that you measure it accurately.

Occasionally, if I haven't got a shim of the right thickness I'll thin one out to the next under size by using grinding paste on a sheet of glass.
Takes bloody hours and wears your fingertips away, but save waiting until the right size is in stock a few days later at the main dealer.
But when that happens I end up with a shim that says one thing and measures another.
You can't trust the etching markings, is all I'm saying.

[TravisZack]

I understand how it all works, my worry was getting them all out at the same time and having to deal with timing marks to set everything back in the right place. That's all explained in the workshop manual though so no worries, just need to measure up properly and order some new shims.

[tony.mon]

Draw a little picture on some cardboard, a grid of two by two for each cylinder, and lay parts in the correct segment.

It's easy to mix things up, and the old saying about measure twice cut once applies- check each shim is going to make the gap bigger or smaller- it's so easy to go in the wrong direction.

[VTRDark]

And it wont affect your timing at all unless you go turning the crank, so work on one cylinder at a time. Just make sure you set the timing to the compression stroke beforehand. You can safely remove both cams but be careful not to loose the chain down the tunnel. Coat hanger does the trick to hold the chain up. just hook it over the side of the head.

Then when it comes to putting the cams back in and putting the chain over the cam sprockets, start with the one opposite the side of the tensioner. Pull the chain taught over that sprocket and then take up the slack up with the tensioner on the other side. Tip for you. Don't fully bolt down the cam caps until you have the chain over both cam sprockets and do not over tighten the bolts. They can snap. I like to tighten them up slightly under the recommended torque unless using brand new bolts, and do them up in a criss cross pattern a bit at a time.

You could work on both cylinders at the same time but you have to know what your doing with the timing. It's easy to mess things up. Also the chain can get snagged as you turn the engine over so that has to be held and pulled taught at the same time the crank is turned over. An extra pair of hands helps.

(:-})

[TravisZack]

Ok so I have some digital calipers and have measured up.

They have come out at:
1.83
2.0 (clearly says 2.2 on it)
2.0
2.0
1.8 (looks a lot like 1.2 stamped in to it )

Either I have the worlds worst digi calipers or there's something weird going on with that last one. The others have nothing legible on them. Either way, going off those measurements the ideal sizes I need are:
1.76
1.98 x3
1.72

Anyone on the forum have a supply or am I splashing out again??

[popkat]

You should be using a micrometer not vernier although you could get away with it, I wouldn't use one.. they are precision instruments, you don't squeeze/do them up tight, they should just lightly grip either side of the shim.. you may know this and possibly be an engineer in which case ignore me as you will know this and more

[tony.mon]

Even if the measurement is not exact, you can still, using the same pressure on the thumbwheel, get a clear indication as to whether you need to go bigger or smaller and by how much.

It's a relativity thing....
Not so much exactly what it measures, but how much different it is from another, known item or value.

I buy my shims from the US but it depends how quickly you need them.

[TravisZack]

So... What do I go for? I'm under the impression I'm gonna spend £25 or more and have it end up worse than it currently is. Could do with a whole bunch to swap out and try but that's obviously not ideal. It's just dragging now, want to get them sorted.

[VTRDark]

You should be using a micrometer not vernier although you could get away with it, I wouldn't use one.. they are precision instruments, you don't squeeze/do them up tight, they should just lightly grip either side of the shim.. you may know this and possibly be an engineer in which case ignore me as you will know this and more

If he was an engineer he would have a micrometer. Got to love the clicking action for precision on a micrometer.

I must admit I tried with a vernier and I would get a different result each time as my finger pressure would vary, so basically you end up doing you sums all again. If you do get yourself a Micrometer make sure it's in 0.25 increments. It simply makes life easier. You can get a cheapo micrometer on eBay which will do the job. No need to go buying the latest digital Moore and Wright.

9.48 diameter shims are what you need. You can pick them up on the bay too.
http://www.ebay.co.uk/sch/i.html?_from= ... s&_sacat=0

(:-})

[TravisZack]

I only bought the verniers as that's what was suggested further up. I found that once they're touchong it took a fair amount of pressure to skew the result, it's just a long way off what is marked on the shim, at least on the two that still have it visible.

I'll just buy what should be the correct sizes from these measurements and go from there.

Thanks for the help by the way, I do appreciate it, it's just gonna end up taking two weeks to do a job that took half an hour on my last bike, and was free. It's putting a halt on things having to wait around for post.