brido wrote:Right lads I need some help again with the valve clearances, I have measured all the valve clearances and the shims, what I need to know now is which size shim to go for, I used the formula in the haynes manual so here is an example of what I got,
a = b - c + d
2.29 = 0.13 - 0.15 + 2.27
Now the shim needed is a 2.29, can I get a 2.29 shim or do I have to go nto the nearest one available???

Correct me if I am wrong

Mate, is above calculation of the Haynes shim formula correct?? (0.13 minus 0.15 makes to me negative 0.02) + 2.27 = 2.25, right?

If on the tight side of measurement, then you need to drop in shim size in order to gain more "gap".
And if on the loose side of measurement, then you need to increase/thicken in shim size to gain less "gap".


Performed my 2nd valve clearance job, done it on my project bike this evening. My second time I'd ever done this. It went a lot easier than the first time last year on my other bike, as I now know what to look for, what to measure and do have access to the necessary tools.

8 x valve clearances needed adjustment as these were on the tight side. I only could replace 6 shims with ones I had left from last time and 2 x shims replaced in between them. I just need to order 2 x new shims 2.275 and 2.300

micpec wrote:

brido wrote:Right lads I need some help again with the valve clearances, I have measured all the valve clearances and the shims, what I need to know now is which size shim to go for, I used the formula in the haynes manual so here is an example of what I got,
a = b - c + d
2.29 = 0.13 - 0.15 + 2.27
Now the shim needed is a 2.29, can I get a 2.29 shim or do I have to go nto the nearest one available???

Correct me if I am wrong

Mate, is above calculation of the Haynes shim formula correct?? (0.13 minus 0.15 makes to me negative 0.02) + 2.27 = 2.25, right?

If on the tight side of measurement, then you need to drop in shim size in order to gain more "gap".
And if on the loose side of measurement, then you need to increase/thicken in shim size to gain less "gap".


Performed my 2nd valve clearance job, done it on my project bike this evening. My second time I'd ever done this. It went a lot easier than the first time last year on my other bike, as I now know what to look for, what to measure and do have access to the necessary tools.

8 x valve clearances needed adjustment as these were on the tight side. I only could replace 6 shims with ones I had left from last time and 2 x shims replaced in between them. I just need to order 2 x new shims 2.275 and 2.300

If u need them asap try your local Honda dealer that has a work shop.
When I done mine I needed them asap so i went to johns of Romford and bought 4 shims @ £5 each but they r slightly cheaper on the web but u got postage cost. I swapped a few around till they were all more less perfect. I got 4 spare now.
Even tho they might have a number on them it not mean they r correct. I bought 2 x228 I think and they were 227's but that's wot I needed anyway

Well, I am not in a hurry for the shims. I normally can order them through local shop and it takes 3 to 5 days, now as a part of my much larger order from Honda I also have some 5 or 6 shims left in the box...sadly not in the correct sizes that I need for completing the valve clearance check.

About that calculation I quoted yesterday...anyone confirm this before someone sets the valve clearance possible wrong and end up with a blown piston to valve or similar

IF you calculate: 2.27 + 0.15= 2.42 - 0.13 = 2.29 (this means you go thicker in shim-size and that means less "gap" and results in new clearance: 0.11 (this is not within the spec of 0.12 up to 0.18 for an inlet valve).

But to me it should be as per haynes formula: (0.13 - 0.15) = - 0.02 + 2.27 = 2.25...am I correct?

You've confused me Jas..

You have a clearance say....0.11 and a shim 2.20

You want it to be maybe 0.15 so you need a shim 2.16

It is simple...sod the formuale, get it in your head when you are working on it and it makes sense.

I was confused by brido's calcuation. Hope all is okay.

CMSMJ1 wrote:You've confused me Jas..

You have a clearance say....0.11 and a shim 2.20

You want it to be maybe 0.15 so you need a shim 2.16

It is simple...sod the formuale, get it in your head when you are working on it and it makes sense.

I agree.

Buggar the formula it complicates things.

Measure the size of the shim and measure the gap.

If you need a bigger gap you need a smaller shim

If you need a smaller gap you need a bigger shim.

They usually come in .05 increments so you can see how your going.

Best thing to do.

Measure all clerances and mesure all shims and write them down.

You can see then work out if you can swap shims around.. ie if you have one tight and one loose you might be able to swap them around, it's often the case...

Once you've got a record of all the shims in the bike you only need to measure clerances next time to work out Whats where...

Neosophist wrote:
If you need a bigger gap you need a smaller shim

If you need a smaller gap you need a bigger shim.

I agree with this too! But the formula given must be read and used correct. And guys, I now know for 100% sure that below quoted new shim size is wrong! Brido needs a smaller shim of 2.25 as he measured a tight gap of 0.13. Therefore, I hope that engine of Brido is still alive and kicking. (I am waiting for my ordered parts including correct shims coming in at end of this week from local dealer so I can finish this job hopefully this weekend ).

brido wrote:Right lads I need some help again with the valve clearances, I have measured all the valve clearances and the shims, what I need to know now is which size shim to go for, I used the formula in the haynes manual so here is an example of what I got,
a = b - c + d
2.29 = 0.13 - 0.15 + 2.27
Now the shim needed is a 2.29, can I get a 2.29 shim or do I have to go nto the nearest one available???

Wow over three months to finally get round to this.

What if there is no clearance? The engine is drained of all oil and and still in the bike so I was have a sort of look round the other day and couldn't see a gap so thought that may be I should test the compression and see what there is. But can you get a viable reading turning the engine over by hand?

katana wrote:Wow over three months to finally get round to this.

What if there is no clearance? The engine is drained of all oil and and still in the bike so I was have a sort of look round the other day and couldn't see a gap so thought that may be I should test the compression and see what there is. But can you get a viable reading turning the engine over by hand?

No you can't.. you need circa 300rpm.

The clearances are quite small.. you need a feeler gauge to measure them.

You also need the engine to be at the right position to measure certain valves.

My smallest clearance was on my spare engine and the clearance was 0.04 on inlet and it should be about 0.14 and shim size was a 2.40 lol