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CBF 250 Small Shim Sorted
Blog Date - 11 November 2013
Further to the previous post re sorting out the valve clearances on the new CBF 250 I enquired at a couple of bike shops to see if they had any dinky shims.
There was no gap AT ALL between the camshaft and the buckets. Normally the gap on the exhaust ought to be 0.15 mm. Using feeler gauges you may find for example that the gap has shrunk to 0.10 mm in which case you need a shim that is 0.05mm smaller than the one currently fitted to that valve. You would then remove the shim, note it's current size then subtract 0.05 mm which would then give you the size of the new shim you require.
But there was NO GAP...hence measuring the gap to calculate how far out the existing shim is became impossible.
Buckets and shims...not one shim is the right size now though.
My first stop, Orrell Motorcycle Centre, took the time and effort to look through a tray of old shims they have in the workshop. Their stock of old shims is low at present and none suitable could be found. However I'm thankful for the effort they made, it would have been far too easy for them to dismiss my request with a simple "no". They tried and I can't ask for more than that.
I was also pleasantly surprised with the service when I asked at Wigan Yamaha. After a few minutes a mechanic appeared with his own tin of old shims and seemed more than happy to pull out all the "7.48 mm OD" shims. The smallest they could find was 1.81 mm, I was hoping for less but anything is better than nothing. I paid a paltry £2 for the shim and went on my merry way.
I was concerned that even at 1.81 mm the shim may not be small enough. I don't have an accurate micrometer but from what I could deduce from my cheap vernier gauge my shims were around 2.00 mm, so 1.81 is not much smaller. I am pleased to say that in fact the 1.81 mm shim was spot on for 3 of my valves and allowed me to calculate my fourth valve as well. It turns out I need 3 x 1.80 mm shims and I've used one shim from one valve in another, luckily a perfect fit.
They are tiny things, 7.48 mm across. Much smaller than even a watch battery. I was expecting more.
I've ordered some valve shims now from fleabay and I have to...blooming well wait. I hate waiting. I really hate waiting. Are they here yet? Now? No? I wonder if it's worth a ride to Brighton to go and pick them up. Probably not.
Reader's Comments
J b Miller said :-
Hi I need a 2 mm shim please can you help me
03/06/2022 14:08:51 UTC
J b Miller said :-
I need some shims can you please send me them
03/06/2022 17:42:29 UTC
Ren - The Ed¹ said :-
Sorry J b Miller, I'm not a supplier of shims or any other parts.
03/06/2022 19:04:46 UTC
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