I need some valve shims

The WR’s way overdue a valve spacing check, and I’m fairly sure they’re out (since it’s so bloody hard to start). I’ve never needed to buy shims before, everything I’ve had that’s needed adjusting has had those nifty adjustable rockers.

It looks like this sort of thing makes the most sense:


(it’s a 2003 WR450F), since I can’t really be arsed to strip it, measure the things and then wait for just the right sizes to arrive.

Is there a better (UK-based?) thing to buy? Would this be cheapest/easiest done by just giving it to someone else to do? Presumably valve shims aren’t really engine-specific and I just need to get some in the right diameter?

why dont you give Matt a call at the OMC, i’m sure he’ll be able to tell.

What you need to do first is check the valve clearances. If adjustment is required use one of the online calculators such as http://www.agbuzz.com.au/valve/valve_intro.htm or do the maths A = (B - C) + D where

A = new shim thickness

B = existing valve clearance

C = mid point of recommended valve clearance

D= existing shim thickness

Then order just the shims you need.

To accurately measure the valve clearances and existing shim thickness you’ll need

A feeler gauge with increments of 0.05 mm such as http://www.ebay.co.uk/itm/Teng-FG21-20pc-Feeler-Gauge-Set-Non-Magnetic-Brass-Blades-0-05-1MM-Metric-Leaves-/252536269429?hash=item3acc55aa75:g:wwAAAOSwgmJX1pu4

and a digital calliper gauge such as http://www.ebay.co.uk/itm/150mm-6inch-LCD-Digital-Vernier-Caliper-Electronic-Gauge-Micrometer-Measurement-/161927100020?hash=item25b39b7674:g:-L0AAOSwGIRXX8dj

I think he’s trying to avoid taking it apart twice.

Though your welcome to do it while it’s still in my garage, lessens the need to reassemble in between.

Yeah, I’m not really concerned with the process of measuring them and I know I’ve got the tools, I’m just trying to already have all the bits I’m likely to need before I start dismantling it.

And, I’ve only not waited to ask Matt because it doesn’t seem right given that I’m not realistically going to the OMC to do this.

When I’ve done mine I’ve picked a week when I’m not using the bike. Dismantle, measure, order (God bless Royal Mail), assemble.

Typically you’ll require 2 to 4 shims every 25 - 30, 000 miles. Seems an extravagance to have a whole box full sitting on the shelf.