05 yfz450 valve clearance


anybody know what the specs are?? also I need the chart to get the right shims.. Thanks..

Intake valve specs are .004-.006 in. Exhaust valve specs are .008-.010 in. I am sorry I do not have my book w/me right now to give you the metric version. For the shims you would take the difference of the actual measured value and the spec value and add that difference to the current shim size if the tolerance is too big. Or if the value is less than spec you would deduct that amount from the current shim size to get the new shim size. Hope I did'nt confuse you. You should measure the shims w/your calipers to be sure of there size and even check your new ones, sometimes they are not exact to there markings.

Do you still need the info? I've been out a few days and just saw your post. Let me know if I can help you.


Blue4ever is close, but those thousands of an inch are important. Adding and subtracting is not quiet the way he explains, but he is confusing. There is no specified measurement for that end of the valve. As if to say that 175 is "standard". Everyone wants their clearance spot on right? The intake shims are the same shims for the exhaust. There is a .002 in or .05 mm difference between each pad. The 175 pad is actually 1.75mm thick, and the 190 pad is 1.9 mm thick. No trickery, and not confusing. TAKE THE GAP READINGS, COMPARE TO CHART, AND THEN CHOOSE THE RIGHT SHIM! That's the fastest way to get it right. At $60 bucks an hour would you want me to screw around when adjusting YOUR valves? :bonk: HELL NO. Do what I do (several times a week) :bonk:

Cold intake measurement should be between .10-.15mm, or .0039-.0059 in.

Cold exhaust is .20-.25mm or .0079-.0098 in. Exhaust will always have more slack in the measurement due to heat expansion.

On the YFZ, I always find my measurements on the quad first. Do each one three of four times and see if the gap gauge smaller or larger will insert. You may be surprised on the exhaust side! Take that and of course then you need to know what size shim you have in order to make any further shim changes by using the chart. I've seen the middle intake valve shimmed with a 165 and up to a 190, so don't think they are all the same-EVERY QUAD IS DIFFERENT. If you can read the numbers, use them and don't chance it by using dial calipers. If you do go with the self measure, use digital calipers on the standard, non metric setting. Metric is better, but the manual references shims by using the inch measurement. And it's confusing to some on how to convert. I'll post the shim chart shortly.

Stumpy :bonk:

Stumpjump- Not everyone has a chart to refer to for shim sizing. I do not beleive I stated anywere that the shims are all the same size. The method I refered to is the way to calculate your shim size w/o a chart. It is very simple and you should understand this method since you are MMI trained! You simply take the difference of the measured gap and the gap spec you are trying to achive and either add it to the current shim size if the gap is too loose or subtract that amount from the current shim size if the gap is too tight! This should be done in mm, since the shims are measured in mm. The inch measurements I gave were rounded off to reflect what most all feelers read.

example- if the measured gap of a valve is at .10mm which = .0039in and you need to get to .15mm which = .0059in. and your shim size is 285mm.


.15mm minus .10mm = .05mm

285 minus .05mm = 280mm shim (replacement shim)


you add the diiference to the current valve shim size.


My reply was not directed at you, just letting "rwfz" know that there is not a particular shim size from the factory, and the later part was to make clear that while whipping out a calculator is easy for some, if you are a DIY'er, stick to a chart so you don't mess up and cost your self time and money if anything goes wrong. There are motors, made by an Italian brand (well known) that suggest the tips of the valves, be ground off to get the proper clearance if the shims don't get it within .02 mm. Every motor may be different, but if you rely on published data you can forget formulas and what not and keep everything simple.


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