Voge valve clearances by model, intake and exhaust

Valve clearance is an inspection item rather than a task generally carried out at home: it requires the engine cold, an understanding of the cam timing and, frequently, shim replacement. The figures below allow the measurement recorded by a workshop to be checked against the specification for the engine concerned.

The clearances

All figures in millimetres, measured with the engine cold.

Model	Intake (mm)	Exhaust (mm)
DS900X	0.11 - 0.20	0.26 - 0.35
DS625X	0.10 - 0.15	0.15 - 0.20
650DSX	0.03 - 0.11	0.25 - 0.33
SR4 Max	0.16 - 0.24	0.34 - 0.42
SR1	0.06 - 0.08	0.14 - 0.16
FR150	-	0.22 - 0.28
SR450X	0.18	0.28
SR3	0.08 - 0.12	0.13 - 0.17
125R	0.13 - 0.19	0.22 - 0.28
300 Rally	0.10 - 0.19	0.15 - 0.24
SR16	0.06 - 0.08	0.14 - 0.16
525RR	0.13 - 0.19	0.24 - 0.30
250RR	0.08 - 0.12	0.13 - 0.17
250 Rally	0.07 - 0.13	0.12 - 0.18

The FR150 manual held here prints only the exhaust figure in its table. The intake value is not legible and is therefore omitted rather than estimated.

What the figures indicate

The exhaust clearance is always greater than the intake. The exhaust valve runs considerably hotter and expands further, so it is built with more room to grow into. On the SR4 Max the exhaust figure is more than double the intake.

The 650DSX intake clearance is unusually tight at 0.03 to 0.11 mm, a range leaving almost no margin at its lower limit. On that engine the inspection is better carried out to schedule than in response to a symptom.

The consequences of an incorrect clearance

Excessive clearance is the audible condition: a light ticking or tapping from the top of the engine that rises with engine speed and is most pronounced when cold. It costs a small amount of power and accelerates cam wear, but the engine survives it.

Insufficient clearance produces no noise whatever, which is what makes it the damaging condition. The valve ceases to seat fully and can no longer transfer its heat into the cylinder head, and it burns. The first symptom is generally a misfire or difficult starting on one cylinder, by which stage the valve and frequently the seat have been lost.

A quiet engine is not evidence that the clearances are correct.

Inspection intervals

The maintenance plan printed in the owner manuals marks valve clearance I at every service, making it an inspection item throughout the life of the motorcycle rather than a single event. The 300 series engine service manual places the first valve check at 15,000 km.

In practice the inspection is carried out to schedule, and brought forward where the engine has begun to tick, has become harder to start, or has lost power without a filter or fuel explanation. The weak engine power page sets out the less expensive causes to eliminate first.

Before the work is booked

The figure the workshop intends to use should be established for the specific model and model year. Two engines in this table sit within 0.05 mm of one another on the intake side, and a range that suits one leaves the other outside its own limits.

Related pages

Spark plug types and gaps for the same engines are in spark plugs and electrode gaps, engine data in idle speeds and engine data, and the service schedule in what Voge asks for at each service.