Pedantic Valve Clearance Q

[dx400r]

Hi Everyone,

Figured it was finally time to join this place and the time to do it is now I reckon with me doing my clearances on my VFR400 NC30.

My question is does it pay to get your NC30 in the middle of the recommended 0.12mm to 0.18mm for inlet and 0.21mm to 0.27mm for exhaust?

So far for mine I have recorded:

Cylinder 1
Inlet: 0.17mm
Inlet: 0.16mm
Exhaust: 0.22mm
Exhaust: 0.25mm

Cylinder 3
Inlet: 0.07mm
Inlet: 0.07mm
Exhaust: 0.24mm
Exhaust: 0.20mm

Cylinder 4
Exhaust: 0.23mm
Exhaust: 0.24mm

And this is as far as I have got :)

So should I aim for getting all of these back in the middle or should I just aim to be out of danger zone? Like No.3 is . If im lucky, the rest should come out fine and I can get the shim ground a bit down at my local bike place. :D

Thanks in advance guys and gals.

[NC35!]

Hi,

If you aim for 0.15 inlet and 0.24 exhaust, the chances are you will not get exactly the thickness of shims you need, but you will have +/-0.03mm to play with, and will easily get all within the tolerances allowed.

Thanks

[fastdruid]

I find typically I'm constrained by the accuracy of feeler gauges anyway.

Unless you have a surplice of shims or its a race/track bike[1], aim for getting them in the middle.

Druid

[1] Aim on the wide side as they'll run hotter than on a road bike.

[zimm]

but not too wide or you'll lose power the rest of the time ..

set my zxr to the race kit tolerance's and lost power at the topend compared to stock clearances, put it back to the wide end of the standard range (what i've always done before) and it's pulling far better.

stock, .12-.17 IN, .16-.21 EX
kit, .20-.25 IN .25-.28 EX

[dx400r]

Cheers for the advice all.

Had a bit of a brown trouser moment down there....

I dropped a shim into the engine. But she didnt like the taste of it so spat it out. So after a good 20 mins of beating the crap out of the sump with sometime rubber ended I finally got to the viffers tummy to find a shim sitting in the sump :D

Sigh of relief.

Also both worryingly and amusingly, I found a ziptie stuck in the strainer on the oil pickup. I know that wasnt me...

[MexicanGringo]

The clearance tends to shrink over time as well, so more of a gap within the tolerance is a bit better than less for the long term

[Neosophist]

Cheers for the advice all.

Had a bit of a brown trouser moment down there....

Also both worryingly and amusingly, I found a ziptie stuck in the strainer on the oil pickup. I know that wasnt me...

My uncle found 2 valve stems in the sump strainer of his 88 Magna 750.

I found the remains of the waterpump shaft in mine ^_^

[RickOliver]

Unless you have a surplice of shims

Druid

Some kind of Druidic ceremonial wear...?

[fastdruid]

Unless you have a surplice of shims

Druid

Some kind of Druidic ceremonial wear...?

Nah, I just do sacrifices, normally of tyres and brake pads but sometimes I pray to the corner god and get down on my knees! :D

Druid