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3.2 Valve Adjustment


sherpa
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Getting ready to adjust the valves on the new bike. Has anyone out there done this yet? Any suggestions, pointers, etc? Is there any particular sized shim that seems to be the norm, or should I wait until after I disassemble and measure the gap before ordering the shims.

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The main requirement is a sound proof room and the removal of all objects that could do harm. I also suggest a warm-up session of swearing very loudly to get it out of your system then you can begin.

The main problem is that the removal and refitting of the radiator it is a complete *******(didn't know that even counted as a swear word these days.....heard worse on the Disney Channel). I got a great tip off Greg and I have pasted it below - it is the only way I have managed to get the radiator in and out. Unfortunately you can't get the rocker box off without removing the radiator.

'Its a tricky thing to fit , what i did was removed it with the fan cowl attached (through laziness i think) , i tried all methods to refit it but the only way i managed to reinstal it was (with rocker cover installed) feed the radiator from front wheel area top tank and filler cap end first in between the frame down tubes , start with the radiator horizontal whilst passing it into the frame tubes , youll get to the fan cowl and it will bind up on the frame tubes , i just worked it past the frame tubes gradually , try not to let it flex the aluminium of the radiator , as you are doing this start raising the filler end of the rad up, this will let the fan motor clear the rocker cover , Once i the upright position (coil and rectifier etc removed for space) the hardest bit i found was to get the radiator into the locating holes in the frame and also getting the bottom hose fitting at the correct side of the right hand side downtube bracket. when the rad is in the upright position there is a bit of room to move it up vertically this alows a bit of wrestling to get the locating dowels into place.'

The actual shim adjustment is straightforward - the only slight difficulty is that the shim has a central depression which tends to be about 1mm but you can measure it with the sharp end of a vernier gauge to be sure so that you know which shim sizes to order. I worked out what shims I wanted first and then ordered them - including one size up and down from each so I had options.The shim sizes are listed in the parts manual which is online at the Sherco site I think.

Best of luck and drop me a PM if you have any problems.

Cheers

Jim

Edited by jimw
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Generally speaking, I would only attempt to insure that the clearances are within +- 10% of the given spec, which as I recall is .1mm intake and .15mm exhaust.

If you can manage to set your guages at a "go---no go" and fall within the range, you are fine. I would not split hairs here. Although one could drive oneself crazy with the measurements iff need be. At the given duty of this motor, one will notice no difference in performance within the range. The basic assurance that things are not too tight or loose is the primary objective here. Use your own discression. ;)

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I disassembled everything and measured clearance at the intake side to be .007" and .009" at the exhaust. Looking in the sherco parts catalogue it looks like the dimensions given are not representative of the actual thickness of the shim. The sherco 4.5 i has a standard 2mm deduction to determine actual shim thickness, is there a similar formula for the 3.2.? I don't have a caliper with a small enough tip to fit into the shims recess to check this myself. Or am I reading something wrong?

Thanks for the help

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I disassembled everything and measured clearance at the intake side to be .007" and .009" at the exhaust. Looking in the sherco parts catalogue it looks like the dimensions given are not representative of the actual thickness of the shim. The sherco 4.5 i has a standard 2mm deduction to determine actual shim thickness, is there a similar formula for the 3.2.? I don't have a caliper with a small enough tip to fit into the shims recess to check this myself. Or am I reading something wrong?

Thanks for the help

I think you have the right idea. I was hoping someone else could chime in to confirm, but a 1 or 2 mm deduction may be in order. I would have to pop them out to get proper measure with a micrometer, then add or subtract accordingly. Looks like it may be easier to do all your measures in metric. If the spec is 0.1mm INT and 0.15mm EX then that would convert to .004 and .006 in roughly. Looks like an added thickness of 0.1 mm on them would be in order. :wacko:

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I seem to recall the shim depression was 1mm so try making that adjustment and see if the shim sizes make sense. Otherwise if that doesn't work I'll dig out my spare shims and measure them.

Jim

Edited by jimw
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  • 2 weeks later...
 
  • 7 months later...

I'm attempting the dreaded valve spacers, It's a little over my head. Here's what i've got measurements wise.

Exhaust valve left:

Gap= 0.50

spacer=2.78

Exhaust valve right:

Gap=0.60

spacer= 2.66

Intake left:

Gap=0.30

spacer=2.69

intake right:

gap=0.40

spacer= 2.78.

Now according to my calculations (and i'm no mathematician) the gaps that I have, they don't make spacers big enough. Does anybody have an idea what may be causing this??

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You are supposed to take the original measure with the pucks in situ, cam lobes pointed opposite the following arms! Sounds as thou you have removed them, then measured?

These clearances seem just too far out of range, and the motor would sound like a thrasher!

Re install pucks and start over. :wall:

Edited by copemech
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Cheers, now could anybody tell me why my cam shaft cover won't go back in?? The holes don't line up... I have since snapped it in a rage, However I will be ordering a new one, and if anybody can tell me why it won't go on... I promise I will never touch anything mechanical AGAIN. IT'S TO MUCH STRESS!!

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