valve shim diameter

I've recently bought myself a 1999 SV650S with 43,000km on it and thought I'd check the valve cleances and do a bit of other maintenance before riding it much.

The clearances were all within spec, but on the low side so I'm thinking I should adjust them closer to the middle/upper side of the clearance range.

I've got some shims from a yamaha fzx250, some of which I could use, but the diameter of the yamaha shims is 7.49mm whereas the diameters of the shims in the sv range from 7.46mm to 7.48mm (of the 4 I measured). Anyone know if the yamaha ones will be ok? What are the acceptable tolerances for shim diameters?

Also, the clearances I measured were:

               Front
exhaust    0.229   0.229
inlet      0.152   0.127

inlet      0.152   0.127
exhaust    0.203   0.229
               Rear

Am I being too fussy adjusting them? The one that is 0.203 is close to the limit, but still within spec. If I can use the yamaha shims I've got, I should only have to buy one or two to get them all in the upper half of the recommended clearance.

[yorkie_chris]

Whether you adjust them is up to you, if they're within spec then I'd say leave them but maybe check again before the next 15k miles.

I suspect that using a larger shim may stress the valve retainer as the shim expands, then again it may not have any affect.

[Spanner Man]

Evening all.

Ditto Yorkies advice. If it were an engine with a lower mileage I'd be tempted to adjust the clearances to the upper end of the specified tolerance. As your engine has covered nearly 30k miles I would think that it's done all of its bedding in, & I'd leave it be.

I have just spent a while checking the diameters of some Suzuki shims, & have found that they vary by as much as .03mm. Some were around the same diameter as the Yamaha shims that you have. So yes, it'll be ok to use them.


Cheers.

Thanks for the advice. I ended up getting a couple of shims from a wrecker and have adjusted them all to the middle of the range, being a bit fussy with this bike (it's still new for me and cost about twice what I paid for my bandit).


I still have to put the radiator back on and fill the coolant. Hopefully the rocker cover gaskets don't leak.. Then a bit of plastic welding, paint the air horn motor casing because it is badly rusted, check the forks to make sure there aren't any more pits (noticed one already that would have eventually destroyed the seals) Etc etc.