Shims for GS550ET 1980 (UK) Urgent

[ukjules]

just returned from garage - i agree - i wont continue myself and see if a machinist can do it.

[ukjules]

Ill keep on this tread for all Shim topics .....

As you know all valves set ok but one using my .003 gauge is too small.
smaller than 0.003.

so i designed - possibly madly - you guys can tell me, to use a uk 2p coin
and measure with it only for stats.

2p coins by my guage = 1.8mm
Gap now with coin is 0.14 (way out of spec - max is .08mm)

the shim i was using measures 2.1 on my guage (his must be 2.15 however as that is the lowest gs one availible)
gap - as we know zeroed out - 0.003 wont go in.

a) can you guys measure a 2pence for me ? so i can be sure.
b) I need a shim 191 - 1.86 (with my measuring of the 2p) (not allowed or in service limits) ? is my calculation right ?

I cant work out what is going on here ? the head is skimmed , all the others are fine.
One thing I must know - the exact thickness of a 2p coin - all other measurements by me are exact.

thanks

[hampshirehog]

I measured,using a digital caliper gauge, 3 x 2p coins and got 1.82, 2.00 and 2.07.

[JTGS850GL]

Be very careful. There is a reason that Suzuki limited the available shims to 2.15. Getting much thinner and you could risk interference with the shim bucket.

[ukjules]

I have ended up using a local engineering firm who have a shim grinding machine.
they did it while i waited.
they inform me the shim is hard all the way through.
I have to take the risk.

the 2p with their measurement was 1.803mm (my was 1.8mm)

i needed a 1.9 - 1.95 shim. I got them to cut down 2 shims from 2.55.

I agree it is a risk but i have absolutely no option ! i cannot take the head off again and start
looking at the valve - too much work at this stage. another time maybe.
cost me a few quid only.

Valves now set perfectly - but agreed with one shim that might worry me forever.

If i did it correctly how would i work out the amount off the valve head ?

[Sand_fiend]

I used two shims i bought off e-bay that were hard.. they lasted about 1 hour before the shattered and chipped the cam, bent a valve that took out the guide in turn cracked the head while tiring to replace the guide.. It's not worth it in my opinion.. don't use anything other than OEM. if your under size on clearance. get a valve job done.....

[ukjules]

My shims are oem ! - proper suzuki. the only issue is thatI ground them down to 1.9mm from the standard 2.15.
I checked the workings of the cam on the shim / bucket and all looked ok. no issue whatsoever
I know i should grind the valve end - but that was not an option at the time - my fault totally there - Check on bench i know.

I had to use the "stuck in a desert scenario" and go with what i had.
200 miles so far and ok - timing, compression, carb balance, valve clearnaces all spot on.