125 valve shims

[vitesse7749]

Does anyone know if there is a valve shim that will fit our 125s? With all the configurations I'm hoping there is the odd Hondsuzkawyam that will slide in nicely. I believe the thicknesses are common in the business. Also do we really have to go through all that "pulling the timing chain and guides"out?

Thanks

[DAVID THOMPSON]

yes the cams have to be removed

grahams for shims parts book on site for down load
http://www.grahamsmotorcycles.com
and my 125 has 18000 miles an all valves read ok ????

dave

edit note if good oil and changed often shims should not be a problem
unless you zoom along at max rpm all the time
from my point of view this bike should have a service life of about 10 to 12 years and 35thousand plus miles
unless you just run the crap out of it

[vitesse7749]

Thanks again Dave. I know some years ago when this shim business took off they had a compression tool to back off those springs.
I'll ride gently as not to rattle the top end so.

[djsbriscoe]

Hi,
I recently did a valve job on my RT125. It isn't difficult as long as you have the correct tools
as well as the MZ special tools listed in the workshop manual. I checked the shims as well but they were OK.
The camshafts need to be removed to gain proper access to the buckets and shims. If you try to pry them out with a screwdriver
you may damage the shim, bucket and camshaft if the tool slips.
If on replacing the shim it is not EXACTLY the correct size it could skip out of the bucket at any time and cause serious damage.
I would not recommend using anything other than the OEM spares for this job as mistakes can be costly.
If you need a list of the tools I used let me know and I will list them here on the forum.
Hope Iv'e been of help.

David

[vitesse7749]

YES please send that lest of tools. I work on all my bikes so I should be able to find them. My workshop manual has the worst photo's .It isw impossible to reckon one end to the other. I presume the shims are steel and can be mageticall removed/installed.

Thanks

[djsbriscoe]

Hi,
STAGE ONE (PREPARATION)
Tools required
a/ Workshop manual (print out relevant pages).
b/ Parts book (download from Grahams Motorcycles website) to look up part numbers for special tools and parts.
c/ Set of quality feeler gauges.
d/ Torx socket to remove valve cover bolts.
e/ Set of metric spanners or socket set.
f/ Best torque wrench you can afford.
g/ New gasket for valve cover.
h/ Crankshaft locking tool (MZ SPECIAL TOOL FROM GRAHAMS M/C).
I/ Camshaft setting tool (MZ SPECIAL TOOL FROM GRAHAMS M/C).
j/ Loctite nut lock fluid for application to camshaft nuts on final reassembly (just a small drop required).

REMOVE THE VALVE COVER AND CHECK AND RECHECK THE VALVE CLEARANCES CAREFULLY BEFORE CONSIDERING DOING ANY FURTHER WORK.
New shims may not be required. If you have to remove the camshafts please follow the instructions in the workshop manual. DO NOT USE MAGNETISED TOOLS
AS THIS CAN LEAVE RESIDUAL MAGNETISM ON THE VALVE STEMS WHICH WILL ATTRACT STEEL SWARF AND CAUSE PROBLEMS (mentioned in the manual).

I don't know how to change the shims once the buckets are removed as I did not have to do this on my engine (clearances where OK).

I am wondering why do you feel the need to work on the valve shims, what problems are you having with the engine?
I did not have a choice when I did the work on my engine as it would not run, the valve seats where fouled and leaking compression pressure.
As I had the cylinder head off I had the valves reseated and put in new valve seals and put a new gasket set on (routine for any engine rebuild).

Anyway any questions please ask.

David.

[vitesse7749]

This bike is almost new but sat up in a shop here in Florida for a few years. It was air conditioned so the bike is tight, no dry or damp damage.
This valve question is me being meticulous about the future of my machines (04 Rockster 1150, 73 TR5T 500 Triumph) Since MZ has no rep. here in the US.
I love the overall of my 125 and want to get everything set for when It comes time to do valve work. I prepare!
This may not be for a while yet however in this situation I must think well in advance.
I'll be back in the UK for a short bit so I'm phoning Ian @ Graham's in Cornwall to order all my parts.
I have many old racer and mechanics at my doorstep here in Daytona so the tech bits may not be too daunting.

Thanks for all your help.

[Billahrens]

It would not be much of a surprise if we can find shims Exactly the same diameter at some Japanese bike or BMW shop.
For example, I set out to adjust the valves on my 2007 KLR 650, needed 2 shims. Measured the odds of the Kawasaki shim, found that it was identical to shims I had accumulated from my BMW K100 RT. Swapped and all good. Reason was, went to Kawasaki dealer, they didn't have any shims, said they never sold any. Hmmmmmm... My 2002 125 SX Has 16000 Km on it and I am planning to check valve clearances, probably was never done from new. Will post progress.

Also just replaced starter clutch, no problem, got parts from Graham in England. Expensive but good service.

Bill Ahrens
2007 BMW K1200 GT
2002 MZ 125 SX

[DAVID THOMPSON]

do check the timing chain tensioner
some have worn a place in the case if they got real loose
and it can cause major damage
dave
2002 rt125 21,000 miles

[stephendacosta]

I have a range of shims collected for my herd of 125's. I have been known to run some of my bikes on the freeway at WOT for up to 20 min. at a time. Never had one with out of spec measurements.