MZ/MuZ Riders

What should be a simple job is proving difficult. Tried to remove the plug preparatory to doing the vales and could not get the plug spanner to engage. The picture shows why, there is some sort of rubber bung sitting on top of the plug but so far no amount of digging around with hooked wire and suchlike has shifted it. It seems to be jammed very tightly and my knuckles are raw trying to dislodge it. My guess is that the rubber is from the inside of an original MZ or Yamaha plug spanner which has become detached and then pushed down by the plug cap but why it should be so tight is a mystery.

Anyone had this problem and if so how did you solve it, I am going to try grinding down an old kitchen knife to make a chisel to try and cut it into smaller chunks but you are working blind all the time and the confined space makes it hard to get any real pressure on the tool.

Makes me wonder how long my plug has been in place.

Peter

Got the little blighter out in the end using my modified kitchen knife as a chisel to cut the rubber down the side of the plug and a piece of wire with a hook on the end to lift it out. The reason it would not come out easily before was it was partly trapped under the spark plug. It was actually the rubber end cap from a long reach angled plug cap which must have become detached though how anyone managed to screw the plug in with it in place is another mystery.The plug cap in use now has its rubber cap in place.

Anyway job done, new plug in place and valves correctly adjusted. The old plug came up as the weak end of good according the that very useful picture chart of plug appearances someone posted on another thread.

PeterF

ITcan be a sod of a job, any how this is what I did to make it a bit easier, and using the plug spanner supplied in the tool kit.
What you need to do.
1, remove the rubber bung from the plug spanner. ( left in, as the plug is unscrewed it jacks the plug spanner up jamming it against the frame.)
2, drill another pair of holes at right angles to the original ones.
3, reduce the length of the plug spanner by about 5mm.
4, Acquire a piece of rubber tube about the same length as the plug spanner ( Calor gas hose is just right )
Method.
Loosen the plug, the extra holes in the spanner allows half a flat at a time turn, when the plug is finger tight remove the spanner, now, this is where the rubber tube comes in, push the rubber tube over the insulator of the plug, unscrew it with the tubing and lift it out.
Reverse the process to refit the plug.
using this kit I've changed plugs at the side of the road in a few minuets.

Thanks for that tip. In fact I don't have an orginal MZ plug spanner with its rubber insert so did not come across the problem of it jamming as you unscrewed. I adapted a suitable sized tube spanner in the same way as you described and also found a small pieces of washing machine cold water hose was a perfect fit to unscrew the plug once it was finger loose.

As you say, its now an easy job to change a plug now that I have got rid of that wretched piece of rubber which was jammed in the hole.

Peter.

Im sure what you had to dig out WAS the rubber bung from the plug spanner that I mentioned, it must have been left behind by the previous owner when they attempted to change the plug.
cheers Eric.