If, as pete seams to reckon, the 100 is a smaller version of the 140/130/115 v4 range then it's a superb engine.
I had a 115 previously, and now have a 130. Never (touching lots of wood here) had a single problem with either. The 115 was about '92 and the 130 is '96. They both drink fuel though!
The 115/130's were made from about '91 and are still a current model. I have never heard of a 100 v4 though. I agree with the 140 being withdrawn, but dident know it was due to the reason you suggest pete!
Er...my final comment, these big old(er) 2-strokes are not worth a lot of £££'s today so make sure you don't pay over the odds, i see quite a lot of 115's very cheap - but like pete said a compression test and good look over the engine is needed.
Hope that confirms what pete said!