Fantic 125 / 200 Engine

[rtm]

I have just started to pull my very old (1979 or 1980) apart to do the crank seals as its as flat as a pancake.

Written on top of the cylinder is

"Keith Horsman ? E.D. Silsden W Yorks 20 M?? 82. The ? means I cannot read the letters. I assume he might have converted it to a 156cc from a 125? It does not appear to be ported as the original castings are untounched.

Also there is a 3mm thick spacer plate under the barrel? Would you put the spacer plate back in and why is it there?

Should this bike have a head gasket fitted? There is a paper one there at the moment which will need changing obviously.

Thanks guys.

[rtm]

I stripped down an old 200 engine this afternoon and the converted 125 is the same in all respects. So I assume the spacer is there just to soften the power.

[bilc0]

The easy way to find out if you need the spacer is to take the spacer out fit the cylinder back on with out the head and bring the piston to TDC if the piston sticks out the top of cylinder you have your answer.

My 156cc cylinder has the 185cc suzuki conversion,because the gudgeon pin hole on the suzuki piston is slightly lower the piston sticks out the top of the cylinder about 3mm,in this case thats why we need a thicker spacer at base.

Have you taken any measurements of the bore.

[rtm]

Hi and thanks for your reply. I knew about the TS piston conversion but it has a genuine Fantic piston fitted.

[29ty]

I am pretty sure Keith Horsman is still alive and well. Some friends of mine had some work done on their classic bikes and I recall them saying this is the guy who did it. He still lives somewhere around Keighley, yorkshire.

If somebody wants to send me an email address I will see if I can get contact details?