dropping exhaust valves 1999 400

[Old scooterist]

Spring was off of the cam shaft.

[roadster]

Spring was off of the cam shaft.

Decompressor mechanism?

[Old scooterist]

Yes, decomp spring.

Just after I got it running sweet with nice power on tap it blew up, again! Same thing, valve heads off the exhausts, Head trashed, cylinder buggered, piston a dozen bits and crank not so good, bin job as a head is already 1200€ new and a few hundred used so I was looking as another 600€ job with used parts and an uncertain quality, again. Now I have a spare variator, clutch, belt, starter clutch, etc.

So searched the internet and off to the Malaga scooter breakers and a low mileage 2002 K2 engine for 450€ less carb' and exhaust, so much for "complete engine" but still reasonable considering.

I managed to get the K2 engine into the 1999 X and get it running, I hope the later version will be more reliable.

I hade to make a few changes and down-grades to do it but not too difficult.

Rear wheel changed for better three bolt version and a new tyre, (49€) this meant buying a used wheel from Poland (75€) rather than changing the gearbox to X and using the ten year old tyre and MkI wheel, (which have problems loosing steel insert). Rear caliper is the same so used the X one but lost my super wavy disc as the K2 disc comes riveted onto an alloy hub but hardly any wear on it, maybe later I will upgrade that.

Coolant pump was changed for the X one as I didn't need the extra spigot on top, just a new set of rubber seals.

Thermostat housing was X as well for same reason and the temp' sensor was ignored on the cylinder in favour of the old single wire one.

The flywheel had to be changed as the sensor on the X is a single tab on the flywheel and the K2 is a series of tabs with a gap so rather than change the wiring harness and CDI at great expense I changed the flywheel. the 'solid' starter gear fits rather than the weaker X one with the holes in. Gasket and cases are the same so I used the X one as in better condition. Had a problem as the puller I used mushroomed the end of the crank ever so slightly, It was VERY tight, so the bearing in the case wouldn't fit over it so I had to dress it down with a stone just a couple of thou' and on it went with a firm tap.

Soon as I got it all assembled I got sparks again so popped the lead on the plug and blat, blat, blat, firing, no exhaust on yet.

Next job is simply to fit silencer (that sounds like a metal maraca when shaken) and the bodywork, for the umpteenth time.

[Old scooterist]

Seems that going by the flywheel I have a K3 engine not a K2.