Well, I just bought it about 4 months back. And the person I bought it from said the top end was done recently.

I just took out for a ride for first time yesterday and everything was running well for the first 20 km. It was running great. Then the thing died while waiting at the traffic light. I was able to restart it, but it looks like only one cylinder was working as I was crawling home. When I got home, I checked the plugs. The front was ok, but the rear plug appear as if piston had rammed against it. Part of the tip was gone and the the rest is welded or pressed again the core. Both plugs looks wet. The plugs are different also. The front is BP9ES and the rear plug is BR9ECM. What's the norm?

The only thing I did was install the HRC jet kit. What do you make of it? Do you think I should do the whole top end on the rear, piston, ring, etc. or will replacing the rings do the trick.

Cuong