I had an 87' Foreman for several years. It was 10 years old and farmer owned when I got it.
I assume the farmer let it sit and idle for long periods and it didn't get full lubrication to the top end. So, rocker arms and camshaft were trashed. I had the top end rebuilt and had no other issues with the engine.
Negatives in my book were:
- Metal gas tank (rust)
- Electric fuel pump (mine went out twice)
- Solid front axle (rougher ride)
With that said, they're absolute tanks. I rode it hard and put it away wet several times. Parts can be had pretty easily. If you ever need something specific feel free to PM me.
