I have had a string of bikes during my riding career, but the first one I actually bought with my own hard earned money is still something I recall fondly. I had been riding a couple of years, being a roaring hellion on the Xl125, but I was beginning to hit the limits of what that bike could do. The attributes that make for a great starter bike soon become limitations. The soft power, the low seat height (which meant ~ 3.5″ of suspension travel), were things I wanted to get away from.
Around this time, I started reading Dirtbike Magazine, and I fell big time for the Yamaha 1/8th liter motocrosser. It seemed to be the best package at the time. (The 79 Honda MXers had the abysmal 23″ front wheel that had NO tire selection). So, I saved my paper route money, and in early 1980, found a good used YZ125F for $600 (new they were $1,200). It would be a huge understatement to say I wasn’t excited.
Of course, it had been raced all season at the PAL MX track, but hey, what can be wrong with a 1 year old bike? Ha ha ha.
It ran OK when I bought it, but it seemed to be low in compression. I pulled the top end (something that was a regular occurrence on an air cooled 2-stroke MX bike), and the rings were way out of spec. Turned out that the “little bit of Piston Slap” was a clapped out bore. The top end probably hadn’t been done all season (when raced, you should replace rings every 8 hours of racing). No big deal, the local Yamaha shop bored it to the first over, and got me a set of rings, a piston, and gaskets.
The first ride was fun. It was completely different than the XL125. It had more power everywhere, it had a short ratio transmission (on a long straight, the XL125 was geared for maybe 75mph top speed, the YZ was probably tapped out at 45mph), and the suspension was magic compared to the XL. Truly lightyears apart.
I rode the wheels off that thing. Over the 5 years that I had it, we probably went riding 40 weekends a year, and it got ridden hard. But I did do the required maintenance. I think it was on the 3rd over bore, and I switched to the 2 ring Wiseco pistons to improve the life. Probably the best modification was adding a (very expensive to me) Metzler fron tire. Wow, what a difference in handling and control. Best $80 I ever spent.
The bike ran great until the big end bearing grenaded. Did a lot of damage to the cylinder head, and forced a splitting of the cages. I diligently got it rebuilt, but by the time I was done, I had my eyes on another bike, the 86 Honda XR250R, so the YZ was sold (for almost what I paid for it, ironically) and I was in line for the new ride.
