bedell99
~SPONSOR~
- May 3, 2000
- 788
- 0
So I changed my top end this weekend after exactly 36.5 hours according to the hour meter. I feel I went approximetely 10 hours over when I should I changed it.There was significant blowby on the rings and a decent amount of carbon buildup on the top of the piston. The cylinder looked really good. Here are a couple of observations for YZ owners. Feel free to add if you would like.
1. You don't have to touch the radiators. How cool is that. Just disconnect the hose off the head. My CR250 both radiators had to come off.
2. The powervalve is complicated. Real complicated. I recommend if you don't have to, not to remove it. Spray contact cleaner on it. Clean it real good. Than wash in a bubble bath and use compressed air to blow it dry. I sprayed silicon lubricant on it when I was finished.
3.Very impressed with the o-ring head gaskets.
4. Couldn't torque down all the base bolts. Had to feel 30 lbs of torque on the front 2. Not that big of deal, but I like using a torque wrench.
5. The govenor power valve gasket took about 30 minues to put on. I was wondering why yamaha glued it on the gasket to the cover. To get the rubber thingy and gasket to all line up was a pain.
6. Carb was real clean inside and getting the carb back on was real easy. I left it hanging arounf the frame when woring on the bike. Compared to the honda this part was a pleasure. I always hated that about the CR was working on the carb.
7. This was the first time I used cometic gaskets in a while. They where real nice. The Honda ones stuck real bad. All the gaskets where steel that had a coating on top. Real nice.
8. I used a B piston in A cylinder. I bought the stiok yamaha piston kit and it comes with B piston. No big deal. I always try to use B piston in all my past bikes.
9. The cylinder came right off. no tapping the sides. On the Honda, the base gasket used to stick real bad. I hated that. I really like the idea of steel gaskets.
10.The bike in general was real easy to work on, suprisingly easier then the honda. i think this was in part of not having to take off the radiators or messing with the powervalve. If you have to work on the powervalve make sure you takw some pics. Its like rube goldberg device. i love how the sub exhuast ports open though. I think that is why the bike works so well.
I will change out the piston every 25 hours from now on. I feel like I pushed it a bit to long. I love the hour meter because it tell you exactly what you have on the bike.
Erik
1. You don't have to touch the radiators. How cool is that. Just disconnect the hose off the head. My CR250 both radiators had to come off.
2. The powervalve is complicated. Real complicated. I recommend if you don't have to, not to remove it. Spray contact cleaner on it. Clean it real good. Than wash in a bubble bath and use compressed air to blow it dry. I sprayed silicon lubricant on it when I was finished.
3.Very impressed with the o-ring head gaskets.
4. Couldn't torque down all the base bolts. Had to feel 30 lbs of torque on the front 2. Not that big of deal, but I like using a torque wrench.
5. The govenor power valve gasket took about 30 minues to put on. I was wondering why yamaha glued it on the gasket to the cover. To get the rubber thingy and gasket to all line up was a pain.
6. Carb was real clean inside and getting the carb back on was real easy. I left it hanging arounf the frame when woring on the bike. Compared to the honda this part was a pleasure. I always hated that about the CR was working on the carb.
7. This was the first time I used cometic gaskets in a while. They where real nice. The Honda ones stuck real bad. All the gaskets where steel that had a coating on top. Real nice.
8. I used a B piston in A cylinder. I bought the stiok yamaha piston kit and it comes with B piston. No big deal. I always try to use B piston in all my past bikes.
9. The cylinder came right off. no tapping the sides. On the Honda, the base gasket used to stick real bad. I hated that. I really like the idea of steel gaskets.
10.The bike in general was real easy to work on, suprisingly easier then the honda. i think this was in part of not having to take off the radiators or messing with the powervalve. If you have to work on the powervalve make sure you takw some pics. Its like rube goldberg device. i love how the sub exhuast ports open though. I think that is why the bike works so well.
I will change out the piston every 25 hours from now on. I feel like I pushed it a bit to long. I love the hour meter because it tell you exactly what you have on the bike.
Erik
