Post by mathius on May 5, 2013 1:38:59 GMT -6
So here's a quick run down of the 87' I built, for those who don't know about it..
I'll start from the beginning......
I had an old 87' that I blew the motor in.
I was having a hard time finding aftermarket parts for it, and thought it was just an obsolete POS. (This is way before I knew what the 1st Gen platform was about?)
I figured it was the perfect candidate for a badass motor swap. So I took the liberty of hunting down a complete 83' Yamaha IT490, and started tearing things apart.
A lot of people have asked me why I went with the IT490? Well simply put, I wanted the biggest aircooled 2 stroke Yamaha made. (Again this was before I knew much about the 490 2 stroke)
So anyway. I jumped into the fire with both feet, and blindfolded... I started cutting, and welding. I was gonna make it work. lol
I mocked up the motor, and welded the mounts in for it. I also modified the swingarm to accept the rear motor mount. It got the ball rolling on the build.
Next I turned my attention to the 490, and this is where I picked up a shitload of information about the 1st gen 490's.
I ended up just rebuilding the topend, as it had been rebuilt at some point in it's past.
The only real mod's I did to the motor was some minor exhaust porting, and a Eric Gorr head mod.
I'm really happy with the way the motor turned out. It run's great...
The next step in my build was building a pipe to fit the frame. I just managed to get really lucky, when I found out that the Honda TRX250 pipes have damn near the same size expansion chamber as a stock 490 pipe. The relly lucky part was when I set the TRX pipe in the frame, and it looked like it was designed to fit the warrior.
The only thing I had to do to make this pipe work was cut a couple inches off the stinger, and make a custom head pipe.
It also turned out really well..
Once I had everything buttoned up, and in the quad. I had to modify the kick start for it.. This is where things got tricky...
Between addressing the cosmetic side of the quad, I decided to make an extended kicker shaft. The shaft rides in a carrier bearing to keep it from twisting out of the case. It was actually a really good idea on paper. Just make one shaft out of 2, and weld them together....
This is where the serious problems that plagued my build kick in..
I had problems with the shaft binding, seal problems, starting issues, and finally the weld on the modified shaft broke.
That broken shaft set my build back several months, but I didn't give up on it!! (I'll get back to that)
Anyway, I kept working at making it look good.
I decided to go with an oldschool 87' YZ490 paint scheme.
I had to modify the front plastics for the exhaust, and the rears for the kicker clearance.. I ended up with a partial race cut, that I still think looks pretty damn cool.
About the time I got the plastics finished, I managed to get a kicker shaft made.. Then I was actually able to start it on video.
I made this with my 4 year old son, he thought it was to loud, and covers his ears.. lol
But it gives you an idea of what the quad is all about.
(I kind of sound like a dumbass in the video, I was trying not to swear in front of the kid)
So that brings us to where the quad sits now. I did manage to finish the paint, and get it all together. But that was as far as I got...
I rode it once off camera, and the power of the 490 twisted the stock swingarm like a pretzel..
Here are the finished pictures from last spring.
The quad has been sitting for almost a year now, but I do plan on getting back to work on it.. I will post future add on's to this thread..
I'll start from the beginning......
I had an old 87' that I blew the motor in.
I was having a hard time finding aftermarket parts for it, and thought it was just an obsolete POS. (This is way before I knew what the 1st Gen platform was about?)
I figured it was the perfect candidate for a badass motor swap. So I took the liberty of hunting down a complete 83' Yamaha IT490, and started tearing things apart.
A lot of people have asked me why I went with the IT490? Well simply put, I wanted the biggest aircooled 2 stroke Yamaha made. (Again this was before I knew much about the 490 2 stroke)
So anyway. I jumped into the fire with both feet, and blindfolded... I started cutting, and welding. I was gonna make it work. lol
I mocked up the motor, and welded the mounts in for it. I also modified the swingarm to accept the rear motor mount. It got the ball rolling on the build.
Next I turned my attention to the 490, and this is where I picked up a shitload of information about the 1st gen 490's.
I ended up just rebuilding the topend, as it had been rebuilt at some point in it's past.
The only real mod's I did to the motor was some minor exhaust porting, and a Eric Gorr head mod.
I'm really happy with the way the motor turned out. It run's great...
The next step in my build was building a pipe to fit the frame. I just managed to get really lucky, when I found out that the Honda TRX250 pipes have damn near the same size expansion chamber as a stock 490 pipe. The relly lucky part was when I set the TRX pipe in the frame, and it looked like it was designed to fit the warrior.
The only thing I had to do to make this pipe work was cut a couple inches off the stinger, and make a custom head pipe.
It also turned out really well..
Once I had everything buttoned up, and in the quad. I had to modify the kick start for it.. This is where things got tricky...
Between addressing the cosmetic side of the quad, I decided to make an extended kicker shaft. The shaft rides in a carrier bearing to keep it from twisting out of the case. It was actually a really good idea on paper. Just make one shaft out of 2, and weld them together....
This is where the serious problems that plagued my build kick in..
I had problems with the shaft binding, seal problems, starting issues, and finally the weld on the modified shaft broke.
That broken shaft set my build back several months, but I didn't give up on it!! (I'll get back to that)
Anyway, I kept working at making it look good.
I decided to go with an oldschool 87' YZ490 paint scheme.
I had to modify the front plastics for the exhaust, and the rears for the kicker clearance.. I ended up with a partial race cut, that I still think looks pretty damn cool.
About the time I got the plastics finished, I managed to get a kicker shaft made.. Then I was actually able to start it on video.
I made this with my 4 year old son, he thought it was to loud, and covers his ears.. lol
But it gives you an idea of what the quad is all about.
(I kind of sound like a dumbass in the video, I was trying not to swear in front of the kid)
So that brings us to where the quad sits now. I did manage to finish the paint, and get it all together. But that was as far as I got...
I rode it once off camera, and the power of the 490 twisted the stock swingarm like a pretzel..
Here are the finished pictures from last spring.
The quad has been sitting for almost a year now, but I do plan on getting back to work on it.. I will post future add on's to this thread..