Gordy
Well-Known Member
A handful of months ago I got my Avenger 85 from @Wyvern for one hell of a deal. Thanks again!
I had no Idea what I wanted to do with it. I was gonna compare it stock tot he phantom 85, but time got in the way and I figured there's enough information out there now. So I decided to build it to make some real power reliably, and as cheap as I can.
I decided on the CDH110 piston. @Mike Cyanide found that it's one of the best options for it. After putting it together amd dropping the jug down to where there's no base gasket, my transfer ports were right where I wanted them, exhaust was super close, but the intake needed dropped about 3mm.
I took an entire afternoon just taking my time to port my jug and got it exactly where I wanted it. I widened the intake maybe 1mm, but otherwise left the port shapes and sizes alone. The jug needed decked about 3.5mm to get a squish of .92mm with a pop can head gasket. Good enough for now. Fine tuning comes later.
Now I don't wanna spend the money on a cnc head yet (I plan to use a YD100 head. Fine tuning the squish and what not comes after that). So I smoothed and polished the stock head and milled it down a bit.
I spent a good amount of time making sure the intake port was symmetrical and had a nice smooth transfer (lowering the port caused a bit of a hump about 5mm from the intake port that I smoothed down). And I also port matched the intake manifold to the port.
The exhaust port was pretty simple. I raised the roof just a little bit and also leveled ot to the top of the piston. It had and odd shaped that opened maybe 2mm on the left side so I made it even and it helped get my timing numbers exactly where I wanted it. After that I smoothed it out woth a sanding wheel and then the little green grinding wheels in the kit, and used a wire wheel to polish it. (Same process I did on the combustion chamber)
I spent a short amount of time cleaning the transfers up. They had some nasty casting flaws that took a short time to smooth out.
I also flattened the mating surfaces on a piece of glass.
Now I can't run a base gasket without throwing off my timing... So I picked up some Permetex Motobond to seal the jug to the case.
The last step to getting this engine running (other than reinstalling the ignition system) is to modify my MZ65 to fit the avenger. I'm just going to cut it off right at the chamber and cut the flange off the stock Avenger header, and weld (probably braze) the 2 together. This will give me a decent belly pipe. Not optimal, but decent.
All together I have less than 150 bucks into this engine (including the pipe) and maybe 6 hours in porting and modifying the pipe.
Again, huge thanks to @Wyvern and @Mike Cyanide!
I had no Idea what I wanted to do with it. I was gonna compare it stock tot he phantom 85, but time got in the way and I figured there's enough information out there now. So I decided to build it to make some real power reliably, and as cheap as I can.
I decided on the CDH110 piston. @Mike Cyanide found that it's one of the best options for it. After putting it together amd dropping the jug down to where there's no base gasket, my transfer ports were right where I wanted them, exhaust was super close, but the intake needed dropped about 3mm.
I took an entire afternoon just taking my time to port my jug and got it exactly where I wanted it. I widened the intake maybe 1mm, but otherwise left the port shapes and sizes alone. The jug needed decked about 3.5mm to get a squish of .92mm with a pop can head gasket. Good enough for now. Fine tuning comes later.
Now I don't wanna spend the money on a cnc head yet (I plan to use a YD100 head. Fine tuning the squish and what not comes after that). So I smoothed and polished the stock head and milled it down a bit.
I spent a good amount of time making sure the intake port was symmetrical and had a nice smooth transfer (lowering the port caused a bit of a hump about 5mm from the intake port that I smoothed down). And I also port matched the intake manifold to the port.
The exhaust port was pretty simple. I raised the roof just a little bit and also leveled ot to the top of the piston. It had and odd shaped that opened maybe 2mm on the left side so I made it even and it helped get my timing numbers exactly where I wanted it. After that I smoothed it out woth a sanding wheel and then the little green grinding wheels in the kit, and used a wire wheel to polish it. (Same process I did on the combustion chamber)
I spent a short amount of time cleaning the transfers up. They had some nasty casting flaws that took a short time to smooth out.
I also flattened the mating surfaces on a piece of glass.
Now I can't run a base gasket without throwing off my timing... So I picked up some Permetex Motobond to seal the jug to the case.
The last step to getting this engine running (other than reinstalling the ignition system) is to modify my MZ65 to fit the avenger. I'm just going to cut it off right at the chamber and cut the flange off the stock Avenger header, and weld (probably braze) the 2 together. This will give me a decent belly pipe. Not optimal, but decent.
All together I have less than 150 bucks into this engine (including the pipe) and maybe 6 hours in porting and modifying the pipe.
Again, huge thanks to @Wyvern and @Mike Cyanide!
