SYM DD50 Build...

[bakaracer]

How do you do the calculations? I thought it was B/A X D/C= Ratio. So for 15x42 would be 42/15=2.8 47/12=3.916 so 2.8 X 3.916= 10.9 to 1 NO???? Please help me figure this out.

its the front 2 gears so 34/12=2.833 and the after market rear gears 42/15=2.8 then multiply the 2 together so 2.8x2.83=7.93. if your putting aftermarket primary(front gears) then it would be the the stock rear gears times the aftermarket front gears

[donaudi]

Thanks Baka, I guess I had a huge brain fart on that one.

I've been real busy lately but I've still managed to get some work done. Here's a few pictures of the head. We've removed the cnc marks and the rough casting marks from the squish area. We also smoothed out the deck surface. If your wondering why I've been saying we, it's because my girlfriend has been helping me out with this build. I told her she can have this ped when were done so we can go riding together. I"ll be riding my CBR1000RR of course.





If you look closely you can see the air bubbles that were in the casting!!

Here's the piston. Made sure to keep the proper tapers to keep oil on the cylinder walls.






Oh, and here's a teaser pic of the CBR...

[bakaracer]

yup!! thats what you do to the piston bottom. you dont want the piston to act like a squeegee in the cylinder wall. dont forget to polish the top of the piston too.

[donaudi]

Here's a OKO 28 carb in purchased form. Not very * material.








Widened the bell out to the very edge for maximum air flow. Polished the velocity side of the carb to a pretty smooth finish. Think brushed aluminum.




Tested both couplers, one that came with the carb and the other that came with the intake manifold. Found out the intake manifold had a better fit. Also noticed that the carb outlet and the intake inlet openings were smaller than the boot inner diameter. I shaved down the last few millimeters of the carb outlet to match the boot and blended it. I also left a rough finish to help keep the fuel mixed in with the air. If you notice the carb outlet side also has a very bad finish.

[donaudi]

BAKA, your comments and suggestions are always appreciated and welcome. About polishing the top of the position.... I was contemplating doing that, but I was concerned about removing the "graphite" coating. What would you think would be better? A polished piston top or leave that graphite coating??

[donaudi]

I've seen a few pics of the OKO carb in black and liked it. A few minutes work with a can of engine enamel.









What do you guys think??? Is it * material now???

[donaudi]

The intake was also quite a bit of work to get up to specs. First like the carb, opened up the intake internal diameter to match the included boot. I had to removed a lot of material, so one word of caution if you attempt this... be careful not to wear through the intake (there is a thin part where the boot hooks into). One benefit to doing this is that the transition from the intake to the big chamber is better. You should be able to see this in the pics. Like the carb I left a textured surface to keep the fuel suspended. If you look at the before pictures you'll notice the mating surfaces are pretty rough from the cast. I smoothed out all those surfaces. One thing that bothered me is the reed block. I you look down the intake assembled you'll see that the reed block protrudes into the airflow path. There's not much you can do, I decided to help make the tradition a little easier (see pics). One more note on the reed block. Where the reed openings are, there are rough little spikes. I sanded then smooth with some high grit wet sand paper. Without further ado....

Original untouched.





Opening of the intake.






Housing.




Reed block. Blockage.

[donaudi]

Two questions....

1. I was contemplating painting the intake manifold black like the carb. What do you guys think? Too much black? Still on the fence.

2. Here is a pic of the reed block. I have read you need at least two millimeters to have a good seal for the reeds. I was thinking of opening up the reed holes, but do you guys think that would leave too little material for the reed to properly seal?

[evilone]

What do you guys think??? Is it * material now???

Yes, now i feel like making some * of my own

[donaudi]

I have another question.. I'm going to "knife edge" the bottoms of the transfer ports and possibly open and smooth them out a little. Is there any advise before I proceed? Beside matching the cylinder to the base gaskets? Also I wanted to widen the exhaust and transfer ports a little as well as smooth out the cylinder side openings. I know some of you stated that you ported a forsaking bore. Is there any advise here? With of exhaust port? With of transfers? Do you go up in height on any of the ports? I'm trying to go for a aggressive street race setup. You help would much be appreciated. Thanks.

[donaudi]

I'm by no means an expert in any way shape or form. I'm doing this to show that with a dremel, sand paper, spray paint, and some patience anybody and do this type of stuff. And more so, I encourage to do better than me. This is all that I can think of doing, but I know a lot of you guys are way more creative and technical than I am.

[kingkamehameha]

I like all your nice p and p work keep it up. How much faster will this make you go?

[donaudi]

That't the funny thing. All this "extra" work may not this motor any faster than someone who just bolts on the parts and go. If there is any diffrence, it will be small. My thought process behind doing this stuff is: If you purchase the parts why not spend a little more time and get the parts up to the best specs possible. And at the end of the day, you have somthing that's unique and that you can call your own. I've told myself that every setup and combo has been done and done many times. It's hard to see a setup that someone has never seen before. Especally here in Hawaii, everyone runs the same or similar setup.

[donaudi]

Here's a little entertainment. It's a video of my buddy and me playing on a mountain road. The camera is on his bike and he's chasing me up the hill. He's on a R6 and I'm on a 636. ENJOY!







Here's the same run, but the camera is on my 636.

[bakaracer]

BAKA, your comments and suggestions are always appreciated and welcome. About polishing the top of the position.... I was contemplating doing that, but I was concerned about removing the "graphite" coating. What would you think would be better? A polished piston top or leave that graphite coating??

you can try it with the coating first and see how fast the carbon sticks. if it sticks fast then polish the top.