SYM DD50 Build...

[bakaracer]

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.

if you have a dental dremel set that has a 90deg head on it then you can widen the ports. the transfers have to point to the middle back section of the piston. if you cant get it to angle like that then you will mess with the flow and can loose hp and torque. the corsa already has an agressive port setup and revs to 11k and makes about 10hp so I wouldn't mess with it.most dio pipes dont rev to high anyways ,thats why most dio kits make its most power at around 8800rpms. the pg long will rev and make good power to about 10600rpms. so I would leave the ports how they are.

[donaudi]

Ok, that's some sound advise. No since making the cylinder to a more aggressive spec if you can't find an exhaust to match. Talking about exhaust... what exhaust out there would you recommend that would match up well with the corsa. Pg long (loud barking sound) as BAKA stated, he also had recommended the scorpion to me (high pitched and harder to tune), are there any great cone counter cone pipes out there? There's a shop selling the malossi exhaust for 72, Leo vence pipe, there's the next R, or any other ones that anyone can recommend. I have the YMS V8 pipe that's going to be used for a more quieter mode (though will loose some top end).

[donaudi]

Oh, and yes I've seen that "dental" porting tool you speak of, but at $1000 it's pretty steep, especially for someone that may only be porting one cylinder. I was actually thinking of picking it up to try, if we weren't slow at work I might have bought it. Oh well, maybe some other time.

[bakaracer]

yeah those tools are expensive.just the 90deg head cost around $200 other good pipes are the Arrow and sef black. use a airbox like the kuka witha fdm outer cover or a ddx airbox to cut down on intake noise. sometimes the intake noise is louder than the exhaust.

[donaudi]

Anyone got info or has tried the somini pipe that treatland carries?

We can get the Sef, scorpion, and pg stuff here locally, but does anyone have a good source for arrow and the other types of pipes. There getting harder and harder to track down.

[bakaracer]

your best bet is to email treatland and ask for specs on those pipes.

[bakaracer]

what exactly do you want your setup to do?

[donaudi]

Emailed treatland they said its for a 70cc. They actually said they don't know much about the pipe. They just stock it for there friends in Hawaii. I guess someone from here has been ordering it from them. Basically looking for a street race setup. Something that will pull nice and hard from stop to topend. Don't mind if I loose a few ponies up top or down low. Is rather have a nice progressive flat torque curve to redline. Other than that I guess I don't really know, I have the v8 for quote and I have a even quieter pipe than that. I would like a nice torque pipe that will carry to the polini's redline to complete my set of pipes. And if no single pipe does this I guess I will have to go with one for all topend and one with mid and top? There has to be something that'll work right?

[donaudi]

Ok, I'm pretty much finished with the intake manifold. Does anyone know if I can remove the reed stop. The reed setup consists of the reed block followed by the reeds followed by the reed stiffener, followed by the reed stop plate. Can I remove the plate? Or the stiffeners?


Here's the competed manifold assembly. I was on the fence on painting it, but now I'm glad I did. I was able to smooth out most of the casting flaws before painting.

[Dakine]

wow you did ah good job at cleaning those sharp edges. you think polishing the manifolds inside would make ah difference or would that mess up the way the fuel runs down?

[donaudi]

As far as I know, you want the inside surface texture to be a little rough. Supposedly its going to help keep the fuel suspended in the air and help keep as low of a surface tension for better flow. If its smooth the fuel will tend to stick to the walls and not atomize. The exhaust you want smooth to prevent the carbon from sticking. Well, that is the theory at least.

So does anyone know if the reed stop can be removed and the reeds just run with the reed supports?

[bradthreee]

Keep up the great work!

[evilone]

So does anyone know if the reed stop can be removed and the reeds just run with the reed supports?

Yes the stop can be removed.

[Red Eft Performance]

Nice work! I highly recommend using some rtv or somthing similar to seal the gaskets and bolts on the ct manifold. I know there will be some RTV haters, but when I pressure test my motors the ct is always the thing that is leaking. It leaks around the gaskets and bolts even when I tighten them as much as I dare.

[donaudi]

I think what Red is saying about the CT leaking is very likely. I personally smoothed out the casting flaws on the mating surfaces of the mani, which should reduce the tendency of it leaking. Here's a pic of the flange surface out of the box.






So the reed stops can be removed. Here's a question I have for you guys. I was thinking of flipping the screws and screw bar to possibly help promote air flow. Which way do you guys think would be better???







Do you think flow would be better with the cross bar or with just the screw heads?

Also, I was shown that you can run Boysen reeds, but the reeds have a two screw hole two pedal reeds. I was told you need to switch the reed housing from a different manifold into the CT, then you would be able to run the Boysen reeds. FYI, does anyone have more info on this?


I also didn't like the rough finish on the carb slide. I fine grit sanded it and polished it along with the inner surfaces where the slide moves across. One thing to note here... be very careful as the come plating on the slide is very thin. If you start to see copper your wearing through the chrome layer. I'll post a pic a little later.