It is about right, but you have to remember of resonble limits and balance-meaningif you keep opening to any of the way try to achive one of the parameters and cross the limit line-engine will just stop perform at all.
Transfer port has to be at certain opening, to have enoough time to transfer all mixture to combustion chamber. Exhaust opening is more complecated. lower exhasut-longer dwelf time-more torq, higher exhaust-smaller dwelf time, less torq, bu higher RPM. Also difference between exhaust and transfer will dictate your pipe performance. There were alot of studies done to find the best suitble difference and so far is about 40 degree. In our aplication little bit different due to our pipe design ( two cycle).
\ Got go, will be later.
Didn't finish.

thanks TG

Thanks TG, think you have a plane to catch...we'll keep this interesting class for some other time....good luck...
AFM

Top Gun 777...can you explain that a little more. I taper the bottom of the exhaust port but not sure if you mean the same. Do you have pictures or drawing to illustrate that? Thanks

In my post I was meaning to make bigger taper in diameter of sleeve, not the exhaust port it self.
i don't have saner to make pics of drawing, but will try find one, after winter nats.

So you mean inside the sleeve so there is slight gap between the piston and the sleeve below the exhaust port?

Hey TG do I buy the P/S/conrod set directly from you. I want to try one in my MR12(3 port) or my NS12 (5 port). PM me

later

Yes you are right. On my P/S sets I have realy big tapering below exhaust port.
My P/S sets were use in Ft. Myers and you can check with Stefan abiout performance, he was the one of the racers who used. He loved it so much and reserved more from me.

Yeh, you can order from me directly. I expectin to have batch comming soon. Not too many left, but I still have some.

EDDIE!!!!!!!
 

Where are you??????????????????

Hey guys,

I'm looking at the package of my mugen P/S set for my MR12. The package says MR RS NS RR...If these engines use the same sleeve what makes the power different?..Is is carb? crank?

What they are telling you is that it "fits" any of those Nova based engines, but it has probably Mugen's port timings, so in effect if you put that sleeve into lets say a RS you are timing it under Mugen's layout, but we still have the issue of crank induction timing which could be different from engine to engine.
I had an experience rebuilding an RBX12 with a Novamega P/S set and tried it with RB's crank and the engine had more torque, when I tried it with the Novamega crank, the engine had more top end
AFM

what are some good numbers for a 4 port .21 to achieve max lowend?

this is my first time playing with timing and below is the numbers from the pos 4 port HPI .21BB I'll be practicing on, I have 4 of these so I can do all the damage I want in the quest for knowledge ;)

• INDUCTION—open 35 degrees ABDC (above bottom dead center); close 41 degrees ATDC (at top dead center); duration 186 degrees.

• EXHAUST—open 81 degrees BBDC (below bottom dead center); close 81 degrees ABDC; duration 162 degrees.

• TRANSFERS—open 67 degrees BBDC; close 67 degrees ABDC; duration 134 degrees

so what way should I go for the HPI to get the most lowend while still giving a little more room on top?

I'm thinking of pushing the induction closing to 55 resulting in a 200 duration and opening the exhaust duration to 170.

Does that sound close?

If you lengthen the exhaust duration you will lose torque and gain top end power. When I tried increasing the intake (sleeve)duration, like 8* or so, I thought it had more power everywhere. if your induction port opens sooner it shuld have more bottom end power, while if you grind on it to stay open longer it should have more top end power, I thought like a 210* duration was good. You can also change your combustion chamber's shape, the taper, band width, radius of the bend/angle, and can put some grooves in it to get the fuel/air to mix better and burn more powerful b/c the rich spots shouldn't be as bad. I have only ran .12 engines so the principles will be the same for .21's but the numbers might differ.