collapse

www.dimecitycycles.com


www.restocycle.com

www.CITYLIMITMOTO.com

www.jadusmotorcycleparts.com

www.bisonmotorsports.com

www.speedmotoco.com

www.lostapostlejewelry.com

www.cognitomoto.com

www.townmoto.com

www.sparckmoto.com

www.Moto-Madness.com

www.pistonsociety.com

www.steeltowngarage.com

QUESTIONS ABOUT THE SITE? TROUBLE REGISTERING? ADMIN@DOTHETON.COM

Author Topic: GT380 ground up build  (Read 706 times)

Offline CrabsAndCylinders

  • DTT SUPPORTER
  • *
  • Posts: 1880
  • Careful With That Axe Eugene
Re: GT380 ground up build
« Reply #20 on: Jun 03, 2018, 01:15:51 »
That is pure motorcycle porn, love it!
Lighter, Quicker, Faster.
ZX-14, 900F x 2, 1100F, R100, CBR600, SR500, GT500, RZ350, KZ1000 x 2, Moto Guzzi Lemans lll, CBX550, RD 350, 750 SOHC police special, RG250, TL1000R, GT750, KTM Super Duke 1290 R, Harris/Z-1, Norton 750 Commando, Green 77 KZ650

Offline themotoworks

  • Posts: 44
    • the motoworks
Re: GT380 ground up build
« Reply #21 on: Jun 12, 2018, 18:38:57 »
how much dead air can be between the piston port and the reed valve?  I'm trying to design a weld in transition to hold the reed valve, but I can't get it all that close to the cylinder without having issues clearing the cylinder nuts... can there be some volume there or is any volume a dealbreaker?

Offline farmer92

  • Posts: 662
Re: GT380 ground up build
« Reply #22 on: Jun 12, 2018, 20:02:11 »
how much dead air can be between the piston port and the reed valve?  I'm trying to design a weld in transition to hold the reed valve, but I can't get it all that close to the cylinder without having issues clearing the cylinder nuts... can there be some volume there or is any volume a dealbreaker?


Why are you using piston porch and reeds at the same time?

Poke a few holes through the Pistons and stuff something in the crankcase to take up space to make up for the added volume.

Offline farmer92

  • Posts: 662
GT380 ground up build
« Reply #23 on: Jun 12, 2018, 20:18:26 »
The more volume between the piston port and reed valve, The longer the delay between piston port opening and read valve opening.

Letís take a look at the limit cases,

 Very Low RPM:
The piston port will open and cause a vacuum air will flow from the dead space into the crankcase eventually the read valve will open ended the pressure will stabilize in both spaces and do the piston port will close.

Very high rpm:
The piston port will open which will cause a vacuum and the air will be drawn from the dead space into the crank case the piston port will begin to close as air starts to flow past the read valve.
The piston port will be closed and the air will slam into the piston and revert back closing the reader valve keeping the dead space under positive pressure.

somewhere in the middle you have different resonance frequencies and overtones going on.

The gist of it is that it will make certain rpmís much better than others depending on that volume and the effects of that volume will be reduced as you manage to shrink it.

It will more than likely make it more difficult to tune as well.

Edit: I seem to have missed understood you after re-reading a few posts back.
When you said the piston ports I thought you meant a piston ported engine as well as reads and not that you were going to cut a window into the intake side of the piston skirt, my bad...

With that being said yes that volume is extremely important to the characteristics of your engine.
If you make it to large the motion of the piston will have a harder time creating enough vacuum to open up the reeds.
« Last Edit: Jun 12, 2018, 20:23:27 by farmer92 »