## Re: 70cc kstar

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Yes, i did enlarge the axhaust port, As you can see it`s wider and higher.

Widening an exhaust port can be done to 67% of the bore. In this case it`s 0.67 * 45mm = 30mm. It can be wider, but then you need to have good piston-rings.

The timing can gives you the hight of the port. I wanted my exhasut on 180 degee, with a blowdown of 25. Blowdown is: (exhaust-timing - timing transferports) / 2.

This is a value who gives an idea about the caracter of the cilinder. 20 is lots of torque, 30 is high power.

I raised the cilinde by 2mm, that gives a transfer timing of 130 degree. Then i had to choose a blowdown value, i schose 25. The exhaust port will be open 130+(2x 25) 180 degree.

Then i calculate the hight above the exhaustport, from top of te port to the top of the cilinder. I do this with a program called: Jaaps puch calculator.

Now the program calculated fo me what the hight above the port needs to be, you can enlarge it.

example:

In original state, the hight above the port is for example 25mm. If you know which timing the port needs to be, you calculate the new hight. If the new height is 23mm, then you know you have to raise the port 2mm, to get the wanted timing.

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Subject Written By Posted
70cc kstarTopic by: bryan 10/16/08 08:54PM
Re: 70cc kstarRe: Jesse -B 10/16/08 09:04PM
Re: 70cc kstarRe: Patrick Moped 10/16/08 10:06PM
Re: 70cc kstarRe: bryan 10/16/08 10:46PM
Re: 70cc kstarRe: Patrick Moped 10/17/08 09:25PM
Re: 70cc kstarRe: Jesse -B 10/21/08 10:30AM
Re: 70cc kstarRe: mark 10/16/08 10:56PM
Re: 70cc kstarRe: mark 10/16/08 10:57PM
Re: 70cc kstarRe: Jesse -B 10/16/08 11:06PM
Re: 70cc kstarRe: Patrick Moped 10/17/08 09:35PM
Re: 70cc kstarRe: Jesse -B 10/17/08 10:14PM
Re: 70cc kstarRe: bryan 10/16/08 11:55PM
Re: 70cc kstarRe: Tom STL 10/18/08 12:09AM
Re: 70cc kstarRe: rob farmer 10/20/08 07:04PM
Re: 70cc kstarRe: Cory (mrtdr 133) 10/20/08 07:22PM
Re: 70cc kstarRe: justin turner 10/27/08 09:10PM
Re: 70cc kstarRe: Jesse -B 10/21/08 10:53PM
Re: 70cc kstarRe: Jesse -B 10/22/08 08:56PM
Re: 70cc kstarRe: Tom STL 10/23/08 04:11AM
Re: 70cc kstarRe: Jesse -B 10/23/08 08:38AM
Re: 70cc kstarRe: rob farmer 10/23/08 01:21PM
Re: 70cc kstarRe: Mike Thomas 10/23/08 04:01PM
Re: 70cc kstarRe: Jesse -B 10/23/08 07:16PM
Re: 70cc kstarRe: David 10/23/08 08:10PM
Re: 70cc kstarRe: Mike Thomas 10/23/08 09:51PM
Re: 70cc kstarRe: Jesse -B 10/23/08 09:52PM
Re: 70cc kstarRe: Tom STL 10/27/08 10:25PM
Re: 70cc kstarRe: justin turner 10/27/08 10:41PM
Re: 70cc kstarRe: William 10/28/08 01:54PM
Re: 70cc kstarRe: justin turner 10/28/08 03:16PM
Re: 70cc kstarRe: mark 10/28/08 04:39PM
Re: 70cc kstarRe: ðŸ‡®ðŸ‡¹ðŸ’¦ Of the Loin 10/28/08 04:45PM
Re: 70cc kstarRe: ) Cupermcnewbster ( 10/28/08 05:38PM
Re: 70cc kstarRe: Mike Thomas 10/28/08 05:45PM
Re: 70cc kstarRe: justin turner 10/28/08 06:56PM
Re: 70cc kstarRe: ren 10/28/08 07:06PM
Re: 70cc kstarRe: ) Cupermcnewbster ( 10/28/08 07:06PM
Re: 70cc kstarRe: justin turner 10/28/08 07:36PM
Re: 70cc kstarRe: AndyC. 10/29/08 01:14AM
Re: 70cc kstarRe: justin turner 10/29/08 03:50AM
Re: 70cc kstarRe: justin turner 10/29/08 03:52AM
Re: 70cc kstarRe: Jesse -B 10/29/08 10:15AM
Re: 70cc kstarRe: rob farmer 10/29/08 12:41PM
Re: 70cc kstarRe: bryan 10/29/08 02:02PM
Re: 70cc kstarRe: Colinswoop . 10/29/08 02:10PM
Re: 70cc kstarRe: justin turner 10/29/08 02:33PM
Re: 70cc kstarRe: Jesse -B 10/29/08 02:53PM
Re: 70cc kstarRe: Tom STL 10/29/08 03:34PM
Re: 70cc kstarRe: Jesse -B 10/29/08 04:37PM
Re: 70cc kstarRe: mark 10/31/08 05:56PM
Re: 70cc kstarRe: Jesse -B 10/31/08 08:26PM
Re: 70cc kstarRe: mark 10/31/08 11:08PM
Re: 70cc kstarRe: Tom STL 11/01/08 12:07AM
Re: 70cc kstarRe: L V 11/01/08 08:45AM
Re: 70cc kstarRe: L V 11/01/08 08:52AM
Re: 70cc kstarRe: bk 11/01/08 09:22AM
Re: 70cc kstarRe: L V 11/01/08 09:35AM
Re: 70cc kstarRe: Jesse -B 11/01/08 05:18PM
Re: 70cc kstarRe: bk 11/01/08 06:21PM
Re: 70cc kstarRe: Tom STL 11/02/08 03:08AM
Re: 70cc kstarRe: L V 11/02/08 08:14AM
Re: 70cc kstarRe: Tom STL 11/02/08 10:50AM
Re: 70cc kstarRe: Tom STL 11/03/08 05:32AM
Re: 70cc kstarRe: Derk Jan. 11/03/08 09:50AM
Re: 70cc kstarRe: Jesse -B 11/03/08 10:09PM
Re: 70cc kstarRe: rockles 11/03/08 06:00PM
Re: 70cc kstarRe: Tom STL 11/03/08 09:34PM
Re: 70cc kstarRe: Tom STL 11/03/08 09:37PM
Re: 70cc kstarRe: rockles 11/03/08 11:45PM
Re: 70cc kstarRe: rockles 11/03/08 11:46PM
Re: 70cc kstarRe: Tom STL 11/04/08 05:49AM
Re: 70cc kstarRe: Jesse -B 11/04/08 10:04AM
Re: 70cc kstarRe: justin turner 11/04/08 02:49PM
Re: 70cc kstarRe: Jesse -B 11/05/08 10:32AM
Re: 70cc kstarRe: Jesse -B 11/06/08 08:32PM
Re: 70cc kstarRe: Graham Motzing 11/06/08 09:31PM
Re: 70cc kstarRe: Jesse -B 11/06/08 09:47PM
Re: 70cc kstarRe: Tom STL 11/07/08 06:51PM
Re: 70cc kstarRe: Pablo Puchasso 11/07/08 07:47PM
Re: 70cc kstarRe: ovc 11/07/08 08:47PM
Re: 70cc kstarRe: Tom STL 11/08/08 05:14AM
Re: 70cc kstarRe: Flagrant - 11/08/08 04:29PM
Re: 70cc kstarRe: Tom STL 11/08/08 10:44PM
Re: 70cc kstarRe: Flagrant - 11/08/08 11:14PM
Re: 70cc kstarRe: Jesse -B 11/09/08 12:42AM
Re: 70cc kstarRe: rob farmer 11/12/08 08:11PM
Re: 70cc kstarRe: Jesse -B 11/12/08 09:30PM
Re: 70cc kstarRe: Tom STL 11/13/08 03:30AM
Re: 70cc kstarRe: Jesse -B 11/13/08 08:30AM
Re: 70cc kstarRe: Jesse -B 11/24/08 08:05AM
Re: 70cc kstarRe: rob farmer 11/13/08 12:43PM
Re: 70cc kstarRe: mark 11/13/08 03:08PM
Re: 70cc kstarRe: Jesse -B 11/13/08 06:34PM
Re: 70cc kstarRe: justin turner 11/13/08 07:30PM
Re: 70cc kstarRe: Jesse -B 11/13/08 08:02PM
Re: 70cc kstarRe: L V 11/14/08 02:46PM
Re: 70cc kstarRe: justin turner 11/14/08 03:16PM
Re: 70cc kstarRe: st. paul sam 11/14/08 04:04PM
Re: 70cc kstarRe: Tom STL 11/14/08 05:10PM
Re: 70cc kstarRe: justin turner 11/14/08 07:23PM
Re: 70cc kstarRe: maciek 11/14/08 10:02PM
Re: 70cc kstarRe: Jesse -B 11/17/08 10:35AM
Re: 70cc kstarRe: ez da snow man !! 11/17/08 11:33AM
Re: 70cc kstarRe: Jesse -B 11/17/08 09:19PM
Re: 70cc kstarRe: Flagrant - 11/17/08 02:12PM
Re: 70cc kstarRe: ) Cupermcnewbster ( 11/18/08 02:45AM
Re: 70cc kstarRe: Jesse -B 11/22/08 09:34AM
Re: 70cc kstarRe: Tom STL 11/24/08 12:06AM
Re: 70cc kstarRe: rockles 11/24/08 04:37AM
Re: 70cc kstarRe: rockles 11/24/08 03:29PM
Re: 70cc kstarRe: Jesse -B 11/25/08 09:54AM
Re: 70cc kstarRe: Tom STL 11/25/08 12:14PM
Re: 70cc kstarRe: L V 11/26/08 09:24AM
Re: 70cc kstarRe: rockles 11/27/08 08:54PM
Re: 70cc kstarRe: justin turner 11/28/08 07:01PM
Re: 70cc kstarRe: Jesse -B 11/28/08 08:59PM
Re: 70cc kstarRe: justin turner 11/28/08 09:13PM
Re: 70cc kstarRe: rockles 11/29/08 12:47AM
Re: 70cc kstarRe: r 11/29/08 03:51PM
Re: 70cc kstarRe: Flagrant - 11/29/08 04:07PM
Re: 70cc kstarRe: justin turner 11/29/08 04:21PM
Re: 70cc kstarRe: r 11/29/08 04:48PM
Re: 70cc kstarRe: Jesse -B 11/29/08 10:32PM
Re: 70cc kstarRe: Jesse -B 11/29/08 11:17PM
Re: 70cc kstarRe: Tom STL 11/30/08 12:19AM
Re: 70cc kstarRe: Matthew Verdes 12/06/18 03:05PM
Re: 70cc kstarRe: Crazy Wayne 12/06/18 05:07PM
Re: 70cc kstarRe: Matthew Verdes 12/09/18 01:21PM
Re: 70cc kstarRe: Matthew Verdes 12/09/18 01:26PM
Re: 70cc kstarRe: Alex Hedrick 01/14/19 06:37PM
Re: 70cc kstarRe: EH ðŸ“£FCC of the QCB 01/14/19 09:14PM
Re: 70cc kstarRe: Alex Hedrick 01/14/19 09:21PM
Re: 70cc kstarRe: Alex Hedrick 01/14/19 09:26PM

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