Author Topic: Porting  (Read 3221 times)

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Offline hughes

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Porting
« on: October 24, 2005, 01:11:33 PM »
Is their any porting I can do myself on the intake side of the motor :?:  :?: Anybody have pictures of their own porting?
Open Class 2-Stroke Kawasaki KX500
Yamaha 2005 YZ250
Richard Hughes
Dirt Hammers - Online Off-Road Journal
hughes@dirthammers.com
http://www.dirthammers.com

Offline KXcam22

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RE: Porting
« Reply #1 on: October 25, 2005, 06:22:50 AM »
Hughes,
  I am not sure how close your cylinder is to my 92 but on mine there was a fair bit of work I did to remove casting flaws to smooth the flow.  Took a few hours but increased the bottom end noticeably.  Look at where the booster ports from the sides of the intake flow down into the main transfers. Also I had bulges in the outside walls of the main transfers (a main flow area), which I smoothed. I did not change any actual port timing.  If you are interrested I can tell you how to build an easy tool for your grinder for polishing. Cam.

Offline Danger4u2

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Re:Porting
« Reply #2 on: October 25, 2005, 07:56:06 AM »
Cam, lets see your home made polishing tool please.

Danger
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Offline KXcam22

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RE: Re:Porting
« Reply #3 on: October 25, 2005, 09:31:27 AM »
Danger,
  It's pretty simple and others may use a similar one. Get a long 6" to 8"  1/4" diam grade 8 bolt, cut off the head and threads to get a straight shaft. Cut a hacksaw blade width slot straight down on end of the shaft about 3/4" deep.  Fit the shaft in the 1/4" chuck of your mini grinder.  Take 12" long strips (can be varied) of 1" wide emory cloth (fine 240 or 320 grit) , put one end in the slot and roll the rest around the shaft in the direction your grinder spins.  Place the roll inside the port and let er fly. As the emory grit wears the cloth comes off always leaving an emory edge to polish with.  Wear eye protection and a dust mask and do it outside as it is a bit messy.  Fast and easy and does a great job.  The length makes it easy to reach deep into ports. The depth of the slot should aways be about 1/4" less than the width of the emory cloth you are using. Hope you can understand my description- can post a pic if needed. Cam.

Offline hughes

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Porting
« Reply #4 on: October 25, 2005, 10:28:43 AM »
Thanks, I am tearing down the engine this winter for complete rebuild and replating. So am going to clean things up alittle.
Open Class 2-Stroke Kawasaki KX500
Yamaha 2005 YZ250
Richard Hughes
Dirt Hammers - Online Off-Road Journal
hughes@dirthammers.com
http://www.dirthammers.com

Brett

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Porting
« Reply #5 on: October 27, 2005, 11:34:45 PM »
One place i think you should clean up which i can't remember being mentioned before is where the intake port goes down into the crankcase. There is 3 or 4 passages that are quite good all the way but when it exits the cylinder it has a harsh exit into the crankcases.  This needs to be radiuised between each port and also matched up to crankcase.  Spewin i didn't bother to take pics when i did mine as a picture would mak more sense.
Hughes we will probaby have motors apart at same time as over here i don't bother riding in summer as is so sandy and dusty. I will prob pull top end off in few weeks to see how badly the crappy wiseco has collapsed, seeing as i backflipped mine on weekend and broke subframe so may as well pull apart repair and clean ready for next dust free winter riding.

Offline YUNGGUNNAZ

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Porting
« Reply #6 on: October 28, 2005, 12:38:29 AM »
also while apart  put new base gasket on the cylinder.you'll notice there is some overlap blocking transfer entrance. trim this back.while the motor is apart take one half of case and put the cylinder on .rub finger up and down where the two meet at transfers there is usually mismatch here.blend this in.oops letting too much out.

Offline hughes

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Porting
« Reply #7 on: October 28, 2005, 12:48:31 AM »
Thanks Guy's thats some good info. I will take pictures of my work this winter. I still have about two months of riding left and then it's teardown time.
Open Class 2-Stroke Kawasaki KX500
Yamaha 2005 YZ250
Richard Hughes
Dirt Hammers - Online Off-Road Journal
hughes@dirthammers.com
http://www.dirthammers.com