Jack's Information on Head Porting

you'll want to use washers on cross tube head studs to prevent scoring head.
 

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My head stand is a bit more complicated but I thought I'd post up a few pics to give you some more ideas. It consists of 2 parts, the frame and a mounting plate for the head. I riveted some aluminum plate to the mounting plate to protect the head sealing surfaces it rests against, and of course, washers (soft brass) are used under the wing nuts on the other side .....

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The I-beam shaped sides allow the stand to be flipped over on either side besides being used upright .....

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I'm even lazier. I used a cardboard box and a few pieces of 2x4's to prop it up, down and sideways. I didn't paint them either. LOL.
On a serious note, Jack, I read all your porting info and studied your picts several times. I used the different grits of emery rolls, they wear out quickly, so buy them by the bag full. I didn't go crazy, I just smoothed out the casting flaws and by your instructions, I worked on the short radius's and whittled down the valve guides. I matched up the left and right hand ports by sight and feel. I did this over a month's time, while re-reading and comparing your picts. To repeat myself, I didn't go crazy, at least I don't think I did.
My 72 xs650 is now a 750, Mikesxs kit, with a 1975 crank & cam and a Pamco. I did all the work except for the valve job. A local shop that does valve jobs and boring for my local bike shop. I was not looking for all out Kenny Roberts power, I want a bike to run well and last a long time. I've got ~8K miles on the rebuild now, and it runs great and seems to have a lot more torque. Oh, and no flat spots all the up to 6 or 7 grand in all gears.
Thanks, Jack!
 
Yes, I don't go crazy on the ports either, just smooth them out and remove the casting flaws, and all the factory "glitches" around the valve seats. I think it helps, I think they run a bit stronger like this.
 
I concur! Jack also mentioned, I experienced it and you, 5Twins may have also, and that is, don't push hard on the bits and sanding rolls. Take your time and be gentle. "Are there any Dentists in the house?" If you,ve never done this before, practice on a piece of scrap aluminum and steel. And for God sakes, wear safety glasses. At the indestructible age of 19, I ported my 125 Suzuki and got a microscopic sliver of metal in my eye. I was an indestructible dumb ass!
Lastly, (lastly, yeah right), put tape over the valve seats. It's not much protection, but it will act as a buffer when you slip. And you will.
 
I'm glad you guys found the information useful and this is why I took the time to see what areas gave the most gains for the DIY and get the heads flowed to verify it . Just a mild clean up of the casting flaws and uncorking the choked up exhaust port does wonders on ports that the factory screwed up in the beginning.
 
I'm in the process of reposting the porting images at the xs650 garage usa,I don't have all of them,they're just lost for good and I'll post some update images also. Take a look and tell me what you think,just click the images. These images we never disappear again unless the site gets dropped.
 
I'm even lazier. I used a cardboard box and a few pieces of 2x4's to prop it up, down and sideways. I didn't paint them either. LOL.
On a serious note, Jack, I read all your porting info and studied your picts several times. I used the different grits of emery rolls, they wear out quickly, so buy them by the bag full. I didn't go crazy, I just smoothed out the casting flaws and by your instructions, I worked on the short radius's and whittled down the valve guides. I matched up the left and right hand ports by sight and feel. I did this over a month's time, while re-reading and comparing your picts. To repeat myself, I didn't go crazy, at least I don't think I did.
My 72 xs650 is now a 750, Mikesxs kit, with a 1975 crank & cam and a Pamco. I did all the work except for the valve job. A local shop that does valve jobs and boring for my local bike shop. I was not looking for all out Kenny Roberts power, I want a bike to run well and last a long time. I've got ~8K miles on the rebuild now, and it runs great and seems to have a lot more torque. Oh, and no flat spots all the up to 6 or 7 grand in all gears.
Thanks, Jack!

I’m going to attempt this soon Marlin, it’s inspiring to see you had positive results.

I don’t have a Die-grinder but I have a reasonable (in my ‘wet-behind-the-ears’) Dremel that I’ve spent countless hours with polishing small parts for my build.

Daniel.
 
I'm in the process of reposting the porting images at the xs650 garage usa,I don't have all of them,they're just lost for good and I'll post some update images also. Take a look and tell me what you think,just click the images. These images we never disappear again unless the site gets dropped.

I saved all of the images you posted in the beginning of this thread Jack and I plan to print them off to create a little booklet for reference.

Will you be posting and context to the images or should I just ask questions as I go?

Daniel.
 
Yes regarding the exhaust, probably Saturday or Sunday got some issues going on that must be dealt with. When you get ready shot some images of the ports and ask away. Talk soon.
 
I’m going to attempt this soon Marlin, it’s inspiring to see you had positive results.

I don’t have a Die-grinder but I have a reasonable (in my ‘wet-behind-the-ears’) Dremel that I’ve spent countless hours with polishing small parts for my build.

Daniel.
Hi Bmoon, I used a variable speed Dremel. My father, the machinist, had all sorts of attachments. The one I used a lot was made from a long sheetrock screw that gave me a 3" reach for the emery rolls. The rolls worked best for me, especially the tapered ones, but they wear fast. I'm not home now, but I think I used 60, 80, 100 & 120grit. The cutting bits work well for a start on the big casting flaws. Stones don't work well, they load up too fast.
 
All I ever used was a Dremel as well. I find the sanding rolls good for the initial cleanup and knocking off the big casting flaws. I use the ball cutters (mostly #191 and #192) for removing and blending the machining marks around the seats, also to smooth out the spot where the valve guide "bulge" meets the port wall .....

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What I use most for smoothing the ports out are Cratex wheels or bits. These are made from grit impregnated rubber and come in all different grits and shapes. I use the plain wheels for most of the port's main walls, cone shaped ones to get into the tighter nooks and crannies .....

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You can get a pretty good high polish finish with these, and that's fine for the exhaust port, but for the intake it's better to have a textured finish. This agitates the fuel/air mix a bit as it flows through and keeps the gas droplets from dropping out of it. So, after I smooth and blend the intakes, I go back with a sanding roll and texture them up a bit .....

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For me, the big thing is removing and blending all these factory machining and "chatter" marks around the valve seats .....

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..... and removing the casting flaws .....

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These things are awful from the factory. It looks like the Lunar landscape in there, lol.
 
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I needed to get these exhaust images up before the weekend showing how I work the guide boss area to un shroud it and turn the roof to increase flow over the guide without creating resistance. Hopefully you can see in the next images clearly how I worked the inner and outer upper portion of the roof.
 
Good stuff Jack! I read some of your D port work the other day. You gonna consolidate that work into this thread?
Btw.... I'ma steal your head stand idea. ;)
 
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I have to say, when I recently rebuilt my stock XS2 motor, I never even considered cleaning up the head, but now I’m beginning to wish that I would’ve given it at least some minimal port work. Something I’m curious about, some of these photos show a lot of material removed around the exhaust port valve guide. Is there any concern about creating a hot spot on those valve guides? I can certainly see how gas flow would increase.
Anyways, I’m enjoying following along and learning something new. Thanks!
 
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