Anyone here ever done a port and polish?

Crab_Cake

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I did a search but I didn't find much on the subject. I am thinking of taking my head the bike to do a port and polish. I have been researching the process quite a bit and I think I can do it.

I have a compressor and a die grinder. I read an article saying that a port and polish is one of the best things you can do to a 650. Anyways I just wanted to know if anyone else has tackled this and any advice you might have.
 
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I've done 4 heads so far. Each time, it gets easier. I just use my Dremel.
 
Ohh the sickness, I found myself reading the thread and following the links when I haven't even got my bike started yet. Maybe I should get the other stuff finished first.
 
The ports as they come from the factory are just so rough and nasty looking, you can't help but want to try and improve things a bit. They're full of casting flaws and machine marks from the valve seat install .....

IntakeBefore4.jpg


IntakeBefore.jpg


A little quality time spent with a Dremel and you can make them much better .....

PortsAfter2.jpg


PortsAfter8.jpg
 
And when you get bored porting stock ports you'll develop the itch to branch out to explore different port options.:laugh:
100_0352.jpg
 
Don't polish? Why is that? I'm with hotrdd. This looks like fun to do but I know I have other things to tend to first.
 
Yes, why not polish? I've seen a picture of ports polished to a mirror like finish.

Also, what type of attachment to the Dremel, just a wire wheel?
 
I rough up the intakes (after smoothing the lumps and bumps) but leave the exhausts polished. You want the intakes "textured" to aid in the fuel atomization. If too smooth, supposedly the fuel droplets can drop out of suspension as the fuel/air mix travels through the port.

I use an assortment of ball cutters, sanding rolls and grit impregnated rubber tips. I also use the flex shaft attachment. It allows you to get in there easier.
 
on any surface that bends air (such as a wing, or a port) there exists something called a boundary layer of air directly over the surface - and this layer of air does not flow with rest of the air current and largely remains stationary. If you polish a surface too smooth this causes the boundary layer to become thicker. Ideally the boundary layer is only about as thick as a molecule, but when a surface gets too smooth the layer can become many molecules thick. this is why airplane wings are not polished to a mirror finish. As far as ports are concerned, obviously if less air flows less air is getting into the engine, but that extra thick boundary layer can also hold fuel, keeping it from reaching the combustion chamber as well.

I've read the ideal texture for a port is around 400 grit... i just smoothed out the casting and tooling marks on mine with a diamond file.
 
on any surface that bends air (such as a wing, or a port) there exists something called a boundary layer of air directly over the surface - and this layer of air does not flow with rest of the air current and largely remains stationary. If you polish a surface too smooth this causes the boundary layer to become thicker. Ideally the boundary layer is only about as thick as a molecule, but when a surface gets too smooth the layer can become many molecules thick. this is why airplane wings are not polished to a mirror finish. As far as ports are concerned, obviously if less air flows less air is getting into the engine, but that extra thick boundary layer can also hold fuel, keeping it from reaching the combustion chamber as well.

I've read the ideal texture for a port is around 400 grit... i just smoothed out the casting and tooling marks on mine with a diamond file.

The rough textured barrier finish soul purpose is to provide a higher pressure point of turbulence behind the low pressure point to aid in suspending the fuel mixture to the main airstream to further enhance the vaporization of fuel mixture before entering the combustion chamber. You will achieve better results using 36 grit or lower to really reap the benefits of building more Hp with lesser amounts of fuel. (Combustion Efficiency) And also there are no diminishing effects of flow or fuel either with rough textured barrier finishes. Just about anyone can produce greater amounts of power by porting but the trick also is to achieve the same amount of power or higher while reducing fuel demands at the same giving RPMs
 
agreed...smooth out the chunks & steps in the intake, leave a rough surface, and polish the exhaust just to get the waste out of there as efficiently as possible.
 
I have been doing it a long time and if you are just doing it for fun and not backing it up by performance parts leave it alone. D porting exhaust helps on race motors and bikes pushing out alot of horse power but i never seen any dyno results on a xs 650. Would like to see them if someone has them. You can clean them up a little and thats cool but gas rolles in and sometime polished up real good hurts more than help. I do alot of drag race heads and i am changing valve size vale guides springs everything to get more horse power with porting. I am doing a cafe bike XS650 now and just opening the intake up a little and matching manifolds for flatslide carbs but i really don'y think i am going to get a big increase but anything is better. I just started doing cafe bikes and would like to know if someone got crazy and did one all out and what increase they got and did it stay together.
GOOD TOPIC
 
I have been doing it a long time and if you are just doing it for fun and not backing it up by performance parts leave it alone. D porting exhaust helps on race motors and bikes pushing out alot of horse power but i never seen any dyno results on a xs 650. Would like to see them if someone has them. You can clean them up a little and thats cool but gas rolles in and sometime polished up real good hurts more than help. I do alot of drag race heads and i am changing valve size vale guides springs everything to get more horse power with porting. I am doing a cafe bike XS650 now and just opening the intake up a little and matching manifolds for flatslide carbs but i really don'y think i am going to get a big increase but anything is better. I just started doing cafe bikes and would like to know if someone got crazy and did one all out and what increase they got and did it stay together.
GOOD TOPIC

You do not need performance parts to reap the benefits when porting the XS head,the head is what ails the lack of performance to begin with,especially the exhaust port with it's lack of exhaling abilities.you do the head first,then add what parts you wish to yield higher performance. If you have the know how and port material to work with or add some material,then achieving a flow percentage gain of 15% for the intake and 25% exhaust would be a reachable goal with no problems. There's no need for D shaping the exhaust port on this head,it has more than enough flow capabilty to handle any HP figure you throw at it,it you know how to work the port,it's the intake side that needs the help. Mild clean up 60 to 65 HP, more radical mods up to 100hp. You need to be careful when opening up the cross sectional area on the intake side cuz port velocity will decline as will low end performance,the crank has short stroke.
 
All I ever did was clean my ports up, never to the extent that Jack goes to. He is the master, me the student. But I will say that the bikes run better. They pull harder and rev faster. It's not a night and day difference ...... they don't pull wheelies off the line all of a sudden ...... but they do run better and stronger.

I've done all the recommended mods to my mostly stock XS. They all helped a little. No one thing put it "over the top". They all added up to one good running bike.
 
Thanks Jack for the info
Sounds like you did a couple of these before. What kind of increase in HP have you got out of a stock head with mild porting and STOCK PARTS and was it put on a DYNO. Have you ever put bigger intake vales in with 3 angle vale job and run into any problems.I done a lot of 4 cylinder motors for drag bikes but thers a difference in just going a quarter mile and running a bike for 2 or 3 hour at a time. I had head crack around vale guide from heat before because of porting and just want to do a mild head on this cafe that i am building then try and open one up and put much larger carbs on or see if one of these can take 10 pounds of boost with a turbo. I have port and polished a TRIUMPH before and got small abound of extra HP. My point is is it worth it to go all out because it a street bike and maybe you can get 130 to 135 MPH out of one of these motor but thats not what i am looking for i want bottom end and mid range power more than top end. I have heads to play with and the right tools to do it. Would really like to see a DYNO Sheet on one and see what real HP gain was there. There are alot of guys who build these motors to race but again race and street are different.
 
Thanks Jack for the info
Sounds like you did a couple of these before. What kind of increase in HP have you got out of a stock head with mild porting and STOCK PARTS and was it put on a DYNO. Have you ever put bigger intake vales in with 3 angle vale job and run into any problems.I done a lot of 4 cylinder motors for drag bikes but thers a difference in just going a quarter mile and running a bike for 2 or 3 hour at a time. I had head crack around vale guide from heat before because of porting and just want to do a mild head on this cafe that i am building then try and open one up and put much larger carbs on or see if one of these can take 10 pounds of boost with a turbo. I have port and polished a TRIUMPH before and got small abound of extra HP. My point is is it worth it to go all out because it a street bike and maybe you can get 130 to 135 MPH out of one of these motor but thats not what i am looking for i want bottom end and mid range power more than top end. I have heads to play with and the right tools to do it. Would really like to see a DYNO Sheet on one and see what real HP gain was there. There are alot of guys who build these motors to race but again race and street are different.

No Dyno time for me,just pants estimates:laugh: I'd stay away from oversized valves for street use, power differences won't be felt till higher up in the RPM( Get some Virago 750 valves and grind'em to 650 specs. Being a Hot Rodder you should know the benifts with thick valve margins ) You can grind 3mm from top but carefully around the guide area and by the way the intakes respond quite well when the floor is raised 3mms with the short turn laid back, port D-shaped for low end mid range grunt, If you're lost as how to port the Xs exhaust port,send me a head and I'll do one port for you to duplicate or I can post a few shots later this week for you.
 
All I ever did was clean my ports up, never to the extent that Jack goes to. He is the master, me the student. But I will say that the bikes run better. They pull harder and rev faster. It's not a night and day difference ...... they don't pull wheelies off the line all of a sudden ...... but they do run better and stronger.

I've done all the recommended mods to my mostly stock XS. They all helped a little. No one thing put it "over the top". They all added up to one good running bike.

Me the master 5Twins,just the opposite my good man :wink2:your work is outstanding ,along with your efforts to educate others:thumbsup:
 
Thanks Jack
I have done alot of D ports on DRAG RACE motors but was looking for as much info as i could before i go into this head to see if the performance helps some or alot.SEAT OF THE PANTS DYNO (i like that) is not what i was after. You put carbs on these bikes and its like day and night first ride on bike. I was looking for anyone who ever put one of these on a DYNO and have some info. Like ALL BIKES there is a breaking point and a MAX point on HP before it goes boom. I seen one of these last year in FL at a track with NOS and the guy said it held up with a small shot and he said he was getting 75 to 100 HP more but didn't run it and bike sounded like a stock motor. So everything so far is hear say and i was looking for a little more. But THANK YOU very much for all your info. Guess i will play and stick it on a DYNO to see. There are many bikes coming up in this area as CAFE BIKES and Street Fighters so i wanted to do a couple and test the market.
 
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