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porting a DR650

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here's a few pics of the porting I did to my 2008 DR650se (before & after).

like usual there was a lot of room for improvement in the stock head. I also did a three angle valve job & milled the head for increased compression.

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so what were the overall gains? what would this cost me?

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so what were the overall gains? what would this cost me?

this will cost you the price of a decent dremmel and some different bits, if you have access to a air compressor i would recommend a variable speed air drill, and then if you can find a second head on flea bay or something to mess around on then your good to go, basically smooth the exhuast so its like glass, and make the intke uniform and even butt still ruff like sand paper to cause turbulance, once you get this down all the little tricks like porting more for top end or low end comes into play,

honestly milk its not that hard, every bike you ever buy you should port and polish and if you do them all yourself youll save bank.

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ok, i have all of the above except fot the extra head... what kind of bits would be required to do this. I have a ton of bits, i used to do engraving/carving and have a pretty decent dremel set up :thumbsup:

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this will cost you the price of a decent dremmel and some different bits,

I'd have to agree & disagree with this.

while it's not rocket science there is a certain amount of skill involved.

if done wrong you could at best lose performance or at worst ruin the head.

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so what were the overall gains? what would this cost me?

I've yet to get it dyno'd because I'm waiting for the rear tire to get worn down a little more.

I can say that I gained quite a bit of power all through the rev range, not just at the top. I focus on getting across the board gains with my head work because it's a lot more usable power. peak power is great for drag racing but for everything else a broad spread of power is Ideal.

if done improperly you could wind up with a motor that only pulls well at or near redline.

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what kind of bits would be required to do this.

I use carbide burrs & cartridge rolls for the rough work & then dremel cross buffs for the polishing.

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I'd have to agree & disagree with this.

while it's not rocket science there is a certain amount of skill involved.

if done wrong you could at best lose performance or at worst ruin the head.

i agree it takes a lot of skill and talent, but you have to start somewhere, and as long as the person takes it slow and easy and takes little steps, basic deburr and polish etc, almost anyone and i mean anyone is capable of doing a stage 1 port and polish the skill sets in at stage 2-3, and some companys claim to have 4 or 5.

i have always ported every bike i have ever owned sometimes buying a new head just because i felt i didnt get it right the first time, but you know what there is nothing better then people hoping on your bike and saying god damn, why does you bike pull so much harder then mine, and you tell them you did it, not so and so. :thumbsup:

plus with pics now a days and the great help here on TT, im sure MILK is capable of doing a stage 1 job on his own, its always easier to go to a shop if you can and watch them do some, invaluable learning experience, when i spent all my time out in cali it was all to learn nothing but the "trade secrets" one of them was anyone with a piece of sandpaper can do a stage 1 port job especially on aluminum :smirk:

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i agree it takes a lot of skill and talent, but you have to start somewhere, and as long as the person takes it slow and easy and takes little steps, basic deburr and polish etc, almost anyone and i mean anyone is capable of doing a stage 1 port and polish the skill sets in at stage 2-3, and some companys claim to have 4 or 5.

i have always ported every bike i have ever owned sometimes buying a new head just because i felt i didnt get it right the first time, but you know what there is nothing better then people hoping on your bike and saying god damn, why does you bike pull so much harder then mine, and you tell them you did it, not so and so. :thumbsup:

plus with pics now a days and the great help here on TT, im sure MILK is capable of doing a stage 1 job on his own, its always easier to go to a shop if you can and watch them do some, invaluable learning experience, when i spent all my time out in cali it was all to learn nothing but the "trade secrets" one of them was anyone with a piece of sandpaper can do a stage 1 port job especially on aluminum :smirk:

now we are on the same page, I can totally agree with that!

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The ports definitely look better, but have you ever flow benched a head before and after you've worked on it?

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The ports definitely look better, but have you ever flow benched a head before and after you've worked on it?

I don't own a flow bench.

I have done primarily sportbikes & have gained approx 10-15 HP in every case just by using my own judgement as to shaping the ports.

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What did you use to shave the head?

I have a machinist that does my milling & valve cutting. John Edwards, he's an author & teacher.

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The ports definitely look better, but have you ever flow benched a head before and after you've worked on it?

PC has some of the latest sonic head chambering equipment available.

flow benches have come a long way in the last 20yrs :thumbsup:

you can find older used ones for 800 bones on ebay its jut the shipping that will kill ya. computerization is where its really at now-a-days,

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I have to agree with some, and also agree with others :thumbsup:

I think the DR head is a great head to learn on, its simple big port, air cooled technology, any porting done especially to the inlet will help no end.

Have a go i say, im constantley looking for a spare head on egay, and as soon as one`s available a porting she will go.

I can give a couple of tips when porting, the term "polishing" should be the last thing in your mind when it comes to porting, a matt finish is the ideal end result.

You can obtain this finish by making yourself a long nylon candle with a slot in the end, in to that slot you insert 1" strips of scotchcloth, you know the stuff you use to scrape/wash last nights dinner off the plate, green in colour.

When you spin that up in your chosen airtool down the port, you achive the said "Matt" finish.

If your worried about breaking through where you shouldnt, especially on a water cooled, just tap your tool on the inside of your ports, when its getting thin it will sound different to when its a chunky bit of ally.

Drop the guides out as well before porting, easier to work the tool without a bollard obstucting your view.

A swirl is what most proffesionals try to achive, a vortex going down a port is quicker than an avalanch coming towards you.

My late father ported some 35,000 motorcycle heads in his time, so i guess you could say he knew what he was doing.

He always said "The head is like your head, the mouth is the inlet, and the exhaust is its arsehole" he had a way with words.

Classic times watching his customers inspecting the exhaust ports on the head he had done for them, they would be squinting away trying to get the shed light to shine down the port & my father would say (in his best hungarian) "YOU LOOKING UP ITS ****ING ARSEHOLE YOU C**T"

Yes, its "****ING ARSEHOLE" as my late father so eloquently put it, was indeed the exhaust port, important if your racing, but the mouth is where you need to spend the time.

I like the post "i port most of my bikes" everyone should have a go.

Mezo.

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Follow up to the last post, the ones on the left are my bothers newer tools, and the ones on the right are my late fathers old tools, and yes he would of earned a million or two with them chunks of alloy.

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A close up of the "Finishing tool" a long nylon stick turned up in the lathe & then a slit cut down the centre to stuff the scotchcloth.

Finishing%20tool.jpg

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Follow up to the last post, the ones on the left are my bothers newer tools, and the ones on the right are my late fathers old tools, and yes he would of earned a million or two with them chunks of alloy.

Porting%20Air%20Tools.gif

A close up of the "Finishing tool" a long nylon stick turned up in the lathe & then a slit cut down the centre to stuff the scotchcloth.

Finishing%20tool.jpg

looks like a well used set of tools. I bet he made a lot of HP if you added it all up!

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looks like a well used set of tools. I bet he made a lot of HP if you added it all up!

Them there tools paid for everything, when you think how many ports some heads have & times that by roughly 35,000+ heads it soon ads up.

You will notice how long the tools are, he used to drape a rubber air hose over his right shoulder & hold the tool like you would a wind instrument, his shoulder took the wieght of the tool allowing him to work on heads all day, every day for decades.

Giving away the family secrets here on this forum eh :banana:

Share the knowledge i say, sorry pops.

Mezo.

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