Thumper Racing Head Porting

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There's more to porting than just grinding away. Compare a grind and polish with a head ported by a professional who then tests the results on a flow bench as he goes along. No comparison! It's not just what you remove it's knowing what to leave.

the way I read this, your having a specific go at me for doing any old work. you don't know what I do or how i do it. in the next post you imply WRONGLY (because your a ******* big mouth) that I

No thanks, wasn't doubting it's a messy job.
The professional I used flow tests EVERY head he works on. So you port one head then copy every other you do? Interesting.

why would I not copy my best result? for a man running a bloody roadbike for christsakes? who just wants 90% result for 50% OF THE COST? i MEAN WHY? :furious::furious:

A good tuner such as Thumper Racing will ask what the customer wants and not do a generic job as you suggest.

YES HE WILL!

I have a couple of home ported heads here I bought from sidecar racers, they may be yours, and they do not flow as well as the head I had tuned by a professional, FACT.

THAT STATEMENT IS THE ONE THAT GETS RIGHT UP MY GOAT. you go casting ******* statements like that and then hold yer hands up going: 'who me? little old innocent me?

while you run a standard cam you don't even need a porting job.

tow4.JPG

when you win two championships in one season against people with double the CC and 50% more power you can talk. now have you done thaT?

HOW ABOUT YOU TWELL EVERYONE HOW YOU KNOW HOW i PORT MY HEADS?
 
Taffys just blunt speaking here, I wouldnt take hes blunt in person, ie I dont know. I know a lot of blunt speaking uk peaps though, so who knows?

However Id like to know more about the 100hp engine. it would take over 400 fps at 28 depression, rather intriguing.
309 is good for 72 on 565cc and 390 is good for 94 on 599, the latter is cheat as its a ducati twin.
I typically post everything about my work, just be open about it and customers will come ;)
 
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HOW ABOUT YOU TWELL EVERYONE HOW YOU KNOW HOW i PORT MY HEADS?[/QUOTE]

I've no idea? Squinting through one eye with a Dremel? Who cares? The OP was asking about a USA tuner. How much do you charge for one of your porting jobs by the way?

A track bike running an 08 cam would not benefit from being ported? Interesting claim? So a before and after on a Dyno would show no difference? Also an experience rider would not see an improvement in lap times? Again, an interesting claim?

Can you give any details on your 100hp engine? I think we'd all pay for that!

What is the relevance of the picture of the mullet haired gentleman with the Ducati in this thread? In your cock waving contest is three better than two?

Best regards,
Big Mouth.
 
Forums can be a confusing place with lots of people talking. As we age, we can get a little cranky and less inhibited. This is no cause for worry and most people understand that this is a natural side effect of the aging process and in most cases you will be given the requisite patience. However, Taffy, you seem to be having enough trouble with this that here's a piece of advice: When in doubt, try looking up at the post title to see if you're on topic.

Furthermore, perhaps your family would be more interested in your keepsakes and photographs as a general topic. I believe that would be a more appropriate venue.


Regarding the topic which is Thumper Racing and their head porting work: I don't recall anything but people speaking very highly of their work, that their knowledge is deep and working process thorough and all quality 100%, that they work with measured and documented changes to flow (as a matter of course, although not all vendors do), and that Travis is super pleasant to deal with.
 
Yes I can vouch for Travis, I've just purchased a third 610 big bore kit from him (2nd one was for a friend) quality and customer service has been great every time. If I lived in the states I'd send my head to Travis, but I don't so I sent mine to Serco in Brisbane. Even though I've been a difficult customer at times I've never been flamed out on a public forum.

Be nice to see some dyno before and afters.
 
Yes Berglsmerg, I agree a before and after dyno session would be ideal.

From what I have heard about Thumper Racing they will be the place I send my head/heads.

Thanks,

Jason
 
Oh its easy Tom Tom you just impart a bit of your alter ego in the form of super dark matter into the aluminium and it creates a self perpetuating vacuum swirl engine with logarithmically increasing volumetric efficiency

In simple numpty terms the more you talk yourself up the faster it goes
 
Anyone know what the big bore JBS Racing 650 engines were putting out?

This would indicate what is possible in naturally aspirated MX style power.
 
Well dr c is at about 85hp

With a big bore, billet dohc head and efi

Hi Bushie and all Husaberg friends!
As I'm slowly recovering from a MAN-COLD (Yes friends, a near death experience), I have time to kill with browsing this thread and noticing how fast it all went bonkers! :) Somewhat entertaining but more worrying.

My last dyno result was 88 RWHP (not for comparison with results from other dynos) and that was with these specs:
Bore: 104mm
Stroke: 80mm
Cylinder volume: 680cc
Intake valve dia: 41mm
Exhaust valve dia: 34mm
Intake max lift: 13,0mm
Exhaust max lift: 12,0mm
Intake cam duration (@0,050" lift): 256deg (little less on exhaust)
Geometric compression ratio: 13,5:1
EFI: Megasquirt III
Throttle body and injector: Ducati 1198

Maybe that gives some reference on what a 680cc thumper is capable of putting out? When i started stop calling it a Husaberg? :) Well, the crankcases, covers, gearbox and clutch are still Husaberg... -ish.

Well, now I will not participate in leading this thread any further from the topic! :)

My 50-cents:
Porting job and flow testing does not tell near half the story, when it comes to finding as much power as possible. With that being said, if you are not changing anything else, nice ports WILL of course give you some positive effect. If that is the case, I'm sure any skilled, experienced head porting company will do it for you! Just correcting possible edges in the casting and ensuring smooth transitions from carb/throttle body to intake to valve seat, will help a lot. Some are tempted to cut off the valve guides, which will increase flow but reduce technical life span. I would have to advice against that, however it might be OK for a dragracing engine. Some are tempted to polish the intake, but it will not increase flow but cause fuel to condensate on the shiny walls (poor air/fuel mixture which needs to be compensated with a richer jetting than necessary). The Husaberg intake is of "dump" type (not "tumble"), so porting should make the most out of that (which is not bad at all). Trying to port it more like "tumble" will not give the benefits a "tumble" type intake normally is associated with. So keep away from taking material from the "floor" close to the valve guide and downstream! All this is yesterdays news to anyone claiming to know their stuff. A nice service minded attitude from your head porting company will maybe be just as important to the whole experience?

If you are feeling free of the boundaries of the OEM design, another world of opportunities to spend money is available to you! ;) The whole shape of the intake plays a big(biggest?) role and second to that, the exhaust system. To my experience the total length (velocity stack to valve seat) and the areas all the way through the intake (not causing any sudden pressure changes), is more crucial than just the flow test results. I have made the largest leaps in gaining power at the dyno, trying out different intake and exhaust lengths. Once I discovered that the velocity stack was a tad too small, causing the air flow going super sonic! Just enlarging the stack (costed me just a couple of hours in the workshop and two cups of coffee) was rewarded with some 10 RWHP! I have more examples, but it´s supper time in Sweden now!

Good luck with Thumper Racing, Big Berg, and may the force be with you!

@Thorgan: "stock 84mm stroke"? Is that true for a 2008 650? Didn't know that! To my knowledge the 644 cranks were 82mm and the 628 cranks 80mm.
 
Hi Bushie and all Husaberg friends!
As I'm slowly recovering from a MAN-COLD (Yes friends, a near death experience), I have time to kill with browsing this thread and noticing how fast it all went bonkers! :) Somewhat entertaining but more worrying.

My last dyno result was 88 RWHP (not for comparison with results from other dynos) and that was with these specs:
Bore: 104mm
Stroke: 80mm
Cylinder volume: 680cc
Intake valve dia: 41mm
Exhaust valve dia: 34mm
Intake max lift: 13,0mm
Exhaust max lift: 12,0mm
Intake cam duration (@0,050" lift): 256deg (little less on exhaust)
Geometric compression ratio: 13,5:1
EFI: Megasquirt III
Throttle body and injector: Ducati 1198

Maybe that gives some reference on what a 680cc thumper is capable of putting out? When i started stop calling it a Husaberg? :) Well, the crankcases, covers, gearbox and clutch are still Husaberg... -ish.

Well, now I will not participate in leading this thread any further from the topic! :)

My 50-cents:
Porting job and flow testing does not tell near half the story, when it comes to finding as much power as possible. With that being said, if you are not changing anything else, nice ports WILL of course give you some positive effect. If that is the case, I'm sure any skilled, experienced head porting company will do it for you! Just correcting possible edges in the casting and ensuring smooth transitions from carb/throttle body to intake to valve seat, will help a lot. Some are tempted to cut off the valve guides, which will increase flow but reduce technical life span. I would have to advice against that, however it might be OK for a dragracing engine. Some are tempted to polish the intake, but it will not increase flow but cause fuel to condensate on the shiny walls (poor air/fuel mixture which needs to be compensated with a richer jetting than necessary). The Husaberg intake is of "dump" type (not "tumble"), so porting should make the most out of that (which is not bad at all). Trying to port it more like "tumble" will not give the benefits a "tumble" type intake normally is associated with. So keep away from taking material from the "floor" close to the valve guide and downstream! All this is yesterdays news to anyone claiming to know their stuff. A nice service minded attitude from your head porting company will maybe be just as important to the whole experience?

If you are feeling free of the boundaries of the OEM design, another world of opportunities to spend money is available to you! ;) The whole shape of the intake plays a big(biggest?) role and second to that, the exhaust system. To my experience the total length (velocity stack to valve seat) and the areas all the way through the intake (not causing any sudden pressure changes), is more crucial than just the flow test results. I have made the largest leaps in gaining power at the dyno, trying out different intake and exhaust lengths. Once I discovered that the velocity stack was a tad too small, causing the air flow going super sonic! Just enlarging the stack (costed me just a couple of hours in the workshop and two cups of coffee) was rewarded with some 10 RWHP! I have more examples, but it´s supper time in Sweden now!

Good luck with Thumper Racing, Big Berg, and may the force be with you!

@Thorgan: "stock 84mm stroke"? Is that true for a 2008 650? Didn't know that! To my knowledge the 644 cranks were 82mm and the 628 cranks 80mm.

Dr.C the smartest guy I knew on here, Bushmechanic refers to you as the higher Berg power. What are your thoughts on the WEB cams vs 08 650 and I am looking into making my own equal length exhaust pipes with the Akrapovic muffler. Do you have a recommended header length for my situation and would a "spacer" between intake boot and head be worth the trouble? This is a bike used 90+% off-road/10% sand dunes with paddle.
 
Dr.C the smartest guy I knew on here, Bushmechanic refers to you as the higher Berg power. What are your thoughts on the WEB cams vs 08 650 and I am looking into making my own equal length exhaust pipes with the Akrapovic muffler. Do you have a recommended header length for my situation and would a "spacer" between intake boot and head be worth the trouble? This is a bike used 90+% off-road/10% sand dunes with paddle.
Gee, thanks, I will have a really hard time living up to that!
I suppose you will have more use of midrange power in your offroad driving. The #08-cam gives a little more top end, compared to the stock #53(?) cam, I managed to get my hand on a #62-cam, which was very good all over the range. In you case I would spend more time on getting the squish right (1,0-1,1mm) and compression to around 13,5. That should give you some good mid range power.

To be able to test different intake lengths, you will need to build an air box. As long as the intake air flows through the frame and the rubber duct, you cannot really get a clear response on changing of the intake length. Also the exhaust systems on dirtbikes are designed to keep away from dirt, driver and gives very small possibilities to really optimize for power. Header length should be in the region of 500-600mm. My current exhaust system has a muffler underneath the engine, with a chamber in the front end, giving that distinct header length I want. After that it's only a matter of getting the exhaust gasses out with low noise and a minimum of resistance.

I'm afraid I'm not not very helpful on OEM and close to OEM applications, as I have not been working with that since 2002, when I rode a 650 in the Nordic Supermono Cup. I think I managed to squeeze about 69-70 RWHP out of that one at the time, if I remember correctly. That was with a 41,5mm Dellórto, relocated larger valves and a fully custom exhaust system.
 
Of course I have to get my 2 cents in lmao.

Now I happened to see Taffy does porting and has no flow bench?????. Who on this earth can port correctly without a flow bench. If you are grinding and polishing and taking a guess then you are not porting correctly. Heads need to be benched while porting to check as if you take to much then your f%%ked, cause you cant put material back. You might be able to port match, but nothing more.

A good port job will be matched and ported for flow tested on a bench.

Porting is not guess work but a science that is done and with a flow bench. You will also need a dyno to check as well. Without these things then its just backyard Bob hacking away and taking a wild guess. You can not gain anything without the correct tools to measure or its just guessing. I cant say how many times I have heard this statement. I have x number of horsepower but yet the machine was never dyno'd by anyone. It is because a shop has threw cams at it, exhaust a bigger piston ect. and taken a guess.

Anything you do that you cant do yourself, ensure you go to a reputable shop who has the correct equipment to do the job correctly as this will save you in the long run.
 

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