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dg400sm

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About dg400sm

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  1. dg400sm

    i question the 3x3 cutout

    Here close to the equator thumpertalk jetting recommendations do not work so old school testing is a must
  2. dg400sm

    i question the 3x3 cutout

    the scooter example was just the short version,of course i played with jetting and went through 4 different exhaust systems and countless weeks using my wideband AFR,all a complete waste of time as that time would have been better spent doing nicer things but we live and learn there is a couple of things which keep coming up and no idea why people are hooked on maximum HP and dynos, we didn't buy the drz because of its great HP we bought it because of its smooth linear delivery. at the same time of owning my drz i also bought a ktm690,i hated it, jerky power delivery,peaky,engine inertia made for poor low speed handling and the engine braking made it tiring to ride around town if the 3x3 is a compromise then why do we have to compromise, some of us buy 37mm fcr because we prefer more low down power ,some buy different exhaust systems to suit different applications, throttle response is important but in slippery conditions we don't want engine speed building too quickly, if for example a 2x2 cutout would be more suited to single track trail guys then when can't we know that information. to the guy that manipulated my words about a ktm690 producing more power i merely asked why would a drz need twice the airflow of a ktm690(obviously it doesn't so there is a flaw somewhere) if everybody is happy with the 3x3 then there is no reason to change but i personally cannot get my jetting right and i have spent years trying to get it right with my wideband AFR, hence the reason i questioned the 3x3
  3. dg400sm

    i question the 3x3 cutout

    i might have thought that too but i've owned numerous bikes where i've been told to open up the airbox and lost power and throttle response, the very first was an rgv250 when i was 20 years old, i was told by a mechanic to drill 10 holes in the top of the airbox to increase airflow, as soon as i did it i lost all low down throttle response, i then had to spend my hard earned money on a new lid,at the time i was young and naive and didn't understand anything
  4. dg400sm

    i question the 3x3 cutout

    so far william your answer carries the most validity, if i had have been told that various configurations were tried and the 3x3 was the happy medium between optimum airflow and a good vacuum signal then that would have stopped me in my tracks but it actually turned into a bit of a pyschology question(of which i also have a deep interest) with out meaning to rub anyone up the wrong way almost 100 percent of people didn't know why they did the 3x3 but were quick to defend the thing they didn't know about. as an expat with no job and too much time on my hands i still think i might fabricate an oversized snorkel to test, it wouldn't take long to make one out of some PVC pipe, i'm still not convinced it is for sound attenuation and a little bit of google research has believing it also plays a role in lamellar flow of the air. having built a big bore engine for my scooter i tried a few configurations, first no airbox and it made no power and constantly showed lean on the plug,second i tried an airbox with no lid and there was a huge improvement but no throttle response, lastly i completely cut the lid open then taped 1 inch tape strips all the way over it until just a tiny hole then gradually tore off each individual strips until i found the airbox opening that worked best and it was only 50 percent bigger than stock so you might be able to see why i would querie the 3x3
  5. dg400sm

    i question the 3x3 cutout

    I might wait a while until I receive more technical answers
  6. dg400sm

    i question the 3x3 cutout

    I like your answer roleyrev and so far the only guy that understand how an airbox works, I'm surprised so many people don't understand it but that does give reason to why nobody questions the 3x3 cut out,my plan was to make my own snorkel from pvc pipe, we know that the fcr 39mm is about 10 percent bigger than a 36mm so my guess would be a snorkel 10 percent larger. The length could also be altered as this has an effect on laminar flow of the air
  7. dg400sm

    i question the 3x3 cutout

    I see that is removable but it still doesn't prove anything. Can I see the literature from Suzuki that says this is part of the derestricting process. The snorkel is the same size for the E as it is for the SM and the E produces 10 percent more power so that just validates my point about airflow needed and again nobody is mentioning resonance frequency
  8. dg400sm

    i question the 3x3 cutout

    Edit* I meant to say 4 times the size
  9. dg400sm

    i question the 3x3 cutout

    With answers like these it means you either haven't understood my question at all or you are just regurgitating. To restate an important question " why do we need to supply 8 times more airflow to produce 10 percent more power and why does it need to be twice the size of a ktm690 that produces twice as much power" answers showing mathematical formulas are generally more authentic than saying bigger is better
  10. dg400sm

    i question the 3x3 cutout

    after being unable to get one of my other bikes running correctly and learning the airbox lid cut out was way too big it got me thinking about the 3x3 cutout of the drz. something about it doesn't ring true, firstly all bikes road or off road run a snorkel, after studying a bit about airbox design for those that don't know a snorkel's primary function is not to keep out dirt and water it acts as a helmholt resonator and aids in the airbox hitting resonance frequency,if you remove the snorkel you lose some of that resonance frequency(for those that don't know resonance frequency might be easier to learn it rather than my half assed explanation)and finally when we cut the 3x3 cutout that gives a surface area of 9 square inches, thats over 4 times the size of the factory 2 square inches, why would we need 4 times the airflow to gain roughly 10 percent more power at the same RPM's with our aftermarket pipes and hotcams????to put this in perspective 3x3 is twice the size of a ktm690 producing 65hp. now before anybody says mx bikes have an open airbox,yes they do, i also own a yz426 and a wr450. the yz426 is an absolute pig to ride in the bush where as the wr450 is as smooth as silk. the 3x3 cutout is way bigger than the wr450 airbox lid opening as well. my question is who made up the idea of the 3x3 cutout and why do we follow it as gospel. why are we not designing better snorkels instead of just saying Lets cut a big hole in it.
  11. could i get peoples opinions on my stator for kdx220 1997 model. the white insulating varnish is starting to crumble,how important is it to get this revarnished
  12. dg400sm

    DECEL BACKFIRE

    is it a decel back fire or popping,they are not the same,a backfire is a rich condition,sounds like a gunshot
  13. after months of trying to jet my kdx220 correctly but just couldn't do it i decided to pull out the reed cage and have a look, what i saw was the previous owner has fitted boyesen 607 reeds but they don't fit properly and there is small gaps in the corners. i put in an old set of factory reeds which were badly warped but still ran much better than the 607 reeds with gaps. you can see the gaps in the corners and the other photos show how much shorter they are than the factory reeds. any body ever seen anything like this? i did think about slotting the holes but they would need to be slotted about 2mm and not enough meat in the reed to do that.also the 607 reeds have much bigger radius which makes the fit even worse
  14. dg400sm

    keihin pwk slide mod?

    it was on the bike when i bought it with the rb mod already done. i switched out the jets that were in it to genuine keihin jets just to make fault finding a little easier
  15. dg400sm

    keihin pwk slide mod?

    you might be right,i measured the slide cutaway today and it is much bigger than a number 5 so the rb mod must have been done to the slide too,now i have no ideas,guess i either check for other sources to the problem or borrow/buy a new carb
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