nklr various stuff

[Alan L Henderson]

At 05:02 AM 5/12/2000 -0400, you wrote:

>Hi everybody, >A contributer to my website has sent me pictures to go with his airbox mod. >And I just finished putting them on my site. >It's pretty good stuff, check it out - >http://www.angelfire.com/mo/motormark/mikescarbmod.html > >MotorMark

Very nice. Was considering doing the same thing my self. I believe the screen is there for back fire protection and since mine doesn't back fire I don't believe I need it. One of my co workers who has raced four strokes always removed the screen and opened up the air box for higher flow. Nice pictures. Very well done. Will take some of the guess work out of the jetting if I ever do the mod. Alan Henderson A13 Iowa

[PRBKLR@cs.com]

Listers, Is it possible to perform the airbox modification without modifying the carb jetting? Thanks, Paul Dallas, Tx

[Verle Nelson]

At 10:41 AM 5/12/00, PRBKLR@... wrote:

>Is it possible to perform the airbox modification without modifying the >carb jetting?

Not if it improves air flow and if it doesn't, why make the modification? Verle Nelson Cedaredge, CO

[Verle Nelson]

> >A contributer to my website has sent me pictures to go with his airbox mod. > >And I just finished putting them on my site. > >It's pretty good stuff, check it out - > >http://www.angelfire.com/mo/motormark/mikescarbmod.html > > > >MotorMark > >Very nice. Was considering doing the same thing my self. I believe the >screen is there for back fire protection and since mine doesn't back fire I >don't believe I need it. One of my co workers who has raced four strokes >always removed the screen and opened up the air box for higher flow. >Nice pictures. Very well done. Will take some of the guess work out of the >jetting if I ever do the mod.

These instructions replace guess-work with third-hand information sourced from a person who thinks the screen is a "restrictor" and who believes his mods netted a 20 percent performance gain. Neither guess-work nor third-hand information can replace plug readings (and that's on the road, not in the garage after the fact) or test equipment. The former is difficult to do; the later requires a properly equipped shop. I'll stick with stock. Verle Nelson Cedaredge, CO

>

[Arne Larsen]

From: Mark Wilson Subject: [DSN_klr650] Airbox Modification

> Hi everybody, > A contributer to my website has sent me pictures to go with his airbox

mod.

> And I just finished putting them on my site. > It's pretty good stuff, check it out - > http://www.angelfire.com/mo/motormark/mikescarbmod.html

This guy went all out with the pics and all. Nicely done. Do you know what kind of exhaust he's running? Also, he says a 160 main jet. To what standard? My understanding (which could be out a whack) is that (for example) a 140 kawi jet and a 140 Dynajet are not the same size. I'm not sure if there even "is" a 140 size - but you know what I mean... Also, instead of shimming the stock needle, at what position would he recommend placing the dynajet needle - which is adjustable. Final note: What's his elevation? Thanks Mark! Cheers, Arne

[Alan L Henderson]

At 12:28 PM 5/12/2000 -0600, you wrote:

>At 10:41 AM 5/12/00, PRBKLR@... wrote: > >>Is it possible to perform the airbox modification without modifying the >>carb jetting? > > >Not if it improves air flow and if it doesn't, why make the modification? > >Verle Nelson >Cedaredge, CO >

Exactly! The whole point of doing the work on the air box is to improve air flow. With more air flowing, hopefully, one needs more fuel to keep the air fuel mixture correct. Alan Henderson A13 Iowa

[Alan L Henderson]

>>Nice pictures. Very well done. Will take some of the guess work out of the >>jetting if I ever do the mod. > > >These instructions replace guess-work with third-hand information sourced >from a person who thinks the screen is a "restrictor" and who believes his >mods netted a 20 percent performance gain. Neither guess-work nor >third-hand information can replace plug readings (and that's on the road, >not in the garage after the fact) or test equipment. The former is >difficult to do; the later requires a properly equipped shop. I'll stick >with stock. > >Verle Nelson >Cedaredge, CO >

Like I said it takes SOME of the guess work out of the process. I would fully intend to do proper plug readings to let me know if the jetting was correct. Alan Henderson A13 Iowa

[wileyE_@excite.com]

I also enjoyed the pics but still have some questions about the need to open the box up that much. Somewhere online I read about Scott Summers XR600 setup and he advised NOT to cut the backfire screen out as it will screw up the airflow and effected the lowend response? Also the need for more air would be in proportion to the added fuel provides by the jet swaps. The change from a 40 to a 42 pilot, shimmed needle and a 148 to a 160 main would be maybe 3-5% increase in fuel flow? Does this warrant quadrupaling the size of the air intake hole? Don't get me wrong I enjoy those kind of postings and am always trying stuff like that out myself and try to learn in the process. wileyE, A6, 155 kehien main (dj mains are shorter and should theoretically should have fuel level raised to compansate, dj needle, 45 pilot, 1.5 turns, rubber snorkle removed, hole-saw holes (previous owner) duct taped closed

> >>Nice pictures. Very well done. Will take some of the guess work

out of the

> >>jetting if I ever do the mod. > > > >

[Mark Wilson]

Hi everybody, I am just trying to get caught up on reading email. Still have 70 to go. I will ask Mike these questions, and post them when I get them. He did send me this today---

>>>>>>>>>>>>>>>>

HI Mark again, I suppose I should answer some of the questions for clarity and to keep some folks from hurting their bikes. 1. Do not do the airbox modification if you are not rejetting the carb. your bike already runs lean and only doing the air box will cause the engine to run even leaner. (To HOT ). As in motor failure! 2. For those construction workers out there, The washer size is 1/16 thick. I hope this helps. Mike ----- Original Message ----- From: Arne Larsen To: dsn_klr650@egroups.com> Sent: Friday, May 12, 2000 4:58 PM Subject: Re: [DSN_klr650] Airbox Modification > From: Mark Wilson > Subject: [DSN_klr650] Airbox Modification > > > > Hi everybody, > > A contributer to my website has sent me pictures to go with his airbox > mod. > > And I just finished putting them on my site. > > It's pretty good stuff, check it out - > > http://www.angelfire.com/mo/motormark/mikescarbmod.html > > This guy went all out with the pics and all. Nicely done. > > Do you know what kind of exhaust he's running? Also, he says a 160 main > jet. To what standard? My understanding (which could be out a whack) is > that (for example) a 140 kawi jet and a 140 Dynajet are not the same size. > I'm not sure if there even "is" a 140 size - but you know what I mean... > > Also, instead of shimming the stock needle, at what position would he > recommend placing the dynajet needle - which is adjustable. > > Final note: What's his elevation? > > Thanks Mark! > > Cheers, > > Arne

[Tom Bowman]

Wiley writes:

> I also enjoyed the pics but still have some questions about the

need

> to open the box up that much. Somewhere online I read about

Scott

> Summers XR600 setup and he advised NOT to cut the backfire

screen out

> as it will screw up the airflow and effected the lowend

response?

> Also the need for more air would be in proportion to the added

fuel

> provides by the jet swaps. The change from a 40 to a 42 pilot, > shimmed needle and a 148 to a 160 main would be maybe 3-5%

increase

> in fuel flow? Does this warrant quadrupaling the size of the

air

> intake hole? Don't get me wrong I enjoy those kind of postings

and am

> always trying stuff like that out myself and try to learn in

the

> process.

I remember that same article - in "Dirt Bike" as I recall - and I was wondering the same thing about Mike's carb mod. The jetting mods would presumably be to correct cold start or off-idle hesitation (pilot mixture screw setting mod), mid-range hesitation/surge (shimming of jet needle), and high speed power lack (main jet increase and air box mod). My A14 doesn't seem to have a problem in any of those areas, so for me the mods are questionable, but perhaps others have running problems mine does not. As for the intake screen, it seems to me that K&N has made a big deal in their advertising for years of the "straightening" effect of the cotton gauze they use as a medium; wouldn't the wire mesh screen provide a similar effect, as well as act as a suppressor for backfire should that ever happen? Perhaps the only way to tell for sure would be to get two identical bikes, run some baseline acceleration and throttle response ranking tests side-by-side, and then modify one in stages and re-test. I'd be willing to contribute my time to set up the tests and evaluate, and my bike as a stock baseline. Any volunteers? Tom Bowman Atlanta A14 Tom Bowman Atlanta