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Discussion Starter #1
Driver, and I drove over to OR. yesterday to get with the best FCR carb guy we know of, we worked on Drivers 505 SX carb, after several hours, we think we have the carb figured out, we made several changes to the carb to get rid of the bog at first hit of throttle, Driver is out riding as I type to see if we indeed fixed it. more to come, I will tell you just adding a power bowl, or adjustible leak jet will not cure it, so don't spend your money on those items just yet.... ;)
 

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hmmmmm sounds good..........

who in Orgeon ???

I added the diagraphm tavel limiter and the rubber band linkage coupler from the JD kit and the R&D adjustable accel pump cover to then fine turn the squirt: these three things made a noticeable improvement.

But if there's more / better to be had............ bring it on !
 

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Well just got back from riding. Burned through two tanks. LOL Anyways what is saying is true. My bike might of well been fuel injected. Felt like a dream. Absolutely no hesitation what so ever. I was so shocked that it was THAT GOOD. Anyways the things we did are pretty involved and Ill leave it to Walt to post that info when it comes to that. But Im super stoked my bike felt that good. The riding I did ranged from 2500ft to 4000ft. and it ran good the whole time. More to come for sure.
 

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okay guys..... I gotta know now........... paypal how much where ;)
 

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Discussion Starter #6
before I do/say anything, I need to talk with site admin on this one, people make there living on this site, Driver and I don't want to step on toes...... stay tuned
 

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before I do/say anything, I need to talk with site admin on this one, people make there living on this site, Driver and I don't want to step on toes...... stay tuned
Ok it has been a couple days cough up the info.
 

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Discussion Starter #8
As soon as I get the go ahead I'll post the carb fix, it's too cold to ride anyway, we have snow on the ground, if I can't ride, no one else should ride, (atleast with a good running bike) :lol:
 

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As soon as I get the go ahead I'll post the carb fix, it's too cold to ride anyway, we have snow on the ground, if I can't ride, no one else should ride, (atleast with a good running bike) :lol:
Hell today it was 70 degrees outside and we have a race in NC this weekend.
 

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hell man we are in a heat wave down here and it's riding weather........
 

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trailrunner, not trying to change post, but what race in NC?
There is an outlaw race saturday north of wilkesboro. You can find info on the race at quadzone.com in the XC forum.
 

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Discussion Starter #15
Any updates on this.
It's posted in the SX thread but here you go

After very extensive dyno testing on the KTM SX ATV model we developed a way to ELIMINATE the dreadful bog that we all have experienced on our machines. We are actively working on the XC, and should have information out on it shortly

WARNING:
USE THIS INFORMATION AT YOUR OWN RISK; WE AREN’T RESPONSIBLE FOR ERRORS IF YOU DECIDE TO PERFORM THESE MODIFICATIONS YOURSELF. THIS INFORMATION IS SOLELY PROVIDED AS A GUIDE. PROCEED WITH EXTREME CAUTION!!!

#1 Leak Jet Installation

To address the lack of adjustability of the accelerator pump we drilled & tapped the bowl for a leak jet. The leak jet allows us to address how far & long the accelerator pump squirts. We found that a #40 leak jet performed the best.

#2 Increase Accelerator Pump Squirt Nozzle Diameter

The next modification we made was to drill the accelerator pump squirt nozzle larger. From the factory the accelerator pump nozzle has a 0.013” opening. We found that by carefully drilling it to 0.016” (approximately 23% larger) it helped make the accelerator pump easier to tune and much more effective.

#3 Replace OEM Pilot Jet

From the factory the #42 pilot jet is too small. To fix this we simply replaced it with a #45 pilot jet. This corrected the some minor idling issues especially when the engine is cold. This is very simple and easy to do.

#4 Replace OEM Needle

The factory needle’s taper is too narrow at the tip which creates a lean issue from 3/4 throttle to wide open throttle (WOT) as well as the incorrect main jet being used. To cure this we replaced the needle with a needle found in the Honda HRC kit; it allowed us then to install the correct main jet.

#5 Install O-ring

Add the O-ring mod to the accelerator pump O-Ring size.number is 010



Drilling the leak jet & squirt nozzle are NOT recommended unless you have experience in dealing with 0.001” tolerances. Not to mention the drill bits are typically special order items.

If you send us the entire carb, we charge $100 to drill/tap the bowl for a leak jet & drill the squirt nozzle (return domestic shipping included). Active subscribing (paid) members to KTMATVHQ.com only pay $85! Parts included,

I am in the process of getting some bowls & squirt nozzles ready to go so I can offer them as a “kit” with or without a core charge. Unfortunately, I don’t have any kit pricing available right now.



Fast64Ranchero & Driver311
 

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It's posted in the SX thread but here you go

After very extensive dyno testing on the KTM SX ATV model we developed a way to ELIMINATE the dreadful bog that we all have experienced on our machines. We are actively working on the XC, and should have information out on it shortly

WARNING:
USE THIS INFORMATION AT YOUR OWN RISK; WE AREN'T RESPONSIBLE FOR ERRORS IF YOU DECIDE TO PERFORM THESE MODIFICATIONS YOURSELF. THIS INFORMATION IS SOLELY PROVIDED AS A GUIDE. PROCEED WITH EXTREME CAUTION!!!

#1 Leak Jet Installation

To address the lack of adjustability of the accelerator pump we drilled & tapped the bowl for a leak jet. The leak jet allows us to address how far & long the accelerator pump squirts. We found that a #40 leak jet performed the best.

#2 Increase Accelerator Pump Squirt Nozzle Diameter

The next modification we made was to drill the accelerator pump squirt nozzle larger. From the factory the accelerator pump nozzle has a 0.013" opening. We found that by carefully drilling it to 0.016" (approximately 23% larger) it helped make the accelerator pump easier to tune and much more effective.

#3 Replace OEM Pilot Jet

From the factory the #42 pilot jet is too small. To fix this we simply replaced it with a #45 pilot jet. This corrected the some minor idling issues especially when the engine is cold. This is very simple and easy to do.

#4 Replace OEM Needle

The factory needle's taper is too narrow at the tip which creates a lean issue from 3/4 throttle to wide open throttle (WOT) as well as the incorrect main jet being used. To cure this we replaced the needle with a needle found in the Honda HRC kit; it allowed us then to install the correct main jet.

#5 Install O-ring

Add the O-ring mod to the accelerator pump O-Ring size.number is 010



Drilling the leak jet & squirt nozzle are NOT recommended unless you have experience in dealing with 0.001" tolerances. Not to mention the drill bits are typically special order items.

If you send us the entire carb, we charge $100 to drill/tap the bowl for a leak jet & drill the squirt nozzle (return domestic shipping included). Active subscribing (paid) members to KTMATVHQ.com only pay $85! Parts included,

I am in the process of getting some bowls & squirt nozzles ready to go so I can offer them as a "kit" with or without a core charge. Unfortunately, I don't have any kit pricing available right now.



Fast64Ranchero & Driver311


[/quote
Any progress on the xc carb yet? Also-on the sx- with the new needle installed are you going leaner or richer on the main and by how much?? :D
 

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Any other info on this for the XC carbs? I already have the R&D bowl on mine. I'm getting a bog in the mid range of the powerband.
 

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Discussion Starter #18
Any other info on this for the XC carbs? I already have the R&D bowl on mine. I'm getting a bog in the mid range of the powerband.

The XC cure has been listed in this forum, I just got word back from mbzchris22 I ported to 41mm and moded his carb, maybe we can get him to chime in and say what he thinks, hope he don't mind me throwing him to the Wolves :p
 

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LOL, It's okay Fast :D .... I don't mind commenting...

Bike runs HARD... NO BOG AT ALL on my 525 XC. Power is real smooth.... like stated by driver, bike runs like it was fuel injected...

Best money i've spent on a mod so far!
 

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Any differance to the carb mod when used on a 450xc you think?
 
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