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traded quad for a 05 ktm 525 mxc, it has a cough

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well any advice would be good to owning this ktm. its my first one. i noticed that when i rev the bike i really have to feather the throttle until about half way so that it revs smooth or else it kinda coughs and then smooths out

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The description sounds like you really really really have to gently twist the throttle- not like you are wacking the throttle and it bogs-

If that's the case- I would verify that your AP circuit is working- kinda sounds like its not-

you should have about a 1 seccond squirt (duration) and it should just miss the slide as it opens (timing)... on that carb you have an adjustment screw for the timing and can adjust the duration to about 1 seccond as Mike suggested with a honda diaphram.

If you do what Mike said it will be a 99% cure to your problem- because the jetting may be off- dirty carb/ blocked jets- and the old diaphram may have crapped out. 👍

also you could/should verify no air leaks on the carb boots, slide is not upside down, check valve clearence- and compression, that way you know what you are starting with and can eliminate those as issues.

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does it matter what Honda you get the diaphram from. Like, I though the 450X had a slower AP action than the 450R

???

and probably have different timing than a 250

The description sounds like you really really really have to gently twist the throttle- not like you are wacking the throttle and it bogs-

If that's the case- I would verify that your AP circuit is working- kinda sounds like its not-

you should have about a 1 seccond squirt (duration) and it should just miss the slide as it opens (timing)... on that carb you have an adjustment screw for the timing and can adjust the duration to about 1 seccond as Mike suggested with a honda diaphram.

If you do what Mike said it will be a 99% cure to your problem- because the jetting may be off- dirty carb/ blocked jets- and the old diaphram may have crapped out. 👍

also you could/should verify no air leaks on the carb boots, slide is not upside down, check valve clearence- and compression, that way you know what you are starting with and can eliminate those as issues.

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does it matter what Honda you get the diaphram from. Like, I though the 450X had a slower AP action than the 450R

???

and probably have different timing than a 250

Diaphrams effect duration not timing, length- not slow or fast or when

Timing comes from adjusting the actuator arm screw

volume and to some degree duration is effected by leak jets (if your carb has them)

improved actuator arms, preloaded springs, and o-ring mods for the most part effect initial volume of squirt and decrease any lag of squirt that may or may not cause any acutal hesitation of the motor....

This is my understanding anyway- JD and Dave have provided alot of info in the FAQ and in the forums.. I would have to search the honda oem schematics but I think the "honda diaphram" commonly refferred to is the one and the same and can be purchased from JD without error.

But for the original poster- just focus on verifying and getting the carb functional and getting a basic jetting baseline and adjust from there- Don't buy any 1 item for over $1oo to attatch to your carb unless you understand what it does and know you need it to address a specific issue. Keep it simple (at least first)

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ok, I meant timing as in, (totally arbitrary for the sake of a question) KTM's diaphram squirts faser, maybe, and if it did, then the honda would squirt longer? cause its supposidly from what I've seen slower.

but thats probably under 'duration' not timing, so sorry, I guess i'm just a sad sad little man 👍

thanks for the help and explanation

Diaphrams effect duration not timing, length- not slow or fast or when

Timing comes from adjusting the actuator arm screw

volume and to some degree duration is effected by leak jets (if your carb has them)

improved actuator arms, preloaded springs, and o-ring mods for the most part effect initial volume of squirt and decrease any lag of squirt that may or may not cause any acutal hesitation of the motor....

This is my understanding anyway- JD and Dave have provided alot of info in the FAQ and in the forums.. I would have to search the honda oem schematics but I think the "honda diaphram" commonly refferred to is the one and the same and can be purchased from JD without error.

But for the original poster- just focus on verifying and getting the carb functional and getting a basic jetting baseline and adjust from there- Don't buy any 1 item for over $1oo to attatch to your carb unless you understand what it does and know you need it to address a specific issue. Keep it simple (at least first)

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ok, I meant timing as in, (totally arbitrary for the sake of a question) KTM's diaphram squirts faser, maybe, and if it did, then the honda would squirt longer? cause its supposidly from what I've seen slower.

but thats probably under 'duration' not timing, so sorry, I guess i'm just a sad sad little man 👍

thanks for the help and explanation

yea- all these terms and meanings- I know what you meant now-

Ktm diaphram has a longer duration

Honda's is shorter

Check out Jd's explanaiton in the FAQ he illistrates a bunch of this

Also on some carbs you can alter duration by limmiting the travel of an exposed ap rod on older fcrs (fcr1) with a Taffy mod, on some of the FCRMX carbs you can do the BK mod by limmiting the travel of the AP link arm by drilling and tapping and putting in an adjustable screw. These mods are adjustable externally and do the same as the diaphram with a longer or shorter button on the bottom of the diaphram that limmits its travel.

But Generally the 1 second duration is what most people find to work the best and is achievable with the honda diaphram alone.

Leak jets and externally adjustable leak jets like the R&D power bowl and the Merge ap cover can further add external adjustment of the squrt's volume and effects duration. Some have found those to be helpfull- some just find that its all not needed- for their applicaiton- I figure its good to know your options but every add on is not often necessary

Just a little more info- on that

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