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2007 yamaha wr250f. I'm trying to get my low end bog issue figured out. The bike ran great for years, now all of a sudden I'm having this issue. It has a JD jet kit with what I believe is a #40 leak jet. I'll be pulling the carb off to clean and check ap squirt. i figured while i'm in it i will replace the ap diaphram. I'm seeing that Krannie suggests updating with the crfs only diaphram kit. Is it right to assume that all FCR carbs are the same and will benefit from this mod. Also ordered the tokyo mods spring. Any input is appreciated.

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What do you mean when you say 'low end bog'.

That would typically mean at lower rpms, the power is lower than normal.

If you mean quick turn throttle is bogging, that would the apump system, regardless of rpm.

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Sorry, I do mean quick throttle bog. As to my question above. Would the crf only mod work on this bike also.

Thanks

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2 hours ago, Krannie McKranface said:

What do you mean when you say 'low end bog'.

That would typically mean at lower rpms, the power is lower than normal.

If you mean quick turn throttle is bogging, that would the apump system, regardless of rpm.

Sorry, I do mean quick throttle bog from idle. As to my question above, would the crf only mod work on this bike also.

Thanks

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9 minutes ago, rushdog said:

Sorry, I do mean quick throttle bog from idle. As to my question above, would the crf only mod work on this bike also.

Thanks

Yes.

Long throw diaphragm, stiffer linkage spring, clean the nozzle, and adjust to never hit the slide.

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3 minutes ago, Krannie McKranface said:

Yes.

Long throw diaphragm, stiffer linkage spring, clean the nozzle, and adjust to never hit the slide.

Ill order the crf only mod and give it a try. Thanks

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59 minutes ago, Krannie McKranface said:

Yes.

Long throw diaphragm, stiffer linkage spring, clean the nozzle, and adjust to never hit the slide.

one more question. is it recommended to use their a/p  cover or the original? Thanks

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1 hour ago, rushdog said:

one more question. is it recommended to use their a/p  cover or the original? Thanks

The whole point of the upgrade is to remove the weak spots in the original 2003 carb; so yes, you want the new cover, diaphragm, rod, and spring.

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Update:

Checked my AP squirt and it seemed kind of weak. cleaned out the ap circuit and while i had it apart installed the CRF only diaphram kit  https://www.crfsonly.com/catalog/product_info.php/cPath/138_147/products_id/3932CRF ,Tokyo mods linkage spring , #50 leak jet and JD brass A/F screw. The bike has no bog and very responsive. I think it pulls better than it ever has.

 

 

JD jet kit red needle 3rd clip

185 main

45 pilot

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