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Bog Fixes- Yam and Honda

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Hi All,

I am new to this forum and modern 4 stoke jetting and have been finding the links on Kehin Accelerator Pump interesting.

I have been working on two bikes, which have this problem, a 1994 CRF240X and a 2001 YZ250F.

I have jest been in the shed trying to measure the AP Squirt. The YZ250F has the sub frame off and the rear of the carb is fully accessible. I have ensured the carb is full and have been giving the throttle a full fast hand full but no squirt at all.

Am I missing something?? Am I doing something wrong?

As for the CRF250X it is stock with restrictor removed. I have already gone up from the STD #40 to ad #42 on the pilot and dropped the clip 1 position, as it felt very lean. It is much better but still bogs off idle very badly. Is there a common problem with these- too little or two much squirt??

Please help.

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I have ensured the carb is full and have been giving the throttle a full fast hand full but no squirt at all.

Am I missing something?? Am I doing something wrong?

If you're not getting any AP squirt you need to check that the nozzle is clean. Try squirting carb cleaner directly into it from the float bowl side, but don't stick a wire in there as it could cause damage. Also check the AP diaphragm to make sure there are no holes, tears, cracks or missing o-rings.
As for the CRF250X it is stock with restrictor removed. I have already gone up from the STD #40 to ad #42 on the pilot and dropped the clip 1 position, as it felt very lean. It is much better but still bogs off idle very badly. Is there a common problem with these- too little or two much squirt??
The bog is usually corrected with leak jets and pump timing, assuming the rest of your jetting is OK. I'm not sure what the honda guys are using for PJ's, but maybe try tuning the pilot per Eddie's sticky at the top of this forum.

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So to do the test do i simply need to check that the float bowel is full and open the throttle and it should work??

I dont need to run the bike to prime the chamber?? :thumbsup:

Also ref the Honda, i think the jeting is OK except the main jet which is still to lead (std #140 i think). Would the main jet make it bog??

Looks like people are all putting a #55 leak and 150 #main. I will check the squirt and then give this a try.

Thanks

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First you gotta have squirt! turn the gas on, let it sit for a few seconds so the bowl is full and it may take a qouple twist to prime the pump if it was dry, if it does not have squirt now something is wrong! Usual suspect is an O ring missing, diaphram upside down or if your bike is older the rod that actuates the AC pump was steel (98 era) and would rust, then sieze into the bronze guide it slides in. Aluminum rod fixed this by 01 and redesign of 02 eliminated that design

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I have checked the squirt on the CRF250X and i it .5 sec long. Bike still bogs.

I do think the 42 pilot did help and i also woound screw out an extra 1/2 turn.

Any sugestions?

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