First off, thanks for any help in advance..

My 2004 recon ES starts idles, shifts and drives great except when at 75%+ wide open throttle towards the upper RPM ( especially when going up hill ). It will start to break up like it's miss firing.

My question: Would this indicate a too lean or too rich condition?

Bought it used, Plug looks great. Battery is charging perfectly and volts go to 14-ish when increasing the RPM.

One thing I did notice. The previous owner claims it's a new OEM Honda Carb, which it may be.. I did however notice that the throttle needle is an 05 through 2016 style with NO clips, as in - a fixed needle position. A 2004 is suppose to have a multi-position needle and clip, but this doesn't.

I'm hoping to get anyone's idea before I go ahead and start playing with the air/fuel mixture needle. I'm not sure if the break up would be from it running rich or starving for fuel???

Inputs?

 

Well it’s not a factory oem carb as there is no fuel mix adjustment at all. Must be some Chinese cheapo. I guess I’m buying a new carb.

 

update #3

I went out a drove it again after checking the jets and cleanliness of the carb. Everything was brand new and clear inside. I went for a ride and typically I would just let off once it starts to break up but i throttled through it. Once it got into the upper RPM's it cleared up making me believe that it's a rich condition during mid RPM range. Once it's in the upper RPM range it screams and pulls extremely hard ( i'm still surprised at the performance of this 250... ).

I'm very tempted to open up my factory snorkel, but i'm afraid I may open up another can of worms before fixing this...

 

Apparently the snorkel is extremely sensitive on the Recon, and works the opposite to what you expect to happen, it runs leaner with a longer snorkel. I'm fairly certain the carb just has an idle jet and the main one, so should go from idle to main fairly smoothly. Late Recons have a weird exhaust gas recirculating system, could it be a problem with that?

 

Well... found out the recon was starving for air. I took off the air box lid and it runs absolutely perfect. Going to be cutting open the snorkels now and I should be 100%. Crazy how something so simple can make such a difference.

 

Adding this for fellow problem solvers..

The brand new Honda carbs have Welch plugs installed (brass cap ) so you cant alter the air fuel mixture screw (emission reasons). I ended up drilling mine out and cutting the casting off to reveal the fuel air/fuel mixture adjuster. Not the cleanest job but it works and is now tunable.

 

They seal it off because you are not supposed to mess with it. It only adjusts the idle mixture anyway, so wouldn't affect the mid range running which you say is the problem area.

 

Funny update for the laughs...

I just completed a valve job and rebuilt the carb on my wife's 2007 Recon. The amazon "OEM "rebuild kit came with a 40 pilot and 107 main jet ( factory is 38 and 98). Put it all together went to drive it after setting idle and it starting breaking up mid RPM/load range as well. Took off the airbox lid and it now runs perfect. This is nuts lol.

That being said, this weekend i'll be cutting off the ends of both Recon's snorkels to allow more air flow.

 

Ref my previous post before hacking up the snorkel. "the snorkel is extremely sensitive on the Recon, and works the opposite to what you expect to happen, it runs leaner with a longer snorkel" not my personal observations but someone else on here fitted a longer one and found this out.

 

correct. I agree completely and it makes sense. That’s why I will be technically shorting and increasing the opening of the snorkel to allow more air. It chokes down with the snorkel attached but when bypassed, it runs better indicating an air flow issue.