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Won't idle - rough at low speed

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Just picked up a 2015 250X in almost new condition.  However, it has sat for a few months and the fuel has done its dirty deed.  At high rpm's, the bike rips, but it will barely idle and spits and sputters at low rpm's.  I have drained tank and fuel bowl, added fresh fuel with a good amount of seafoam, and sprayed seafoam into throat, while the bike is running.  None of this has helped.  

I've read countless articles over the past two days, which lead me to believe that the main culprit is the slow jet.  It appears that by loosening the tube clamps on either side of the carb, it can be rotated to gain access to the float drain bolt.  Then the slow jet and the main jet can be removed and cleaned.  The articles are for older models and I haven't seen anything specific for the 2015 but, after looking at my carb, it appears to be doable.  Any suggestions?

       

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Yes, slow circuit.  However rather than trying to clean the jet, I would simply replace it.  Their tough to get truly clean.

Hopefully the slow circuit passages are not plugged (again, tough to clean).

Jim.

BTW, I'd also check the hot start plunger and make sure it's not hung up.

Jim.

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My attempt at trying to rotate the carb was unsuccessful.  Getting to the hot start plunger is equally difficult and probably requires removal of the carb.  I pulled the plug and it is pretty dirty.  However, if it was the plug, or even the hot start, would it run smoothly at high rpm's?   It does fine once it is opened up.  This leads me back to the slow jet.  I don't think I want to tackle removing the carb, so it will probably end up at the shop.

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It is not a fun job but really not terrible removing the carb. It just requires removing the subframe and other stuff attached. Just plan on an evening or afternoon to take your time and do it piece by piece. Any shop will charge you an arm and a leg to do what you really can do yourself. And you will learn a lot about your bike. If you don't have one I suggest getting a Honda OEM shop manual also.

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I could probably do it, but figure it will take the better part of a day, when you add in the time to clean the carb or replace jets.  I had just as soon pay someone to do it.  I do contract work at home and can spend that time making money to pay a Honda mechanic do the job right.  If I could figure out how to just rotate the carb, it would be an easy task, but it just won't rotate enough to get to the drain bolt.    

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Taking the jets out is pretty easy. First time it might be easier to remove the seat and tank. Then loosen the band clamps on the engine side and air box side of the carb (you'll need a flashlight to see the Phillips head screws). From the left side of the bike rotate the carb, pulling the bowl toward you. You might turn it a little more if you move some of the hoses out of the way, especially near the top of the carb. Be careful not to put too much pressure on the hot start nut, it's plastic. You only need to rotate it enough to remove the bowl drain cover (I think it 17mm). Once removed you can see both the main jet and pilot jet. It's a little tight but accessible.

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I saw that video.  I can rotate it some, but not enough to get a straight shot at the jets. The 2015 has more hoses and wires than some of the older models, which make it difficult to rotate.  I'm afraid of damaging something. 

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13 hours ago, doomaflotchy said:

 I do contract work at home and can spend that time making money to pay a Honda mechanic do the job right. 

Don't count on that.   Some mechanic's that work at Honda shops are not the best.  I think some are good too, but under the gun to get work done in as little time as possible.   Don't get me wrong; I'm sure there are very good mechanic's out there,  just don't count on it.   Plus, you don't learn anything in the process. 

I had a brand new CRF450x and took it in for a recall on the starter decompressor.  I wanted to do the work myself and asked for the parts, but they told me because it was a recall, I could not.  Said it would take about an hour.   When I took it in, it was running and I had at best 10 hours on the motor.  I wasn't ridding it much because it was so lean it stalled half the time coming off idle.

Called after a few days...."it's not done yet".   Called after a week...."it's not done yet".   End of second week, "what they heck is going on?".   "We can't get it running".   Couple days later called again.   "your welcome to take it, but it's not running".   I refused, then got into a major shouting match with shop manager who basically said "you brought it in on a trailer, we don't know if was running when we got it".   Uh, well of course I brought it in on a trailer, it's an off-road bike.  Mind you, you can tell it's brand new just looking at it.  but they did everything under the sun; leak-down test, then took the head and cylinder off, inspected everything and sill not running.  Manager said he wouldn't put any more time into it.

Started asking for the owner of the dealership and kicking up a fuss. Got no where with service manager.  Spoke to the sales department and got some understanding and at least a civil conversation, but really nothing they could do.  Told them I was going to the Honda regional rep and would be filing a complaint.

 Get a call from the service manager a hour later saying they'd take another look at it.  Supposedly put three mechanic's on it.   Low and behold called me next day "It's running". When I picked up the bike, the manager was still giving me attitude like the whole thing was my fault. 

 Anyway, got it home and took a quick spin down the street and back.  Was running OK, but I heard a banging and buzzing sound.   I found the clutch cable holder hanging free (it is supposed to be bolted with one of the engine mounts) and traced the buzzing down to the ground wire on the coil not being attached (it was arcing on the frame).  Really, with three mechanics working it?

Moral of the story; don't assume your going to get a good mechanic.    

And as far as that dealership, I have never set foot in it again.

Jim.

Edited by Jim Dettman

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I've considered that too.  I just don't want to screw anything up taking it apart.  Trust me, I really don't want to take it to the shop.  I am 95% certain it is just the slow jet.  There has to be a way to rotate the carb enough to get good access.  I've read a few posts that talk about how easy it is, but all the posts and videos are for older bikes.   

Edited by doomaflotchy
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 Well getting the carb out is not all that difficult as has been said and the work that needs to be done can all be handled with common hand tools.   Probably the only thing you might not have is a torque wrench.

  But  I guess it depends on how you feel about wrenching.   If your not into it and can afford the shop rates, then it might be best to take it to someone.   Just ask around first.  Check Better Business Bureau listings for complaints, etc.   I didn't want to scare you with my horror story, but just to point out that it can happen.  So do a little home work first before dropping it off at a shop.

  If you do decide to tackle it yourself, there are lots of video's on-line, you should use your phone camera a lot to take pictures before taking things apart, and take notes as you do so.  And of course you can ask a lot of questions here.   It does look complex, but when you start breaking it down, it's not all that bad.   And a new bike will be easy to work on.

 If you work on more things beyond the carb, then you'll definitely want a shop manual.   If you don't get one for this job, someone here will be able to give you torque specs for the sub frame and the top shock mount (you need to left the sub frame, which gets the air box out of the way,  and remove the top shock mount so you can push it aside).

  For many, the DIY route is the way they go because it saves a ton of money with most shops charging $80/hr or more.

Jim.   

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Jim I use a 1/4" ratchet to get the slow jet out. You don't really need a straight shot. The only thing you need to be careful is not to strip the threads putting it back and don't over tighten it.

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17 minutes ago, brethren said:

Jim I use a 1/4" ratchet to get the slow jet out. You don't really need a straight shot. The only thing you need to be careful is not to strip the threads putting it back and don't over tighten it.

Everything I've read says a flat screwdriver for the slow jet and a socket for the main jet.  Are you sure?  Anyway, I can't even get it rotated enough to get anything in there yet.  

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20 minutes ago, Jim Dettman said:

 

 Well getting the carb out is not all that difficult as has been said and the work that needs to be done can all be handled with common hand tools.   Probably the only thing you might not have is a torque wrench.

  But  I guess it depends on how you feel about wrenching.   If your not into it and can afford the shop rates, then it might be best to take it to someone.   Just ask around first.  Check Better Business Bureau listings for complaints, etc.   I didn't want to scare you with my horror story, but just to point out that it can happen.  So do a little home work first before dropping it off at a shop.

  If you do decide to tackle it yourself, there are lots of video's on-line, you should use your phone camera a lot to take pictures before taking things apart, and take notes as you do so.  And of course you can ask a lot of questions here.   It does look complex, but when you start breaking it down, it's not all that bad.   And a new bike will be easy to work on.

 If you work on more things beyond the carb, then you'll definitely want a shop manual.   If you don't get one for this job, someone here will be able to give you torque specs for the sub frame and the top shock mount (you need to left the sub frame, which gets the air box out of the way,  and remove the top shock mount so you can push it aside).

  For many, the DIY route is the way they go because it saves a ton of money with most shops charging $80/hr or more.

Jim.   

Yeah, I've just decided to do it myself.  I'll need those torque specs, if anyone has them.  My biggest fear is the screwing up the cables.  I'm comfortable wrenching, it's the delicate cables, springs, electronics, plastic fittings, etc. that scare me. 

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I've never had the carb off my '12, and have changed both pilot and main jets along with the needle. I did this to install the excellent JD jet kit, which I highly recommend if your bike hasn't been rejetted already. You can do it without great difficulty. I removed the float bowl for better access.

The trickiest part was getting the new pilot jet back in place. Since it's recessed way up a small channel, it can be difficult to get it in place. I skewered the pilot jet with a super long deli toothpick and positioned it easily while also threading it loosely in place. Be careful that whatever you choose to skewer the jet with will not leave burrs or other debris. Then finish tightening with your long/thin slotted screwdriver.

While you're at it, do yourself a huge favor and install an RD Flexjet adjustable fuel screw. It's high quality and will allow you to easily dial in your idle circuit with the bike running.

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17 minutes ago, motrock93b said:

I've never had the carb off my '12, and have changed both pilot and main jets along with the needle. I did this to install the excellent JD jet kit, which I highly recommend if your bike hasn't been rejetted already. You can do it without great difficulty. I removed the float bowl for better access.

The trickiest part was getting the new pilot jet back in place. Since it's recessed way up a small channel, it can be difficult to get it in place. I skewered the pilot jet with a super long deli toothpick and positioned it easily while also threading it loosely in place. Be careful that whatever you choose to skewer the jet with will not leave burrs or other debris. Then finish tightening with your long/thin slotted screwdriver.

While you're at it, do yourself a huge favor and install an RD Flexjet adjustable fuel screw. It's high quality and will allow you to easily dial in your idle circuit with the bike running.
 

I'd really like to know how you did it without removing carb.

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It was a while ago.  I believe I removed the seat and tank and fuel line.  I loosened both hose clamps and rotated it clockwise as far as I could.  Then I removed the float bowl for greater access to the jets.  Then I just used one long thin slotted screwdriver to remove the pilot jet, and a small socket and extension to remove the main jet.  Installation was the reverse, with the exception of skewering the pilot jet on a long toothpick to get it in position and start the threads.

A bit tricky, but not all that hard.  Good luck.

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Well, I pretty much had to disassemble the bike in order to remove the drain bolt and access the main jet and slow jet.  Both were spotless.  I reassembled and put in new spark plug.  Nothing has changed.  It won't idle, runs rough at low rpm's, and runs like a scalded ape once opened up.

New info.  Just talked to the seller.  I got the impression, when I bought it, that it had sat for a while.  I asked him again and he said no, that he ran it once a week up and down the street.  So, this has me second guessing a dirty carb.

Defective hot start maybe?  Would a bad hot start allow it to run good at high rpm's?

Edited by doomaflotchy

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Everything I've read says a flat screwdriver for the slow jet and a socket for the main jet.  Are you sure?  Anyway, I can't even get it rotated enough to get anything in there yet.  

Sorry you are correct. I was thinking of the main jet. Here is a picture of both
20161123_141503.jpg20161123_141445.jpg20161002_120744.jpg

If the pilot jet is not the problem, then my guess is its time to remove the carb and give it a good cleaning. Sorry about that, I know you were trying to avoid it. Might be something plugged in the idle circuit. Take lots of pictures along the way, comes in handy

Here are a few torque specs you wanted

20170327_201214.png20170327_200827.jpg

Hope this helps

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Thanks for all that brethren.  I really don't think it is the carb now.  The main and slow jets were spotless and the owner says he ran it frequently and only used non-ethanol fuel.  The bike is literally like new.  It ran fine when I test rode it.  I just don't know.  Since I put a good amount of seafoam in the tank, I wonder if it would help to go out and just run it to see if it clears up?  I am afraid of doing damage to the motor if the fuel delivery is jacked up.  

 

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