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High or sticking idle??
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Hey all. New to the forum. I posted this over on Thumper Talk, and got no response, so I decided to make an account here. 

Its a 2005 US model. I got the bike last year. I did the basic stuff, took the baffle out of the pipe, rejetted, took the snorkel off of airbox, etc. 

That's when my problems started... 
When I start the bike, it appears to be fine. I let it warm up, and start riding. 
Sometimes it is immediately after I start to ride, sometimes it takes a minute, sometimes it's even before I start to ride, but all of a sudden the idle goes up 2-300 rpm (maybe a little more) and stays there. When I give it a quick blip of half throttle or so, the idle goes back down. When I barely give it any gas again, the idle goes right back up and stays like that. 
So far, I've had the carb out about 10 different times. I've used every combo of jets I can with what I have (2 sizes up above stock for the pilot and main)
Right now I have it back to stock jet size, and it still does it along with having flat spots in the power and wierd bogging spots in the top end of the rpm range. That's of course because the main jet is too small.

I know what you're thinking... "Air leak". 
I've used a can and a half of carb cleaner trying to find ANYTHING... And nothing. 

I don't know what to do. I've taken everything apart and cleaned it, nothing is lose, my throttle isn't sticking, my air/fuel screw has been adjusted back and forth and nothing helps (although it does change the idle and how the throttle responds a little bit, like it should)

I am to the point of either swapping to a TM33 carb (Mikuni I believe) or just selling the bike. I love it, but I just cannot figure this out! I am absolutely tired of working on it, I just want to flippin' ride!!

 

Any help or ideas on stuff to check would be very much appreciated!!

 

Thanks!

David



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I would have gone with a leaking inlet stub but if your sure it's ok 

Are the cable freecplays set correctly might be a case of the cables not letting the carb close correctly 

 As it been opened up  it may need the next size up on the pilot jet and set the mixture adjuster and idle again 

 



-- Edited by ttboof on Sunday 30th of October 2016 06:55:12 AM

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i would say the same as above air leak but if you are certain this is ok why not take both cables off the carb & try that by slowly do revs by hand in different positions if not it can only be the slide thats sticking & not going to its stop position

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worn needle & or emultion tube...



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Sorry to hear of the problem David!

You are not alone on this one. I had a very low mileage 2004 TTR with the same symptoms and, after a lot of head scratching, a strip of the carb showed the throttle linkage securing screw to be loose. Worth a check!

With regard to Thumper Talk, I think you will find that most TTR owners have migrated over to this forum wink

Brian

Inside top of carb.jpg



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I will check for any air leaks again, but I'm like 95% sure there isn't one. I've literally sprayed everything down and I can't get anything to happen.

 

I'll also check the needle and emulsion tube. I was actually thinking about that last night after I posted. That could definitely cause this. 

TTRfan, I've never looked at that. I'll definitely check it out today when I pull it off again! 

 

Thanks. 

 



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I pulled it apart again. Totally forgot to spray it down with brake cleaner looking for airleaks, but I did check the screw TTRfan told me to check. It's tight, and everything else in there is tight too. 

I was going to check the needle to see if it was worn out... But this bike is almost new. It still had the stock tires on it when I purchased it. It's only got 1000 miles on it. It wouldn't be worn out that quick would it?

 

 

 



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I sprayed every single hole in this carb with carb cleaner today. Re assembled it with a size bigger pilot and main jet (52.5 pilot amd 140 main) The hanging idle thing appears to be gone (but it's also "dissappeared" before and then come back) Thinking maybe there was something I just missed clogging one something up. 

 

Now the problem is, there is a bog if you open the throttle up all the way from idle. I know my accelerator pump is working, because I tested it. Do I need to raise or lower the pilot jet size? I'm honestly not sure. The air fuel screw doesn't seem to do much at all. 



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Hey Okie, mine had similar symptoms, did as you did and as Brian suggested and checked everything a million times. For me it was the carby slide being worn. It has some sort of coating on it and wears over time and when the motor is running, vacuum causes the slide the push against the throttle body and stick a little.

Mine had 20,000k on it and was doing it on and off from about 12k and gradually got worse.

Someone mentioned carby cleaner can damage the surface of the slide. I don't know, but I wont use carby cleaner on the slide anymore just in case as they cost more than Donald Trump's hairpiece. I cleaned the old slide and the throttle body where the slide moves up and down with alcohol like Metholated spirits instead and that actually helped a little. The cloth was pretty dirty after "polishing" the carby neck. Anyway a new slide in the end fixed it for me. Not unusual to see people write about this symptom.

1000 miles is nothing, but I wonder if something or carby cleaner has damaged the slide?

Leigh

 

Assuming its not a cable sticking or throttle tube issue.  



-- Edited by leigh on Wednesday 2nd of November 2016 11:12:22 PM

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Definitely isn't a sticking cable. 

The slide looks brand new, so I doubt it is that... But when I pull it apart again I'll look it over and see if anything appears to be wrong with it. 



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Hi folks , just my two penneth for what's it's worth , I have also become versed in removing the carb quite frequently to try and get here to run without , bogging down , misfiring , not starting etc etc etc and eventually changed all jets ,the emulsion tube , the needle , all the o rings and diaphragms , checked float level using the clear pipe on the outside of the carb method connected to the float drain , fitted a new inlet mount and checked the whole lot for air leaks , but was not satisfied until ..... I had one final check ... Dropped needle one click to slightly richen the mixture which helped but my success really came when I decided to brave removing the float pin and replace the float valve , and tucked up inside where it fits is a very small dome filter on top of the float valve and it was coated in crap which I removed and replaced with new parts .... Bingo one perfect TTR, worth a try and I may be wrong so forgive me if I am , but it's not mentioned in any of the already excellent guides on the forum for carb servicing etc and it sorted me out ... Happy days and good luck

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have you got a picture of this filter never seen one on my carb strip is it a std carb off a ttr

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I haven't got a good picture - this is the best I have.

Float_valve_filter.jpg

This is where the float valve filter is located:

Location of float valve filter.jpg

 

I will look back at the carb articles and add some info about it but, yes, it is surprising what debris can gather on it bearing in mind how fine the filters are on the fuel tap confuse

I did post a message when I found a particularly dirty filter - see http://ttr250.activeboard.com/t45797183/petrol-filter-above-float-needle/

Brian



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I'll check that out. thanks



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I still haven't checked that filter out. I'm about to do that. (Taking it apart now)
I did pull the spark plug, and it looks totally fine.. Maybe even a tad rich. That confuses me.

I'll update you guys when I get this filter checked out.



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The small filter TTRFAN talked about is spotless.



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I'm not sure what else to do. I've cleaned the entire carb (that I can tell) checked every screw, nothing. Everything is as it should. I'm about ready to give up and toss the bike off into a nearby lake. Atleast there it won't give anyone else problems.

ANY ideas??


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Have you tried returning everything to stock? As in using an airbox with a full snorkel and no air holes, stock jetting etc and see how it runs?

I've always been tempted to try the airbox mod in the hunt for more power, but my TTR pulls flawlessly throughout the rev range, even when it's just about to stall out greenlaning, the throttle picks up with no bogs or hesitation. So I've never been able to justify changing it.

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Good to put it back to original and see if that works. I take it the inlet stub was fine?



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By inlet stub, do you mean the rubber hose (for lack of a better word) that goes from the carb to the engine? If so... No. It is not leaking. I have sprayed the entire thing down with starting fluid about 10 times. Nothing idle change, anywhere. It also still rubbery and bends (not dry and cracked)

I've put it back to stock jets, and put the air box snorkel back on. That doesn't change anything. Right now it has a 140 main, and 52.5 pilot. Im not even see where those are compared to stock, I forget what they come with.


I'm stumped.

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I guess I should also say that it runs great, pulls good with no flat spots or drop in power, no bog. It's jetted perfect. If only it would idle.

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have you sprayed wd40 ali around carb to inlet on tickover if it races up slightly its drawing air thats what it sounds like to me also does slide go up/down free without spring on

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I've sprayed everything down, idle doesn't change.

I will check the slide when I get home. I did notice when you pull the rottle lever by hand (not hooked to cables) you can feel a drag almost. But it appears the slide goes all the way back down everytime.

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Hi David

So now the only thing is the idle speed?

I take it you have tried altering the idler speed? Interesting thread about it here http://ttr250.activeboard.com/t54555922/idle-speed-screw/

Steve

Edited bit, also if you have a bit off sticking, I found it can also be up at the throttle, sometimes just tacking the throttle and checking the throttle tube and putting back together helps.,

Please don't throw it in the lake, sure we will get to the bottom of it.

 



-- Edited by ttr steve on Saturday 4th of February 2017 05:54:54 PM

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if you have done the wd40 bit take carb off couple up cables work throttle look down at the slide from inlet or outlet you must be able to see its not releasing it could be one cable fighting against another adjust cables to suit hope this helps

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Cables are adjusted fine, already checked that.

Ttr steve, that was a helpful post. I've always had the same problem with it not wanting to back out. I filed it like he did and it works great now!
That still doesn't fix my problem. But it was nice. Lol.

I re installed it today, it seems better now but it still idles high sometimes. I'm about ready to just give up and ride it. Maybe it'll fix itself.

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A few days back, I found a little brass piece laying in the floor. I had remembered seeing it a loooong time ago, inside the carb. Did a little looking and it was the "check valve". I don't think it does anything at idle, but it's back in there now. Bike has run fine everywhere else so I'm not sure what that does.

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Hey OkieRider,

Given that you have checked the cables and the slide is not sticking, I would suggest that you are using a #52.5 that is too rich for the bike to handle with your set-up. Try using the stock Teikei (US) #50 and see if that is the problem. If you have used a different brand of jets other than stock Teikei or 6 Sigma this could be your problem too. Different brands have jet sizes that does not correlate to others so keep that in mind.

In regards to the accelerator pump it does not effect the idle at at, it comes on from about 1/3rd throttle, it helps to regulate the accelerator response by shooting a squirt of fuel when the throttle is rolled on. This is the reason why I would not change the stock carb personally, it helps to stop the lean condition (less accelerator response) that other carb's have that do not have this feature.

I personally would not recommend to take the snorkel out, I would be enlarging the inlet. Search 'air-box modifications' and you will see how I did it. Edit: Just remember you might need to use the #52.5 pilot jet

Let me know how it goes for you.

Jarrah



-- Edited by TT-R250M on Saturday 11th of February 2017 03:11:03 AM

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Stock pilot didn't help any when I tried it.

It seems like it is running better now, so until something else happens... I'm gonna leave it alone.

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i'm having the same problem. new bike to me, 2004 ttr 250. I haven't seen this carb before. is the slide that everyone is talking about part #14 in the diagrams, called "valve, throttle 1"?

http://www.partzilla.com/parts/search/Yamaha/Motorcycle/1999/TTR250+-+TTR250L/CARBURETOR/parts.html



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Yep - weird name Yamaha have given it eh?



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IMG_2167.JPG

I dug into my problem today. Here's a youtube link of what mine was doing.

www.youtube.com/watch


I took the carb out, thank you to all who have posted instructions here!! It went pretty well, hardest part was getting one of the throttle cable out of it's clip. The intake tube from the airbox was loose, and I think that was one source of my issues. It basically fell off, and I could see an indention in the rubber that it didn't appear to be seated properly. I didn't even have the unscrew the clamp, so that's my clue there. I went ahead and cleaned the outside, then dove into the guts. I removed the to piece, and peered inside. It appears clean, and I didn't feel comfortable with removing the needle.

I replaced the gasket, and removed the bowl. Removed the jets, and they were clean. I replaced with Mikuni 52.5 and 140 jets. I removed another portion with the nickel sized gasket, and replaced it. The bowl gasket was flat and brittle too. I couldn't get the float needle pin to budge, and since everything else looked good inside, i decided against possible breaking those pin mounts, and left it alone. Lastly, I removed the cover for the accelerator pump diaphragm. this piece was stuck to the outer cover, and was brittle with tears in it. I think that was a problem too. That piece has been ordered, so I hoping all will be resolved later this week.

 

With the rebuild kit I received, it had a single small o ring. I used it on the new fuel screw, as it didn't have one on it from the kit, but the old did have an o ring, however it looked flattened out.  All the gaskets were flattened or brittle, by the way. 

A huge thank you to all who have traveled and documented this road before me. I truly appreciate it. Cheers!! I will figure out how to load photos later tonight.

 

IMG_2158.JPGIMG_2160.JPGIMG_2162.JPGIMG_2163.JPGIMG_2173.JPG

 

This is as far as the jets went in.  The stock ones were in further.   Is this correct?

IMG_2174.JPG



-- Edited by Jumpn on Monday 20th of March 2017 02:06:43 AM



-- Edited by Jumpn on Monday 20th of March 2017 02:10:13 AM



-- Edited by Jumpn on Monday 20th of March 2017 02:12:32 AM



-- Edited by Jumpn on Monday 20th of March 2017 02:16:49 AM

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Here is how it was running before.
www.youtube.com/watch

Notice how the rpm's stay elevated after the rev, lack of responsiveness.   the throttle return snaps back fine, and the choke is off. It dies by itself. 

 

Here's a video of my carb after cleaning.   I'm awaiting a new accelerator diaphragm assembly before it goes back on the bike. 

 

https://www.youtube.com/watch?v=VZzlHaWUsYQ



-- Edited by Jumpn on Monday 20th of March 2017 02:31:41 AM

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Thank you for documenting the carb rebuild so well especially with the photos and videos biggrin

I think you have done an excellent job on the carb and it all looks squeaky clean.

As the carb was working before the strip down then it is more than likely that the float needle is free and working properly.

My suggestion is to put the carb back on when you get the diaphragm and see how it runs. It could be that the slide was a bit sticky from not being use for a while. Maybe running it for a few miles will sort your problem out. If not, we will need to give it some more thought but at least you will have a running TTR to get out on and enjoy riding wink

Brian



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Thank you. I hope that it all comes together. I will report back when the diaphragm assembly is in and the bike is (fingers crossed) running well.
The diaphragm should not have been stuck to the cover, should it? Or does it keep suction there all the time? It was very dry and cracked though.

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Lots of posts on this thread!

If you said you were also having problems keeping a good even low idle I'd type "pilot jet" in all caps, but I think you're saying it will idle nice and low but then jumps after you hit the accelerator and won't go back to a nice low idle? I still say pilot jet but in lower case letters.

Just to be sure, you tried the STOCK (Teikei?) #50 pilot? Not the Mikuni. And it was a NEW stock #50 pilot? They can't be cleaned. I swear its this bike's Achilles heel (the pilot jet that is).

Those Mikunis drove me crazy. I found the #140 main jet too big, even with the airbox opened, went back to #137 (stock!) and leaned the needle from there.

I have a 2003 US model.

BTW what ever Jarrah ttr250.activeboard.com/m1686051/profile says about the carb is probably right.

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Jumpn wrote:

Here is how it was running before.
www.youtube.com/watch

Notice how the rpm's stay elevated after the rev, lack of responsiveness.   the throttle return snaps back fine, and the choke is off. It dies by itself. 

 

Here's a video of my carb after cleaning.   I'm awaiting a new accelerator diaphragm assembly before it goes back on the bike. 

 

https://www.youtube.com/watch?v=VZzlHaWUsYQ



-- Edited by Jumpn on Monday 20th of March 2017 02:31:41 AM


 Jumpn Dude!  I just watched your video.  PILOT JET (new, stock).  If I'm wrong I'll buy you a beer.  I will now change my handle to "pilot jet."



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Well, I hope you are right. I replaced with the larger jets, but do have new stock jets if it seems to need them.
I decided now is a good time to clean. Bathroom scrubbing bubbles do a great job!

IMG_2179.JPG

 

I cleaned up the airbox. and noted a crack in the rubber piece between the intake tube and the black "box" thing on top.  Guessing I should silicone seal this up? It looks like previous owner already tried. What does that box do?

IMG_2178.JPG

 

Along with this conical piece, what is it's function?

IMG_2177.JPG



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Some information on the "black box" here - http://ttr250.activeboard.com/t51169250/yamaha-energy-induction-system-yeis-boost-bottle-air-chamber/

The conical device is an emulsifier and pulls most of the oil mist out of what gets pumped from the crankcase breather pipe to the airbox. Needs emptying regularly.

I would assume all the parts and connections should be airtight for them to work effectively wink

Brian



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OK, so the emulsifier is like an oil catch-can thing. thank you. I will empty it prior to re-install. From what I gather, the air chamber is a separate piece, and isn't "molded" into the rubber boot as I originally thought. I didn't want to go prying things off. Thank you

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My new accelerator pump diaphragm and o-rings came today. I put them in the carb, now it's going to be time to re-install the carb. Anything I need to look out for on reinstall?

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Just about everything you could want is in the carb stuff pages: ttr250.activeboard.com/f611253/carb-stuff/

I've found these two particularly helpful: ttr250.activeboard.com/t55374798/rebuilding-a-ttr250-teikei-y30p-carburettor/; ttr250.activeboard.com/t47674647/carburettor-pictorial-guide-to-stripping-and-checking-a-carb/

And don't forget the NEW STOCK #50 pilot jet and while you're at it might as well install a new, STOCK #137 main.

Once you get it dailed in you'll know it, the set up is pretty bullet proof with basic maintenance.


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Another great one on jets and needles: ttr250.activeboard.com/t49951533/carb-jetting-information/


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www.youtube.com/watch

It lives!! It took a little while to get fuel to her I think, but with a blip of throttle while hitting the start button, she lives!! So much easier to ride with a good idle. Thank you to all here on board!!

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I adjusted the air screw just a tad, now it fires with just a press of the magic button. No cranking at all, just BAM, and she hits. so nice.

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Good job!



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