Jump to content
Sign in to follow this  

My bike runs like poop.. :(

Recommended Posts

I have a 2006 yz250f that is not running right.. i put it away last winter with all the stock jets and stock everything and it ran well.. how a stock yz250f runs. Anyways i put a pipe on it along with adjusted the valves over the winter along with putting in some new jets, i put a 175 main in from a 182, a 55 leak jet from an 80, and changed the needle clip from the 3rd to the 4th along with the o-ring mod. Now it is breaking up down low and running like crap, once it gets hot and dies it will not start! I chanced the clip back to the 3rd position since i figured it could be starvin for gas, did nothing. Took out the o-ring, did nothing. Now im left with the only other 2 changes leaning out the main and smaller leak jet.. but these both make since and wouldnt cause this problem i dont beileve, i dont want to change my leak jet back because everyones running 40-55 leak jets.. Anyways sorry for the long post hope someone can help! Thanks in advance!!

Share this post


Link to post
Share on other sites

Just want to put a post here so I can keep track of this one. A buddy just had the same problem with his. I think it was bad gas. Did you drain all your old stuff before riding?

His blew a spark plugs tip off. Did you check/change yours?

I would think with the new exhaust you would have to go up in Jet size to accomodate for the increase in air volume going thru the bike.

Again, just my uneducated thoughts.

Share this post


Link to post
Share on other sites

Yea the gas tank was completely empty when i put it back together along with a drained the carb i ran about 5 tanks through the bike since, I also have a brand new iridium plug.. im pretty stumped on this one.. maybe the plug? Just thought of that.

Share this post


Link to post
Share on other sites

Leak jet is not you problem.

Once the bike was heated up, did you reset the fuel screw according to the perscribed procedure?

Did you check the float height? Was the slide out of the carb?

Did you change anything else on the bike?

Share this post


Link to post
Share on other sites

Yes ive been playing around with the fuel screw constantly the other day when i was adjusting it it seemed like it wasnt doing anything then all of the sudden the idle went abnormally high and sounded great so i turned it down road it then it still dosent feel right..

Share this post


Link to post
Share on other sites

Playing around with it and then getting a hanging idle is not the correct method. How about the other things I mentioned?

Fuel Screw/Pilot Jet

Fuel screw settings in the 'book' are recommended starting points. Every bike is different, as is the temp and altitude. Set the screw according to this method. Do it with the bike fully heated up.

Gently turn the screw all the way in. Now back it out two turns. Start the bike and fully warm it up, go for a 10 minute ride. Set the idle to speed to 1,500~1,800 RPM as best you can (I know, without a tach this is tough, just set it to were it idles relatively smoothly). Once warmed, slow the idle to the lowest possible speed.

*** When turning the fuel screw, keep an accurate 'count' of the amount you are turning it and record it in case you have to reset it for some reason. Makes life easier when you can just set it from notes Vs. going through the procedure again.***

Turn the screw in until the idle becomes rough or the bike stalls.

if it stalled, open the screw about 1/4 more turn. Restart it and slowly screw it in till you can just perceive a change.

If the screw can be turned all the way in and the bike still idles perfectly and does not stall, then you need to go down a size in pilot jet.

Now very slowly, open the fuel screw till the idle is smooth. Blip the throttle, let the bike return to an idle, wait say ten seconds. Confirm it is the same smooth idle.

If the screw has to be opened more than 3 turns to get a smooth idle, you need to go up a size in pilot jet.

If you find it does not stall with the larger jet but has to be open more than three turns with the smaller pilot jet, put the larger one in and set the fuel screw at 1/2 turn.

If the idle speed increased, adjust the idle speed knob to return the bike to a real slow idle speed. You must then re-visit the fuel screw. Keep doing this till the fuel screw is opened just enough to provide a nice steady idle at the lowest possible RPM. Once this is done, increase the idle speed to the normal one for your bike, typically about 1,800 rpm, but go by the spec in your manual.

Share this post


Link to post
Share on other sites

Alright cool! Thanks alot man ill play with it some more today, it seems like its starting to run a little better but once im idleing or riding through ruff woods and it stalls it does not want to start. But i know that has something to do with a mis adjusted fuel screw so ill play with it.. Thanks again

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

  • Similar Content

    • By SNORE125
      Anyone else have 130 main and 38 pilot jets already in the carb I took the wifes ttr 230 carb apart to add the bigger jets and this bike from 05 that I bought new already had them in it? I was reading that they came with a 125 main and a 36 pilot.
    • By Charles Joseph Miron
      Hello all.  Need a helping hand here..  
      I bought an older TT225 and am not about to spend almost $600 on a new carburetor for it. So I'm hoping someone can help me out with an idea of what (other than original carburetor) style, type and brand I should go with..  I'm also having a bit of trouble finding info on this bike.  It's a 1986 Yamaha TT225.  
      Thank you in advanced
      Charles
    • By Br0ck
      Hey guys, I went on vacation all summer and let my bike sit (2002 CR250). When I got back I ripped it apart and cleaned carburetor and put it back together and it started fine and ran alright, but idled really high. I adjusted the idle screw and realized it was a ridiculous amount of turns out. I can't remember exactly how many but id say 6+ turns out. My killswitch was a POS and didn't work anymore so I replaced it with an oem replacement. My last ride I crashed the bike pretty bad and I was off the bike for 2 weeks. I can't get the bike to start ever since I got installed the new killswitch. I think I wired it right I just replaced one wire at a time and it looked pretty straight forward. I verified it by testing spark while holding it in I was getting no spark but with it in running position it would spark. 
      Anyway I am just looking for some base settings for the Mikuni TMX to get my bike running again, my carburetor has a 35 Pilot and 380 Main jet which appear to be stock. I am located in Edmonton, AB, Canada which is about 2500ft and usually ride between 10-25 celcius.
      Thanks for any replies. 
    • By Goon Rides
      Hey guys... so I have a problem... I took the bike at Cal City, broke it in, and while I was doing so, the bike was bogging in first gear (Yes, first gear). Also it doesn't idle at all. I have to keep blipping it otherwise it'll stall. So I adjusted the screw circled in image 1. Well I was listening to the sound of the of the bike, yet the rpm's weren't increasing, and it was still stalling. So then, I unscrewed the screw in image 2, well I found out that it was fully twisted to the right. So then, I twisted it to the left, still nothing; it was still stalling... where's the idle screw? I am sure that the screw in image 1 is for the air/fuel mixture screw, and the screw in image 2 is the idle screw, just broken? I don't know, any and every help would be appreciated.


    • By Zach7018
      So Ive decided its time to pull apart my favorite machine and freshen it up, and I'm looking to make some improvements in the process. I already have a 3x3 mod and a JD jet kit done and it seemed to have changed the world. The stock bike just plain sucked and now its a lot better. I never expect 450 race bike power here but I know there is a little more and I'm wondering if the juice is worth the squeeze. I already plan to add a header and exhaust, an FCR39 carb and stage 1 hotcams. After some research it really seems like those places are where the gains actually come from, so would it be worth it to throw a 434 big bore kit at this bike or just stick with what I already mentioned and a new stock bore top end??? Also my rides are often solo and pretty isolated,how much of a reliability headache can I expect with these mods? 
×