Question about 2004 Yamaha YZ 250 F

2 Answers

Wont rev past 3/8 throttle!! I NEED HELP.

My 96 yz250 will run fine at lower rpm's but when u go over 3/8 throttle it acts like its hitting a rev limiter and bounces revs real quick....could this be my cdi box going bad?

Posted by on

  • peter smith Dec 23, 2013

    it sounds more electrical than fuel mianly if it was happening in low revs it would be your idle jet which are very small if it was running alright before and not now the main jet is useally not a problem the jet is so large and it useally a problem if you change a exhaust or do a port and polish then it is a job to go for a larger jet size so it would not be that .i am sorry to say it does sound like a cdi or try another coil. hope this helps cheers pete

×

2 Answers

  • Level 1:

    An expert who has achieved level 1.

  • Contributor
  • 3 Answers

Check your jetting in your carb. It seems like your idle jet is fine but your main jet may be plugged or the wrong size.
url

Posted on Mar 15, 2013

  • Level 1:

    An expert who has achieved level 1.

    Corporal:

    An expert that hasĀ over 10 points.

    Problem Solver:

    An expert who has answered 5 questions.

  • Contributor
  • 9 Answers

Could be. I had a 91 kx 250 that was acting crazy and it turned out to be the stator and cdi box. you can check the stator easly with a omes meter but the cdi box is nearly impossible to check. you pretty much have to buy a new one and try it. also check to see if your power valve is working.

Posted on Jan 22, 2009

1 Suggested Answer

  • 9 Answers

SOURCE: MY YZ250 WONT REV PAST 3/8 THROTTLE. I NEED HELP!!

It does sound like an ignition timing problem, but could also be a breathing issue, air flow in or exhaust flow out could be restricted i.e.:dirty air filter, excessive carbon build up in exhaust pipe from burning too much oil or rich fuel mixture.
possibly and more likely some junk got into your fuel system and partially plugged up the main jet in the carb, -or has the needle on the slide been moved? The little circlip at the top of the needle, if it has one.
1.Replace the spark plug, check gap, check spark, it should be bright blue and fat.
2. check the fuel filter, if no filter check the carb for dirt.



Posted on Jan 20, 2009

Add Your Answer

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

1 Answer

Hi my name is robbie my mito won't go over 6000 rpm when riding it just splutters


Hi, Robbie and the usual suspects are:
1. Severely drained or faulty battery.
2. Faulty regulator/rectifier or high output coil.
3. Faulty power valve, solenoid or installation.
4. Clogged air filter or exhaust.
5. Cracked or incorrect float level.
6. Float needle is not seating.
7. Faulty reed valve.
For more information about your question please visit the website below. Good luck and have a nice day.
bike wont rev up past 6 000 rpm please help
need help My bike will not rev up and hit the power band
http://www.carlsalter.com/pdfs/Cagiva_mito_ev%201994.pdf
Cagiva MITO EURO2 125 2004 parts OEM Motorparts
http://www.cagiva.nl/media/owner_manuals/?tx_motomondo_pi4%5Bmodel%5D=&tx_motomondo_pi4%5Byear%5D=-1&tx_motomondo_pi4%5Bmanual%5D=

Aug 22, 2014 | Cagiva Mito 125 Motorcycles

1 Answer

2008 suzuki boulevard gears change good going up but not so good coming down


1. Is it a new bike for you? or do you own it for a while?
2. try checking the clutch. it might need tightning. try from the lever on the top. if you don't know how to, then ask a mechanic.

3. check if you need to "rev it up". when lowering a gear, you let go of the throttle, pull the clutch, give a quick twist of the throttle (pull and let go) while lowering a gear to match the rev's of the engine to the gear, and ease of the clutch off.

4. check you oil level. Some bikes are very sensitive to low oil. My v strom when hitting half, will start acting out with the gear.

Apr 21, 2014 | 2008 Suzuki Boulevard C50

1 Answer

When i hit the throttle hard it bogs down it also wont rev past 6,000 rpm


When you say it won't rev past 6k what happens? Does it bog down and eventually choke itself out?

sounds like the carb needs a good cleaning. Have you replaced the fuel and air filter? If you take the air filter off does it run better or worse?

Sep 25, 2013 | 1980 Suzuki Gs 550 L

1 Answer

My 2000 yz 250 runs but wont rev up it just sputters


Hi, Anonymous and the usual suspects are:
1. Severely drained or faulty battery.
2. Faulty regulator/rectifier or high output coil.
3. Faulty power valve, solenoid or installation.
4. Clogged air filter or exhaust.
5. Cracked or incorrect float level.
6. Float needle is not seating.
7. Faulty reed valve.
For more information about your issue and valuable "FREE" downloads that you will need please click on the links below. Good luck and have a nice day.
YZ250 bad reed Yamaha 2 Stroke
1999 yz250 not hitting power band
YAMAHA YZ250 LC Owner Service Manual
OEM parts for Yamaha
http://mybikemanuals.com/yamaha/yamaha-yz-owners-manuals

Aug 06, 2013 | 2003 Yamaha YZ 250

1 Answer

WONT REV ABOVE 3500 RPM


Hi, Anonymous for this situation I would call my local dealer or reputable shop's service/parts department and inquire about any possible quick fix, answers, or parts inquiry. If necessary, transport your bike to the dealer or shop and have a professional technician take it for a test drive, if it is in running condition, and give you a written estimate of repairs and answer any specific questions you may have about your problem. For more information about your issue and valuable "FREE" downloads that you will need please visit the websites below. Good luck and have a nice day.
Rpm wont rev past 3500 ScootDawg Forums
2 stroke scooter won rev under load
Derbi Boulevard 125 150 200 Factory Service Repair Manual Download Manuals...
https://www.oemmotorparts.com/oem2.asp?M=derbi
http://www.derbi.com/fr/images/stories/modelos/37/manual.pdf

Mar 16, 2013 | 2008 Derbi Cross city

1 Answer

2005 V-Star 1100 flooded condition. Changed plugs...same result. Removed and cleaned carbs and set the floats a few times. Each time the bike stareted and ran mint at lower engine RPM. The problem is it...


Hi, Anonymous the following applies to carbureted also fuel injected models and the usual suspects are:
1. Severely discharged or a damaged battery, should have 12.5 volts or better and be able to pass a load test if necessary.
2. Failed alternator/generator and or voltage regulator.
3. Loose or corroded battery terminals and or cables especially the "NEGATIVE" cable, look for loose, corroded, or broken connectors inside the cable harness at "BOTH" ends.
4. Failed main circuit breaker or ignition switch, check for loose connections and continuity.
5. Failed system and or ignition relay, check for continuity.
6. Failed ignition coil, ignition/electronic module.
7. Failed CKP, CPS, CMP, MAP, TPS, or BAS sensor, corroded, loose or broken wire connector pins/sockets.
8. Throttle cables and or idle speed improperly adjusted hot idle speed should be 950 RPM to 1000 RPM.
9. Air/fuel mixture screw improperly adjusted.
10. Water or dirt in the fuel system, carburetor or filter.
11. Restricted, blocked or kinked fuel line.
12. Fuel tank empty.
13. The gas cap is not venting properly or fuel tank venting system blocked.
14. A failed fuel pump, pressure regulator and or fuel injectors.
15. Vacuum line from intake manifold to petcock broken, cracked, or not attached, carburetor vent line plugged.
16. Needle and seat stuck closed in the float bowl.
For more information about your issue and valuable "FREE" downloads that you need please click on the links below. Good luck and have a nice day.
http://www.starbikeforums.com/forums/18-engine-work/8857-2005-v-star-1100-wont-rev-past-1-3-throttle.html
https://yamahaclub.com/forums/topic/15251-idles-fine-but-dies-upon-throttle
http://www.sloneservices.com/SilverBack/Other-Stuff/V-StarShopManual99-07.pdf
OEM parts for Yamaha
http://www.starmotorcycles.com/assets/service/manuals/2000/LIT-11626-13-36_96.pdf

Oct 10, 2012 | 2002 Yamaha V Star 1100 Classic

1 Answer

MY YZ250 WONT REV PAST 3/8 THROTTLE. I NEED HELP!!


It does sound like an ignition timing problem, but could also be a breathing issue, air flow in or exhaust flow out could be restricted i.e.:dirty air filter, excessive carbon build up in exhaust pipe from burning too much oil or rich fuel mixture.
possibly and more likely some junk got into your fuel system and partially plugged up the main jet in the carb, -or has the needle on the slide been moved? The little circlip at the top of the needle, if it has one.
1.Replace the spark plug, check gap, check spark, it should be bright blue and fat.
2. check the fuel filter, if no filter check the carb for dirt.



Jan 19, 2009 | 2004 Yamaha YZ 250 F

1 Answer

998 cutting out at 9000rpm


so I don't think it should be the rev limiter at 9k. It's not bouncing like a rev limiter it just stops firing the cylinders and the comes back again when the throttle is released. It has the stock 996r ECU. Since I got it I've fitted a smaller battery to make room for frame sliders. Could this cause the bike to cut out earlier? It cuts out then runs fine again. The other things I can think of is fuel delivery. But I'm not sure the symptom is correct for that? Any thoughts would be appreciated. In any case I'll put the stock battery back on to see if that helps, but I wont know the answer until next Friday when I'm going to the track,I recently had a problem with one of my Guzzis acting like that at 6k RPM. Always at 6k RPM, but only under load. Ended up being a restricted air intake. Really strange, because it acted just like a rev-limiter. So, does it only act this way under load, or also if you just rev the bike in neutral? If it's a limiter problem or tach error, it should still have the problem even with no load. If the problem is only under load, then it's either a fuel or air problem.,,,

Nov 10, 2008 | 2002 Ducati 998 S Bostrom

Not finding what you are looking for?
2004 Yamaha YZ 250 F Logo

Related Topics:

470 people viewed this question

Ask a Question

Usually answered in minutes!

Top Yamaha Experts

Steve Sweetleaf
Steve Sweetleaf

Level 3 Expert

1128 Answers

D. E. Hev

Level 3 Expert

1059 Answers

mikeuk

Level 2 Expert

61 Answers

Are you a Yamaha Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...