Question about 2003 Yamaha YZ 250

2 Answers

Backfire i have a 1989 yz 250 that wont start but has fuel compression and spark. i can only get the bike to backfire through the exaust hard enough to blow the exaust outa the spark rester. any suggestions would be much appreciated thanks

Posted by on

2 Answers

  • Level 1:

    An expert who has achieved level 1.

    Hot-Shot:

    An expert who has answered 20 questions.

    Corporal:

    An expert that has over 10 points.

    Mayor:

    An expert whose answer got voted for 2 times.

  • Contributor
  • 42 Answers

Your plug may be firing in a fouled area. When I have a problem like this, I 1.change the plug. 2. Take the carb and have it cleaned in a sonic bath and my honda dealer(They are the only one with this cleaner in my area) for about $25. 3. Check to insure that the fuel mixture screw is set correctly(about 2.5 turns), and 4.clean the air filter or replace it.

Posted on Aug 28, 2010

  • Level 2:

    An expert who has achieved level 2 by getting 100 points

    All-Star:

    An expert that got 10 achievements.

    MVP:

    An expert that got 5 achievements.

    Vice President:

    An expert whose answer got voted for 100 times.

  • Expert
  • 200 Answers

I assume this is kick start only, and by now your right leg is twice the size of your left one ! correct?If you can't find a long nearby hill, get a trusted buddy to pull your bike w/ another bike or car/truck. Attch rope to bottom triple clamp and don't go over 20 mph, use 2nd gear...this may sound risky but i have done it many times and find that nothing clears out an engine faster !...Good Luck to you friend...Tim

Posted on May 10, 2009

1 Suggested Answer

6ya6ya
  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi,
a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
goodluck!

Posted on Jan 02, 2017

Add Your Answer

Uploading: 0%

my-video-file.mp4

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

×

Loading...
Loading...

Related Questions:

1 Answer

Can't start my yz250fp dirt bike


Have a trained tech service and properly jet the carb and set idle and idle mixture.
If you have spark, compression, and the valves are adjusted properly the only thing left is the carb. The FCR carb is as complex as the entire engine!

Apr 04, 2014 | 2003 Yamaha YZ 250 F

1 Answer

I have a 2001 yamaha yz426f that backfires after start and shoots flame from exaust and the exaust gets so hot it glows red.


Hi, Anonymous 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. Check battery terminals for damage or corrosion, check the battery cables at "BOTH" ends for loose, corroded, or broken connectors, "INSIDE" and outside the cable harness, perform connector wiggle test and check cables with an ohmmeter if necessary.
3. Faulty main circuit breaker and or connections.
4. Faulty ignition coil and or connections.
5. Faulty spark plug, oil or gas fouled, wrong heat range or service type, wrong gap, loose in the cylinder head, broken electrode or insulator.
6. Faulty spark plug cables, leaking or broken, internal damage.
7. Faulty ignition module, switch, CKP, MAP, CMP, sensor and or any connector in the ignition circuit could have corroded, loose, or broken pins/sockets
8. Burnt exhaust valve or air leak in the exhaust system.
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.
http://www.raptorforum.com/forums/66-raptor-660-maintenance/71417-just-cleaned-carb-now-exhaust-getting-red-hot-after-idling-only-2min.html
YZ 426 RED hot header pipe backfiring YZ 400 426 450
Yamaha YZ426F Owner Service Manual
OEM parts for Yamaha
Yamaha YZ450F Owner Manual Page 3

Feb 08, 2014 | 2001 Yamaha YZ 426 F

2 Answers

Kawazaki kdx 125 wont start


KICK HARDER TRY PULL STARTING IT..IN SECOND GEAR..DOES IT HAVE ENOUGH COMPRESSION TO START?IT SHOULD START PULLING IT...START OFF WITH NO THROTTLE THAN IF NOT STARTING CRACK THE THROTTLE SO LIGHTLY AND SHE SHOULD FIRE OFF WHILE IN GEAR BEING PULLED OF COURSE BE CARE FUL NOT TO RUN INTO. WHO EVERS PULLING YOU..USE A LONG TOW ROPE..IF YOUR NOT A SEASONDED RIDER AND KNOW YOUR BIKE VERY WELL I WOULD NOT ATTEMPT THE PULL START...IF NOT CHECK YOUR COMPRESSION AND TIMING..MAJOR VACUUM LEAK MAYBE AT BASE GASKET..IS ENGINE SUCKING TO MUCH AIR? GOOD LUCK..

Mar 02, 2013 | kawasaki KDX 125 Motorcycles

1 Answer

Yz 250 wont start


Bad injectors or they are out of adjustment!

Jun 02, 2012 | Motorcycles

1 Answer

I have yz250f the bike is hard to start,I took out the plug and it seems to be running lean,is that a jetting or air mixture issue?


could be both ? roughly speaking if your fuel mix screw is more than 2.5 full turns out then jet is gummed up or dirty or to small
to test you can only compress air clean all the carbi with jets out reinstall and test ride and read your spark plug for clues you will also get backfiring and or poping on de acceleration if to lean
another very common reason for a slightly older YZ four stroke being hard to start is valve clearances out of spec and or a slightly leaky vale
when you got the carbi off would be worth checking your valve clearance you only need the cam cover off to check them take you 5 minutes as already stripped down you want .10 -.15 intake and .20 - .23 in metric best way to confirm leaky valves or motor for that matter is a leak down test but there is some art to this so take to shop for this if you are not confident to do this

Apr 15, 2011 | 2003 Yamaha YZ 250 F

2 Answers

VERY hard starting takes way to many kicks usually play out befo


There is a proper way to start the engine. Four controls are on your bike to assist in starting.
  • The choke, used when the engine is cold. Pull the red knob for choke.
  • The " Hot Start " Lever, used when the engine is hot. Pull the lever to lean the fuel mix when the engine has been running.
  • The de-compression lever, always used.
  • The throttle, used to prime the cylinder.
Don't kick, instead, push the kick lever downward. You will feel the back pressure as the piston is going upward on the compression stroke to the point the pressure is great enough that the kick lever "locks up". You are very close to TDC. NOW, pull in the de-compression lever. Push the kick lever a little bit more to get the piston past TDC. Release the de-compression lever. Give the throttle a 1/4 turn then let it snap closed. A diaphragm in the carb gives a shot of gas when this is done. DO NOT do this multiple times because you will flood the engine. Leave the throttle closed when kicking. Give a strong kick through the full sweep of the kickstart lever. Quickly get your foot off the kick lever at the end of the kick to avoid any chance of "kickback" from a backfire. It can be very painful, and can even break a leg. I am serious about that. Repeat the process (but without the throttle priming), until the bike starts. A good battery, a clean spark plug, a clean carb and clean air filter will also aid in starting.

Top rating for this answer? Thanks!

Jun 11, 2009 | 2003 Yamaha YZ 250 F

3 Answers

Yz 250 wont kickstart


Hi!
You obviously look after your machine and very sensible when laying up, however as you are probably aware 2 strokes rely heavily on compression, A. to produce excellent combustion and B. to draw fuel into the chamber. So when you try kick starting you can't get enough revolutions to draw the correct amount of fuel into the cylinder, where as you push start you constantly turn over the engine increasing compression slightly and bingo it fires.
Can you remember how when kick starting it before this problem the feel on resistance when kicking over? has it now become a lot easier? if so you possibly have worn or broken compression piston rings.
A compression test will reveal this, I hope this sorts your query?
Press the Blue button please for my FREE effort,
Thank You!
Paul 'W' U.K.

Feb 06, 2009 | 2000 Yamaha DT 125 R

5 Answers

1997 yz 125 wont start, please help


2 stroke bike are very dependent on compression. and being a bike that is 12 years old my best educated guess is that the top end needs to be rebuilt. i usually have to have the top end done on my honda about every three years.

Jan 12, 2009 | 2003 Yamaha YZ 125

Not finding what you are looking for?
2003 Yamaha YZ 250 Logo

408 people viewed this question

Ask a Question

Usually answered in minutes!

Top Yamaha Experts

dhnguyen

Level 2 Expert

281 Answers

Steve Sweetleaf
Steve Sweetleaf

Level 3 Expert

1144 Answers

Tony

Level 3 Expert

2600 Answers

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

Answer questions

Manuals & User Guides

Loading...