250f is backfiring, popping, and shooting flames

Lonewolf · Apr 29, 2003

i just bought it yesterday, it's a 2002 yz 250f. i brought it home from the dealer and started it and it was backfiring, popping, and had flames shooting out of it, is this normal? i called the dealer this morning because the were closed by the time i got the bike home last night, they said somebody probably jetted it. im really upset about this because the reason i bought a bike from a dealer is because i wanted a bike that was looked over and made sure it was it good operating service before was sold, i just wanted that reasurance. even when the bike has been running for 5 minutes it does this and it also doesnt idle. i talked to someone i work with and his friend has a 250f and he was with him yesterday and he said that his doesnt do the backfiring, popping, etc... i just want to know if this normal. there is also no warranty with this bike and im kind of scared.

Rich Rohrich · Apr 29, 2003

Check to make sure the fuel screw in the bottom of the carb hasn't fallen out. This screw is prone to vibrating and falling out when guys crank them out too far. When it falls out the engine goes really lean, the combustion is slowed down and it burns in the pipe causing the flames and popping.

It's easy to check if this is the problem. Start the bike and put your finger over the fuel screw access hole to keep it from sucking air. If the bike settles down you'll know it's the problem.

Lonewolf · Apr 29, 2003

you said somethings that interest me, the lean condition and the buring of fuel in the pipe. i has a lean bog to it, kind of sounds like the boowahh a little bit, i runs better with the choke on, and the pipe got extremly hot within 30 seconds and sometimes there is a little bit of black smoke not much that is coming out of the pipe. im just really ticked off, in fact if things dont get any better i dont want the bike but i dont know if there is away out of the loan. my mom said that you usually have 3 days to get out and i bought it last night.

Rich Rohrich · Apr 29, 2003

The fuel screw costs $27 US and takes 2 seconds to install. Don't give up hope.

Smitty · Apr 29, 2003

Would an open hot start circuit cause similar conditions? Check to make sure the hot start is pushed in.

Rich Rohrich · Apr 29, 2003

Sure it would have the exact same issue. Good call Smitty.

JasonJ · Apr 29, 2003

Dude, let me know what you find, I want to see if I can get flames to shot out of my pipe!

Brianc · Apr 30, 2003

Originally posted by Lonewolf
im just really ticked off, in fact if things dont get any better i dont want the bike but i dont know if there is away out of the loan. my mom said that you usually have 3 days to get out and i bought it last night.

Call the loan company and tell them not to pay the dealer. Tell them you purchased the bike with the understanding that it was in running condition, which it is not. Most states have specific laws regarding the good faith understanding that the dealer must disclose the fact that the vehicle is running or not. All of the bike shops around here run their used inventory to eliminate that kind of problem. Take the bike back and make the dealer fix it for free. Call your Attorney General Office, they will help you for free. Dealers that treat people like you were treated give a bad image to the industry and deserve all the legal heat you can apply. They are no better the the old slime bucket used car lots of the past. Make them fix it.

Camstyn · Apr 30, 2003

LOL, why not just bring it back to the dealer and see what they're willing to do before you call in the national guard?

mikeolichey · Apr 30, 2003

I agree. Give the dealer a chance. It can be something as simple as bad gas. I had a 426 that would do what you describe (shoot flames, foul plugs) if I tried to use the oxygenated (ethanol) gas they mandate here in the winter.

mikeolichey · Apr 30, 2003

Oh-one easy thing you can try now is put in a new plug and see if it gets better. Keep the old plug. Is it black and sooty looking?

Moto Squid · Apr 30, 2003

Originally posted by Camstyn
LOL, why not just bring it back to the dealer and see what they're willing to do before you call in the national guard?

exactly...call your salesman and say "hey, my bike is doing this this and this and I'm not happy. When I bring it in can you have one of your guys look at it right away so I can then go riding :thumb: " If you're nice they'll probably be accomodating to you

whyz · Apr 30, 2003

Originally posted by JasonJ
Dude, let me know what you find, I want to see if I can get flames to shot out of my pipe!

That's funny,, You could tap a hole the same size for a sparkplug,Screw it in there and hook it up to a coil with a handle bar switch.battery or whatever that makes it spark.
Give her gas and hit the switch:flame: KaBoom!

:laugh: That would look pretty cool in the dark.
I'd probably burn down my garage though :confused:

flynbryan · May 1, 2003

Originally posted by whyz

That's funny,, You could tap a hole the same size for a sparkplug,Screw it in there and hook it up to a coil with a handle bar switch.battery or whatever that makes it spark.
Give her gas and hit the switch:flame: KaBoom!

:laugh: That would look pretty cool in the dark.
I'd probably burn down my garage though :confused:

:scream: O god if some enviromental extremist comes in here right now we're SCREWED! :eek:

JasonJ · May 1, 2003

Originally posted by whyz

That's funny,, You could tap a hole the same size for a sparkplug,Screw it in there and hook it up to a coil with a handle bar switch.battery or whatever that makes it spark.
Give her gas and hit the switch:flame: KaBoom!

:laugh: That would look pretty cool in the dark.
I'd probably burn down my garage though :confused:

Heheh,,, dont laugh, I have a set of the OEM fuel injectors from my Mustang and the stock fuel pump, I saved them to see if I could tap spark plugs into my tail pipes,,, Oh, you want to tailgate me ehhhh???? FaaaaWHOOOOaaaaaaaaappp. :) .
This is for on road use of corse so the greenies need not fear scortching of rocks or anyting,,, unless they feel pavement is a natural resource since it has gravel in it :)

Just kidding,,,,,,,,,, maybe!

Brianc · May 3, 2003

Originally posted by Camstyn
LOL, why not just bring it back to the dealer and see what they're willing to do before you call in the national guard?

He did call the dealer. Read his first post, the dealer said no warranty. He posted his concern after the dealer refused to help.

Brianc · May 3, 2003

Originally posted by Moto Squid

exactly...call your salesman and say "hey, my bike is doing this this and this and I'm not happy. When I bring it in can you have one of your guys look at it right away so I can then go riding :thumb: " If you're nice they'll probably be accomodating to you

In his original post he said the dealer would not help

shifting · May 3, 2003

I feel your pain lonewolf. I bought my crf new from the largest dealer in town thinking I would be set up from there. I'm at 4800ft ele. and the jetting was still set at sealevel, stock. So, I decided to set my jetting corectly starting with my main jet. Full wide open 4th gear, pull clutch, hit kill button and let off gas at same time. Pulled my tank and spark plug wire and thought I would look down in there just in case. Guess what I found? Dirt and what looks like a pice of a shop towel!!! :flame: To say the least I lost all faith in them and wonder about the rest of my bike. Sorry to hear about your problems but don't feel alone.

WVWWVWVWWVW · May 5, 2003

I know your pain as well. Picked my bike up a couple of Saturdays ago and after 3 days of intense pain trying to get the thing to work, it blew the rings and scuffed the piston all to pieces. The problem is either the shop used terrible fuel in it, didn't put it back together properly or it was terminally ill right from the factory. I know she's a two-stroke but that doesn't make her bad.. I think. I called the loan company and they pretty much said get lost and that they would do nothing... everyone loves screwin me over... must not scare people enough. I just decided to stop by thumper central and see what life is like having a bike that doesn't blow itself to bits every 20-30 hours... must be nice for you guys to be able to ride instead of service and maintain your bikes like me and the poster seem to have to spend a lot of time doing (I know a four stroke is the main problem but it isn't engine related... Maybe god rides a quad and he is trying to tell us something....

smarttoys · May 6, 2003

He did call the dealer. Read his first post, the dealer said no warranty. He posted his concern after the dealer refused to help.

In his original post he said the dealer would not help

I fail to see where the original post said that the dealer wouldn't help. It sounds more like he assumes that the dealer won't help out because of the no warranty thing. Even though the bike is sold without a warranty, the bike is expected to perform reasonably well when leaving a dealership. Any decent dealer will take care of it warranty or not. I know our dealership would.

Lonewolf, what you needed to do was take the bike to the dealership and show them and explain to them what is happening. It would have been best to take it there the next day.

Shawn Mc · May 14, 2003

Heres the problem and Im surprised Rich didnt catch it.

The dealer said "somebody must have jetted it"

Well, I can tell you right now, (if the fuel screw is in the bike) what happend.

Somebody took the slide out and put the face of the slide back in upside down. Is super easy to do, and actually looks correct when assemebled. I did this very thing while I was cleaning my carb on my YZF. I chased that condition for 2 and 1/2 hours before I figured out what I did. I raised the float level and it got better,screw out, a little better, but it was way wrong.

spittng flames out the pipe, backfiring like craziy and throwing sparks too!!

Check the slide face in the carb, I'll bet you 10 bucks its upsidedown.

Lonewolf · May 15, 2003

i totally forgot about this post. i took the bike back to the dealer and had them look at it and it was the fuel screw that one of you guys mentioned. there was no charge for what they did but i think it was because i started to cause a little bit of a scene in front of customers at the dealer when i took it back to have them look at it. what really makes me mad is the fact that it went unoticed when it was at the dealer. you would think a dealer would at least start it and check it over before accepting it for a trade. the day i bought it they said they were going to push it back service to get it ready for me, i dont think they did anything to it. they said they changed the oil which they might have did because the drain plug was loose and leaking oil so i had to tighten it up for them. thank you all for showing your concern and willing to help me.

Rich Rohrich · May 15, 2003

Originally posted by Shawn Mc
Heres the problem and Im surprised Rich didnt catch it.

It looks like I did catch it . :confused:

OldManIn · May 15, 2003

It sounds to me like you just need to go through a jetting procedure. Also, the hot pipe is normal for the high compression 4-stroke bikes. Mine will glow in the dark within seconds of starting it. Go over to thumpertalk.com and look under the 250F section. There is a lot of good info on jetting the bike and setting things up on her. Once you have things dialed in you won't be sorry you purchased the bike.

Have patience and Good Luck.

BSWIFT · May 15, 2003

Originally posted by Rich Rohrich

It looks like I did catch it . :confused:

:)

250f is backfiring, popping, and shooting flames

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