Bike will not stay running!

Hey I need some help this morning. My 450 will start and run for a little while before it pops alot on decel and dies. Once it dies I normally cant get it started again (I put a hole in my shoe trying to kick it so many times). I have had a problem with it running rich, and was going to try to work on that problem (I have had the bike apart all summer, and have done lots of maintinance to it), but now it seems much worse. Is this a carb problem? I do not know what jets the previous owner has in it, but today Im thinking about pulling the carb and replacing the jets with whatever my local yamaha dealer recomends I put in there. Another posibility is old gas, I have almost always been good about putting fuel stabilizer in my gas if I wont be burning it in the next month, but I am just not sure if I added it to the gas that sat in the bike. Im going to get fresh gas in the next 30 mins, so hopefully this will help.

Any thing to look into/advice?

Also are jets and a carb rebuild kit (gaskets etc) normally in stock at most dealerships?

Try draining the carb and then restarting. My '03 has a similar problem where if I'm idling or going very slow the engine will die. But if I'm on the gas hard I have no problems. Could be a float level issue?

I'd think the jets and carb kits are at you local dealer.

Good luck.

Thanks for the help, its definitely encouraging. My best friend (Grieby54 on TT) bought his first bike, a CRF450, last night. I am just pressed to get my bike running so I can go out to the track with him tomorrow.

So far the carb, suspension, and bottom end of the motor are the only things I have never really messed with. So I guess today is carb education day.

Im sure this will not be the last question I ask today, so thank in advance for the help.

Ok, today I pulled the carb and cleaned it out really well (it was pretty dirty). I have it all installed and hooked up, but the hot start connection keeps coming out. I have removed the carb and put the hot start cable back in there twice, but it just comes out again. Is there a secret to getting the cheap rubbery plastic to thread and stay?

I kicked and kicked and the bike wont start with the wire not connected right. At the moment the lever is really hard to pull (but its easier when the cable is connected correctly). Is there any kind of adhesive I could put on the threads to coax it to stay? such as a little bit of weather-striping adhesive?

Sigh... there is always something else that will go wrong. Ive had this bike apart all summer and its starting to look like I will go an entire summer without riding (even though riding is the ONLY thing I wanted to do this summer). I'm going to mess around with it some more tonight when I get home, hopefully I get the hot-start in and the bike finally works.

Sounds like the plastic nut is stripped out - I have done this a couple times - you will have to replace it = I suggest ZipTy Racing for the alum nut - which is must better

The bike will run like crap with it like it is :thumbsup:

Alright, im going to try some teflon tape, and if that doesnt work... ZipTy nut it is.

Haha hopefully im not pulling an all nighter in the garage just so I can ride tomarrow. I know that if I cant get mine going Grieby54 will share his bike with me (he rode my 250F for like 6 months), I just wanted to be able to play around and race with him a bit.

If I have more questions I will keep you guys posted, thanks for the help. Your the plural form of "THE MAN!"

Yeah that plastic piece where the hot start cable goes is really cheap. Mines cracked and striped before trying to replace the darn cable, you just gotta buy a new one. And for the pop on decel and die issue I'm not sure, but sounds like a possible carb problem. Good luck

Have you checked to make sure that the gas tank is venting properly? If not, you will continually run out of gas in your carb even though your tank may be full.

Supafreak - Did you get the bike running?

Ga426 - How will the disconnected hot start cause the bike to run bad? I assumed it just would not allow the use of the hot start lever.

Ok, today I pulled the carb and cleaned it out really well (it was pretty dirty). I have it all installed and hooked up, but the hot start connection keeps coming out. I have removed the carb and put the hot start cable back in there twice, but it just comes out again. Is there a secret to getting the cheap rubbery plastic to thread and stay? I'm going to mess around with it some more tonight when I get home, hopefully I get the hot-start in and the bike finally works.

If the hot-start wasn't in properly before, that's a good reason for your bike not to stay running; too much air! I was also gonna ask if the fuel screw had fallen out, which would also result in too much air. Once you get that sorted, it should run ok, hopefully. While you're at it, put grease on the plunger to keep it working well and to help keep water out to prevent it siezing up.

So much for my advice ........... I got thrown off of my 03 470 after I landed off a jump yesterday and it bogged out....with a lot of compression it stopped dead and I went flying.....damn float bowl. Ouch :thumbsup:

If you still have problems after you fix the hot start, I would put in a new ignition coil or swap with someone else. All YZ and WR 450 take the same coil. Older models supercede to the newer models coil.

I chased Jetting issues on my WR for a year before I swapped out the coil to fix it.

Most likely the Hot start was leaking and allowing the bike to draw additional air which will m,ake it run really lean. That should solve it.

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