Need help!!!

[jacob.jd7]

I have a 07 trx450er it has a hmf slip on k&n air filter aluminum air box and a hrc kit. Well last time I rode it was running fine and it just randomly started stalling and finally it just wouldn't start so i changed the gas thinking it was bad gas so i drained and today after i put new gas in it still wouldn't start at all. I just got it back from the Honda shop the valves are in spec and they said the carb was clean. Do you guys have any idea what it could be

Thanks, Jacob

[LeGaCyGiAnT124]

I have a 07 trx450er it has a hmf slip on k&n air filter aluminum air box and a hrc kit. Well last time I rode it was running fine and it just randomly started stalling and finally it just wouldn't start so i changed the gas thinking it was bad gas so i drained and today after i put new gas in it still wouldn't start at all. I just got it back from the Honda shop the valves are in spec and they said the carb was clean. Do you guys have any idea what it could be

Thanks, Jacob

Do you have spark?

[blacknblue#2]

agreed check spark. If you have spark then run a conpression test. Just because the valves are in cpec dont mean you have enough compression. Rings could be shot.

[jacob.jd7]

Well I feel stupid lol I changed gas and just ran straight 93 pump gas because I have a 45 minute drive to get sunoco gt100 and a friend wanted to ride so I just put 93 in it. I'll never do that again..

[jacob.jd7]

Well after changing the gas it ran for a few minutes and its back to the way it was it runs sometimes sometimes it won't. Could it be a accelerator pump or a jet clogged or what?

[jacob.jd7]

And the rings are good

[LeGaCyGiAnT124]

And the rings are good


If the 93 is fresh, that's all you need for your mods you have. Does it have any internal work done? You only need higher octane with a high compression piston. Make sure you check all of your wiring. This sounds like an electrical issue. My guess is that you have a worn wire somewhere, a stator starting to go out (shuts off when it's warm), or a faulty CDI.

[jacob.jd7]

I bought it used and he said there was nothing done internal expect hrc cam. I justcalled my local Honda shop and talked to the mechanic and he said intake valves could be tighting up once it gets hot but I always thought it expanded once it gets hot not gets tighter

[kbass24emtp]

Put some SeaFoam in the gas. Shake the quad to mix it up in the tank and try to start it. If it starts let it idle for a few minutes and then go run it. It sounds like your carb is gummed up. I always turn the gas off and let it run until it dies to get all the gas out of the carb and I have never had a problem letting it sit. Also with your mods 93 is all you need. Now unless the sunoco gt100 is leaded gas I would run that over the 93 because your valves will last longer. If your rings were shot your quad would smoke. It would have to sit a long time to seize a ring.

[jacob.jd7]

Put some SeaFoam in the gas. Shake the quad to mix it up in the tank and try to start it. If it starts let it idle for a few minutes and then go run it. It sounds like your carb is gummed up. I always turn the gas off and let it run until it dies to get all the gas out of the carb and I have never had a problem letting it sit. Also with your mods 93 is all you need. Now unless the sunoco gt100 is leaded gas I would run that over the 93 ubecause your valves will last longer. If your rings were shot your quad would smoke. It would have to sit a long time to seize a ring.


If the carb was gummed up wouldn't it not start at all. Its starts right up after its sit all night but slowly builds a bog. Could this be because the gas has time to sit in the carb and build or what? Sorry guys im new to 4 strokes I've always rode 2 stroke bikes

[blacknblue#2]

Put some SeaFoam in the gas. Shake the quad to mix it up in the tank and try to start it. If it starts let it idle for a few minutes and then go run it. It sounds like your carb is gummed up. I always turn the gas off and let it run until it dies to get all the gas out of the carb and I have never had a problem letting it sit. Also with your mods 93 is all you need. Now unless the sunoco gt100 is leaded gas I would run that over the 93 because your valves will last longer. If your rings were shot your quad would smoke. It would have to sit a long time to seize a ring.

While the symptoms he is explaining now dont seem compression related I will say that i have seem many of these 450 motors reach the "wont start" phase before they will smoke due to a bad top end so just because you aint smoking dont mean you dont need a top end. These motors dont hold oil in the crank sump. Any oil laying in the sump is forced back into the stator cover when the piston is on a downward stroke. So that makes it hard for a case of bad rings to vacuum enough oil to the top of the piston to cause noticable smoke....Now is this the same Honda tech that told you your valves were in spec prior? .006 +/- .001 is "in spec" so even if they were at .005 then heat is not going to cause your valves to move .005. Honda took all that into consideration when the tolerances were engineered. Personally i wouldnt run anything through it. You know you have fresh gas in the tank. I would pull the carb and visually make sure every jet and circuit is clean. If that dont fix your problem then Its definitely electrical. But a carb clean is basically free. Any of these electrical components can fail when they warm up

[blacknblue#2]

OOOOHHHH and another thing. If you have a stubby vent hose on your gas cap PULL IT OFF. I dont know how many times i have seen those things fail and cause the gas tank to vacuum not letting gas get into the carburetor

[jacob.jd7]

I think I am going to clean the carb by myself and I have a standard gas cap. And also could my spark plug be bad. Sometimes it will get spark sometimes it won't

[jacob.jd7]

Alright well I called my local Honda shop and they told me my valves was in bad shape but they put them in spec. It turns out I have a stuck intake valve according to them