Alright guys i have an 05 400ex and i just moved to michgan from colorado. I know the elevation is way lower here so could that mess up my jetting enough to make to flood/foul spark plugs? I just put a new one in it two days ago and it already shot craps. Also could standing it up on the grap bar with the gas on do this to the plug? I tring to get this figured out asap so i can go to Silver Lake dunes on saturday so any info would be great. Thanks

Eli

 

Don't ride the bike until you get a rejet! You are running lean and will toast your engine. More air at lower altitude, requires more fuel to keep the mixture correct. You need to jet up.

 

Depends on where in colo it was jetted for. If it was jetted for high altitude, then it will be too lean, at sea level. Thats something that should be taken care of.
If it were running too rich, its not a big deal...that only wastes gas, nothing will break. But running lean can really screw up a motor, if allowed to happen for a time.
Do you have any symptoms of the motor running lean?


Typical Lean Conditions:

- Poor acceleration; the engine feels flat.

- The engine won't respond when the throttle is snapped open, but it picks up speed as the throttle is closed. (A too-large main jet also mimics this symptom.)

- The engine runs hot, knocks, pings and overheats.

- The engine surges or hunts when cruising at part-throttle.

- Popping or spitting through the carb occurs when the throttle is opened. Or popping and spitting occurs through the pipe on deceleration with a closed throttle.

- The engine runs better in warm weather, worse in cool.

- Performance gets worse when the air filter is removed.

 

I couldnt tell you if i have any of those. I havnt had a chance to ride it sence iv been here. So you guys thiunk the problem is with the jetting? If so what should i do to correct it? Can i adjust the ones in it now or do i need to buy a new jet kit. I probably will do the jet kit anyways so what should i look to get?

 

Well, like i was saying, its posible that it wont need any changing. The only way to know, is to drive it and see if it experiences any of the symptoms of lean. Then youll have to pull the carb apart, and look at the size of the main jet (its stamped with a number), and get one or two bigger. Then drive some more ,and see if the symptoms have gone, and if not, go bigger.
The mixture screw should take care of the idle circuit, with an adjustment.
It wont hurt it to ride a bit, and see how it goes. If it shows signs of lean, then it needs to be richened up.

 

Alright man thanks for your help. Ill see what i can find out today when i change the plug out. Ill try and ride it some but i dont know if i will be able to being in town and all but ill do my best. Thanks again for your help.

Eli

 

Well guys i talked to the dealer today and they said it was jetted for sea level so i know thats not the problem. I put a new plug in it again today and rode it alittle and couldnt find any of those syptoms so i think it was caused by a crappy factory plug and me flooding it the second time by standing it up with the gas on. Thanks for all the help again guys.

Eli

 

Wow, you rode it all that time in Colorado jetted for sea level? (What humiliation!) Your combustion chamber, valves, and exhaust are probably all carboned up, not to mention your plug.

I doubt it is a "crappy factory plug", seeing nobody else ever has that problem. If it's an NGK, they have excellent quality control. Is your plug in the correct heat range??? A to cold plug will run dirty.

You also may have a change in fuel types between the two locations.

 

How was i to know it was jetted for sea level? I figured the whole time it was set for colorado so im not humilated at all. I havent had the thing more than 3 months and dont ride it that much so i dont think i have anything to worry about carbon wise. There may be some build up but not rear as much are you seem to think. Everything is fine now so i dont need to worry about it anymore. Also the factory plug was not an NGK either it was some off brand ive never heard of so it may have been. I have NGK in it now.

 

The only way to know, is to take the float bowl off, and the jets out. The sizes are stamped on the jets, then compare that to stock. Unless, someone drilled out the jets bigger, then you wont know. But if anything, the jets would be too small, because when they rejet for alt., the main jet is smaller than stock size.