Stock main jet to lean?????

[Zingnut]

I recently read this on a webpage of tips and tricks. "From the factory the stock carburetor is set to run too lean with a 148 main jet. If it is not bumped to a 150 you will run hot (you will see the exhaust headers turn blue for half their length). This will cook the exhaust valve seals. You will know this when puffs of blue smoke are produced on backing off the throttle coming into a corner in a race. (blue smoke on acceleration is a sign of worn rings)" Is there any truth in this I went out today and bought a 150 main for 4 bucks and am planning either tonight or tomorrow night to run some plug tests. Just curious to hear if anyone else has heard this??? My mods are slight and can be found in my sig, but I would think they would need no jetting changes. Just wondering about the stock jets being to lean.

Thanks for any input on this matter.

[knighttime]

The Honda manual from www.helminc.com states that the 400ex comes lean from the factory. :(

with just the racing graphics you probably need to jump at least two jet sizes
you can expect 5-10hp from the graphics alone

[VegasEx'r]

Originally posted by DOD Racing
with just the racing graphics you probably need to jump at least two jet sizes
you can expect 5-10hp from the graphics alone

So if you put 2 graphics kits on your quad, will you get 10-20 more hp? If so, guess what I'm ordering today? :p :macho

[Zingnut]

"Geez!" Come on with real answers not just the smart *** comments. I enjoy them, but am wondering about the original question regardless.

[tj's400ex]

DOD,
what jets are you running? I have simlar mods as you and I just jetted last night but I won't have a chance to do a plug check till I can get out of town to ride this weekend.