small issue

[bigbad400]

i just did the 440 kit on my 400 about a month ago now and i have it running good, the pilot is 42 and the main is a 170 the needle is on the second from the top position. fuel skrew at 2 1/2 out.

my issue is that i heard, and the manual suggests not to move it past the 4th up and i have it in the 5th, what is the reasoning for that and what would i have to do to make it run the same but put things in proper order?

i wouldnt think that i should drop my main any more on a 440 i ran a 170 dynojet main in it with stock bore and piston. it just seems funny to me that nothing changed much. i even think that for summer im gonna use a 40 pilot because it seems rich on hot days with a 42.

i figured a 440 would need alot more gas than the stock would.

am i just goofy or is everything ok. plug looks nice and with a 175 main it stumbled on top a little, but not with the 170.

[honda400ex2003]

if it runs good and the plug looks good then there should be no worries. i run my needle on the second position along with quite a few others. good luck, steve

[bigbad400]

i 170 DJ is the same as a 190 keihin?????? that makes no sence at all how would my stock motor run good with that? now im really lost on jetting.

[mcgrath]

If your bike runs good and the plug looks good, Id leave well enough alone. I just use keihin jets it saves alot of confusion. For me anyways.

[TRXRacer1]

Time to drop some science!

Now that your engine is 40cc's bigger it takes bigger breaths. Those bigger breaths result in higher velocity. Higher velocity results in a pressure drop in your carb. The lower pressure results in drawing more fuel. Basically you just made fuel go through your carb faster then it did before. On paper you could be fine with the jetting you had or need leaner jetting. Your carb is going to act differently then it did before because you just mounted a different engine up to it. Forget what the jetting was and just make it right for what you have now.

[bigbad400]

thanks trxracer, thats good advice right there, i never put the dj kit in it was in when i got it i just had to move the main one when i did the hmf and the air box. i always use keihin jets.


so if my needle is up to hi and it uses the main would i be able to drop the main one and move the needle back to middle?

or is this just to much worrying and im fine as long as everythings running good?

[mcgrath]

For sure you could try. Thats the whole deal with jetting, trial and error. Make a note of where you started and mess around with it a little. As long as you know where you started, you can always go back to where you started if you need to.