where is cals400ex when you need him?

[northeast400]

I finally rode my quad this weekend. I took your advise and it was perfect. The only trouble is now I run with the airbox lid on(do to mud). I am at 520 feet above sea level. The quad is a 426ex,11:1 piston, 450/451 web cam, UNi filter, runs race gas, no choke, 40 pilot.Any suggestions before I start tuning. I could use anyones advise. By the way does no air box lid really make a difference?

[northeast400]

anybody?

[hondarider2006]

Well what size mj are you running? All I did was go down a from a 165-155dj(I was running the 165 with no lid in the winter, and run with a lid in the summer) so just go down a size, maybe 2 on the mj and you should be fine.

[northeast400]

I am running a 180 main jet now per Hmf

[zephead400ex]

What is the problem? Is it running too fat? lean?

Technically it doesn't matter if you are running a lid, but of course thourgh mud, dust, etc. it is a good idea to have the lid on. With the lid on, you are more rich. With the lid off, you lean it out. If you jetted without a lid and now have added a lid, you are probably running too rich.

Drop a couple sizes on the mj. But a desription of the problem would help.

later

[cals400ex]

i honestly wouldn't go that big on the main. i didn't tell you to run a 180 did i?? i would probably not run larger than a 165 keihin with the lid on and the mods you have to your bike. try the needle clip in the 4th positon and a 40 pilot might be alright. you could go larger if you wanted though. if you were to stick with the 40, i would turn the fuel skrew out 3-3.5 turns.


with no air box lid, i really found my all out performance for DRAG racing was no better. on a track the low end power was a little bit more crisp but overall power isn't as much as some people say. well, for drag racing it isn't anyways. i my 406 will run just as good dragging whether i have the lid on or off. however, i do make jetting changes for each. with the lid off i usually run a mainjet 1 or 2 sizes larger than with the lid on. many people think they feel a difference with the lid off because of the extra noise and vibration on the seat. i don't say the difference is drastic by any means...

sorry, i wasn't on the site any earlier today. i had to observe a doctor for school purposes.

[quadmx7]

yeah i think the 180 is too high with the lid on, i am running a 180 in my 426 with the lid off.

[northeast400]

No you did not, I did not make it clear. you said 40-42pilot, 165 main, lid off, and needle in 4th psition and it was perfect. pulled hard. I ran some oxygenated race fuel so I upped the the jet to a 180 main. I only wrote that because at the time that is what was in it. I just wanted some suggestions with the lid on and reguler race gas. GOD I NEED FUEL INJECTION!!! :blah:

[cals400ex]

fuel injection would probably be more of a pain to tune in than what you have. however, you could send it in and have someone else do it for some $$

[northeast400]

After checking all the other posts, jetting seems to be "the issue" after all this typing I played with it a little a 160 to 165 seems to work. I don't know why the guys at HMF said to use 180-200

[hondarider2006]

[i]I don't know why the guys at HMF said to use 180-200 [/B]


Their jetting specs are way to rich. I am running a 155 with my HMF slip-on

[quadmx7]

down here my cosuin's 400ex with hmf slip-on needed a 175.

[stupid driver]

i have a 178 in mine, my mods are below. I am at 1100 feet

[skemp]

HMF does what most of the other aftermarket companies do; suggest overly rich jetting specs to ensure that nobody will tweak a motor from running lean and blame them. They just suggest really rich specs.