jetting what do you think?

[kickass400exRI]

hi guys i was thinking about jetting my 400ex and getting a slip on my ? is it worth it? is there a good power diff? does the bike go threw more gas? is it good for the bike and why? thanks guys

[400eXr1d3rZ]

Bike will run lean and hot, a lean condition isn't good for your motor. It's best to jet when putting on anything that's changing airflow (even motorwork). I believe while lean the bike is starving for gas, and getting too much air. If you're getting a slip-on then start with a 152 main, 42 pilot, 2 1/2 turns out a/f screw and needle on 3rd clip (From top). What's your elevation/tempature? That can determine your jetting (155 for a piped/filtered quad in my area is perfect but if i was to go up north 'higher elevation' then i would be rich and would have to go down on the main)

[Def-e-nition]

...I hate coining a phrase , but i see this often on the posts - "what he said ! " .

Elevantion is Paramount to Anyone giving you advice - it will determine whether their information they provide would be relevant to your altitude or not .

i had my ex set up at 14.1 :1 That is a Light setting - close to be running too lean . Richer means More power , but also cooler engine . Which is good . So why I set it that high , is because i like fiddling ..... meaning I like to play with Jet sizes . So - I had it set up on a bike Dyno , got the guy to leave the lid on , and take lid off , give me both readings , and what jet sizes worked lid on , and lid off . 155 Dyno to 160 dyno , we saw it made around a.3 change on the c/o setting ( 14.1: 1 , down to about 13.6:1 ) So when i play , i can figure out more or Less where im heading to . Also - when the Airfilter starts clogging up in Dusty conditions , it makes the bike start to run richer ( as Less air is being let through the filter ) , and because we run in a dusty environment - i opted for the Light setting to compensate .

if you set the bike up for a Great 13.1:1 Setting and run a filter well oiled - pretty soon it makes the A/f run below that - far below that . would hazard a guess and say 12.4 and down . Then your bike starts sipping the juice , Plus , it will also wash out the sleeve , and I dont like that idea too nicely . this means that any small deposits of oil left on the sleeve are , to a SMALL degree , washed off by the richer , unburnt section of fuel not used in the combustion process . Not good . hello wear , bye bye money .

Anyhow , once you get into it , and believe me you will ,

;) , you'll find out how nice it is working on these bikes .

the Only thing that might throw your tuner off , is the fuel accelerator pump , which pumps fuel into the carb in a stream . I f hte guy blips the throttle - he's going to get an Overly Rich reading , try to compensate for that - and on the end - run too lean . im not at that level yet , but i pay as Much attention to what the guys are doing when they dyno my bike . around here , you cannot trust just anyone , Ive seen them hop onto a blokes bike and run it onto the rollers , nevermind warming the thing up - WHAM! , straight up to 8000 rpm . That day i promised myself -never agin would i leave my bike at a shop unattented .....

Anyway , I hope this helps you .
Pm gp racer 2500 , he's good with things like this . nice Bloke .