Im Buying A slip on I have few very easy questions

[400exrapes]

Yeah im buying an hmf sport series slip on. My Father and I want to know all the information about the jet kit and sizes. Im aware i need to rejet my quad, if I buy the hmf basic jet kit will it include all of the parts I need to do so? If not what are all the parts I need to rejet with an hmf slip on?

[400eXr1d3rZ]

I suggest you go to www.jetsrus.com and buy an individual Keihin jet. What is your elevation, average tempatures, and other performance mods (piston, cam, aftermarket airfilter etc...) Is your lid on or off?

I suggest you start with a 152 main and 40 pilot, 2 1/2 turns out fuel screw from lightly seated.

[400exrapes]

i have no other engine mods, it will just be an hmf slip on. The elevation is about 400 feet above sea level and average temperature in the summer its high 80's low 90's, in the winter its between 5-32 most of the time so im not too sure what to tell yoiu on that

[400eXr1d3rZ]

I say start with a 152 main (buy a 155 main also) and a 42 pilot. That should get you in the general area, and might even be perfect.

2 1/2 turns out fuel screw from lightly seated.

[400exrapes]

alright Ill buy a keihin 152 main and 155 main. Whats the Pilot? Is that its official name because im looking in my owners manual and i dont see the pilot jet

[400eXr1d3rZ]

Originally posted by 400exrapes
alright Ill buy a keihin 152 main and 155 main. Whats the Pilot? Is that its official name because im looking in my owners manual and i dont see the pilot jet

It might be labeled as a Slow Jet.

[ImplodedMindZ]

maybe this picture will help you out Slow
jet (http://www.imagessite.com/OEM_Images/honda_atv_images/H99TRX400EX19.gif) Its labeled as #37 next to the main.

[400exrapes]

okay nice i purchased everything now all i have is one last question. Jetsrus.com, How long will shipping for a 42 slow jet and a 152 Main Jet take?

[400eXr1d3rZ]

Roughly three-to-five days.

[450r ride red]

i have a hmf slip on my ex i just got a 160 main works perfect

[400eXr1d3rZ]

Originally posted by 450r ride red
i have a hmf slip on my ex i just got a 160 main works perfect

You're also like 1000 miles away too, it's different for everyone.

[idro]

i got a 155 mj, with my fuel screw 2 more turns out. got the spark plug pretty close. all i have is a hmf pipe

[Ruby Soho]

does the jet size matter with what modifications are done to the engine?

[400eXr1d3rZ]

Originally posted by Ruby Soho
does the jet size matter with what modifications are done to the engine?

Yes.

[Honda#4]

You will be to lean with a 152 main put in the 155 main and adjust your screw accordingly.

[400exrapes]

I already got the 152 and I didnt order a 155 what does lean mean?

[400eXr1d3rZ]

Originally posted by 400exrapes
I already got the 152 and I didnt order a 155 what does lean mean?
You get too much air and not enough fuel, rich means too much fuel and not enough air.

[6858-400ex]

start out richer on your jet size, it is always better to be rich than lean. i live around 3000 ft. i have a 170 main jet

[400exrapes]

alright well i dont want to get disapointed yet, we it end up messing my engine up or will it just make a slight difference i might not notice?

[stvemerz]

Just my 2 cents..I ordered the HMF sport series...It comes with a Keihn 42 pilot...152 main...I have a stock 400 ex 2007...With UNI filter..after a lot of playing around...the 152 worked great...but after a full day of riding..It was a little to lean..155 keihn really works great with just the slipon...The rest can be dialed in with fuel screw..2 turns out for me......That should get you going pretty well...

[400exrapes]

alright well im going to try out the 152 main, if i leave it like this am i just missing out on slight power or will i mess up the engine

[400exrider113]

well there is a chance that you can hurt the motor if your running really lean but the motor prob. wont start

but if your running rich which is too much fuel not enough air you should hurt any thing it is always better to run rich than to lean

[400exrider113]

oh and keep checking the plugs

lean = white or gray
rich = black or dark brown, Wet or sooty
perfect = light brown,

here's a perfect plug..

[hornetgod13]

Looks a tad rich to me. Try a size smaller.
This is much better.

[400exrapes]

alright well two things.
1.Lets say I keep the 152 Main Jet in, What Can I do to make the jetting or spark plug perfect?
2.I was gonna ask how to get the spark plug but i got the owners manual

[hornetgod13]

The 152 main jet may or may not be the best size for your quad. It depends on a lot of variables like, temperature, altitude, and other engine, exhaust or air intake mods. Once you install your new exhaust, put the 152K jet in and test ride it for a while. Afterwards, pull the plug and see what color it is. The color of the spark plug and the "seat of the pants" test riding will let you know if you need to change it a size up or down.

[400exrapes]

alright well all i have is a slip on exhaust pipe and thats the only engine mod im like 400 feet above sea level and the temperature is 0-35 degrees for the next month and then in the spring and summer like 40-95 degrees normal temperatures

[makale 400ex]

i had an 05 and i bought a TC slip on with air filter and no lid and i didnt have to mess with the jetting at all.
makale

[400exrapes]

well im def jetting it ive seen the results of my friends quad who didnt rejet and his quad is continuing to get worse and worse

[hornetgod13]

Originally posted by makale 400ex
i had an 05 and i bought a TC slip on with air filter and no lid and i didnt have to mess with the jetting at all.
makale

I seriuosly doubt your quad is jetted correctly. How did you check it? I bet your quad is running quit a bit lean. Running lean will generate a considerable amount of additional heat and can impact the long term durability of the engine.
Anytime you open up your air box, install a hi flow filter, add a full or slip on exhaust you should rejet to ensure the engine is running properly.

[Honda#4]

No quad is jetted perfectly with just adding a pipe and filter on.

What can be a perfect jetting one day can be the total oppisite the next.

[400exrapes]

why does hmf's website recomend such a high main jet i looked just for an idea and only like the newer models have to 152 main and 42 pilot they recomend like a 165/170 for a 2001 or 99-03 are they way off or should i have told you what year my quad was

[hornetgod13]

A 152K or 155K main jet should be close for your set up. The year doesn't make a difference.

[makale 400ex]

i didnt do it. my cousin did when i bought all my **** for it. hes a mechanic, has his pro card, and has a teaching class for kids just learning to race. i think hed know if it was jetted rite.

[Eviltanker]

Dude your about the same elevation and temps as me. I ran a 152, Needle in the 2nd, and a 40 and 2 to 2 1/4 ish turns out

[400exrapes]

alright so if were at the same elevation and temperatures then a 152 with needle in stock position with a 42 pilot should be good/close to perfect?

[makale 400ex]

i never changer elevations. ya no crap u would have to re jet it for elevation changes im talkin about where i live and race.

[hornetgod13]

Originally posted by makale 400ex
i never changer elevations. ya no crap u would have to re jet it for elevation changes im talkin about where i live and race.


?:confused:?
What are you trying to say?

I'm helping 400exrapes rejet his quad. Makale 400ex you are right about having to rejet for altitude changes. Each quad and situation is different however, if you add a slip-on exhaust, hi-flow filter, and/or remove the air box lid, you should rejet. The additional airflow will make your quad run lean. Your quad needs more fuel to compensate. Running your quad lean will eventaully kill the motor long before it's time. If you don't rejet that's your call and your motor to replace. Do what you want, it's your money.

[400exrapes]

hey man i appreciate the help but no dissing hortnetgod13 he's the man you cant do that

[hornetgod13]

It doesn't bother me. If he chooses not to rejet when he should than that's his call but, I just don't want others to think they don't have to rejet if they do significant changes to the air intake or exhaust systems. They must rejet to ensure the engine continues to run smoothly and last as long as it should.
Rejetting is not that hard. I was intimidated at first and I know why some people are hesitant to do it. Once you actually do it, you realaize it's not that hard at all.

[400exrider707]

just listen to what hornetgod is saying...

if you put a pipe/filter/remove lid and dont rejet... thats just plain ignorant! Almost every quad sold is sold from the dealership lean to begin with to pass emissions.

[400exrapes]

yeah dude i knew basically nothing before i got my quad and then as soon as i got it about three months ago i wanted to learn everything i could learn and one of the most important is to set your carbuerator to the right main/pilot jet otherwise your going to get poor engine performance just like my friend who put alot of money into his 300ex with just a slip on pipe his quad has lost all its power down to where he loses races to the stock blasters

[idro]

Being a mechanic and knowing quads is 2 different things. I'm qualified to work on multi-million dollar aircraft, but i had to come on here asking all sorts of questions... its called being humble :P