Lots of Questions

[Rohr397]

Okay so I am still pretty new to 400ex's as far as working on them goes (I say this because we had a 400ex for about 3 years before I got mine but it was 100% stock for my mom). I have a lot of questions so here it goes.

1. I am trying to find a good basic graphics kit for my quad that I can have printed with sponsor logos. Something like Fusion Graphix but for a quad. Anyone know where I could find that?

2. I've noticed as the temperature has dropped it's become hard to start my quad. I know that sounds dumb because it's pretty obvious the colder it is the harder it is to start but I'm noticing that my quad won't idle and backfires when I am trying to get it started. I also just added a new exhaust and have a little popping on decel. I'm assuming it's a jetting issue but I am terrible with jetting so what should I try? Plugs don't seem to read abnormal :confused:

3. So I've decided to go with Sparks Key and a Stage 1 cam for some extra power, might as well if I'm going to race with the 450's on a tight budget. What cam's are good? I know that Hot Cam's are good but I was thinking about looking into some of the smaller companies that build parts for dune quads, like Trinity Racing.

4. Finally I hear a lot about people adding cooling fans to their 400's. I already have a Mickey Dunlap oil cooler, but I run in triple digit temperatures sometimes during the summer (Eastern WA) and I've overheated a Trx450r out there without even running it hard. I was wondering where I could pick one of these up? I know people probably don't think I need it but I would still rather be safe then sorry.

[DragonGunner]

1. Try goforitgraphics.com

2. Go up to a 42 pilot jet for easier starting, go up on the main jet because your running lean. If you have stock main jet,(148) jump up to a 165 an try that.

3. Hotcams are good to go. Suggest a higher compression piston also.

4. ?

What kind of racing...MX, XC...I raced alot of yrs. agaisnt the R's...its tough, I liked 18" tires in the rear an 16/38 gearing if top end isn't a issue...you can corner an accerlate better, but you have to be a better rider or it won't matter...good luck.

[01boneless]

i had g4it graphics on my ex there good but way overpriced and no logos. 42 piliot is great should richn you up just right!.

1. contact weast coast graphics.com they have awsome graphics with sponcer logos ill post a pic of mine below.
2. your to lean poping on decel is a sign and the hard start is from cold being lean. in the winter you always wanna richn it up a little cause the cold weather makes it a little lean . (choke is a good thing to have)
3. stage 1 cam is the only way to go. not many other cam makers for the 400 anyway. the hotcam is great.
4.ALOT of people run the fan on stock ex's because the air cooled motor runs hot from the start. Go on ebay type 3in spal fan. there is awsome threads on how to install it on the cooler. they run about 20-30 bucks

[Rohr397]

Okay I will try that with the jetting stuff, I have no choke so that doesn't help. As far as graphics go I like the ones you suggested but will they actually let me pick what sponsors I want on there? I got sponsored by DNA Energy and they don't have stickers so I have no way of putting there stuff on my bike without getting a graphics company to print their logo onto a graphic :/

[Rohr397]

Also to answer your question here's what I'm looking at for racing.

MX-Production C class and Modified 400, WORCS and some dune/desert events.

All but the MX races are long endurance races rather than sprints, and my 400 has more power than either of my 450's (Basically stock Trx and High Comp YFZ). I just want to make sure I'm right there with these 450's.

[01boneless]

dont know of any that will let you pick your sponcers. 11:1 hotcam stage 2 (my setup) would keep you right with a stock 450 . but the key and stage 1 will keep you on there A** :devil:

[DragonGunner]

Originally posted by Rohr397
Okay I will try that with the jetting stuff, I have no choke so that doesn't help. As far as graphics go I like the ones you suggested but will they actually let me pick what sponsors I want on there? I got sponsored by DNA Energy and they don't have stickers so I have no way of putting there stuff on my bike without getting a graphics company to print their logo onto a graphic :/

I took my choke out, an the 42 will work perfect, when really cold you may have to give it a couple pumps on the throttle to start an then it will idle right up. Your long races like some of my Grand Prix races are more about suspension set up an endurance. Try an get by with 4 ply tires as the 6 ply are very heavy an ROB horsepower.

[B.C.#11TRX400EX]

Curtis Sparks makes a good cam I hear but I think a hot cam stage1 would be good enough

[Rohr397]

I took my choke out, an the 42 will work perfect, when really cold you may have to give it a couple pumps on the throttle to start an then it will idle right up. Your long races like some of my Grand Prix races are more about suspension set up an endurance. Try an get by with 4 ply tires as the 6 ply are very heavy an ROB horsepower.

Alright I'll go ask the dealership for a 42 main this week, maybe even tomorrow. They usually give my jets for free :p haha. As far as suspension goes my EX is setup pretty great with the full PEP/Lonestar stuff. I'm thinking about 19 inch rears and 20 inch fronts so I am not too big for MX or too small for desert. Anything over 21 is just too big for me, I don't like cornering with that much tire.

[DragonGunner]

Originally posted by Rohr397
Alright I'll go ask the dealership for a 42 main this week, maybe even tomorrow. They usually give my jets for free :p haha. As far as suspension goes my EX is setup pretty great with the full PEP/Lonestar stuff. I'm thinking about 19 inch rears and 20 inch fronts so I am not too big for MX or too small for desert. Anything over 21 is just too big for me, I don't like cornering with that much tire.


Don't get a 41 main...lol....a 42 pilot jet. I run 20" up front also, good choice....I really like the handling of the 400EX, the 450R always feels like its too high. To get more power you can always fabricate a KTM 520 into the frame...I did.

Actually its called a SLOW jet, not pilot. Stock is a 38, go with the 42. I also raised my needle one notch, by lowering the circlip one notch. Lets a little more gas in...I did this after putting a aftermarket pipe an air filter on.

[Rohr397]

Lol oops I didn't mean to say main hahaha I was tired last night.