Back to sport quads and the 400. Trail build time.

[honda400ex2003]

im a woods guy myself, riding mostly in northern WI.

if i was to build one, good shock are #1.

2) stage 1 for the low end fun factor

3) slip on exhaust with the header welds ground down

4) 6 degree timing advance if you are going to leave stock compression piston in there. this timing advance also brings back some of the top end lost due to the stage 1 cam but you dont lose the low torque.

5) if you want to bore- 416 10:1 was my favorite of any i had. didnt really have to worry about heat while cruising slow in the twisties where the bigger stuff you have to keep an eye out along with 11:1 compression.

6) arms +2 if your trails allow. the stuff i ride, often doesnt let me run that wide. we have posts and gates to get through that are 50" wide, it makes it tough to get through when you are almost exactly the width of the gate (they arent all perfect 50")

just my .02 though,
steve

[RNL]

im a woods guy myself, riding mostly in northern WI.

if i was to build one, good shock are #1.

2) stage 1 for the low end fun factor

3) slip on exhaust with the header welds ground down

4) 6 degree timing advance if you are going to leave stock compression piston in there. this timing advance also brings back some of the top end lost due to the stage 1 cam but you dont lose the low torque.

5) if you want to bore- 416 10:1 was my favorite of any i had. didnt really have to worry about heat while cruising slow in the twisties where the bigger stuff you have to keep an eye out along with 11:1 compression.

6) arms +2 if your trails allow. the stuff i ride, often doesnt let me run that wide. we have posts and gates to get through that are 50" wide, it makes it tough to get through when you are almost exactly the width of the gate (they arent all perfect 50")

just my .02 though,
steve

Thanks for sharing your thoughts. Sounds like we ride the same type of trails, yes 50 inch is max in some places so I am not going to spend money on new a arms. I was looking up info on the header grinding, does it really make enough of a difference? Also the cam choices are baffling, so many people have different views on them. Some swear by stage one, others by stage two. I am 226 lbs and am trying to find a nice shock setup, debating on 450r shocks or some Elkas.

[RNL]

Oh and I think I might get some new tires and rims, maybe a touch more offset to make it a hair wider, but not much. And either Flexx bars or a Precision anti vibe bar clamp. Been just riding it around my house, forgot how fun these things were.

[honda400ex2003]

very true on the views of the cams. lots of differences in riding style and where people ride.

a full header on a stock-ish engine is probably not going to warrant enough power to waste the $$ on it. the little bit of extra flow from grinding doesnt make an arm pulling difference but it helps out some. it does help in conjunction with other things though.

i beat and ran along side a 416 11:1 JE piston, stage 2 hot cam, 400ex stock carb, e-series exhaust, and some other things on it with my 10:1 wiseco, stage 1 hot cam, 400ex stock carb with the choke removed, header welds ground, 6 degree timing key and a t-4 slip on. although it depends on the day and the carb adjustments, you can make many different setups just as fast as each other.

tires and rims are a good option for doing a bit of width increase, its a nice upgrade anyway to get rid of the stock tires.

handle bars are nice, esp anti vibes- that being said, other than wishing my tag t-2s were slightly taller on occasion, i like them quite a bit.

lots of fun stuff you can do with a stock-ish machine for relatively little money by comparison to a bore and such. id go stage 1 hot cam just because it is a blast to blip the throttle and wheelie it over logs, mud holes, and other trail obstacles. the stage 2 imo wouldnt really do that on a stock bore/compression machine. the extra flow from removing the choke and doing the welds, along with a timing advance would give you as much pull as a stage 2 would up top, without really sacrificing any low end.

just my .02 though,
steve

[RNL]

very true on the views of the cams. lots of differences in riding style and where people ride.

a full header on a stock-ish engine is probably not going to warrant enough power to waste the $$ on it. the little bit of extra flow from grinding doesnt make an arm pulling difference but it helps out some. it does help in conjunction with other things though.

i beat and ran along side a 416 11:1 JE piston, stage 2 hot cam, 400ex stock carb, e-series exhaust, and some other things on it with my 10:1 wiseco, stage 1 hot cam, 400ex stock carb with the choke removed, header welds ground, 6 degree timing key and a t-4 slip on. although it depends on the day and the carb adjustments, you can make many different setups just as fast as each other.

tires and rims are a good option for doing a bit of width increase, its a nice upgrade anyway to get rid of the stock tires.

handle bars are nice, esp anti vibes- that being said, other than wishing my tag t-2s were slightly taller on occasion, i like them quite a bit.

lots of fun stuff you can do with a stock-ish machine for relatively little money by comparison to a bore and such. id go stage 1 hot cam just because it is a blast to blip the throttle and wheelie it over logs, mud holes, and other trail obstacles. the stage 2 imo wouldnt really do that on a stock bore/compression machine. the extra flow from removing the choke and doing the welds, along with a timing advance would give you as much pull as a stage 2 would up top, without really sacrificing any low end.

just my .02 though,
steve

So you remove your choke? Wasn't familiar with that mod.

[honda400ex2003]

you certainly can, just put a bigger pilot in there. (a 42 usually works)

http://www.atvriders.com/articles/in...arb-choke.html

steve

[honda400ex2003]

i wouldnt do it for the winter months but it is certainly a decent mod for summer time. jet accordingly with the main and your exhaust (usually a 150 with a lid, 152/154 if you pull your lid depending). it does start hard when its cold outside, even with the bigger pilot jet.

if you end up grinding welds, removing the choke, adding a slip on and removing the air box lid, id go 156 to start and do a plug chop. may end up at a 154 but worth trying out the 156 to see how it runs imo.

steve

[Zakradu398]

I honestly think a slightly modded 400ex is all I will ever need, I had a 450 before and never came close to using to its potential. Interesting point about the stage 2 Hotcam, in my reading I found the stage 2 is suppose to be for higher compression motors, but your saying it's good in a stock piston? I'm not going crazy on building this thing, I may look into 450r shocks, but have read they are stiffer? I'm 226 lbs so would they be good for me?

I did my stage 2 HC and 11:1 piston at the same time (which I forgot to mention but highly recommend as well) so I can't tell you exactly how it would respond with stock compression, I imagine it would be the same just slightly less power throughout the powerband because of lower comp.

450r shocks will help for sure, if you got them revalved it would be a massive difference over stock. Stock 450r shocks do work well though, not the best obviously but much better than the stock 400 shocks.

I didn't remove my choke when I had my 42 pilot in but I never needed the choke from 80deg down to about 25. Anything less than that I don't ride lol.. No choke will open up the venturi of the carb a little bit more, possible requiring a bump on the main. Never tried it, just ASSuming again..

[FixxxerKH202]

I don't even see a need to mod the 400ex for just trail riding. Just a good set of tires, a better set of bars, chromoly tie rods, maybe a gearing change depending on your style, and set the factory shocks properly for your weight and they are awesome. All my friends who messed with theirs regret it because the aftermarket exhausts draw cops for those non legal areas, the big bore kits and cams can ruin some of the reliability, and making them wider can ruin the versatility in some of the trails.

The 400ex's are great quads with just a few simple mods to strengthen them in their very few weak spots, other than that I haven't seen much reason to mess with mine for trail riding. If you plan to race it then that is a different story.