Modding the 400ex

[thunderisland]

Hello everyone just purchased a 400ex for my son and considering modding it some where to start.It has a Bill Ballance pipe and k&n air filter and nerfs and razor tires both front and back.Any opinions I would appreciate nothing extreme he is 13 but handles the quad pretty well so far,moved up from a mini quad.thanks

[quadman 05400ex]

id say thats fine but if u want to mis with egos you could get dif handle bars but other then that it sonds pretty good got pic's:D

[firefighterjosh]

I would say some shocks. Shocks make a huge diffrence. Handle bars would be a good investment. (try diffrent bends)

[thunderisland]

Thanks for the input,I am planning on getting shocks soon I heard the yfz shocks would be a good upgrade so we might try them.The handlebars what would you guys suggest?The bend and name brand.He wants different plastic at least on the front,we had heard 450r plastic will fit anyone know if not what will.Thanks for alll your advice keep it coming what about sprockets front or rear?

[firefighterjosh]

Originally posted by thunderisland
Thanks for the input,I am planning on getting shocks soon I heard the yfz shocks would be a good upgrade so we might try them.The handlebars what would you guys suggest?The bend and name brand.He wants different plastic at least on the front,we had heard 450r plastic will fit anyone know if not what will.Thanks for alll your advice keep it coming what about sprockets front or rear?

I don't think the YFZ shocks fit. But the 450r shocks do. There is a how to on how to fit the 450r shocks on. I like Tag bars. I personally like the CR High Bend set up. What year 400ex? I dunno about 450 plastic fitting but the newer model 400's have look - a - like 450 plastic stock.

[thunderisland]

Thanks for the inputs keep them coming.As far as the yfz shocks I'm pretty sure they will bolt up with a little grinding on the top mount.It is a 2002 400ex I'll try to take some pics this weekend if someone can help me post them.Any info and tips that could help us out would be appreciated.Thanks for the comments on bars didn't know they were that important.I understand a swingarm skid is a must if he is doing trail or woods riding but maybe too much weight for mx.Appreciate all the comments like I said earlier the more the merrier.I heard the 450r shocks throw off the geomotry some and are sit higher.

[monson]

ive got the pro taper atv mid bends and i like them a lot. but if your son is 13 and a little smaller he may like low bend bars better. just a suggestion

[johnsls]

Originally posted by thunderisland
Thanks for the inputs keep them coming.As far as the yfz shocks I'm pretty sure they will bolt up with a little grinding on the top mount.It is a 2002 400ex I'll try to take some pics this weekend if someone can help me post them.Any info and tips that could help us out would be appreciated.Thanks for the comments on bars didn't know they were that important.I understand a swingarm skid is a must if he is doing trail or woods riding but maybe too much weight for mx.Appreciate all the comments like I said earlier the more the merrier.I heard the 450r shocks throw off the geomotry some and are sit higher.

I have a 02 400ex and I didn't notice that the 450r shocks made it ride any higher. I also don't think the YFZ shocks fit.
I'm also looking at getting different bars but not sure which ones.

If he's gonna be riding the 400ex for awhile maybe you ought to look at widening the rear with a new axle or a-arms (LSR or durablue) especially when he starts jumping.....

Good luck

[ilpadrino113]

the 450r shocks make a huge improvement. The 450r shocks don't make it ride any higher if they are revalved correctly. The YFZ shocks can be made to fit, but it doesn't fit nearly as well as the 450r. 450r shocks will bolt right up with some grinding.

Originally posted by ilpadrino113
450r shocks will bolt right up with some grinding.

Same with the yfz shocks.

Originally posted by johnsls

If he's gonna be riding the 400ex for awhile maybe you ought to look at widening the rear with a new axle or a-arms (LSR or durablue) especially when he starts jumping.....

Good luck

Go LSR for the axle. Durablues life time worrinty Ends up costing you $$chaching$$. LSR will keep replacing/fix axles for free if you break/bend them.

[thunderisland]

Again thanks for the input he is about 5'9 or 5'10 so I think he is tall enough for the high bend.As far as jumping ,yes he is jumping some now, but definitely wants to, so looks like an axle and a-arms are a must.My mechanic tells me that the 450r shocks will throw the geomtry off some so I didn't want to take that chance being new to this quad.I realize that are several people that have used them just not sure that's what I want to do.keep the comments coming I love all the advice he loves the quad.

[F-16Guy]

The geometry of the front end is determined by the location of the pivot points of the a-arms/spindles/tie rods, NOT the shocks. The only thing the shocks will do is alter ride height and/or amount of a-arm travel. Ride height is mostly a matter of preference. Travel is pretty important because you want to make sure you don't exceed the maximum range of motion of other components, such as ball joints and tie rod ends. The 450R shocks don't pose this problem. If anything, they don't have enough travel, but that can be corrected by GT Thunder. I have them totally stock on +2 a-arms, and they feel good; I'm 205 pounds and 6'3".

Originally posted by thunderisland
My mechanic tells me that the 450r shocks will throw the geomtry off some so I didn't want to take that chance being new to this quad.I realize that are several people that have used them just not sure that's what I want to do.keep the comments coming I love all the advice he loves the quad.

The 450R shocks would knock off the geometry UNLESS you get them revalved (which is what I did)

Haven't mounted them yet, but total cost was $600, which puts you in the ball park for some other options (Used Elkas, PEP, etc or new Elka rec shocks)

Actually we need to know what kind of riding he'll be doing to answer this question.


XC set up is VERY different from a MX setup.

[johnsls]

It also depends on a few other things too

How much money are you willing to spend

If money isn't a problem then get goo aftermarket a-arms & shocks.

If you don't want to spend too much and he is a decent rider then the 450r shocks will do for know. By the time he needs new ones the cost to have them revalved by (GT thunder or others) would cost a lot less.

Again it does depend on the type of riding or racing he'll be doing.

I'm not good by any means but I have the 450R shocks and I'm waiting to put on the LSR axle, which will widen my rear and help in the turns and all.

Asking advice on mods seems to be a loaded question cuz you'll get a million responses. It depends a lot on the riders ability and what type you intend to do.

[thunderisland]

Sorry he is just learning to ride the 400ex right now I think he wants to do mx also some trail riding he hasn't mentioned xc yet.Budget is a big concern so inexpensive mods is what I'm asking.I appreciate all your opinions and I will take all of them under consideration.

Originally posted by thunderisland
Sorry he is just learning to ride the 400ex right now I think he wants to do mx also some trail riding he hasn't mentioned xc yet.Budget is a big concern so inexpensive mods is what I'm asking.I appreciate all your opinions and I will take all of them under consideration.

cheepest rought
yfz shocks (costed me $150)

ASR +2 or +3 a-arms (ebay from quadpartsguy costed me $380 with life time garrinty. They sell cheeper ones for $280 still with the garrinty)

Axle G-force ($250 or sumthin like that) or get a LSR off here for $200

[johnsls]

Slow -- right on!! :macho Your right.

How do you like the a-arms from quadparts guy? Are they good quality. I was unsure about them because the price is soo much lower.
Do they handle the jumps and whoops real good?????

Originally posted by johnsls
Slow -- right on!! :macho Your right.

How do you like the a-arms from quadparts guy? Are they good quality. I was unsure about them because the price is soo much lower.
Do they handle the jumps and whoops real good?????

Idk. They look just like lone stars and come with hemi ball joints which are better than normal ball joints.
They look really good.

I haven't used them yet cause i put them on and tryed to start it and the motor locked up so i havent tested them yet but they havea life time garranty so they must be strong like said.

If you get them in black they chip easy.

Shipping took 6 week days and costed $22

You have to use lock tight on a bolt on the ball joints or they come loose.

[400exMO]

IMO the smartest thing you could do is not pour much money in it. If he's handling a 400 well at 13, he'll be wanting a 450 in acouple years. And 400's are having bad resale.

[F-16Guy]

Originally posted by slow
Idk. They look just like lone stars and come with hemi ball joints which are better than normal ball joints.
They look really good.

I haven't used them yet cause i put them on and tryed to start it and the motor locked up so i havent tested them yet but they havea life time garranty so they must be strong like said.

If you get them in black they chip easy.

Shipping took 6 week days and costed $22

You have to use lock tight on a bolt on the ball joints or they come loose.
Heim joints are NOT better than ball joints for a couple of reasons: Heims are meant to take a radial load (push/pull), not axial (up/down). In that position, they wear very quickly because the load bearing surface is very small -- just the small lips on either side that keep the ball from coming out. Secondly, at least for ASR, is that the joint is not sealed, so dust and grime that accumulates during riding causes the joints to bind and squeek, and speeds up wear even further. These things become potentially dangerous because the spherical bearings in the joints are not captive, so if the wear is enough to allow the bearing to pop out of the race, there goes your wheel. I shouldn't have to explain how bad that could be.

If it weren't for the Heims and the crappy "powdercoating" (more like Krylon), I would say they are pretty decent. By the time you get done fixing what's wrong with their arms, you could get some Burgards or a good set of used arms. I know all of this first hand, because I have a set on my 400ex. I upgraded the lower heims, which should be done if you decide to run these arms, because the lower ball joints support the weight of the quad. I also watch the joints for play, and try to keep them clean so the wear and binding is minimal. You may also want to invest in rubber dust boots for the Heims.

If ASR would change a few things, I would say "go for it", but for now, I would spend my money elsewhere and stay away from Heims.