making a 400ex slower

[1fst400]

This is a new one. I need to make a 400ex slower. my gf is geting one soon. I talked her into the 400 over somthing eltse because thats what I know how to work on and I have a gazilion parts for them. But I dont want to scare her away from it by it being to fast. she drives my quad from time to time but its just plain to much power.

altho a 400ex has quite a bit less power than my quad. I still would like to see it slower.


I was thinking higher gearing. but then she would be days trying to learn how to use the clutch.

[underpowered]

Originally posted by 1fst400
This is a new one. I need to make a 400ex slower. my gf is geting one soon. I talked her into the 400 over somthing eltse because thats what I know how to work on and I have a gazilion parts for them. But I dont want to scare her away from it by it being to fast. she drives my quad from time to time but its just plain to much power.

altho a 400ex has quite a bit less power than my quad. I still would like to see it slower.


I was thinking higher gearing. but then she would be days trying to learn how to use the clutch.

i think it still has the throttle screw on the throttle assmbly. just crank it in a little so she cant give it full throttle. change the gearing would work, but dont you mean lower gearing? umm thats all i can think of.

[rooster300ex]

Lower gearing,throttle screw, or somehow take the plate off the top of the throttle on the handlebars and put something inside of it that makes it where she can't crack that sucker to WOT.

[1fst400]

lower gearing would abolutly rip her arms off with torque. Im not woried about speed, just power. so higher gearing would make it seem like a slug. And the stock motor wouldent pull it on the top end anyways.

limiting the throttle would work, I would simply loosen the adjustemnt in the cable tho.



mabie making a exhaust baffle? more flowing exhaust = more power. put a baffle in that thing and wouldent it slow it doun? Probly not, but Im just trying to think of somthing other than the obvious dont go wide open.

[400eXr1d3rZ]

smaller tires will lower top speed but add acelleration. put stock pipe on, or some crappy one like DG or cobra. go up a few teeth on the front sprocket, it will lower acell but make top speed go up, but sence your gonna block something on the throttle off, she wont be going to top speed anyway. she might get scared of the torque

[1fst400]

ppl. thanks for the help, but your all repeating yourselves!


any gearing other than stock isnt what im looking for. higher will = poor aceleration which will equal lots of stalling trying to take off.
lower will = to much torque.



It just hit me tho, I could just run a restictor plate between the intake adaptor and the motor, correct?? just like they do in nascar to lower the cars HP.


Im not trying to me to much of a arse, I understand you guys are trying to answer my question. But just keep in mind when you are replying that I built a hybrid, and am fairly up to date on how to change the over all top speed of a quad.

[TravEX]

Put some Yamaha stickers on it to slow it down!!!

J/K LOL!!!

[1fst400]

Originally posted by TravEX
Put some Yamaha stickers on it to slow it down!!!

J/K LOL!!!


lmao!!
finaly someone that knows what they are talking about.

[F-16Guy]

Then he'll just be working on it all the time.:chinese:

[Toadz400]

Why can't your gf handle a stock 400EX?

I taught my ex-gf and her little sister (13 at the time) how to ride on a piped Predator and my YFZ. My ex-gf doesn't ride anymore because she torn a ligament in her knee and just isn't interested anymore but I constantly ride with her little sister, she keeps up with me just fine on her Pred.

I would lower the gearing, she will not be scared of the torque because as the 400EX has a lot of low end it's nothing scary. Raising the gearing will only cause more stress on the clutch and make it that much harder for her to learn how to ride, and if she's riding on trails it'll be such a pain to ride that she'll probably lose all interest in riding.

Limiting the throttle is also a good idea. I would move that screw farther in to limit how far the thumb lever can move. Your ideas of limiting the intake and exhaust are a little extreme I believe. I really do think your gf can handle a stock 400EX if she is taught properly. You said lower gearing would absolutely rip her arms off because of the torque? My only suggestion is to get a gf who isn't made of string :p .

[firefighterjosh]

This is how I taught my GF to ride.

She didn't have a quad and all I had was the banshee. I sat on the back and taught her how to ride it. She was dencent. She could get it into the power band but then she would get scared. Well even then she was hooked

She bought a 250ex. A good quad for about a year

Then she moved on to a KFX 400.

I wouldn't worry about it beign too fast.

Just set her on it show her how to work the controls, just have her put around 1st gear or 2nd in the flat yard for a while. Then show her some slow easy trails. She will get ust to it. Thats how I learned to ride and I am sure everyone else did to.

As long as she isn't a stupid gitty blonde (no infence) she will be fine.

[1fst400]

she rides snomobiles, but not quads. Its more her mom useing the quad and seeing how powerful it is, then geting pissed off that I talked her into buying a 400ex.

[rooster300ex]

I think you should of got her a smaller quad, regardless if you had alot of parts for one.

the easiest way like i said is put some that makes it where she can't open the throttle wide open. Underneath the thumb throttle plate.

[PismoLocal]

Originally posted by TravEX
Put some Yamaha stickers on it to slow it down!!!

J/K LOL!!!

Lmao ya throw some yamaha stickers and a DG pipe on Her 400 that will slow her down.

[bwamos]

Originally posted by 1fst400
I need to make a 400ex slower.

TRX90 Thumb throttle, has an adustable throttle stop so you can limit it to like 75% throttle, etc.

Fits right up.

Easier pull to boot. ;)

Drop a tooth or two on the front, and you have a noce slow machine with plenty of torque to get up the hills. ;)

[stalefish_132]

plug up the stock snorkle half way and rejet it (less air ) keep the stock pipe & baffle and maybe even jetting it rich would make it seem less powerfull maybe. the TRX 90 thumb throttle is a good idea. this might be a but extreme but what about doubbling up the head gaskets? less compression but who knows if it how long it would last before it blows 'em out, then again maybe the stocker would take it. i'm sure you'll find a way.;)

[gopeddin400EX]

i think the plate would be easy, just a piece of sheet metal with like a 2 1/2 inch hole drilled in the center restricting the flow. Just sandwich it between the manifold and the head? its so easy its worth a shot.

[firefighterjosh]

Just screw in the bolt that adjust the throttle position. No need for all this work to get a quad to go slower.


Just screw in the bolt so she can use 1/2 Throttle. That should be plenty for crusing around. Then start backing it out as she gets better.

If she has road some kind of offroad machine before she will get ust to a quad really fast.

[wilkin250r]

I can imagine a few problems with a restrictor plate. If it's not perfectly flat, or if it's not sealed proplerly, you can end up with an air leak and suck dirt into your engine, as well as lean out your jetting. That doesn't mean it's impossible, it just means you need to be aware of the issues and plan accordingly.

You could also plug up the exhaust side, too. Maybe a washer between the head and pipe.

You want a really easy,cheap, temporary solution? Go to the store and buy a package of tube socks. Slip about 4 of them over the air filter.

The best solution, I think, is still the restrictor. They give you all the low-end power you need, so your GF won't have to feather the clutch, but restricts the top end wherever you want, depending on hole size. Plus, your GF gets used to using the full throttle range, and the restrictor can always be widened a little at a time to let her gradually get used to more power.

[hks308]

i have an idea:

trade that 400ex for my 300ex

[1fst400]

I like the restrictor plate idear alot. But I'm not up for rejeting and anything eltse that I may need to deal with.

The quad has a twist throttle on it now, when I go to pick it up tomorow Im going to swap it out for a stock style. while im puting it on I will limit how far it opens the carb by leaving some slack in the cable. Im shure she will learn fast. I just dont want her to end up geting hurt and loose intrest in the sport.

She drives her uncles yamaha kodiak 400 4wd often. Its an auto trany tho.


Im shure what ever I do to it, within an hour she will be saying " this things slow!"

[firefighterjosh]

MY GF rode her 250ex for about 1 Month (and it was her first quad) then she was stealing my banshee when ever she could cuz hers was slow.

The biggest thing is riding up hills and stuff. My GF just wrecked her KFX down a huge hill last week and brusied her self up.

[krt400ex]

Originally posted by 1fst400
ppl. thanks for the help, but your all repeating yourselves!


any gearing other than stock isnt what im looking for. higher will = poor aceleration which will equal lots of stalling trying to take off.
lower will = to much torque.



It just hit me tho, I could just run a restictor plate between the intake adaptor and the motor, correct?? just like they do in nascar to lower the cars HP.


Im not trying to me to much of a arse, I understand you guys are trying to answer my question. But just keep in mind when you are replying that I built a hybrid, and am fairly up to date on how to change the over all top speed of a quad.

u could use 2 head gaskets or 2 base gaskets to lower the compression a little. it would bring the power down a little, it would give it a litlle less bottom end, otherwise i can't help u.

[krt400ex]

Originally posted by firefighterjosh
Just screw in the bolt that adjust the throttle position. No need for all this work to get a quad to go slower.


Just screw in the bolt so she can use 1/2 Throttle. That should be plenty for crusing around. Then start backing it out as she gets better.

If she has road some kind of offroad machine before she will get ust to a quad really fast.


there is no bolt on the 400ex throttle.

u can get one by buying an aftermarket thumb throttle. that would allow u to limit the throttle. also, aftermarket throttles will allow u to change the ratio, so when she hits the throttle it would be les abrupt then stock(only some throttles allow this though)

[krt400ex]

Originally posted by 1fst400
she rides snomobiles, but not quads. Its more her mom useing the quad and seeing how powerful it is, then geting pissed off that I talked her into buying a 400ex.

most snowmobiles r a heck of alot more powerful than any 400ex

[1fst400]

She has been riding it fine for the last cuple days. I forgot just how slow a 400ex was I guess.

[Toadz400]

Originally posted by 1fst400
She has been riding it fine for the last cuple days. I forgot just how slow a 400ex was I guess.

Told ya' :p .

[krt400ex]

Originally posted by 1fst400
She has been riding it fine for the last cuple days. I forgot just how slow a 400ex was I guess.


can i see a pic of ur quad. i noticed that it is a hybrid in ur sig. i love hybrids, and i will be building one in a couple of yrs.

[1fst400]

this is a pic from when I first built it. Its been a cupple months now. so its a little difrent.

[krt400ex]

that's pretty cool, thanks