XR 400 Motor Ideas (dont bash, Its the same motor)

[NickG5755]

So heres my new idea. Ive been going back and forth between what new bike i wanna get. But reliability of the 4 strokes doesnt impress me (the 450's anyway)

So heres my new idea

XR 400 with these mods


Motorwise
416 11:1
Stg 1 Hotcam w/ CRF timing chain (stg 1 cuz i want bottom to mid)
Sparks Advance Timing Key
450R Carb
And If itts possible id liek to put the 400ex Sidecover on so i can have E-Start

then

Aloop plastic kit (comes with a smaller MX style tank and CR style seat cover)
And CR500 Front end

My main question is how does that motor setup sound? My main worry is that the motor will run hot. What do you guys think?

Heres a pic of the XR400 Aloop kit

http://i98.photobucket.com/albums/l275/ngarulle/100_4443.jpg

[exracer416]

i really like that bike! it shouldnt run hot if its jetted right, those motors are bullet proof

[drew416ex]

Im not sure about the sparks advance key with 11:1 compression. It might run a little hot with that.

[NickG5755]

Well someone on here said its good up to but not including 12:1 or 12.5:1

plus when you put a cam in your true compression drops from what ive read

so im guessing my true compression will be under 11:1

I dont know nearly as much about 4 strokes as i do about 2
But i do know more than the average joe.

I appreciate the input. Anyone have a setup similar to this?

Im thinking with the timing key and the 450R carb this thing should be a beast in the woods.

Also when putting a cam in is this thing gunna be harder to start (unless i get the 400ex side covers to work then i could care less)


And yes I really like this bike too. Ive ridden a stock 400XR and it was pretty quick for what it was. So im thinking this should be a killer setup. Better handling and more power. What isnt there to liek about that?

[exracer416]

how hard would it be to do the front forks?

[fastredrider44]

Before you go soupin up the motor on an XR, you should just ride it. I dragged an XR on my old 426ex, and got smoked. I read somewhere they make more power than the 400ex. Combine that with a lot less weight and different gearing, and these bikes will scat. As for the forks, just a set of triple trees and forks, and they will bolt up right?

[NickG5755]

Its not to bad if you have the right tools. I read a how to on thumper talk about it.

I belive ther was a guy that used a CRF 250 front end and all he had to do was use the CRF steering stem and have it machined down to accept the XR bearings (the CRF stem is beefier) then he cut it down to length and threaded it.

basically ya just gotta get the whole CRF forn end and machine down the Stem to fit.. its not to hard but ya have to take it to a machineist to have it done.

i aso read that the 89 CR 500 front end bolts directly too the XR 400. this may be a better cheaper option for someone not as serious about riding.

I for one am gunna ride this bike hard and race it a few times. not out to win a district chamoionship or anything. But riding on a 12 mile loop with 250+ riders is a rush. So im def gunna do this conversion. as soon as i find a suitable XR 400 to do it on.

[NickG5755]

Originally posted by fastredrider44
Before you go soupin up the motor on an XR, you should just ride it. I dragged an XR on my old 426ex, and got smoked. I read somewhere they make more power than the 400ex. Combine that with a lot less weight and different gearing, and these bikes will scat. As for the forks, just a set of triple trees and forks, and they will bolt up right?

i have ridden bieks for a long time. Ive ridden XR 400's too. They Are torque monsters but when you wanna build a dual sport bike to ride with your friends and they ride bikes like 525XC's ya kinda gotta modify the XR400 to hang.

thats why im doing the basic motorwork and the Suspension upgrade.

I plan on keeping this bike for a long time, so i feel the costs are worthy. not to mention it would be 1 of a kind XR400 that i garuntee no1 around here can match. Im all about being different. So i think this idea works for me.

[F-16Guy]

What you listed is what I have, minus the carb and timing key. My only suggestion would be to make sure you get heavy duty head studs installed. If it were me, I'd order all of the parts you need from the cheapest place and then send the cylinder and new piston into GT Thunder to have it bored and have the studs installed. I know some people say you don't need studs with an 11:1 piston, but mine took a crap, so it can happen, and it's money well spent for the studs. With all that being said, I love the way my quad runs right now. It pulls like a tractor, but the stage 1 cam still has enough top end to bounce off the limiter if you take it there. I'm sure there are faster 400ex's out there, but my quad has a ton of useable power, and that is far more important as far as I'm concerned. I'm not too sure the e-start conversion would be as easy as you think, but if you have it jetted correctly, the XR400R/TRX400EX engine (they are actually different, but very similar) is really easy to start. I would try it first before you spend the time and $$$.

[NickG5755]

Yea i was thinking about doing HD studs.

The E-start you can get as a kit for 600 bucks but I think i can put the kit together for cheaper. Its def not one of my top priorities.

the order of mods would go liek this.

1. Front end conversion Aloop plastic/tank
2. Exhaust/ Choke delete while im jetting it.\
3.Sparks timing key

then im tihnkin save a good bit of money and do

4. 416/426 with HD studs most likely
while the cylinder is getting done ill prob send the head for a mild port/polish and maybe a valve job, Hotcam also
5. E-Start kit if neccisary


the estart would be ano brainer for me if it didnt extend that side of the motor by 2inches. Only having to push a button when stuck on the side of hill is kinda nice.

[NickG5755]

why dont us good americans get the good stuff


http://i98.photobucket.com/albums/l275/ngarulle/SA2T1742.jpg

[01exrider 281]

^^ we do it is called a drz400sm.

[NickG5755]

yea but its not a honda! lol... watercooled = 1 more thing that ca break.

[01exrider 281]

two good point but mainly the honda one. i love riding my dads. with a pipe and jet kit it runs really good.

[1krazyquadridr]

You are correct in your idea that most aspects of both motors are very similar or the same. The XR crankshaft is narrower than the EX due to the addition of the electric starter gear and clutch, this makes is lighter with less rotating mass which in turn allows it to rev a little faster. I know there are companies that sell an adapter that adds length to the end of the crankshaft so you can add these components. But since you are going to be into the motor anyway why not just put an EX crank in there? You can pick up a whole EX bottom end and utilize the crankshaft and all electric start components while still keeping your kick start for a few hundred bucks. I am currently doing a similar project, but I am putting a XR kick start and transmission in my EX, everything exchanges perfectly. Just some food for that may save you some headaches and money.

[GPracer2500]

I dual sported an XR400 for several years. I wouldn't want electric start on it. They start easy and they're heavy enough as it is. The last thing I would want to do is add more weight.

If an XR400 with engine, suspension, and body mods is really want you want, then go for it. Personally, I'd spend all that money on a factory build bike that will probably do most things better anyway.

I like XR400's and enjoyed owning one. But much of it's allure for me is in how expertly Honda put together a tough as nails, do-it-all, general purpose dirt bike. I feel like if you mess with one too much you risk ruining what makes them such good bikes to begin with.

Only $0.02

[NickG5755]

1krazyquad - Thanks for the info. The Electric start is going to be a "Last Resort" if i find myself getting stuck on the side of hills and stuff and being unable to start it.. Which i doubt will happen.

GPracer- I see what your saying to but as for taking away the reliability with mods , I dont see that as being a problem. On this forum thers a tonnn of people that have highly modded ex's and none of them really have problems.

As for the plastic and whatnot. My main reason for that is to make it more rideable in the woods. Bt lowering the tank/seat that bike will most likey feel lighter since the weight isnt so high up.

The reason for me to build this bike is i want something different.

When was the last time you saw a XR400 with inverted front forks Radiator shrouds and a motocross style body?

Also a bike that would spank a 450?

I appreciate the input tho. Keep it coming!!:macho

[NickG5755]

as for price? i think i build this one of a kind biek for under 3 grand.

i can find a 400 that isnt to bad but isnt perfect probably for 1700 bucks.

freshening the motor up up will come in around 400 so we are up to 2200

i can get a CR500 front end for liek 200 bucks or less off ebay or if i go the extra mile i can get a CRF front end. and you can get the plastic /tank kit for 400

pluss 200 bucks for a slip on. 3000 and i have a sweeet XR 400 worthy of "bike of the month" lol and best of all its what i wanted and its not another KATOOM (KTM) in the woods.

Did i mention its a honda?

[F-16Guy]

I really like the concept for a woods bike. I would much rather have that kind of tourqey power than the light-switch delivery of a 450. I've always loved the A-Loop kit since the first time I saw it, and even more with the inverted fork conversion. I think it will be a unique and fun bike that will give the 450's fits in the woods!

[NickG5755]

yea that has alot to do with it to. thers kids around here with piped 450's that have never been to a harescramble

they dont really know what real bikes are made of. one kid saw a boysen sticker on a 450 carb (it had the boysen quickshot on it)
his response to seein that was "you had to put new reeds in it already?" :rolleyes: he then informed us his quad had a coil pack lol

But yea a machine that can run for a few years without problems , smoke a 450 in the woods/in a straight line , and still be something your neighbor will never had is something to really liek.

not to mention being able to do this and not have any worries

http://www.dirtrider.com/features/141_0604_honda_xr400_underwater/index.html

this has had me smiling alll day..


plusss i read that EX to kikc conversion thing that steve wrote up and im thinking about loosing some weight on the flywheel :) that should make this beast rev liek a SOB.. if i do that i might leave the stock cam in. or go for the HRC clone cam.

[NickG5755]

So basicallty im about to start crying liek a little girl

went on a local webiste imgine this.. a 1998 XR 400 WITH THE ALOOP KIT ALREADY ON IT AND THEY ONLY WANT 1200!!!!!!!!

my job interview isnt until tuesday and i dont think ill be startin till nxt monday.. so basically im hopin this is still there in 3 weeks cuz if it is ITS MINE!!!

http://i98.photobucket.com/albums/l275/ngarulle/IMG_7934.jpg


its already got the headlight i wanted a pipe and the aloop kittt

man this is frustrating. i could probably get it for a grand too. which leaves 700 bucks in by budget for ?????

it looks like the head gasket is leaking but i mean for 700 bucks les then what i was planning on spending its sooo worth it

[fastredrider44]

As far as the forks go. I had an 89 CR250. Same forks as the 500. They were showas, and actually rode very well. You said your friends have KTMs. Get one. I am well pleased with mine, and can say that it would take one heck of a mean XR400 to keep up with my 525EXC.

As far as the 400 in the pic above, be leary, looks like it may have been rode hard and put up wet in the past.

[NickG5755]

Yea it does look ridden. Buit i can probably get it for a grand (it has a title) and the motor will be gone through anyway.

The plastics/tank kit is 500 bucks. a skid is 80 barkbusters are 40 (cheap ones) and that headlight is like 50 or more. thats like 670 right there and it also has a pipe (200ish) and a pumper carb(300ish).... Its a great deal when ya think about it.

Itll sit in the corner of the garage most likely until the winter. But it will be rebuilt

The whole reason for me building this, is becasue I DONT WANT A KKATOOM!!!... lol theyre everywhere... and ill bet that when that XR is done ill be able to keep with ya in the woods...Its more rider than bike.. and ive got plent y of rider to make that bike look fasttt lol

BTW i jsut found out that theres a certain bearing you can buy that makes the XR - CRF fork swap a bolt on installation...im pumped to say the least.