XR400 bottom end

[PaRedneckRiders]

Im thinking about Putting an xr 400 bottom end in my 400 and have a few questions

1. Will the 400ex cylinder, head, and cylinder head cover fit the XR

2 What motor mounts would i need to change, do the swing arm pivot and cylinder head cover mount line up so i would have to make new bottom mounts

3 No matter what i look for i can not find a stroker crank for an xr400 and im pretty sure i couldnt use the EX crank in the XR, Right

4 What are any major differences between the XR motor and the EX motor besides kick start and it would have diff motor mounts

I just need some help before i would start this build, i would really like to have a Build stroker XR/EX motor in one of my quads

If u can answer any of my questions it would be much appreciated, Thanks

[TRXRacer1]

All top end parts bolt right up.

The swinger pivot is in a different location.

Cranks are NOT interchangeable. You'll need someone like Powroll to make you a stroked unit if you really want it.

Some mounts will be different.

Basically there is zero advantage to using an XR bottom. If you want a kicker that bad just convert what you have.

[PaRedneckRiders]

ok well not really into the kick that much its just i have found some cheap xr400 bottom ends around and was wondering if its worth putting in the EX

[TRXRacer1]

Originally posted by PaRedneckRiders
ok well not really into the kick that much its just i have found some cheap xr400 bottom ends around and was wondering if its worth putting in the EX I would say no. If it was bolt in then maybe.

[PaRedneckRiders]

ok man thanx for some info

[PaRedneckRiders]

Just found a 4mm stroker from powroll but has crank piston, rings, and clip i might contact them to see if i could get just a crank
Heres the link
http://www.powroll.com/P_HONDA_XR400R.htm

[TRXRacer1]

They'll stroke anything but you might need their piston for it to work. See what they say. Regardless it will be a pain in the *** installing that XR bottom in an EX.

[PaRedneckRiders]

ok might call them tommorow

[droppedmazda]

hey how much can you get a xr bottom end for. if its cheap enough i might be interested in buying one off of you if you can get an extra. xrs are really hard to find around here because we have very few dirtbikes and id really like to have one.

[PaRedneckRiders]

Originally posted by droppedmazda
hey how much can you get a xr bottom end for. if its cheap enough i might be interested in buying one off of you if you can get an extra. xrs are really hard to find around here because we have very few dirtbikes and id really like to have one.
Found 2 one was locked up and both were like 300 talked to a guy that had the one and he sold it and i cant find the other one again so i im sorta SOL right now and looked on ebay and there like 6-700 and there not even complete

[sc400ex_rider]

the xr400 trans gears roc in a 99-04 ex. the gears are spaced better. I think there taller, sadly just another ex detune.

[PaRedneckRiders]

Ok so could i buy the trans from an xr and put it in the EX?

Does anyone know how much of a difference it is exactly

Also how would i convert what i have now to a kick start, i like the idea of kick start EX, I just have a normal EX bottom end nothing special about it

[JOHNDOE83]

Theres a really cool detailed thread in this section, use the search engine at the bottom of the page, you will find it.

The xr gears wont work I dont think, the crank and all is alot bigger also? I think?

[1krazyquadridr]

I've done the xr/ex trans swap and there is really nothing special to it. The xr trans is geared differently, and is better suited for motocross. Everything is a direct replacement with the exception that a few of the bushings/bearings will have to also be swapped because some of the shaft sizes are slightly different. If you want to go to kick start you will also need the xr clutch basket because it has a gear riveted onto it that the ex doesn't. As for the xr crank, because the xr does not have electric start and the one way clutch, the crank is not as long. It could be put in an ex if you went to kick start, but you would also have to find a xr stator cover that is shallower than the ex's. Hope this helps.

[JOHNDOE83]

Here is some detailed info.

http://www.exriders.com/vbb/showthread.php?s=&threadid=293068&highlight=kick

[PaRedneckRiders]

Thanx guys also the XR is a 5 spd right?
Im kinda figuring they r but i have heard they were 6spd??
What r they because i think they are a five speed but not sure

[1krazyquadridr]

Yeah the xr is also a 5 speed, the gear ratio differences are:

EX XR
1. 12:35=2.916 13:34=2.62
2. 16:31=1.937 19:35=1.84
3. 19:28=1.473 20:28=1.40
4. 22:26=1.181 25:28=1.12
5. 26:26=1.00 27:25=.93

[PaRedneckRiders]

Originally posted by 1krazyquadridr
Yeah the xr is also a 5 speed, the gear ratio differences are:

EX XR
1. 12:35=2.916 13:34=2.62
2. 16:31=1.937 19:35=1.84
3. 19:28=1.473 20:28=1.40
4. 22:26=1.181 25:28=1.12
5. 26:26=1.00 27:25=.93
Ok cool thanx

[PaRedneckRiders]

Originally posted by JOHNDOE83
Here is some detailed info.

http://www.exriders.com/vbb/showthread.php?s=&threadid=293068&highlight=kick
Just went through that theard and ive got some good answers to my questions, but i have a couple more that it did not answer

So could get an xr400 flywheel that does not have all the e-start components and put it on the 400 ex motor without changing anything other than removing the starter and putting in the XR flywheel, then just do the kick converion??

And i know that he was running alot of mods that i dont have, but would i notice a good increase in torque with
the mods in my sig under the 02 426 that will also have a stage 2 cam and a P&P head??

[1krazyquadridr]

If I remember correctly, the starter clutch is just bolted to the flywheel. So if you were wanting to go kickstart you could just unbolt the starter clutch and just install the flywheel back up to the crank. You would save weight, and everything with the charging system would still line up since the flywheel has a tapered fit and would be in the same position. I actually had Steve #7 the original author of that thread lighten my flywheel and help me with my conversion, and I saw a signigicant difference in how quickly the motor revved up, but not so much torque.

[PaRedneckRiders]

Originally posted by 1krazyquadridr
If I remember correctly, the starter clutch is just bolted to the flywheel. So if you were wanting to go kickstart you could just unbolt the starter clutch and just install the flywheel back up to the crank. You would save weight, and everything with the charging system would still line up since the flywheel has a tapered fit and would be in the same position. I actually had Steve #7 the original author of that thread lighten my flywheel and help me with my conversion, and I saw a signigicant difference in how quickly the motor revved up, but not so much torque.

well i was thinking about shaving some weight off the flywheel to begin with so it would rev quicker but personally do like the kick start even if i have to cut my fenders, E-star has never let me down totally unless my battery dies which it has a few times or if the cylinoid goes, Could i see a couple pics of your set up if u have any??

So ive never really payed attention to the left side of the crank, but it is tapered so that the flywheel only slides on so far and that the e-start components slide over a part that is bigger in diameter than the outer shaft right??

[1krazyquadridr]

The end of the crank is is tapered and keyed, and you are correct about the larger diameter towards the center. It's been a while, but I believe the starter clutch has roller bearings on the inside that fit around the larger part of the crank.

[PaRedneckRiders]

Originally posted by 1krazyquadridr
The end of the crank is is tapered and keyed, and you are correct about the larger diameter towards the center. It's been a while, but I believe the starter clutch has roller bearings on the inside that fit around the larger part of the crank.
Ya im pretty sure of the bearings, its been a while since ive had that side of the EX apart lol

But if i take the flywheel off i will throw in a +3 key also and see how that works out, working on getting a 450 carb and shocks then sometime i will get it ported and polished and if my buddy give me a cylinder cheap i might resleve it for a 12.5:1 440

[PaRedneckRiders]

Does anyone have a close up pic of the kick shaft coming out of there case?

How long is the XR400 kicker or could i use some other kicker that is shorter that still fits on the XR kickshaft

[TRXRacer1]

Just make sure you're getting 99 or newer XR engines because before that they had smaller kick shafts and were prone to breaking.

http://sphotos.ak.fbcdn.net/hphotos-ak-snc4/hs204.snc4/38547_1389577217773_1182369384_30946155_6977733_n. jpg
http://sphotos.ak.fbcdn.net/hphotos-ak-ash2/hs104.ash2/38555_1389577377777_1182369384_30946156_7042259_n. jpg

[PaRedneckRiders]

Originally posted by TRXRacer1
Just make sure you're getting 99 or newer XR engines because before that they had smaller kick shafts and were prone to breaking.

http://sphotos.ak.fbcdn.net/hphotos-ak-snc4/hs204.snc4/38547_1389577217773_1182369384_30946155_6977733_n. jpg
http://sphotos.ak.fbcdn.net/hphotos-ak-ash2/hs104.ash2/38555_1389577377777_1182369384_30946156_7042259_n. jpg

Ok how did u modify the brake lever because wouldnt the kicker hit the brake lever??

[JOHNDOE83]

Originally posted by PaRedneckRiders
Does anyone have a close up pic of the kick shaft coming out of there case?

How long is the XR400 kicker or could i use some other kicker that is shorter that still fits on the XR kickshaft

http://www.exriders.com/vbb/showthread.php?s=&threadid=293068&perpage=10&highlight=kick&pagenumber=4

[PaRedneckRiders]

Originally posted by JOHNDOE83
http://www.exriders.com/vbb/showthread.php?s=&threadid=293068&perpage=10&highlight=kick&pagenumber=4
Ok thanx i must have missed that page because it shows the kick shaft and how he moved the break lever

[TRXRacer1]

Didn't mod anything, those are pics from my XR400.

[PaRedneckRiders]

Originally posted by TRXRacer1
Didn't mod anything, those are pics from my XR400.
O, i was wondering why the peg was up but i left it go figuring it was just something u changed
And used an xr side case because of the 2 pieces