xr400 engine does NOT bolt right in

[maxamillion]

Just a heads up to anyone thinking of doing the xr400 complete engine swap... I found out the hard way that the rear engine mount where the pivot bolt goes through sits 1/2 inch higher on the xr400 cases compare to the 400ex cases. I got mine to fit but a had to smash the tubes in the frame down some with a hammer. Then it throws all the other mount holes off slightly so you also have to modify them. Deffinately no where close to a direct bolt it swap.

Ill get some pics up later if anyone is interested. I've ran into more problems then I planned for but it should be worth it once I get the bugs worked out. I got the kick start to clear the frame but it wont recoil for some reason :ermm:

-Max

[dariusld]

There has been a thread on this before. But some people on here say it is and I'm not going to argue about it because I haven't actually done it.

[maxamillion]

ye I read alot of those threads there was a lot of good info but some of it was misleading. I'll get some pics up soon so you guys can see how it throws things off a bit.

[CJM]

Not for nothing, but if you went so far as to swap the motor-why didnt you weld or fab up the mount that would work-beating it into submission doesnt seem like a good idea.

[maxamillion]

denting the lower frame rails some with a hammer sounds alot worse than it is. Some ppl might not feel comfortable doin that to their frame so they may wanna shy away from this swap. I think if you tried modifying the pivot mount that would throw off the swing arm angle and who knows what else. Here are some pics tho I finally got the kick start workin like it should. Next project is making a custom upper engine mount...then last will be the wire harness.

[maxamillion]

this shows how I dented in the cross members of frame. I took the pic upside down cuz I had to tilt the motor up some.

[maxamillion]

I had to make it clear underneath the oil drain plug to.

[maxamillion]

kicker in motion. My rear plastic are shaved it prob wouldnt clear otherwise.

[maxamillion]

diff angle

[maxamillion]

last one for now. just my rear plastic design has nuttin to do with the topic tho. :D

[Homerx]

Originally posted by maxamillion
Just a heads up to anyone thinking of doing the xr400 complete engine swap... I found out the hard way that the rear engine mount where the pivot bolt goes through sits 1/2 inch higher on the xr400 cases compare to the 400ex cases. I got mine to fit but a had to smash the tubes in the frame down some with a hammer. Then it throws all the other mount holes off slightly so you also have to modify them. Deffinately no where close to a direct bolt it swap.

Ill get some pics up later if anyone is interested. I've ran into more problems then I planned for but it should be worth it once I get the bugs worked out. I got the kick start to clear the frame but it wont recoil for some reason :ermm:

-Max

So then why do it?

for the work involved i think it would have been cheaper not to mention easier to just swap to kickstart, get a new piston and cam which would be faster than the stock xr400.

[buck440]

maby your frame was bent? looks kinda beat up and it could be possible, i wish i had that motor so bad :grr:

[Homerx]

What advantage does this motor have over stock, besides no electric start ?

[CJM]

correct me if im wrong but doesnt it also have 6 vs 5 speeds?

[86 Quad R]

nawt bad, nawt bad at all but may i suggest that you re-inforce the swinger gusset where ya modded it. :cool:

[maxamillion]

The advantages are quicker revvin motor because of less rotating mass, Less electrical to worry about, cleaner look, less weight, etc. It is a 5 spd tranny but has diff gear ratios.

Putting the kick start on the 400ex will end up costing you about the same amount of time and money. You have to buy a xr400 side cover, hinson clutch cover to clear the basket, weld the stator side cover shut where the shaft comes out of the starter, remove the starter clutch bearing, and then you still have side covers that stick out further instead of the narrow look on the XR.

This is deff a learning process for me. Im doin this more for the cleaner look and reliability it will be used for MX only. It should gain some power tho but if I need more Ill just jump on my YFZ.

Thanks for the comments

[86 Quad R]

Originally posted by maxamillion
The advantages are quicker revvin motor because of less rotating mass, Less electrical to worry about, cleaner look, less weight, etc. It is a 5 spd tranny but has diff gear ratios.

Putting the kick start on the 400ex will end up costing you about the same amount of time and money. You have to buy a xr400 side cover, hinson clutch cover to clear the basket, weld the stator side cover shut where the shaft comes out of the starter, remove the starter clutch bearing, and then you still have side covers that stick out further instead of the narrow look on the XR.

This is deff a learning process for me. Im doin this more for the cleaner look and reliability it will be used for MX only. It should gain some power tho but if I need more Ill just jump on my YFZ.

Thanks for the comments

then you most certainly need to re-inforce those swinger gussets. ;)

[maxamillion]

hah its been reinforced with triangle gussets already. ur right tho it wouldnt hurt anything to weld in a couple more

[86 Quad R]

we talking the same thing here? i'm referring to the gusset where the swinger bolt goes through.

[maxamillion]

Ive never had any problems with that area, I didnt modify the pivot gusset. Im talking bout the triangle shaped area next to the foot pegs.

[maxamillion]

finished making the wire harness tonight. Only thing there is a stator, cdi, and ignition coil. gotta wire in the kill switch later.

[maxamillion]

since the motor sits lower...so does the carb unfortunately. I had to cut part of the subframe tube so the boot would clear. This will get reinforced later.

[maxamillion]

another pic of the intake

[maxamillion]

one more of intake

[maxamillion]

heres how she sits now. I still gotta make the upper engine mount, rear brake pedal and the clutch cable holder.

everything about this build is terrible sorry. frame bashing and pieces cut out... the motor isnt worth what your doing. you could have easily just got a cam, piston, and lightened flywheel for the 400ex and it would rape the xr400 motor without the need to cut and bend important things. seriously when the frame twists and cracks giving out and you come on here to say something I will more than likely laugh. there was no need to do what you did. kickstart swap would have been cheaper and easier. the other mods would have made a much better motor.

[buck440]

i think if he isn't racing and just wanted to do this for the reason of having the kickstart alone, so what. even with the tubes smashed a little i wouldn't think it would really matter.

[maxamillion]

Originally posted by FlewByU352
everything about this build is terrible sorry. frame bashing and pieces cut out... the motor isnt worth what your doing. you could have easily just got a cam, piston, and lightened flywheel for the 400ex and it would rape the xr400 motor without the need to cut and bend important things. seriously when the frame twists and cracks giving out and you come on here to say something I will more than likely laugh. there was no need to do what you did. kickstart swap would have been cheaper and easier. the other mods would have made a much better motor.

relax man. everyone has there own opinion. this quad will get raced and beat on. The areas I modified are not going to cause the frame to crumble into a little peice of tin. Should be running by the weekend and it will get raced March 15. If it does have problems I will be the first to say.

[sab24711]

so did it work! or crumble to small pieces of tin?

[Snipe]

I would say had problems, maybe not with the corner mounts but def with the subframe since there prone to breaking in MX even when not cut on.

[dirtcrasher]

Sounds to me like he did his research and felt it would be a decent swap, probably got a decent price on the motor too....

There are 6 ways to do every swap, it's all in what you can dream up and what skills you have.

It may be yet ANOTHER case where clowns post up that this swaps with that and there are no or little mods or you just need a longer bolt blah blah blah.

[Snipe]

Its not a case of getting a decent swap or getting a good price. Yeah I got the motor to fit but at what price? I mean beating in the frame and cuting a major tube on the subframe in half.

[BamBam21]

If someone could make a STICKY for a "How to convert to Kickstart" , I've done it and have all the info and would post it in a STICKY.

Thanks BB

[sab24711]

regular threads become sticks after the moderator set it to be a stick...... i think thats how it works. just make your own new thread. i know there are many people who would deff like that thread, cant hurt.

[sab24711]

WHAT HAPPENED!!!!!!!!!!!!!