Need opinions/info on 400ex to "650ex" ?

[MisterGraphic]

Hello Everyone,

I posted this in the hybrid section but I figured it
would be nice to have opinions from "both sides"

For the past 4 years I've owned a stock 2001 400ex.
I've added a few things to improve handling (kfx450
front shocks, burgards + 2 a-arms and rear wheel
spacers, gncc holeshots, protaper bars)

Believe it or not, the motor is completely stock.
(I don't get to ride that often)

It recently started to burn oil and I've been itching
for more power. I've seen a couple of ex with the
xr650L motor and thought
that maybe a good solution for me.

What do you guys think about that motor swap ?
Would it be better than putting money to improve the 400's power ?

Random details : I mostly ride trails and am looking
for reliability. (example: last year we did a rally and
drove almost 400km in 3 days) I still like to go in pits
fool around on jumps and climb hills.

Thanks for the help and opinions,

[flyboy1294]

Tayyo on here has made a swap similar, if not identical to the one you are considdering. I'm sure he'll chime in here shortly...

[Pipeless416]

the 650l is different from what he swapped. he used a liquid cooled 650r. the r is definitely an awesome engine, but the only thing i like about the L is that it looks very close to the 400ex engine.. sleeper.. however, from what i understand, there is not a HUGE difference stock for stock between the 400ex engine and the 650l.

[tayyo789]

The L would be a much easier swap, and would be a lot easier to maintain and such. There wouldn't be a radiator, a kickstart, etc...

[honda400ex2003]

that would be the one i would be using if i did it. much easier than mounting all of the stuff. you would need to fab up mounts, run a new throttle from the 650 and make sure it is lined up for purposes of the chain. a custom exhaust would have to be made but you could most likely use an aftermarket header from a 650 to get it started. steve

[tayyo789]

Exactly. Just the fact that you have to put a radiator on a ex frame causes soooo many issues

[TRXRacer1]

I have an xr400r, and I've had some seat time on an xr650l. The weight difference is huge. I mean the 650l is one heavy feeling SOB. No BS there is almost a 100lb difference if you look them up and a lot of that is engine. Not saying it's a bad idea but just be ready for a heavier ride if you go that route. If I did this build I'd be all over the XR600R engine. It would be a kicker but much simpler, lighter and the aftermarket is far better. You can make those motors down right BEASTLY!!!

[tayyo789]

The engine weights arent what make the bikes heavier. The 650L engine weighs roughly 15 pounds more than the 400ex

[TRXRacer1]

Originally posted by tayyo789
The engine weights arent what make the bikes heavier. The 650L engine weighs roughly 15 pounds more than the 400ex Sorry, there's no way in hell. That engine is a beast. I know the bike itself is heavier but a battery doesn't weigh 90lbs.

[tayyo789]

I'm just going off of what I've read. I know the R motor a lot better than the L, and I know the R motor is 8 pounds lighter than the ex

[MisterGraphic]

Woah, hard to believe the R engine is 8lbs lighter than the 400ex engine.
I guess that what happens when you remove the cooling fins
and all that stuff....haha

Thanks for talking about the Xr600R, This seems like it would be even better! I found this on another forum :

Stock XR600R Horse Power???
I had mine dynoed by a local shop when I first bought it. At the time it was stock,
except for the Husky muffler. The dyno came back with 46hp at 6000rpm's. I have opened it
up a bit since and now
I am at 49hp at 5800rpm's. Not bad for a bike that weighs 282.

46hp compared to 31h is a HUGE difference, I'll have
read more about it because it seems pretty "extreme"
if you compare the displacement.

Back to searching! I guess the down side of the
Xr600R would be No electric start and all that....

[TRXRacer1]

Originally posted by tayyo789
I'm just going off of what I've read. I know the R motor a lot better than the L, and I know the R motor is 8 pounds lighter than the ex That I could believe. I guessed when I said 15+ but with out the electric starter I could see it being pretty close to neutral weight.

MisterG, I wonder if an LT250r rear fender could be matted up on the EX? If it did those were made for a rear kicker. When I bought my XR400 I had gotten pretty spoiled by "the button" and was a little concerned about loosing the convenience but when dialed in these XR motors start real easy. I don't miss electric start at all.

[TRXRacer1]

I wanted to add there's a big following at ThumperTalk on the XRs just in case you want a good forum to talk to others about what to expect and modding the 600 or 650.

[tayyo789]

x2 on ThumperTalk.
They know their XR's over there.
XRsOnly has some stuff worth looking at too

[MisterGraphic]

Thanks for the input everyone,

I'll keep reading / searching.

I'm trying to build a folder with
all the information I gather.

That will hopefully help me make
the right decision.

I'll keep you updated and will
have a build thread if I go forward
with this project.

Thanks again!