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View Full Version : 400ex isnt indestructible ( $$$ race)


004exkid
03-19-2002, 02:31 PM
I raced the 2nd hare scramble of the season sunday on my fresh 416 ex. I always thought i couldn't break this motor but I guess I was wrong. I'm not sure on the exact cause yet but my engine is now destroyed. I think rope tangled up in my rear brake and caused an extreme load on the engine. Here is the damage :

1. Both engine cases completly destroyed. Softball size hole in front and many cracks.
2. Connecting rod broke into 3 peices.
3. Fresh 416 10.8 je has a chip out of the skirt.
4. Hole punched in the bottom of the sleve.
5. Bent shaft in the transmission.
6.Broke the end off the internal clutch shaft.

I split the cases last night, it was ugly. Im gonna try to get it going again unless anyone knows of a cheap 426 ?
03-19-2002, 02:41 PM
bet wit all that crap floatin around in the bottom end, thers alot more damage, check ebay or cycletrader, thats gunna take a f*ck load a cash to fix.
MIKE400EX
03-19-2002, 03:47 PM
004exkid, Sorry to hear about that bike! What mods did you have done to the motor?
004exkid
03-19-2002, 06:23 PM
The only internal mods I have done are a 416 je 10.8/1 piston and a xr cam. I don't think it had anything to do with the top end becasue it didnt seize up. Once the connecting rod let loose it and the counter ballencer destroyed the engine. I just took the transmission apart and the shift fork shaft is twisted along with one of the gear shafts.
papaw
03-19-2002, 06:51 PM
atving.com or ebay had a 400 motor for like 1800 bucks. ithink it was basically a crate motor.........maybe it'll be better to start over
again.........
SGA
03-19-2002, 07:56 PM
That engine is toast. Start over with a rebuilt engine from one of racing engine builders. It will be strong and reliable.
ChadEXer
03-20-2002, 08:59 AM
if that ever happens to me I will just cry:(
MIKE400EX
03-20-2002, 09:21 AM
004exkid, were you using a modified rev/ignition box?
250exmaster
03-20-2002, 12:32 PM
this might sound a little weak but i would stick a .60 over blaster engine with stronger gears in there and have fun with it in ablaster clas or a 200cc class
TrX465
03-20-2002, 01:39 PM
hey man same thing happened to me with my 440 but my rod snapped clear in half and cam out of the back instead of the front i didnt cost all that much and we orderd all new bearings everything...it was easy to
trx400ex
03-20-2002, 01:44 PM
so the moral of the story i swhen adding more power replace the rod? i saw a heavy duty rod on sparks website www.sparksracing.com
004exkid
03-20-2002, 02:01 PM
I was actually thinking of getting a blaster engine and race the 200 class this year. I think I would be kicking myself once I came to the first hill I had to go up tho. And Mike400ex, the ignitoin system is stock. I am going to look at a 1977 yamaha dt175 friday for $100. That will at least give me something to ride.
400exdad
03-20-2002, 03:57 PM
I hate to hear about that! I think I would strongly suggest buying another 400 and consider parting it out. Hopefully you can recover most of the money....... At least you were riding it hard. Some folks with '01 Raptors are blowing trannys just cruising around. Think how that must feel. Good Luck in getting it back together.
Nausty
03-20-2002, 04:56 PM
probably the high compression piston or you got rid of the rev limiter and ride it when you should be shifting and it makes more power at a lil lower than full throttle anyways. Cheaper and easier to probably just do like the others said and buy a new motor.
NJ300ex
03-20-2002, 05:29 PM
He explained why it blew up in the original post.
03-21-2002, 07:15 AM
Just wondering it there's a connection with the brand of oil you were using and others who have had engine problems.
03-21-2002, 07:23 AM
Just wondering it there's a connection with the brand of oil you were using and others who have had engine problems.
004exkid
03-21-2002, 02:23 PM
I dont think it had anything to do with the oil i was running. I dont think the engine has enough torque to completly self destruct its self like it did. I belive it was from the rear brake locking up and the connecting rod breaking... I am bummed rite now tho because I was just out bid on the 400ex engine on ebay. Somone used the buy now option I was plaining on using once the owner got back to me. So if anyone knows of a 400ex engine please tell me.
03-21-2002, 02:28 PM
call Ken Cornwell at rocky ridge racing,,,270-259-9604. ,I'd bet he's got 1 or 2 sittin around..
papaw
03-21-2002, 02:31 PM
i have a crank,2 jugs,and a head with valve train all needs some attention.if you have to piece one together.just trying to help..........