Rebuilding engine

[StreetLegalEX]

Well, I've had little luck with my 400ex yet...

Blown my head gasket twice. (repairs done by different mechanics)
This time I am going to try and fix it myself because I don't have enough money left to pay a mechanic to do the job for me.
Plus I will hopefully learn something about my quad... :)

Well, I am planning to take the engine apart, flattening the head and cilinder, using new taps and new bolts everywhere I can, and ofcourse brand new Honda OEM gaskets.

What should I look out for, pay extra attention to, to prevent the head gasket from blowing again? (and since this is my first time doing an engine rebuild)
Should I retighten the cilinder-bolts after a few hours riding?

Any extra tips?

[RideRedEX]

people have the same problem when using stock head bolts with big bore kits. just go buy the head bolts for a 440 kit and it should help with your probem

[K_Fulk]

Maybe your head or cylinder is slightly warped?

[stupid driver]

you only need a few things to rebuild a motor CORRECTLY.

1. A good set of tools
2. a SERVICE MANUAL
3. Most importantly....a six pack of your fav. brew(in rico's case maybe a 24 pack)

that will get ya through the task

[zfire_28]

Originally posted by stupid driver
....a six pack of your fav. brew ;)

[StreetLegalEX]

Thanks I will keep that in mind ;) :D

[StreetLegalEX]

Originally posted by K_Fulk
Maybe your head or cylinder is slightly warped?

Yes is what I thought also, once I have it all apart I am going to have them both checked for warpage.

I am also going to try and get those extra strong bolts.

[Waynes400ex]

I was told by Powroll that bigger studs make the problem worse. I guess they (spelling is wrong) healey coil it and keep the stock studs, they also told me to follow honda's head torque and pattern and that it should be good. What comp and size engine r you running?

[nakomis0]

Instead of OEM I would get the gaskets that you don't have to re torque the head bolts.

Not re torque'ing the head bolts on your last 2 gaskets could of been what made em blow. Checking for head warpage is a good idea too.

[StreetLegalEX]

Do you really have to retorque OEM Honda gaskets? Yes that could've def. been the problem.
How long should I run it before retightening?

I am running standard comp. and cc-size.

[chevrolet486hp]

for around $10.00 a machingist will put a good strait edge on a pice of foot long steal . then you could check the head out . if not to worped betwen .002-.004 you can fix it your self.you will need a good flat surface ,COUNTERTOP,WELDING BENCH, on a sheet of 400 grit sand papper move the head back and fourth RECHEKING the amount of worpage


Hope this helps

[ZeroLogic]

Bump the noob!:blah:

[DAVE14]

as long as its all straight & true it should seal well without any problems as for blowing its normally caused by higher compression not an overbore I use gt thunder studs in my higher comp 440 no problems at all the stock studs will pull out in time with more compression & blow countless gaskets if not upgraded

[DieselBoy]

Dude you must have a high compression piston in there....that shouldnt be happenin...

[BLEEDRED]

Also check the 8mm head cover bolts. There are three on the timing chain side that thread into the jug. They play a big part in keeping the head gasket tight on the right side of the motor. Make sure you follow the torque specs. when you set the motor back up. And don't overtighten the 8mm head cover bolts. The correct torque is just less than 8 footpounds. Good luck!!

[StreetLegalEX]

Dude that was a long time ago :D

The quad has been rebuild like 3 times before I finally sold it.
It has made lots of people unhappy ever since, sometimes it pops up on ebay etc. Nobody gets it to run right I guess :D

I have my KFX400 for 2years now, without any problems at all :D

[DieselBoy]

Poor b.astards who own it. LOL

[StreetLegalEX]

Yeah felt sorry to sell.....but it was makin' me poor.
Spent way to much on that quad.

The guy that bought it said it ran better than his friend's Raptor660...not for too long I guess.....

To bad....