Putting a new engine in the 400ex

[yungair23]

I am wondering if i buy a new engine is a job that can be done at home or does a shop have to put it cus of certain tools needed etc??? Need to know before i buy one...

it can be done with a set of metric wrenches, and a set of skrewdrivers. some alen wenches. as metric socket set will also make live a lot easier but not 100% needed.

[zeppelin]

do you mean taking the whole old motor out and putting a completely new one in, thats a big wate of money if you ask me, but if you really wanna do it do what mittimj said

[yungair23]

im better off doing it because i need to replace my valves, rings, and need a new transmission and also on top of all that my exhaust bolts broke...i think it would be less money to buy a used but fairly new one...dont you

[zeppelin]

not really the ri help ou figure it out if you want (btw im not trying to offend you in any way, just wanna help you out) okay rings $20, valves $120, piston $100, .20 bore $75, and the exhaust bolt will easily come out iv you have a pair of vise grips and a new bolt is like $2,are you sure the tranny is shot and its not just the clutch, what does it do wrong

[yungair23]

ok first off the be able to do all this i need to bring it to a shop so on top of all that there is also the cost of labor...and the transmission issue started off with it slipping then catching and then it got to the point where second doesnt move my quad al you hear is clanking and clicking...i think seconds gone wich is expensive...

[yungair23]

i can get a motor with low hours on it for under 800 i think the tally for all the work on this motor will be more than that but maybe im wrong

[zeppelin]

if i were you id go get a shop manuel and do all the work my self, but if your tranny really is shot and you can get a new motor for 800 than that probably is the way to go, maybe see if you can just get a bottom end for a little cheaper and get like a 416 or 426 kit for your bike it would probaly cost 600 with the bottom end and you would also learn somthing from it

[yungair23]

ok i think i could get a bottom end for cheaper and if i get a 416 or 426 kit that still means i will have to get valves or rings rite? and also i will need a new cylinder fer the larger piston no? please not sure exactly what you mean...

[zeppelin]

with the kit you get a new set of rings and a piston if you get the 416 i think they just bore out the stock cylinder sleeve and with any thing higher like the 426 and 440 i think you get a new sleeve and you bore the actual cylinder

[yungair23]

yea but if im blowin blue smoke witch means im burning oil i could have burnt up my rings or i could have also ruined my valves which if the 416 kit gives me rings i still will need valves correct and how am i suppose to put a 416 kit in if i need to bore then i need a shop to do it right? I am catching on to yur idea though

[zeppelin]

yeah okay what you do is you tear it down your self and bring it to a shop so the can bore it out the put everything back together yourself rather than having the shop doing everything, btw if you have the balls you could tear into the tranny and repalce the broken gear od shift fork but thats if you are a pretty competant mechanic, but the top end should be pretty strait forward and eaay for even a newbie mechanic. ohh and im pretty sure you just need the rings and no valves im pretty sure that if that valves are shot the smoke is supposed to be white

[yungair23]

ok just to let you know i think i am going to not replace 2nd right away because i ride road alllooootttt lol and can go straight to third i think this is why my engine is so burnt but i decided to begin to take it easier after i rebuild anyways

so what i should do is take the engine out right? then remove the top end correct? and then bring it to the shop give them the piston and tell them this is what i want to bore it to? and then put the gaskets and rings that should come with the kit and w.e else in with the new piston and put it back together?

also i do know a few people who can help with this task that know about engines...and i am getting a honda service manual wich should help taking the top end off right..

also whats a good 416 kit to buy ? and where ?

( also whats (btw) ? )

[yungair23]

also lets say i get it bored and have the 416 kit in this will solve my blue smoke problem? I am assuming it will only if i need new rings but if not this means i need valves right?

lol, if you get a bigger bore you need bigger rings and piston regardless.


I cant say much because he may be buying a motor from me. but hear is my opinon.

by the time you get all that stuff done to the motor it will be lets say 400 ( I have no idear what it will be). I know that if I put my own engine together every time I started that thing I would be flinching that somthing really bad is going to happen. I dono, but I dont like the sounds of your mechanics skills, it would be sad to have all that money into the motor and have it blow up in 2 secconds because a circlip was missing or sumthing.

buying a stock engine just seems better.

swaping motors is a peace of cake. just take all the wires off that go to the starter. then the spark plug wire. drain the oil. take the swing arm bolt out, scary!!. if you havent had it out then this will be a major chore. you will have to take the front plastic off. along with the gas tank. then the carb. dont undo the throttle cable just let it hang. then un do some bolts that hold the motor down and done. I put my motor in, in maby 1 1/2 hours.

but if you havent gotten that swing arm bolt out you are in for a real treat.

[yungair23]

yea well i have never removed anything on my bike at all except for my exhaust wich after bolting up bolts broke and now need new one lets say i SUCK at motor stuff lol

[yungair23]

also Tim can i get some photos of this engine? Email them to me as soon as you can yungair23@yahoo.com

sorry I was waiting for teh camera bateries to charge up.

[zeppelin]

im not tryimg to ruin your deal or anything mittimj, but i think your taking advantage of him. yungair heres is exactly what i think you should do. take all the plastics and gas tank off, clean the crap out of your whole bike( so that dirt doesnt fall into the motor when your working on it). then using the manuel take the cylinder off with the motor still in the frame (easier that way). after you get your cylinder buy either a 416 or 426 kit (it will come with piston rings and i think a sleeve with the 426) after that bring your cylider to the shop and tell then to either press the new sleeve in (the 426) or bore it out to a 416. when you get your cylinder back instal the new piston and rings but do it with one of your mechanicly inclined friends and a manuel. also before you tear it down have some one thats been around quads awhile ride it to confirm the tranny is hot. if its shot ask around and see how much a shop would charge you just for labor. after that decide wiether you wanna get into the tranny or have someone else do it ( i personaly am scared chitless of the tranny)btw, btw stands for by the way sorry for the long post let us know if you still got more Q's i tried to explain it the best i could

what happends if the tranny is shot. he takes 1 lap around that yard, picees of the shot trany go up into the head. then he is back to whare he started.

[zeppelin]

sorryfor the confusing jumbled up post, but i suggested that he let a mechanicly incliend person whos been around quads awhile ride it around a little to verify if it screwed up or not

[yungair23]

how much do you think its going to run me for a good kit? And will it be expensive to have the shop bore it out or press the sleave in? I just need an estimate...also i was talking to my friend that knows a little about this and he said the valves are gone or almost and need replacing is this expensive...?

[zeppelin]

i am 97% sure your valves are okay, but if you wanna have them checked out, bring it to a few of your local shops and ak them if they look okay or not, i posted some price estimats on the last page, im just in a hurry right now to look them up for you again sorry

[400exmatt]

You can usually find a bottom end cheap when i busted my cases on my blaster i bought a whole bottom end in great shape for 60 dollars and all i had to do was put the pison in slip on my cylinder slap on the head and i was riding.