Engine Rebuild

[thomasdjames1]

I need to rebuild my engine because it is burning oil when you first crank it up. It blows out blue smoke for a little while when you first crank it up and it is getting a little worse with time. I am very good a working on anything and think I can tackle an engine rebuild but I have never done one before. Anyways what I am wonder is exactly how the engine comes apart (I know I need to buy the shop manual). Do I just pull the head and cams to get the timing chain out and then unbolt the cylinder from the transmission? I guess you just pull the cylinder upward and the piston falls out of the bottom still attached to the rod. Do I have to take the transmission apart to get the crankshaft out or can I just leave the crankshaft alone? I want to just unbolt the cylinder and pull upward and put a new piston, rings, cams, and valve seals in and then just use a ring compressor and slide the cylinder back down ever the piston, reinstall head, cams, timing chain, and go. Is this doable or do I have to take the transmission apart and get the crank out. Also how high of compression piston can I use with the stock crank? I want to use the JE 13.8:1.

[reekers529]

QUOTE (Thomas @ Mar 2 2009, 10:14 AM)

I need to rebuild my engine because it is burning oil when you first crank it up. It blows out blue smoke for a little while when you first crank it up and it is getting a little worse with time. I am very good a working on anything and think I can tackle an engine rebuild but I have never done one before. Anyways what I am wonder is exactly how the engine comes apart (I know I need to buy the shop manual). Do I just pull the head and cams to get the timing chain out and then unbolt the cylinder from the transmission? I guess you just pull the cylinder upward and the piston falls out of the bottom still attached to the rod. Do I have to take the transmission apart to get the crankshaft out or can I just leave the crankshaft alone? I want to just unbolt the cylinder and pull upward and put a new piston, rings, cams, and valve seals in and then just use a ring compressor and slide the cylinder back down ever the piston, reinstall head, cams, timing chain, and go. Is this doable or do I have to take the transmission apart and get the crank out. Also how high of compression piston can I use with the stock crank? I want to use the JE 13.8:1.

sounds like your just doing the top end no need to pull crank or mess with the tranny, i read something like the stock crank has to be replaced after 10-15 hours after adding a high compression piston so if your into more motor work in the near future go with the high compression if not stay stock compression and add cams.

[walshyfz86]

It sounds like your rings and cylinder are shot. Stock cylinders plating is horrible. And you probably have a bad wear front and back of the cylinder. A renickel you would need definitely. Pretty cheap to. Id bet your intake is filled with oil to as that also causes a blowby into the crank and pushes oil out of the crank case breather that runs into your intake tube on most intakes

Well the top end is easy.

First remove the 2 caps on the non exhaust side of the motor down by the stator

Get a 17mm socket and turn the crank till you reach your TDC line

loosen timing chain(The chain adjuster sticks out on the non exhaust side and has a 10mm nut at the end. Stick a skinny flat head in there and turn clockwise all the way tight so it locks

Remove cam bolts.8mm Cams show a order on how they should be tighten and loosen. And i think it was 12lbs torque

Remove cams. Becarefull for the clips on the bearings dont fall in.

Remove 4 head bolts. 12 or 14mm i forgot? Torque is 44ish lbs.

Then there are 3 allen key bolts 2 holding head to cylinder and one holding cylinder to case

Slide up and theres your piston. If you decide to put rings on there is a certain way the ring opening should face.




Now if you want to change your crank your self . Very easy. You will need a flywheel puller and a air gun can zip the basket off no problem. Once the cases are split the tranny will stay in the exhaust side case and you wont need to take it out or mess with it. Sometimes you need to press the crank out of the bearing other times not really. You can use a steering wheel puller to push it out if needed. And its all pretty simple. I would defiantly get a book before going into the bottom end. But if you no what your doing changing a crank is a 3 hour job tops. a 13.8:1 is to much for a stock rod. Stock rods are not that there weak but its a metal on metal. You can buy a DLC wrist pin for about 200 and it would solve your problem to. Or you can go get a carrillo rod ( the best rod on the market right now, Same in factory bikes and on walsh cranks.) for about 300 then bearing and install. Also you can have your rod sent out and a brass sleeve inserted in wrist pin area and it acutlly works pretty good as that what i use in my rage motor.

Let me no if you need anything els

[kawirider55jaylew]

NO NO!!!!!! THE CAM TORQUE IS NOT 12!!!!!! IF YOU DID THAT THE ENGINE WOULD NOT EVEN TURN OVER. ITS 7.2 FOOT POUNDS. AND HEAD BOLTS ARE 48.

[walshyfz86]

I believe the head bolts are 44 i dont have the manual with me and wasent certain on the cam bolts. thanks for clearing itup.

[thomasdjames1]

[quote]
It sounds like your rings and cylinder are shot. Stock cylinders plating is horrible. And you probably have a bad wear front and back of the cylinder. A renickel you would need definitely. Pretty cheap to.

When I pull the motor apart I am sure I will have the cylinder re-plated but I do not know too much about cylinder plating. Am I going to be forced to have the cylinder bored bigger then platted? I guess what I am asking is how does the plating shop get the cylinder exactly the right diameter and then re-plate? It seems to me like you would have to first bore the cylinder the get the old plating out then put new thicker plating on. I do not know. I am assuming that the motor does not have a sleeve and that the coating takes the place of a sleeve but how thick is the plating?

[walshyfz86]

Um from what i understand they kind of dip it in acid and it eats away the nickel on the stock cylinder. then they put nickel on thicker and bigger then from there they just bore/hone it out. I am no expert but im almost positive thats what they do.

[thomasdjames1]

Has anyone ever dealt with Millennium Technologies or JE pistons? I called JE pistons yesterday because this spring / summer I will pulling my motor and building it. I want to make more power with the motor but I hear that if I use the 13.8:1 compression piston I will have reliability issues with my crank shaft. JE makes pistons that are +2mm, +3mm, +4mm in various compression ratios but I am told by JE that if I bore more than +2mm I will need to put an aluminum sleeve in the motor. They recommended me call Millennium Technologies and ask about boring and installing a Nikasil plated aluminum sleeve if I wanted to use the +3mm or +4mm piston. The +4mm setup seemed great to me because you would a compression ratio of 13.0:1 and standard stroke which would make 488cc. Any thoughts on reliability? I am hoping 13.0:1 is still ok for the stock crankshaft? Millennium Technologies said the price for boring and installing the Nikasil plated aluminum sleeve would be $400 (actually like $395 or $399 I cannot remember the exact number). Wondering if anyone has done this or knows much about putting aluminum sleeves in ATV engines and what affects it will have. I think I could have a strong build for not too much.
$350 KOQ intake
$400 Cylinder
$200 piston (guessing)
$325 Hot Cams
$1275 Total

Not exactly sure but I would guess I would be somewhere in the 55 hp range.

[chzeiw]

your crank is buld for 10 to 12 hours of us with hi compresion piston it wil not last

[alger388]

make sure you bust the small allen bolts on the head before the big bolts. If not you have all that tension on those small allens and will more than likely snap them.

I just tire mine apart yesterday. I broke 4th gear, well the dogs that contribut to 3rd gear anyway.

crank gear nut is reverse thread. I found that out after awhile. im used to my yfz engines where its not reverse threads.

CP pistons or bust too