doing a topend for the first time on my own

[drag101]

hey guys i just figured out what my jetting problem was its cause my rings r soo bad my oil is getting on my plug so i guess i gotta rebuild but ive never done it befor so i have a few questions for u guys
1-should i rebuild and take a week or 2 off from my races or wait till fall and do it then and just hope i can go 2 hours in a haircsramble wihtout blowing a plug cause of the oil
2-how hard is this 2 do ive done everything else on my quad befor and havent had much trouble so far
3-should i keep stock bore or bore it out and if so 2 what
4-should i replace the piston or just the rings
5-how much money am i looking at in parts if i bore it and if i dont im doing most of the work at home but sending it out to get bored if i do



thanks for any help guys

[gnccguy]

hey man all your ?s r really up to u if it needs to b rebuilt to b fast and safe on the track do it now. For the bore ? u need to mic the cylinder to c if it needs it un less ur wanting to do a big bore kit. You will have to take the jug to have the bigger sleave put in it isnt cheap if u want to do a big bore kit. U should replace the piston to not just the rings. u would b able to put it together for around $300 give or take that is if all u need is piston rings and gaskets and cam if u do a big bore (440cc) ur looking at around 500 for parts and a good bit for the bore work its self. It isnt to bad of a job if u have a good manual. Only advice 4 a first timer is to read the maunal that deals with the rebuild and if u dont understand something dont start work till u do.

[JW450R1]

If your going to break into the motor.I would bump it up some.I just bought a 440 kit,and stage 2 hot cam off ebay 4 $301 shipped.If u deside to go with a 440 kit,I would recomend a crf 450 cam timming chain while you are in there.I think it was like $500. for the 440 kit,stage 2 cam,timming chain,gasket,and stage 1 port.Man that 400ex came alive.Just make sure u torque everthing down to specs

[drag101]

what kind of of power gains should i expect from a hotcam and a 11:1 numaric piston and would i have to rejjet agien

[ncsmash]

If you do the 440 i would strongly recommend HD studs or get used to blown head gaskets