03 yz250f rebuild

[Natedawgrebuilds]

Pick up this yz250f for a good deal had issue tho like trying to kick it over when warm. Lost of compression. Could move the kickstart lever down by hand easy but it runs mint.
So first thing first is checking the valve clearance. I already have a gasket set order and piston and rings but im wondering if my vavle clearance are inspect can i reuse the shims when i put my new piston and rings or do i have to order a skim kit, even tho i would need to order one if valves are off. Will keep you gets updated on the build, as i just finish using a extractor kit on the valve cover bolt as the previous owner stripped the shit out of it. Will post the measurement tomorrow of clearance.

 

[Natedawgrebuilds]

So open up the valve cover. Gasket was finish idk why the previous owner reuse ot but all the bolts on both camshaft were loose and one was threaded all the way out i can take out by hand. Also my crankshaft cover is striped so i had to find tdc with my kickstand. There a dot in the middle of the timing cover i know its tdc but my intake cam lobe is off so im thinking it skiped a tooth on timing or previous owner wasnt mechanicaly incline so no point of checking clearance. Take everything out re doing piston and rings and gasket

 

[Natedawgrebuilds]

I meant kick starter not stand ahah

 

[Rich Rohrich]

Given the state you found it in, you should pull the valves and check them for wear along with inspecting the valve seats. You'll also want to replace all the valve springs. They are only good for a season or so of regular riding. Luckily they are really cheap. You can reuse shims, but chances are good you will need different sizes then what is currently in the engine. Investing in a Hot Cams shim kit is money well spent if you are going to own a four-stroke.

 

[Natedawgrebuilds]

I hear what ur saying rich and i finally got to my piston today how holy shit does it every look ruff. Piston has deep vavle stamps on it and the piston wasnt at tdc but the little dot in the timing cover is align. So i play with the piston till it got tdc and the mark shown in the timing cover is HI. I know it says dont turn the crankshaft when vavle are out due to having to do timing. Anyways i already need to do base timing because i did some diggin around and a found a old magneto in the bag of parts that the previous owner gave me, the thing that goes into the crankcase and bolt on with the nut u use to find tdc. So im thinking buddy didnt do base timing but the bike back together and sold it to me. So i have to do my base timing as well has new piston and rings and probably like you said valve spring and forsure check my valve for damage i can visual see any but will measure it forsure. I will be posting more info on the build when the parts get here.

 

[Natedawgrebuilds]

I cant visually see anything* i meant

 

[Natedawgrebuilds]

This is my first time open up a dirt bike and the vavle did hit my piston the piston is oem and look like that. I always thougjy it was flat on the top of piston but i my rings were done. Order a wiseco piston and rings but i was looking at my connect rod and i had abit of up and down play. Would it be easier to replace the whole crank. I can order a hot rod crank for around 450$ because either way you have to split the case to change the connecting rod but right now im take the engine out of my bike to work on it better and stripping my frame to get it sent out for podwer coating still debating on the colour. And also i order a new timming chain.

 

[Natedawgrebuilds]

Valves didnt hit the piston