HI to everyone, i`m new here and after some friendly advice and help. i bought a 2006 yz85 bw for my son on the understanding it needed a rebuild, is this an relativly easy job( i`m mechanicaly minded) and what about diagnosis- will it b obvious whats wrong when stripped. Thx

Welcome to the forum.

Not familiar with the yz85. Sounds like a good place to start to learn about fixing bikes though. 

Parts like a broken piston or piston rings etc. will probably be quite obvious. What is hard to spot is wear/excessive wear in components like bearings and clutch plates etc. and won't always jump out at you and will require either measuring or close examination.

If you get a manual for the bike it will help alot.

Thats all i can think of for the minute, someone else can probably add more.

Vez.

Hi vez and thx! when i bought the bike it would`nt kick over at all so i`m hoping the person or young lad that abused the bike has simply not looked after it and its seized, so i spose it could b a number of things rwealy? it seems to go through the gears fine and into neutral so hears to wishfuul thinking

Welcome si, its a competition 2 stroke MX bike yes?

is it seized, what have you dome so far? i'm wondering if it has a special plated barrel, maybe having a word with professional re-borers would be wise ...try PJME

Your boy is so lucky to get this

...Paul

Hi, paul, yes it is a off rd bike but i dont think the owner before used it in competition, he came into inheritance money and bought it new, took it out to the local clay pits and thats it, not touched it yet me self, kick start wont buge, it has v-force 3 reeds on it and a fmf gold series competion exhaust system...

hi people, today i have removed the engine from the frame and exposed the piston which seems to be fine?, whilst still in the frame i managed to move the kick start and the piston moved 2 but this has now stopped and if u put pressure to kick it it wont buge but move it lightly it will eventualy move to the bottom but not turn the engine over- i`m thinking its got to be something to do with the kick start? maybe worn teeth? any ideas peeps

The piston isnt seized so that is very good news. next job then is to drain the oil and remove the clutch cover casing to examine the kick start mechanism, hopefully you will identify the fault when you see in there.

Hi-al, next i have drained the oil which looks very silvery( i think thats bad-yes?) and removed the clutch cover casing, i havent gone any further as i`m a bit worried something will spring out at me..lol... but i`m reckoning its gearbox or kick start still?

The only thing likely to do that would be the kickstarter return spring. I was kinda hoping you would see the fault when you removed the casing. Look at the kickstart return spring, if it is still located correctly it may be advisable to photograph it while it is in position for future reference. silvery oil is not good.