starting an old engine

[mainline]

G'day, I've got three engines to pick apart to make one or two good ones for the YZ, one of them turns over with fairly good compression and is fairly clean overall.

My question is, not knowing the history of the engine or how long since it's run, do I take a chance, clean the carb and filter and try and start it, or am I safer to pull the thing apart and have a look first?

[holeshot buddy]

i would at least pull barrel off check bore and piston and check big end for movement
also pull off ignition cover check for up and down play on flywheel
which would indicate worn main bearings
if all looks ok try it

[Doc]

been known to try the lazy way on a dunger Mainline but I don't advise it unless it's a worthless heap

obviously best to whip some bits off for a look at least..only takes 5-10 minutes on a removed motor to check the critical stuff Russell mentioned above. Check how much spanner work has been done by looking at screw heads, bolts, nuts and gaskets..sus the gearbox oil while you are at it..if I find any metal particles or it's not reasonably clean I tear the engine down and replace all bearings, seals and gaskets before I think of starting it.   

[Bamford#69]

If you are an optimist,and think you could get lucky,  and you  don't want to split the cases (yet) remove and clean the carb,take the head off ,look for rust marks in the bore, remove both the ignition cover and clutch cover check for free play or roughness when spinning over by hand, at the crankshaft,if there is no sign of moisture anywhere,and the transmission  oil is clean ,fill the the crankcase with diesel fuel thru the inlet,  lube the bore and rings, spin the crankshaft with a speedbrace by hand as fast as you can,now drain the diesel from the cases, if there is no contamination evident ie; clean diesel drained out, you might be lucky,someone may have stored it properly.
Reassemble everything with clean oil and clean fuel, and have a go.

[mainline]

Thanks for the info, I'm on a fairly tight budget and I'm going nuts seeing the pics from the different events coming in, while my bike is in bits.

Is most of the bottom end rebuild stuff DIY if you fairly capable, or are there too many specialist tools involved?

Thanks again

[vandy010]

http://ozvmx.com/community/index.php?topic=1499.0

heres a link to another thread, in it, is a pic of a crankcase seperating tool i made up.
tools for bottom end stuff i use are, crankcase seperating tool, flywheel puller,clutch basket holder, and a good set of verniers. take your time the first time round, ask heaps of questions and if theres something your just not sure about or confident with, it'll be cheaper to take a partially dismantled motor to the local bike shop than it will a complete one, so it'll always be a step in the right direction.
and lets face it, if we're going to play this "build up the old bike" game, to learn these skills will make each and every project that little bit easier.
cheers.

[mainline]

Thanks Vandy, the flywheel puller I have, the verniers I've been meaning to buy. Thanks for the link to the other thread, some good info on there. I try to search this site before asking too many questions, but sometimes I'm not using the right terminology in the search engine.

Hopefully this weekend the engine will get looked at and I'll see where I'm at.

Thanks again