How hard is it to rebuild an engine?

[mkramm]

I have never dealt with a 2 stroke engine before, so how hard is it to rebuild? What is all normally done in a rebuild? Whould I be better to take it to a shop and have them do it & how much does that cost normally? I have limited mechanical skills, and I dont want to try and tackle something that will be too much. However I am willing & able to learn

[86250RZ]

Much easier than most would believe. But since you have limited mechanical skills I would suggest that you get someone to do it for you and if you could see if they will let you help on rebuild (if you know an individual this would be possible but if its a shop your chances arnt so good) and get yourself a shop manual they are a must if you plan on doing any kind of maintenance yourself. 2 strokes are by far much easier to rebuild and maintain than 4 strokes. just my 2 cents worth. hope this helps.

P.S. you would normally change piston, circlips, ristpins, rings and gaskets

[TG]

2 strokes are easier to rebuild than 4 strokes simply because they have fewer moving parts. You could do a "top end" rebuild which means piston, rings, rod bearing, cylinder hone/bore, or the whole thing, including transmission bearings. Just depends on what it needs, and that can be the hardest part, to know what needs done. If you know basic mechanics and how to use calipers and micrometers, you could probably go through the factory manual and measure what needs measuring, to know what needs fixing.

Even with your limited mech knowledge, I would not hire someone else to do engine work, unless you know for a fact they are good and reputable. I'd get in good with a top rate machinist at a machine shop
(machine shop, not "automotive machine shop," unless they are into drag racing engine building) and get a factory manual that covers your engine. You could possibly do it if you study the manual and practice taking the engine apart and putting it back together in stages.

The two critical things are to never, ever hit a new bearing with anything, and get a straight, properly bored or honed cylinder with proper port chamfering, or youll destroy it in a hurry. Leaving parts out doesnt help either, they dont design spares in LOL

Might start with a small 2 stroke lawnmower engine to get your feet wet.
[/u]

[TimSr]

Ill just add, with your limited experience, its probably best to have it at least looked at by an expert. While labor rates may seem high, potentially your greatest cost could be in deciding and judging what needs done and what does not. For example, getting a bore job, piston, and rings, when all you need is rings and a hone, or reassembling a new top end over a crank with worn out bearings.

[250rmanfmf]

if you need the bottomend rebuilt, have a pro do it. it is very complex and you need certain tools like a crank truer. but topend is not too hard But you still need to know what the hell you are doing. if it is a 85-86 250r and you order a weisco piston from them. you need to patch to two holes in front of the piston, otherwise bye bye piston and it will cost you. I would say have an expert do it but have him go through what he did so that next time you can do it.

later

[atc86r]

get a digital camera. On a side note its good to see the "geek" is here.

[TG]

Aww, Im busted. Hi Wil, hows teh ol girl coming (not the wife, the 250R)?

[atc86r]

I'll be posting some pics. put it off for the summer to fry some bigger fish.

[J.D.]

I'll be posting some pics. put it off for the summer to fry some bigger fish.

MMMMMMMMM....fish, what kind ya fryin'?

[plkmonster2]

halibut..... lol....... i tore apart an antique 4 stroke briggs when i was 8, and put it all back together..... didn't get the timing right tho :? oh well it never ran! since then i have torn apart a 2 stroke tor mower engine, which took about 10 bolts lol. ive also torn apart a 10 hp 4 stroke vertical engine, which i put new valves in and still runs (and its 23 years old!!!) then i got a clinton 4 stroke 3.5 hp engine that i tore all apart (was full of water) and it is still running. dont have a clue where it was made, or what year it is.... recently i tore apart an atc 110 engine, which i honed and put new rings in, although it needed a bore (i was too poor!) my latest project is a ytm 200 ngine, which was pretty easy, although very heavy. still waiting for a cylinder tho. all these engines are very easy to tear apart. there are countless other engines that i have fixed in my day, including snappers, craftsmen etc, mostly lawnmowers. a 4 stroke is just a little harder than a 2 stroke, unless it has an overhead cam or valves, which u have to disasemble first. it all depends on skill. i started the 110 engine over 3 years ago when it died. i was only 10-11. ive never known how to fix it until about a year ago. in that 2 year period i went from "i can atleast tear em aprt" to "i know how to tear em apart, rebuild, and put em back together" the 110 was a trial and error. i was still a beginner with little help. im almost intermediate, i really only hate the electronics, im more mechanical. right before the 110, me and my dad tore apart our 86 buick which broke the cam chain and needed a full out overhaul. well it still runs great, but we need new lifters soon... like a said, its all about skill, but u can have no skill and all guts and still go for it. so start out with little engines, and work yourway up. the smallest i have ever wokred on are those little tempermental r/c 2 strokes, and now im 14 and working on cj jeep engines...