Starting bike after sitting for 20 years?

[KAlger15]

First off I want to say hi to everyone, I'm new to the site and just bought my first ATC about a month ago and I am new to the whole two stroke motor.so with that being said I have a couple of questions if you don't mind helping me answer.

the bike is an 86 250R, in pristine condition, one owner and it's completely stock except for a KN filter. The last owner drained all the fuel but the bike has sat for 20 years. The bike has great compression when I crank it with my hand And it doesn't feel like anything's sticking.

So my question is how should I go about firing the bike back up, do I just dump fuel in it with the premix and try kick it over? do I pulled the head off check the gaskets the piston etc? new spark plugs?

Thank you everyone

[ps2fixer]

New plug & oil. Maybe mix the gas a bit heavy on the oil side (so it lubs up well right away). Most likely the carb will need to be pulled and cleaned. Since it's a 2 stroke, there's no valves or anything to stick. Other fluids should be checked like for the brakes, but isn't 100% needed for just a fire up to get it running. Mice love air cleaner boxes, so be sure to check if the air filter is in good shape and the box isn't full of 20 years of mouse poo. Also check over the gas tank for rust. If there was no fuel in it, most likely the rust would be high up in the tank, but checking the lowest area wouldn't hurt if you can get an angle. If the carb was ran/drained of gas, it might be just fine too.

When you first fire it up, listen to it carefully. Head gaskets are pretty tough, but a crank seal or crank case gasket leaking isn't good (lean condition). Not going to hurt anything for a test fire, but if it's a problem you'd want to fix it before doing a bunch of riding and such.

Can't really think of anything else. To be honest I generally just check the tank, air box, and make sure it's full of alright looking oil (after kicking it over so water would mix in if there is some), and see what it does, but you said it's in great shape, it's worth taking more time on (most of mine are parts machines that are trashed).

If it doesn't fire up up after all of that, then it's to the basics, compression (you already said it does), fuel, and spark. Spark is generally the next easiest thing to check.

Anyway, good luck with the machine, and don't forget photos, we love photos lol.

[KAlger15]

Thank you very much ps2fixer for the information. Very helpful. I just don't want to damages that motor trying to fire it up. since it is a two stroke and I'm not very familiar with with them I'm just kind of tiptoeing around. And want to get some tips on this motors before I jump in. I know the brake fluid is crystallized so I need to get all new brake lines going to try to rebuild the calipers

[ps2fixer]

Yea I'm not super on top of 2 strokes either, I know the basics fairly well though I think. I only know of 2 main things that kills 2 strokes, heat (too lean condition, air leaks etc), or lack of oil in the fuel. There's no valves to stick, no timing chain, or any extra stuff like that, so in one respect, they are much simpler, but in another respect they are more complicated (tuning is kind of critical and air leaks are not good).

My context with 2 strokes are mainly from chainsaws even though I do own a couple 250r's I don't really do anything with them though (both air coolers).

[fieldy]

Hi, glad you bought a good machine and asked the forum. You should do a search on air leaks and leakdown testers here. They are cheap to make. You can also get a free manual on this forum
You can find some air leaks by running the motor and spraying carburetor cleaner around the engine. The cleaner will try to kill the engine at the leak. The leaks are the sure way to do damage. Some times a bad 2 stroke leaking can cause hi reving. That can happen when debris gets in the carburetor jets too. The power valves can get stuck and that would mainly hurt performance and not hurt the motor. Some water cooled machines have a bleed valve that has to be opened up if the coolant was ever drained. I think oscarmayer is where you search here for manuals. Good luck, many things to learn about the 2 stroke motor, which makes them interesting.

[ps2fixer]

Ah yea good catch on the service manual, here's a link to Oscar's page. I just google atc manual and it's like the 3rd link.

http://www.oscarmayer.net/atc/manuals/

Also I can second the fact that air leaks or lean condition in general can cause damage. I have a chain saw that's always been ran with the right mix etc, but has a scored cylinder because of a fuel delivery issue. Really odd one, but it runs perfect, but while in the cut, or wide open for 5+ secs, it leans out (revs higher under no load, looses power while in the cut). It was really clear what was going on with a digital tach, red line on that engine is around 14k rpm and it rev'ed to that just about perfect (13.8k if I remember right), then when it went lean it rocketed to 14.8K by the time I could react to the jump. So much for the rev limiter that it should have, guess I got a special one lol.

[350for350]

One more thing. You don't have to worry about rust in the gas tank. The 85/86 250R had a plastic tank.

[ps2fixer]

I didn't know Honda had a 3 wheeler with a factory plastic tank. Never owned an 85-86 250r though. I figured they started that around 88 or so since the TRX models still had a metal tank in 86-87. I guess the 250r was the high end machine getting the latest and greatest parts.

[KAlger15]

Thank you again everyone I really do appreciate all the help. now that the holidays are over I think I can find time to start tackling all this. And the service manuals was a great help, I went downloaded that thing right away, very much appreciated!!!

Here is a few pictures of the bike

[350for350]

MAN! Is that thing ever NICE!