250R enthusiast needs wisdom.

[steakneggs]

I have finally conqured my pilgramige to what I consider the best thing ever.

Finally bought an 1986 ATC 250R. I need some help with this. It's a nearly compleate resto project, that needs to have the rear brakes fixed, and a few other very minor things like an air cleaner/ETC.

I know little about the 250R.

1. 2cycle mix? what % and what oil is considered best?

2. Engine was rebuilt/never started 10 years ago. it's not siezed, but should I put a little marvel mystery oil in the spark plug hole and let it sit to help prevent any scoring, before starting?

3. FLUIDS! How much? Where? What is best?

4. ENGINE BREAK IN: some say beat the heck of it as soon as it's running, others say be slow and work it in slowly. ??

5. TIPS, SECRETS, FLAWS, From the masters.. YOU know the little atc things that may happen, or upgrades to avoid disaster. What are they?


Thanks in advance!

[Dirtcrasher]

Start with the shop repair manual, run any good oil and don't mix it super rich...... Guys like Klotz, Motul, Belray - any of them..............

Rich makes the silencer gooey and the motor sluggish.

It's stock, so no break in is required, but a few heat cycles work great :D

Spend time on the board, use the search feature and you'll find TONS of 250R info without asking and awaiting responses.....

WELCOME ABOARD!!

[Mosh]

I dont wanna sound like Dreary Dave here, but that engine sitting for that long unfired is bound to have some rust from condensation from sitting.

At minimum here is what I would do.

Pull the clutch cover, and examine the lower end internals for rust on the gears, clutch plates, and things like that.
You will be able to see some of the internal trans gears, but not much.
If there is very light rust, then you can probably wipe it down with 10w-30 motor oil and wippe it off, or even WD-40.

I would at least rotate the piston down and examine the cylinder walls thru the intake and exhuast ports on the jug..
If the cylinder wall is rusted, I would get a top end gasket kit and pull the jug and hone it, to deglaze the rust.
While it is off, I would fill the crank area with 2 stroke oil and rotate the crank over to prelube the bearings.
As far as Mix, get a Good 2 stroke oil.
Klotz R-50
Klotz Super technipplate,
Maxima 927
Or maxima super M, and mixt the ratio at 24-1 for the first tank full.
Then lean back after a tank to about 40-1 and see how it runs.

Break the engine in like this.
Start it, let it idle and warm up with gentle revs on the throttle, but dont hold it at high RPMS.
Let it run about 15-20 minutes and shut it down and let it cool down for about a half hour.
Then fire it up let it warm up again, and putt it around careful not to over rev it, or hold it at any constant RPM.
Vary the throttle up to about Half throttle for the first hour of run time.
Let it cool down again, then Ride it some more, this time getting open to about 75% in short burst.Do that for about a Hour,let it cool down again, then the next time you warm it up it should be good to go ahead and start going further to Wide open.
This is when you want to check your jetting, make sure it isnt too lean, and do some plug chops.
Do a thread search on plug chops, there are many on here that will tell you what to look for.

But definately examine that 10 year old shelf engine for rust first.
Hopefully the seals wont be dry-rotted from sitting that long, most important would be the crank seals.

This is the "hope for the best" method.

Personally, a complete teardown would be the best thing to do, just so you know for certain, the engine is clean from rust and ready to run.

A complet gasket and seal kit will only cost you about 60 bucks to do it right, but the tear down process is not for folks of little engine experience, so you may need some help from a experienced engine builder, if you have little yourself.

Oh the crankcase oil, a 10w40 Name brand oil for cars will suffice,and the R takes just a fuzz less than 1 qt, but sometimes after a bottom end rebiuld, they can take a qt and a half.
There is a check bolt on the clutch cover.Remove that bolt and fill till it runs out, then install the check bolt and run it for a few, shut it down and recheck and top off as needed til it runs out the check bolt hole.
If you do go for the Run it and hope for the best method, change that crankcase oil after 1 hour of run time, to get any rust particles out.

[MonroeMike]

Welcome to the board, post some pics. Check over in World Class Help for a manual.

[Dirtcrasher]

Sorry - when I said "It's stock, so no break in is required, but a few heat cycles work great" apparently I missed the part that it had never been run.....

Mosh has ya covered :D

I even wonder about my crate 350X motors, I HATE to tear into them but I know I'm gonna have to. I store them in a dry place, but who knows where they were for the last 20 years :)

[jeffatc250r]

Aside from what mosh and D-C said, these things are pretty bulletproof with normal maintaining. Get a manual, and read it cover to cover a few times to get farmiliar with everything, it's worth its weight in gold.

[boosted96cobra]

All good advice...except re torque the bolts after the first couple heat cycles. Heat makes stuff expand.

I also prefer 32:1 ratio on the mix. I switch alot between Klotz R-50 and Techniplate. The R-50 will protect a bit better under really hard use, but it has more spooge/goop than techniplate does.

[steakneggs]

I pulled the 250r apart a little. Good thing!. The reed valve needed a little cleaning. I'll probably upgrade it to at least power reeds in the future after I break it in.

As far as the engine and rust goes.. well NONE!! i examined the top end, rings crank and such. They all look perfect. Even when I saw a dark brown spot it turned out to be cosmoline? assembly lube? either way it wiped off to reveal a perfect surface.

I really appreciated the suggestion in the thread to pre-lube all bottom end-ETC. with 2 stoke oil. I did this with a pressure syringe I built.

One question. The svc manual calls for 20:1 mix ratio. Many suggestions are at least 24:1 or as high as 40:1. What is the theory behind this?

[jeffatc250r]

With the technology of todays oils, 32;1 is just fine. I run that in all my stuff, including my saws, which see ALOT of use every day. Me, I run klotz benol in the summer, and techniplate in the winter. The oil from days past just isnt what is available today. You will have no problem running leaner than what the service manual says so long as your carb is tuned in right.

[steakneggs]

First much thanks to mosh and jeff ATC!!!

Here's the story

GOOD!

After sitting for over 10 years, the 250 sputtered [stable] on the 3rd kick!! 3 more with a little throttle and it was RUNNING!! almost perfect!! MAD EASY. ( I had to thumb the throttle/it wanted to bog/had to work the idle adj. ETC. Smoked like a MoFo! Probably b/c of all the 2 cyc oil I pumped into the intake/exhaust.

BAD!

Anyway, After about 5 mins I got a stable idle. It runs good! I noticed a tiny weeping near the head gasket. COOLANT!. There is a tiny weepage somewhere in the top end........

Well, I drove it around a little without getting out of 1st gear. No leakage. seems tight!!! ( not riding b/c of break in procedure {THANX MOSH}..Driving miss Daisy..ETC)

Already plan to re-tourque the head to spec/as needed

Any similar abberations someone may have run in-to?