Topic: Would you feel confident running an old 2-stroke for 24 hours straight?

[Tugboat]

This would be for our $500 24-hour challenge thing. Would you feel confident running an old 2-stroke for basically 24 hours straight, without doing anything major to the motor and assuming that it runs okay? The only 2-strokes I've ever had were 500cc "nopeds."

[ekpent]

Sure why not if it was in descent condition to begin with. They were the dominant bikes on the roads from the Japanese excluding Honda back in the day and some other countries as well. Just have injection lube or know how to premix. You guys circling a track or out on the open road ?
   What brand/model are you contemplating is the big question ?

[70CB750]

This guy travelled around the World on 350 two stroke Jawa:

http://www.jawakolemsveta.cz/trasa

I am sure well maintained motorcycle will handle 24 hours with ease.

[Tugboat]

"Well maintained" - that's the issue, for $500...

[Don R]

 I'd use the new synthetic two stroke oil. Burns clean and lubes better. Now I've started a 2 stroke oil thread. sorry.

[ekpent]

I'd use the new synthetic two stroke oil. Burns clean and lubes better. Now I've started a 2 stroke oil thread. sorry.

At least that might be the first one on this forum though Don. Next we will be getting into chainsaws !!

[seanbarney41]

Make damn sure your jetting is correct and have extra spark plugs.

[seanbarney41]

Also, for that kind of dependability, you will need to replace the crank seals.  This requires the cases to be split and the crankshaft to be pressed apart and re-assembled with specialist equipment for most multi-cylinder machines.  This is not only an oil leak issue.  Leaking crank seals are equivalent to leaky intake boots on a four stroke machine and a lean cylinder is likely to seize on a 2 stroke.

[Tugboat]

^This is the advice I was looking for. That would be an expense that we couldn't afford with our $500 budget.

Would you mind explaining how all of that works Sean? I have very little understanding of 2-stroke bottom end mechanics.

[seanbarney41]

I am not really an experienced 2-stroke mechanic, but I am interested and have done some reading.  I don't think all 2-strokes need this much work to replace crank seals, but many multi-cylinder machines do...just make sure and check out the situation before buying.  Basically, if the crank seals leak, gear lube, crankcase oil, and/or most importantly air can leak into the cylinder, fouling and/or leaning out the mixture.  If oil is getting in you will have detonation, which will lead to a hole in your piston.  If air is getting in it will run lean, just like a 4 stroke, but 2-stroke are much more susceptible to seizure from overheating as they are much more reliant on the correct fuel mixture to cool the piston (cuz there is no oil, except what's contained in the gas!)  The nice thing is a 2-stroke engine rebuild can be done in 1 long afternoon, as there is no valve train.  I think the going rate for a crank rebuild is right around $500, so if you get something that needs it, you are probably screwed...and it is my understanding that just as many old neglected 2-strokes need crank seals as old neglected 4 strokes need new carb boots.  Google USA 2-strokes or 2-Stroke World for forum info.
     There was an annual benefit ride/race around Lake Erie going several years ago that was limited to 250cc.  I do not if it is still going on, but several guys did it on 2-strokes in 8-12 hours, so I think what you want to do is do-able.  You are just gonna have to do more specific research on your own and get familiar with 2-strokes in a hurry.

[70CB750]

And you don't want to break using the engine - like long way down the hill in gear and gas on minimum. , Idling  two stroke engine lubes very little ( remember the oil is in the fuel) and it could seize on you.

Another - always close fuel valve when parked. Leaking fuel can and will fill crankcase through the carburetor.

I will ask friends over in Czech, they ride Jawa/CZ 2 strokes for the sport of it, and will let you know.

[Stev-o]

I would....I have 3 smokers.  Extra plugs are a must.  What bike do you have in mind. 

[Wobbly]

Back in the 70s, I recall the little 50cc bikes running all day long while the kids that drove them were not exactly taking it easy on them. And the larger two-stroke bikes, like the GT Suzukis were what people travelled with. But with a purchase price of $ 500, you might not get the most reliable vehicle independent if it is a two-stroke or four-stroke. No offense, but perhaps you should be looking at bicycles if $ 500 is all you have for purchase, repair, and maintenance. But if this is just one of these challenges I enjoy to watch on BBC's Top Gear, then the two-stroke option might not be so bad. There is a lot less to go wrong with in a two-stroke engine.  In the end, either way, you need some luck when making the purchase.

[750cafe]

A 500 twin cylinder Suzuki Titan can do it easily. Is that the model that you are planning to run?
And do use the synthetic oil mixed with the castor oil (Blendzal). No smoke and a happy engine. 
It is what I have found works best in my old two smokers that no longer smoke to the dismay of most that know 2-stroke bikes.   

Eric

[grcamna2]

I would....I have 3 smokers.  Extra plugs are a must.  What bike do you have in mind.

Yeah Tug,you said "noped",is that what you have ? I have a little tiny NC50 Honda Express 'noped' myself and just did a full restore on it and switched over to premix only(the oem autolube injection didn't have a good check valve and just kept leaking down into the crankcase when parked)using Amsoil 'Saber' full synthetic at 100:1 ratio which sounds very lean,that Saber is excellent premix oil and keeps the engine/exh. from getting carboned up too much while providing Great lubrication even at 100:1 ratio which works out to 1.3ozs. per gal. 

[Tugboat]

Nah. We don't have one picked out. In fact, bike selection doesn't "officially" begin until next month. I was simply wondering about the practicality of 2T vs 4T. 150cc is the limit, so having 2T's as an option would've widened our pool of available models. But frankly it sounds like a bad idea. We'll be sticking with 4T bikes. Thanks for the input guys.