Yep, I did it. Picked up an '86 Honda 250R 3 wheeler tonight. Mint condition too, this thing is sweet. But I have a question about it. My friend that has had 2 strokes all his life said not to run it under 30 degrees. He says this is because it's liquid cooled and it would run so cold from the snow being on it that my piston would shatter. He said it has happened to him a few times. Can I ride it in the snow? Is there any precautions I should take before doing so? And one more question, the kid I bought it off of insists that I use a champion N5C plug. To me this seems entirerly too hot. I am going to run an N3C. The reason he put in that plug was because he said it always fouled plugs. Which I have ridden with him before and it does, but the only reason because of that was that he doesn't know how to drive a 2 stroke. He lugs it and doesn't clean it out, what would be the best plug to run in it. And I want to run a champion because if I was to run NGK, I would half to drive about a half hour, where I can get a champion just a bit up the road, any input would be appreciated.

 

The N5 seems way to hot, if it fouls plugs the jetting should be looked at. 250R's and similar high performance 2 strokes are not really designed for extreme cold weather riding and because there is no thermostat, it is possible to overcool the engine. Piston scuffing and partial/full seizure is a definte possibility. A good gentle warm up is mandatory and for very cold weather it is a good idea to put a strip or two of duct tape on the radiator to block some airflow and maintain proper running temp.

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Tom Bukowski

 

Me and all my buddies have 2 strokes and we run them below 30 degrees. important thing is to let it warm up before you ride it. look at all the new liquid cooled, 2 stroke snow mobiles out there these days. just warm it up before you get on it hard and you will be ok.

 

I've been using this article for years and thought everyone would benefit from it. Print it out and keep it in your tool box.

It maybe long but very worth it.

When most people feel that their ATV is not jetted properly, they switch the main jet. However, 90% of the time that's not the problem. You have to pinpoint the problem, area and make adjustments accordingly.

The jetting sequence goes like this: The pilot jet determines how the bike runs from zero to 1/8 throttle: from 1/8 to 1/4 the slide cutaway is working: the needle and needle jet ( mikuni TMXs and Keihins have fixed needle jets( can be changed to affect response from 1/4 to 3/4 throttle mix is regulated be the main jet.

Of all the jetting components, the needle has the most variables-length, diameter and taper all play part in the machine's response. Changing the length is comparable to moving the clip on the needle, that is, a longer needle will be slightly leaner, such as when moving the clip upwards. The diameter affects 1/4 to 1/2 (fatter is leaner). Finally, the taper affects 1/2 to 3/4 throttle(fatter is leaner).

Most of the nations top tuners have their own way of jetting a bike, here is just 1 method. Run the bike in 3rd, under a load (like up a hill). Without a load on the engine, it will tend to require larger jets, and you'll lose performance when you actually get riding. These notes pertain to both 2 and 4 stroke engines.

PILOT JET: turn the air screw all the way in and the engine should die, if it doesn't die the jet is too lean GO to the next size larger. As you back the air screw out, the engine rpm will increase. If you've gone out past 21/2 turns and the rpm is still increasing, go to the next size leaner pilot jet. It is imperative that the air screw and pilot jet be dialled in together for optimum response. Once you determine that you have the proper size pilot jet, back the air screw out from fully seated until the rpm quits increasing, then turn it back in just a touch.

SLIDE: The slide is lean (too much cutaway) if you're experiencing a hesitation at 1/8 to 1/4 throttle. If the engine sounds like it is breaking up, it too rich.

NEEDLE: Your ATV spends most of its time being ridden "on the needle" so this part is most important. The needle is too lean the engine feels flat, or the rpm fluctuates at a steady throttle setting between 1/4 to 3/4 throttle. If the engine breaks up (stutters) or won't pull through to the top, it's too rich. The needle is adjustable by a clip and a series of grooves in the top of the needle. Moving the clip up ( dropping the needle) will make the bike run leaner and vice versa.

MAIN JET: The main jet is too rich if your bike blubbers and breaks up at full throttle, under a load. If it is too lean, the engine will "lay down" or feel like its just not making power on top.

When making jetting changes, be careful, and don't make any radical adjustments. Take the time to make changes in small steps, because on mistake could mean an engine rebuild.

 

Running a 2-stroke below 30 degrees is no problem at all. Just richen your jetting to account for the increased air density and make sure to warm up the motor before riding. I've ridden my 250R's down to -20 with no problems. It's not a matter of whether the machine can handle at those temps....it's a matter of whether or not you can handle it. Properly jetted and warmed up, you can ride it all winter.

 

Waymond is right about jetting, I once mentioned the same thing. People seem to assume the main jet is the culprate, but it only kicks in on top-end, usually the problem is in the mid-range, but you have to make sure its jetted correctly everywhere.

Sickman

 

Adam,

Ride that thing all winter long, just warm it up first and fatten up the jetting. I've been riding 85/86 250r's for almost ten years now and beat the crap out of it on the ice. I'm not too familiar with the Champion plugs but OE was a B9ES or BR9ES, I've been running a B8ES for a few years now with no piston trouble and have gotten dozens of hours on a single plug. When you are ready to hot rod that bad boy let me know I can set you up with a killer combo that'll make alot more power than stock. By the way if you want to sell it let me know first, I have two now but another is always welcome if it is nice.