Hello Everyone, I just picked up an older Polaris TrailBoss 250cc today. I'm not new to ATVs however I'm new to 250's as well as Polaris. Before this I had a 150cc and 90cc e-ton just to toy around on. This is alot differant than my e-ton. Not sure where to start. I picked it up for a good price reason being is it needs some work. It runs/drives but needs some tlc.

Number 1. It came with junk front tires they're flat and don't look the right size. Does anyone know the factory front tire size so I can go out tomorrow and look for some.

Number 2. It seems to smoke a lot, I know it's a 2-stroke and they smoke but it has more than I've ever had it smokes out of the exhaust.. It has old fuel and possibly is mixed with too much oil but still seems like a tad too much.. What might cause this? Rmember, Im new to 250's so be easy on me haha. It seems like at one time it had a seperate 2-stroke oil res and someone converted it to pre-mix. What is correct mixture, 32:1?

Number 3. I plan to clean the carb out tomorrow is there anything I should expect that may be differant than a 50-110cc style carb, aside from bigger size obviously.

Finally Number 3. (this is a 2 part question) There is no battery however it has pull start. Do I need a battery for the lights to work (I would think yes but just wondering). Does it hurt/put strain on electrical system to run the quad without a battery?

I'll post some pics of it tomorrow! It's not a new sportsman or anything but I'm hopeing to get it running to par! Any help appreciated.

Thanks everyone,
Mike

 

P.S. I want to put new engine oil in since it's been sitting a while. what do I use, 10w-40 motorcycle wet clutch oil? it's an automatic with reverse. and how much do I use? Also what kind of spark plug should be in this, just to make sure I have the right one..

There is no air filter on this and looks like no choke unless it's an auto choke, It was about 30*F out today and it was sitting for 3-5 months the previous owner said and after a few tugs it started right up.. definetly running rough but not as horrible as I expected!

I guess alot of these questions could be answered with a service manual does anyone have a link to one? feel free to PM it to me.

Sorry for the loads of questions I have the weekend off and would like to get something going.

-Mike

 

P.S. Not sure of the year of the quad will have to check the vin but it looks exactly like this one minus the racks.. Also when I mentioned about it smoking it smokes similar to the one in this video maybe a little worse.. (fast forward to about halfway or 3/4 and you'll see what I mean) YouTube - Working on a Polaris ATV
so I'm assuming it's normal? none of my other 2-strokes smoked like this!

 

Mizzie, I have a 1988 TrailBoss 2x4, just like the one in the video. (and, mine has the same problem described in the video, whcih is a known issue with the older clutch cover plastics)

I am a newbie to ATVs and engines in general, so keep that in mind (there is a lot of real expertise on this board):

The air filter is in the airbox, under the seat. Remove seat, remove airbox lid to expose the airbox, there should be a cylindrical filter there. If not, you need to buy one.

The choke is up on the handlebar mount, in the middle between the handlebars. It is a small lever which you push up and forward for "choke". (Mine doesn't need too much)

Not sure what you mean about the engine oil. There is no actual separate oil system for a 2-stroke; there is oil that is mixed with the fuel (hence the propensity to smoke). That oil in the fuel also lubricates the piston and crank. Mixture I believe is about 50:1 for normal use. If everything is working properly the oil pump will ensure the proper amount of oil per fuel; you could of course mix yourself and pour in the fuel tank to "be sure" but have to accept more smoking (I did that until I tested the oil feed and confirmed it worked -- opened at 2~5 psi per the manual). The oil is in a separate reservoir up underneath the fuel tank (bolted to the inside of the fuel tank), with the filler neck sticking up through the top of the fuel tank. You will need to buy actual "2 cycle oil" available at any dealer.

For parts, check out Cheap Cycle Parts, Arctic Cat, Polaris, Suzuki, Kawasaki, Honda, Yamaha, Sea-doo, Can-Am dealer Muskegon, Michigan, and I am sure there are other popular sites. (NOT normally cheap, unfortunately)

 

Quick correction: finished watching the linked youtube video, and the known clutch cover plastic problem, which I had on mine, is NOT what ended up being the problem in the video.

 

Thanks for the reply. What I mean by engine oil isn't 2-stroke I'm reffering to the actual engine/case oil in which you pour into engine case. some people use gear lube as well I believe. I've never had a 250 however all of my 50, 90, 110 and 150cc's over the years have needed engine/trangear oil.. am I wrong about a 250? I'm by no means a mechanic I can do basics such as carb cleans and oil changes! So I appreciate all help.

About the airbox, well this quad doesn't have an air box or filter it's just the carb.. I guess I'll have to buy an airbox assembly.. While waiting for air box is it unhealthy to the quad to run it without airbox? as long as i'm not mudding or anything crazy/dirt prone. I've ran my old quads without air filters and never had a problem just wondering.

Post some pics of your quads engine please if you can I'd like to make sure mine is all there haha! Also, I believe my has been converted to pre-mix since there seems to be a hole where the oil reservoir cap would normal be near the gas tank cap.. is this right?

I'll post pics tomorrow it's dark right now.

-Mike

 

P.s. can you tell me a little about the handle bar switches.. Nothing is really marked.. I can assume the kill switch and elec start switches not sure on others.. also can you tell me about the gears.. is it Reverse - Neutra l- Forward2Low - Forward1high/regular or? and can I shift while idleing or do I need to shut engine off or is there a switch that needs to be pressed? I test drove it a little but tires are bad and it was 25-30 degrees so I just made sure it ran and looked decent gave the kid the money and threw it in my truck straight to the back yard covered and locked up. (garage is full with a jeep project i'm working on so no room, hope it can hang in the cold for a few days till i make room!) so I haven't had much time to examine it. Tomorrow is the day I'll mess with it which is why I'm trying to soak up as much info as possible. -mike

 

So I took the cover off and snapped a quick pic. can't see much it's dark & my phones camera isn't great.

 

MIZZIE your 250 2 stroke requires a special oil for the motor, there is a separate tank located on the front of the quad below the head light you ONLY use 2 stroke injection oil. there is no oil in the bottom of the motor because that is where the injection oil and gas mixes before it makes its was into the combustion chamber.
2 strokes do smoke so get used to it I don`t think at this point you need to worry about adjusting the injection pump. When there cold they tend to smoke more than when they are warm. if it don`t smoke then its time for concern.
Yes you need to have a battery or you will blow the lights because the voltage regulator can`t tell when there is enough power and to stop charging. with no battery the voltage spikes and damages things that require 12 to 14.7 volts regulated.
There should be a choke on the quad the choke lever is located beside the ignition key on the left side. if you were to stand on the foot rests looking down towards the carb you will see the round slide and looking kinda at the 1 o;clock position you should see a brass cylindrical looking type of nut there should also be a jamb nut on it thats where the choke cable goes into the carb.
On my old 92 trail boss the only motor oil used was for lubrication in the tranny and the book called for SAE 30 from year to year Polaris used different fluids in the trannys so you should find your model number and ask around.

 

Regarding the engine oil: what Randy said. You should not dump separate oil in the case for that reason.

The shifter on my 1988 Trail Boss 2x4 is located on the right side of the quad, near my knee, and is horizontal running back to front. Positions are, from rearmost to frontmost: lo, neutral, reverse, hi. Quad needs to be stopped to shift (need to brake and stop the rear disk brake from spinning; it is located on the right side of the transmission)

The handlebar and "console" setup on my quad are as follows: on the right handle is the throttle thumb lever. In the middle console, on top of the steering column behind the front headlight are: 2 lights, green for neutral and red for reverse, and behind those toward me are the key (round ****) on the right, and the choke lever (a plastic lever) on the left. On the left handle is the brake fluid reservoir, then switch for: off/run (needs to be "run" with the key on to start), horizontal light switch, and "start" button on the bottom. There is also a reverse limiter switch on my left handle, but mine never worked.

Regarding the air box / filter: yes, you can run without the whole airbox, (carb tuning *without* will be different from *with* airbox and filter in place of course), and per your comment your risk is getting foreign material in the carb, but you have to manage that risk until you get the airbox.

Per randyness's post, with the seat off and airbox out you should be able to get a good view of all the cables on lines running down to the carb, and can see them working when you hit the throttle and choke levers.