I picked up a 1993 350l 2x4. It is in super nice, low hour condition, the original owner claiming the 500 miles on the odometer is correct. I believe it, as everything is bone stock, original, even the tires! It’s nice to see an older atv that is not torn up and botched together. It gives me a good pallet to enjoy!

Two things I noticed though. He said it has not been ran for quite some time. So I took it out and within about 15 minutes the hot light came on. I stopped and checked the reservoir. It was right in the middle. I opened the radiator cap (engine off) and it was a tad low. When I started the engine, the level dropped big time. I had to add about 2 cups of antifreeze. I could see it moving around in the radiator fine. When the hot engine light was on the fan was not running. Now, I’ve noticed that the hot engine sensor is on the cylinder head (logical) and the fan sensor is at the top of the radiator. When I took the quad back out for about 20 minutes all seemed fine. Of course everything seems to be bone dry, no evidence of any leaks anywhere. The fan was still not running, but I was not out that long. I’m hoping that the level was so low that the sensor could not even tell that the fluid was hot, as even the top of the radiator was not hot when the light was on. But I’m sure the fluid was not circulating. When does the fan come on?

Secondly, the low beam and “fog” lamps both do not work. The high beam works fine, nice and bright. New battery. Coincidence? Or is it possible that just all three bulbs are burnt out.

Other than that, she’s clean and mean! Nice and tight, seriously rides like a new one! Looks like new too!

Thanks!

 

Jump the radiator sensor with needle nose pliers to see if the fan comes on. If fan comes on just replace the sensor. Bleed the 10mm screw on the head that's down from the hot light sensor first. Top off the coolant in the radiator and recovery bottle. If the coolant drops while running and no visible leaks,check the counter balancer fill plug for any milky color.Item #25 on the parts break down.http://www.cyclepartswarehouse.com/f...1993&fveh=5369 Possible that the water pump seals are leaking and filling counter balancer cavity with coolant. If it fills too much, coolant will run out of the counter balancer cavity vent hose. Bulb burnout was a constant problem on these. Just pry off the outer shell or pop out of the rubber housing(which ever one you have) and check the bulbs. If you have problems on this older machine,you really need a manual.They can be clean with low mileage,but still can have problems. Look over this manual link. Will help you on servicing and any problems on the 350. http://gh-ftp.com/ORV%20Manuals/Pola...e%20Manual.pdf

 

Ok OPT, thanks you assistance is always appreciated!

In regards to the fog beams, which I guess are the "low" beams. Yes they were both burnt out. I didn't guess that those are the "low" and the headlight is "high" only. I tried to switch the headlight out and realized that it is high only. So all i good on that front!

The atv was just low on coolant. The fan works too! It runs great, and like I said you can tell it is a VERY low hour machine. It’s very clean, feels tight, and you can tell it is “untampered”. I even have the original purchasing papers and sales brochures! Pretty cool to look at the prices and "features" back then. 350cc was considered big!

Well on my first decent maiden voyage, it ran great. I was out for about 20-30 minutes. Idles great, runs smooth, lots of power. Starts easy, etc..
However on 3 occasions, when deaccelerating, it would backfire. One backfire was tiny, one pretty noticeable, the other shotgun loud. All when off the throttle coming down from speed.

When I first got the quad I did a full cleaning, inspection, fluid change, air filter, carb clean. Like I said everything seems very tight and new-like.

When I googled backfiring, one thing that seemed to spark my interest was the freeplay in the throttle. I did notice that there was lot of freeplay. I took the cover off and tried the ETC out. Sure enough, when I hold the throttle open and press the ETC switch closed (or let the throttle mechanism come back as if the cable broke), the quad would start to cutout and die. So that’s working.

There was about ½-3/4 inch freeplay. A lot. So I adjusted it to the minimum, or almost none at all. So far a little bit of riding has shown no backfiring. But for the life of me, I don’t see how this would make it better?? If you are going 30-40mph then let off the throttle, doesn’t the throttle lever hit and close the ETC? Wouldn’t this cut the ignition? Then when you open the throttle back up would a bunch of fuel be in the cylinder ready to ignite?

I have also noticed that the reverse override does not work, ever. I know some people disconnect this, as I would likely to as it's annoying. Perhaps this has something to do with it?

Thoughts?

Thanks

 

No,if the throttle slack is adjusted right the etc contact points won't touch retarding spark as you let off the throttle. The throttle slide closes off the main jet and what fuel is in the combustion chamber moves up the transfer ports and ignites,with only what is allowed in by the pilot jet. Once you open the slide a fresh batch of fuel/oil/air mixture enters the crank case. On these older models 1/8" slack really doesn't apply as most times you have to adjust them to where there is no slack at the thumb lever. Just make sure you can turn the bars side to side with no idle increase. If it does,back off the adjuster a tad. They CAN back fire on these first year models even if the etc switch is adjusted right though.I've had them back fire enough to blow the exhaust manifold from the springs. This happens at a high speed when you suddenly let off the throttle. Before the slide closes fuel can flood the crank case and cause a loud back fire or in many cases when the carb bowl dumps fuel it will bog when you hit the throttle again because of fuel starvation. This is because of the natural vibration of this engine transmitting vibrations to the carb itself. Remove the seat and you can see what I'm talking about.Have it neutral,give it wide open throttle and then let off. As the rpms decrease the engine and carb start vibrating.A fix came about on the late model 94s,early model 95 400s to where a rubber dampener was installed on the transmission under the carb to help stop the carb from moving,which helped on fuel dumping/ bogging and back firing. I installed plenty on the early model 94s that didn't have this dampener under a service bulletin. Only problem is the dampener doesn't work on the 93 models because the transmission and bolt layout were different. Some people just made their own dampeners for the 93 models. Here's the dampener on a 95 400 2x4. Item #8. Dirt Cheap Yamaha, Honda & Polaris OEM Parts & Accessories – Cycle Parts Warehouse

 

OPT. So can you walk me through the adjustment process some more? I didn't check out the carb, but I thought the only way to adjust the throttle slack was at the handlebars. Using that method, I screwed out the adjuster until I had virtually no slack. I removed the ETC lid so I could see how the mechanism works. When the slack was removed, the throttle mechanisms, or levers, return all the way to the left. This in turn closes, or presses on, the sealed switch. In my eyes, that would cause the ETC to activate when the throttle is closed.
If I loosen the throttle cable, then yes the levers do not return to the left position which would NOT press on the ETC switch.
I'm confused.
Is there an adjustment on the carb?
When the throttle levers are all the way to the left, against their stops, they are pressing on the ETC switch making an audible "click".
Thanks

 

Just turn the throttle adjuster back in a bit. Slack in the thumb throttle is ok. Basic setting on the air screw(right hand side, rear of the carb) is between 1 to 1 1/2 turns out from a lightly seated position. Turn the big idle adjuster screw(located in the center of the carb) in a little. Hold the throttle open enough to where the etc contacts aren't touching then crank the engine. While still holding the throttle open a tad,turn the idle adjuster screw in or out to get a steady idle. Kill it and then adjust the play at the throttle housing to where it doesn't retard and start limiting or dies while at an idle with no pressure on the lever.Most of the time I ended up with little or no slack at the thumb lever. Your machine may be different because of original position on the cable adjuster on the carb cap.

 

Ok, well I'm a little confused then.

If I raise the idle, it is just too high of an idle. Yeck, I'm only 2 turns from maxing out the idle adjustment anyhow.

If you look at the attachment, the mechanism that is physically attached to the thumb paddle ("A") ALWAYS returns against the ETC ("B") switch. Even if I raise the idle, the "A" always goes back to it's original position, all the way against "B". So in my eyes, the "B" is always activated when the throttle is closed. Even if I put some slack in the cable, "A" always returns back to "B", closing the switch with an audible click. There is no adjustment to "B". So if I hold "B" closed and start raising the throttle, no much above idle you can hear the "limiter" kick in and start making the engine miss.
So to me it's just weird that if you rev the engine up, aka whack the throttle wide open, when the throttle is closed the "B" is activated and the limiter kicks in until the engine returns close to idle.
It just seems like "B" should only come into play when the throttle sticks.

Am I missing something??

 

Before you go crazy over this just pull the tank cover and on the left side is the circuit board. It has two black wires connected at the top. Pull the black wire from the reverse limiter module and see if it helps on adjusting the idle and quits limiting.The other black wire is the cdi kill wire. Shouldn't be that hard to adjust the idle and throttle cable slack.

 

Well I'm over it. I took my 4yr old boy for a ride. Within 5 minutes I got a nice big backfire again.

So, there is no issue with idle or idle quality. It idles perfect. What I just don't understand is how when the throttle is closed, it closes that safety switch and kills the ignition. The result is when you let off the throttle going down the road, it sounds dead until you come to a stop. At that point, when the rpm's get low enough, the safety switch no longer comes into play.

When I look at my father-in-laws 400, the switch NEVER comes into play until the throttle "sticks". Under normal use, the switch never closes. Unlike mine where the switch is closed every time the throttle is closed.

I pulled the switch out of the cover so it is bypassed. It revs and feels like a "normal" quad now. So far no backfiring. I'm just flat out confused on the logic behind this setup?

 

Did you ever pull the black wire from the reverse limiter module? This module works in tandem with the etc switch.If you pulled the black wire,the it's possible the etc switch was faulty.Plus have you tried to brace the bottom of the carb bowl to help stop vibration? Yes you can defeat the switch,but it's actually one Polaris safety feature that works if it everything else is ok. Have had several people tell us at the shop that have cables snatched by tree limbs and the etc kept if from running wild and possible injury.Just be careful with the etc switch by passed.