Mechanic just cost me $500

[Escanabajosh]

First off I wanna say thanks for taking the time to read this and with any help,I'm sorry this is going to be about a 4wheeler. I dont talk on any 4wheeler forums but this is about motors so should be the same :)

So my fiance and I have been together for a while now and about 3-4 years ago move into a house with garage. She has a 1993 polaris 350L 2x4 (2stroke),she bought it 2 years old and has had it since...things in nice shape for the age.

she bought it from her uncle who ice raced it when he bought it,was said to been bored out. she rode that thing along with her little bro and sister for 15 years.

We moved into the house and I bought a 250sx and told her she should get that thing here before the kids break it riding it everyday.

we went to camp and took the kids with us and once to the end of the road it starts puffing lots and lots of white smoke.....kids are like hey it's doing that again....wtf do you mean again....it happen when we rode it last....great!

we take it in and find out the jug has a hair line crack where the water jacket is.....damn about $500 for parts.....so being the nice guy I am I order up the parts ( i wanna ride) her dad is a self proclaimed mechanic who can fix anything! so he takes it in and puts the parts on.....her half sister from outta town is here for a week so we take her riding....machine breaks down at end of trail....wtf.....get it hom and looking it over theres no anti freeze in it!

so I'm sitting on the bike with the key on but not running, trying to think what it could be my thumb lighly presses the throttle and the fan quits? what the hell......try it again and sure trailprotrailprotrailprotrailpro....so I start it up and hit the gas just a little not even enough to move,yup fan shuts off

I have her call up her dad and she asks if that fan he said he re wired was before or after the motor took a trailprotrailprotrailprotrailpro....he said he did it before and its' a good thing cause the fan wasnt running.

so he has a polaris 500 4x4 4 stroke that he was comparing the fan kicking on to her polaris 350l 2x4 2 stroke....said it was kicking on just not as much as his so he wired it to be on all the time!!!

so now I hope it's just a head gasket but I think the motor is blown again....the day me and her sis took it out it was in the mid 90's and she rode for a hour or so with no fan


her dad is anal about stuff and would ask if I was starting it everymonth it sits and blah blah,well she said not it's blown again and told him about re wire job blowing it up..hasnt said a word about it since

oh another thing, when we first got it here i did a look over on it.....swing arm bearings,axle bearings,hubs/wheel bearings,tie rod ends and might have been one or two more things go for a ride on it and it's like riding a water bed......I ask her dad about it and he says polaris is the best machine he hasn't done anything to hers but add oil and gas!!!

so now i'm stuck with yet again a blown 4wheeler...dont think i'm gunna stick another $500 into the motor and then $500 into bearings


I guess what I am asking from yous guys is am I right about the fan being wired to not run when on the gas is what caused the motor to blow?


sorry about the long rant but this ticks me off...........gunna pick up a new head gasket and try it

[fire1]

..... Read post wrong

[fabiodriven]

I can't offer any first hand experience with this particular bike, but it doesn't make sense to me that the fan would only come on at idle, unless that's the way Polaris has it set up. The only reason I could think that they would do that is to use the air flow when at speed to cool the radiator rather than the fan. It's not impossible I suppose. You've got the right idea by finding out the correct way it's supposed to be. I don't think hard wiring the fan to run all the time is a good idea either. It's thermostatically triggered for a reason.

[Escanabajosh]

Thanks for the help....I kinda drew out the first post

this sums it up

Her dad had thought that the fan wasn't turning on as often as it should....it still turned on just not as much as his did when they rode them....his is a 500 4x4 4stroke that he was comparing it to,hers is 2 stroke 350 2x4 not even close.....so since the fan wasnt kicking on as much as he thought her opened up the fuse panel thing on the side and tapped into a wire....when he turned the key the fan came on so he thought he had it hard wired but didn't know it shuts off when you are on the gas.....a few weeks later it blew up....I paid $500 in parts and he put them on....we rode it not even half a tank in break in and now it's sucking antifreeze again....I was so ticked I put it away for winter....just wondering if a bike like that with no fan in summer temps would cause the motor to blow,making it her dads re wire fault....hes claiming it was overbored yet its been rode for over 15 years like that

[fabiodriven]

just wondering if a bike like that with no fan in summer temps would cause the motor to blow,making it her dads re wire fault...

I think you already know the answer to this question.

The fan is there for a reason.

[Escanabajosh]

ya i figured....thanks for the help

looks like I'll have to set that on the back burner and look for a 400ex or something for her.....she has been riding my SX but dont like the 3wheel thing

anyways,thanks again

[swampthang]

They can still run for along time without a fan,but they won't last very long at all without antifreeze. I would say the fan might have been a longterm killer but the lack of coolant finished it off right away.

The fan on my Honda Rubicon locked up and wouldn't turn. I prolly rode it most of the summer before I noticed it. Never gave me any problems. As for the Polaris unless there is a emotional attachment to it it's not worth puting more cash into it. It's a 93 2stroke 2x4 not alot of guys out there searching for them. I see nice ones sell for less the $800 on Craigslist.

[Scootertrash]

The fan on those machines is operated by a temp sensor in the radiator. If you pull open the little plastic "hood" you will see it right at the top of the radiator, towards the motor and below the radiator cap. There is also a sensor in the top of the head. The sensor in the top of the head is for the overheat light.

The fan will only run when the radiator sensor tells it too. If the fan isn't (wasn't?) running enough it will overheat and the temp light on the dash will come on. Touching the throttle shouldn't turn off the fan, unless he tapped into the TOS (throttle over ride switch), And I'm not even sure that would make it shut off when you thumb the throttle.

As an example, The fan on my 91 350L 4x4 seems to only come on after I stop, but I'm sure I can't hear it when I'm riding. ;) All I ever did was wire the fan to a battery terminal on the terminal board so the fan will run with the key off if it needs too (always has juice to the temp sensor, fan only runs if the sensor says it needs to). The 2 Polaris 400 Scramblers we have do the same thing, I just haven't rewired them to run with the key off yet. The Scramblers have basically the same motor as the 350L machines, just a bigger bore, as well as the same cooling system.

You should be able to redo the top end for less than 500.00, unless you are taking it to a mechanic, same with the bearings. The swingarm uses a bushing/sleeve type set up, not a bearing.

THIS IS IMPORTANT!!
Before you drop a bunch of coin on this machine, you NEED to drain the counterbalancer compartment and the crankcase and check for oil/coolant cross contamination in both . These machines had a reputation for frying the counterbalancer/water pump shaft seals and allowing coolant to get into the crankcase if proper maintainence wasn't performed, like changing the CB oil regularly or using proper coolant to keep the water pump shaft from rusting. The counterbalancer shaft runs the water pump.

If you need more help feel free to PM me if you want

[Escanabajosh]

thanks scooter,

I stuck $500 into the top end and didn't know about his re wire job and the fan till after it went on a ride on a hot day and I think it might have blew again....gunna try a head gasket when I dig the machine outta the shed....not sure if i want to dump another $500 into the thing might just get her a new machine....she bought it 2 years old and was her first machine,think she got it when she was like 12...hang on to it and work on it hear and there I think

thanks for the advice and I'll keep ya in mind when i get it out of the shed and in the garage, I'll post a picture also of where it was wired up at.

[Scootertrash]

Yea, let me know what you find.