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Discussion Starter · #1 ·
I don't like oil injections system, so i rather it be unhooked and go premix.
My question is how do you go about dis-connection the oil injection on a 1991 polaris 488 fanner. Just crimp the lines? and premix? an you just remove the oil pump gear drive and put the cover back on?
Thanks.
 

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Oil injection made my storm motor blow up.
You have to buy a oil injection block of kit. HI-Perf is the cheapest.
http://www.hiperf.com/acatalog/Snowmobile_Parts_Miscellaneous_Performance_Accessories_70.html

get the second part down. Its the oil injection cover. I have had one on my ultra for one season with no problems.

For your oil to gas ratio 40:1 is good, 50:1 is leaner on oil but is also good.f

my injection kit only took a week to get here so its mildly fast.

Good luck.
 

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leo_kendall said:
I don't like oil injections system, so i rather it be unhooked and go premix.
My question is how do you go about dis-connection the oil injection on a 1991 polaris 488 fanner. Just crimp the lines? and premix? an you just remove the oil pump gear drive and put the cover back on?
Thanks.
Is the injection system still working? I wouldn't go pre-mix if it is! You will need to cap the fittings on the carbs to stop air leaks but the real headache in premix is rejetting the carbs. Once you add oil to the mix you displace the fuel and current jetting the carbs have is now lean. No one hear can give you a magic number for the jets, you'll just have to keep testing different jets and do plug chops until you have it right.
 

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I dident have to rejet. switching over to premix is the best thing i have done to my sled. It takes a little work and time but in the end i will do it to every sled i own. plus without the oil bottle there is a great place to store things behind the airbox.
 

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Discussion Starter · #5 ·
To be honest i have no idea of the oil injection system works as it should. never picked up the sled yet. Going to do it this weekend. Ever sled i have owned i always have diss-conected the oil injection system. Never did trust it. Seen to many sled with a melted piston because of oil injection.
To re jet shouldn't be much of a problem, grab a bunck of jets and try them out if needed. Keeps checking on the plugs.

I took a look at the link, and and the cover with the plug. Is the cover just a piece of alum that with a gasket fits over the hole? If so that can easily be made up on the mill. The plug though maybe a little more trouble. If i knew the size and material it's made from, i prob can fab it up on the lathe.
When i gets the sled i'll give it a good going over and see whats on the go. if i do keep the oil injection hooked up i'm still going to mix the gass a little bit just in case, to check to see if the oil is going down in the tank.

The sled is a 1991 polaris trial supertrak and was given to me for free, from my wife's uncle. Hoping it will be a good sled to take the family on a few trips with. He said it never ran by the choke but ran by priming gas down through the heads, so i'm hoping it just a dirty carb.
Thanks for the replys
 

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The cover is just a piece of aluminum with a couple holes drilled in it. that i would just make. but the plug, for $12 its better to just buy it rather then spend the time trying to get it right. for the gasket on the cover I just used some High temp RTV to seal it up and i havent had a problem.
 

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The mikuni oil pumps are extremely reliable. Other than for reasons of racing I would would look at this like taking the starter off your car and putting a hand crank on it.
 

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its been a few years since I had a fuji apart but I don't think you can take the gear out unless the case is split. If it will pull out remove it. If it doesn't pull out leave it in.
 

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the oil pump comes off with two screws, inside the hole there is a shaft and gear, grab it and pull the entire thing will come out and there will be nothing in it. then the plug that you ordered gets incerted in after you lube it with some 2-stroke oil. once the plug is in you take the plate, put some high temp RTV on it and seal it up. when your done it will look like this.


201083118309279_30620.jpg

then for the oil lines coming off the reed boots i just took a screw, put it in each line and then put the little clamps over that. hasent made any problems yet.


2010831183018670_30620.jpg
 

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leo_kendall said:
Never did trust it. Seen to many sled with a melted piston because of oil injection.
oil injection failure would most likely not melt a piston, crank damage cylinder damage yes. melted pistons are a lean problem.
removing the oil injection on a trail sled is just nuts to me. have never seen a properly maintained sled have oil pump problem.
 

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Discussion Starter · #12 ·
The sled i seen that failed and did sieze the engine was the older ski-doo's, mostly talking about the ciatations and safaris, etc, that ran there oil pumps on a plastic gear.
This is the first polaris that i owned.
 

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sTOrMy96 said:
I dident have to rejet. switching over to premix is the best thing i have done to my sled. It takes a little work and time but in the end i will do it to every sled i own. plus without the oil bottle there is a great place to store things behind the airbox.
Yeah, and just how easy is it to sit at a gas station mixing up an other tank of gas while all your friends are wanting to leave! Its not the easiest thing to have when trail riding.
 

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Discussion Starter · #14 ·
pretty easy if you ask me, trow a bit of oil in the tank then poor the gas in with it. While the sled is running the gas gets mixed with the oil pretty easy. I usually adds a little bit more oil than i should just to make sure she lube up. Just buy a bottle of 500 2 stoke oil and trow it in with 20 liters of gas.

I have also heard when it gets so cold out that oil will thicken and not flow as good. Before someone jumps the gun, i do do that different oils have a different thickness at different temps.

With oil injection i just see how many things can go wrong, pump failing oil lines breaking, wrong setup (to little oil), oil lines plugging, oil level switch failing, cable breaking, etc. A lot of this can be solved buy just premixing.

Remember this sled is 20 years old, it isn't new by all means.
For some reason a question of how to remove the oil pump turned into a argument between pre-mix vs oil injection.
 

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It takes the same amount of time as pouring oil in the oil tank.
grab a quart of oil and a ratio rite cup. look at how many gallons you just put in your sled, fill to the correct line., and pour it in your tank. you dont ave to shake your sled or anything. oil is made to mix with gas. plus by the time you move your sled 10 or 20 feet the gas is sloshing all over the place in your tank mixing it together.
 

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my understanding on the pump removal is that if you remove the oil pump, drive gears, you need to refil the void left in the crankcase being that the gear runs off the crank. if the void is left you will have improper crankcase volume, and different on one side to the other.
 

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bigwedgies said:
my understanding on the pump removal is that if you remove the oil pump, drive gears, you need to refil the void left in the crankcase being that the gear runs off the crank. if the void is left you will have improper crankcase volume, and different on one side to the other.
You are correct. I tryed to run with just the pump and no gear and 2 cylinders ran lean and one ran way rich. thats why you need the kit.
 

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Discussion Starter · #19 ·
What if you leave the pump and gear all in tack and just plug all the lines?

The plug is that made of steel?

also is the center bearing in the crank a sealed bearing? If not wouldn't the crank share the same volume between the 2 cylinders?
Just poping out random questions. sorry.
 

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Its $30 to do it the right way... don't cut corners, It will just make things worse in the long run.
The entire kit is aluminum.
and yes there is a center crank seal. that way you can lean out one cylinder if need be. If there was no seal and you dropped a jet size both cylinders would go leaner.
 
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