Polaris ATV Forum banner

1 - 20 of 43 Posts

·
Registered
Joined
·
50 Posts
Discussion Starter #1
Starting a new thread about my Polaris Boss 350L -91.

I'm new to this ATV business so a few guidelines along the way would be good.

It's an old atv that i bought but need to look over the whole machine.

Anyway, currently I'm using it but need to fix some minor things. Plan is to do a major repair when winter comes, so trying to ride as much untill then.

My rim popped right off yesterday, all but one nut flew away and it started to wobble and messed upp the bolt holes and the pinn bolts. Douse it exist any new alu rims to my Boss?. Or do I have to try to repair the old one..

Looked on the tire and it says 25"10.00-12 so the rim i have can be between 10 to 12 " ?

please reply.
Thx /jorpe
 

·
Registered
Joined
·
6,903 Posts
A quick answer, I'll try to get beck to you when I am on my home computer, your tire reads like this (height x width - rim diameter. So with those tires you need 100% to get a 12" rim. There are no other options with that tire size as far as rim diameter goes.

Steel rims are generally stronger them aluminum rims. Alum rims are much lighter. On a machine like yours, you are probably better off going with steel wheels. Stronger (generally) and cheaper.
 

·
Registered
Joined
·
50 Posts
Discussion Starter #3
Blueline15
Thx for quick reply.

Have to measured the hole circle and the inner hole diameter and then start chasing new rims.

I rather take aluminium rims then steel, I just use the ATV for transportation.. Fishing vehicle, no work related stuff.

I'll be back in this thread when I run in to more trouble.

Thx /jorpe
 

·
Registered
Joined
·
50 Posts
Discussion Starter #4 (Edited)
Allright, have measured the rims and the bolt pattern.
Found this on the web: Alu rims

12SS8B13 (F/R) 4/156 4 + 3 (FRONT)
12SS8B10 (F/R) 4/110 5 + 2 (REAR) (But measured the bolt pattern to about 103mm but it has to be 110mm?)

Back tires dimension is 25X12.50-10 so need to find new tires if i buy those rims.

But got another issue, on my front tire it says 25x10.00-12 and they don't have 10" wide rims, is it possible to use the 10" tire for the 8" rim? Or is the only option to buy new tires to the front rims.. :O

And got another thought, is it totally overkill to have 10" wide tire on front wheels. Is it enough "flotation" with 8" tires in front? Please help me with pro and cons?

Thx /jorpe
 

·
Registered
Joined
·
50 Posts
Discussion Starter #5 (Edited)
So the summer is over and the major repair is at if first phase.

I've already done a lot, and have some big plans for this ATV. It's gonna be awesome, and a rule thats very importing for me is to have FUN! Thats why I bought a lightweight 2 stroke ATV. 4 stroke is for boring riding, actually I would put the 4 stroke to no riding at all. Can't see any benefits actually, thats my opinion!

Anyway let's continue with my project. Start with a pic from the summer, went hill climbing with my brother and it flipped over and the steering bar got bent, leveled with the gasoline tank. The trip down was even worse!
Fixed the steering the same day and could ride a few more weeks before winter.


And a few months later I brought it home and now it's time to rip of a lot of parts.
Started with some plastic to get to the clutches.

Because the machine needs to be Dyno pulled!

It's a 91 and probably the same piston, don't know what power output Polaris promised? Anyway [email protected] rpm, and two peaks. :) U just got to love the two strokes!.

Shredded TrailBoss:

Got the head of just to see how it looks down there.



And this is the reason why the Boss got it self in the Dyno:

400cc TrailBoss cylinder. Found a 88mm Wiseco piston. Going to order it but the delivery time is probably long. :( But it's gonna be fun when I get started on the engine.


Thats it for now.
 

·
Registered
Joined
·
50 Posts
Discussion Starter #6
Ok, so I tried to get the transmission loose from the frame.. But can't get this bearing of the axel. See picture.

Is there any custom puller that I can copy and build my self?

And the rear shock is worn out, so can that be renovated or is it just to throw away? I've got some old shocks from some snowmobile and the white one fits with minor modifications, but would prefer the stock one.

Std shock.


Edge shock.


Rev shock, probably to long.


Thx!
 

·
Registered
Joined
·
50 Posts
Discussion Starter #8
So made things easy for me and bought a Trail Boss service book. I've had some trouble to get that bearing of the axel. But it said that it should just pop off easy, so cleaned it real good and started to heat the bearing and made a custom puller and it got loose. Finally! Transmission came off! Got my uncle to check it and he said that one bearing needs to be replaced, apart from that it was in mint condition! :top:



Ordered the piston, don't know how long until it will come. So going to start with the cylinder probably next week if I can find time. :biglaugh:
 

·
Registered
Joined
·
50 Posts
Discussion Starter #9
Time for a quick update, not much that have happened because all my time been taken up by work and my snowmobile.. Got the head on the milling machine straight tough, so its ready for machining the cylinder. :)

The piston have arrived.



And ordered some other stuff like aaen pipe + new chains and spockets. Going to be fun to get going with this project as soon as possible, just need to find some time to get going.

 

·
Registered
Joined
·
50 Posts
Discussion Starter #10
Alright, so got started with the cylinder for the boss.
Want to have a plane surface before I start with the welding.





At least i've begun with the cylinder. I'll assure you, this will not be a fast build project. : )

Peace
 

·
Registered
Joined
·
50 Posts
Discussion Starter #11
Got started for real now, on tuesday I took a look in the cylinder. And it was in real bad shape, so that would be trouble to get it straight in the lathe. So decided to take a fine cut.

Progress so far, gave the cylinder to a co-worker so he welded the ears to reinforce it. So thats done, and the decompression hole is going to be welded shut. Can't just leave that bottom end horse-power thief open :). Apparently it was hard to get close enough with the tig since the handle was to big, so thats a issue. But he had some idées how to solve that.. Tomorrow its probable finished.

Peace
 

·
Registered
Joined
·
50 Posts
Discussion Starter #12
Alright, he finished the welding this morning. Looking good. Got some pictures trough Yesterdays/todays work.

Reinforced cyl.


Decompression hole shut.


After weld i thought its best to get the bottom surface straight..


Not the best result on the looks of the surface, but its nothing wrong with it. Its nice and smooth..


Next big thing will be to bore it up so the new piston fits :) Peace
 

·
Registered
Joined
·
50 Posts
Discussion Starter #13
Time for update.

So got the cylinder bored yesterday.
Boring :hmmm:

Fits like a gloooeeve.

Smooth looking cylinder.!


Next big thing: The head, combustion chamber.!
Stay tuned!
 

·
Registered
Joined
·
370 Posts
Hello Jorpe,

Saw your thread on the active topics list and thought I would check in. Looks like you have stripped your machine down to it's undies. They look so naked without their plastics. I am proud for you that you have the skillset needed to do all the work you are doing. I had my guy, Tony, who had excellent skills but...let's just say I was on his back burner for six months. He didn't have to do anything major to my engine, but a ton of other more involved things to everything else. He did a great job, it just took a while.

Keep chipping away at it. You'll get there.

Really like the pics of your progress.

Mick
 

·
Registered
Joined
·
50 Posts
Discussion Starter #15
Hello, fun that you dropped in here, hope you like what you see. Wont be nothing big like your thread. :) But we are here to share the fun! Hehe.

Yes your right, they do look a bit naked and cold, awful sight. Hehe.
Thanks for the compliment, I work with lathe and milling so I got the machines to do stuff like this. And I love the two stroke engines! Its a good opportunity that I'm not going to miss. Yeah i recognize that issue when you need help with something, its hard on you. Not so fun to nag every now and then either. Anyway, what work did he do on your engine? Bored it up to next piston dimension?

Think I will have some update to bring middle of the week. Stay tuned!

/jorpe
 

·
Registered
Joined
·
50 Posts
Discussion Starter #16
Back again, havent had much any time to work on the Boss and no energy to update.

Did manage to get the new chains and a few new spokes on. :)


And got the work on the case done so the new cylinder fits and the new piston, just used a rotating file.

It did went through to the bolt that keeps the case together but that dosent matter.

And I need to rise the cylinder so i get the piston in the right hight in the cylinder, so need a spacer. About 8mm, that should be perfect.

Started to work on it last weekend, and close to finnishing it up. The thickness on the space is going to be 6mm and then i use 1mm gasket material on each side.

This is about were i stopped working on it. Brought it home today.


And got a nice picture of the engine, its acually looks real nice. :) Thinking of getting it cleaned up but dont know if thats any point since its going to stay clean out in the terrain. :p



thats it for now,

Ill bring more progress in a couple of days.
 

·
Registered
Joined
·
370 Posts
Anyway, what work did he do on your engine? Bored it up to next piston dimension?
/jorpe
Fortunately, the previous owner had already bored it up to 400cc and had it tuned up pretty well when I got it. He decided to sell after getting the engine right because the other repairs were too much for him. He was able to get a new one.

The first thing Tony (my mechanic) did was to make sure the engine ran good. His opinion was that it didn't make sense to work on the rest of the machine if the engine didn't run. I couldn't argue with the logic of that. According to him, I have a very good power plant in my machine. He never confirmed to me what dimension the bore is, but he knows it has excellent compression, and he fine tuned the carburetor to a mix of three ounces of oil to a gallon of gas. That is 1:42.6, pretty lean, I thought, but he says it is just the right mix to lube the engine and not leave a lot of burn residue. He says two stroke engines should all smoke a little. He was very adamant about not using anyone elses (borrowed) gas.

I don't know if you saw the article about Two-cycle Fuel by Tim Ard that I put on my thread around page 5. It is good info that you will want to read, if you haven't already.

Two Cycle Fuel

Another thing, do you have the Polaris manual that Ricko posted? You can download it from his thread, which I just happen to have the link to here:

http://www.polarisatvforums.com/forums/atv-repair-maintenance/25743-rickos-1992-trailboss-350l-project.html

It is an excellent manual. It has exploded diagrams and pictures of your machine and reliable parts descriptions, etc. I read where you bought a manual last year, but if you have room for one more, this is it. It is free.

Thanks for touching base. Keep posting your project. We are out here paying attention.

Gotta Jet---------------------------------------->
Mick
 

·
Registered
Joined
·
50 Posts
Discussion Starter #18
Fortunately, the previous owner had already bored it up to 400cc and had it tuned up pretty well when I got it. He decided to sell after getting the engine right because the other repairs were too much for him. He was able to get a new one.

The first thing Tony (my mechanic) did was to make sure the engine ran good. His opinion was that it didn't make sense to work on the rest of the machine if the engine didn't run. I couldn't argue with the logic of that. According to him, I have a very good power plant in my machine. He never confirmed to me what dimension the bore is, but he knows it has excellent compression, and he fine tuned the carburetor to a mix of three ounces of oil to a gallon of gas. That is 1:42.6, pretty lean, I thought, but he says it is just the right mix to lube the engine and not leave a lot of burn residue. He says two stroke engines should all smoke a little. He was very adamant about not using anyone elses (borrowed) gas.

I don't know if you saw the article about Two-cycle Fuel by Tim Ard that I put on my thread around page 5. It is good info that you will want to read, if you haven't already.

Two Cycle Fuel

Another thing, do you have the Polaris manual that Ricko posted? You can download it from his thread, which I just happen to have the link to here:

http://www.polarisatvforums.com/forums/atv-repair-maintenance/25743-rickos-1992-trailboss-350l-project.html

It is an excellent manual. It has exploded diagrams and pictures of your machine and reliable parts descriptions, etc. I read where you bought a manual last year, but if you have room for one more, this is it. It is free.

Thanks for touching base. Keep posting your project. We are out here paying attention.

Gotta Jet---------------------------------------->
Mick
AHA! :) So you also got a bigbore boss! The power increase should come in handy every day hehe.

Now you talking gallons and onces to a Scandinavian, and im used to meters, liters and kilos hehe. But tried to calculate it to percentage instead, and its sounds a bit lean (2% - 2.2% oil mixture). But on the other hand should not be any problem with the low power outtake on these engines.

No havent seen that article.
Going to check out the 2 stroke page after this post.

Thanks! Downloaded the manual.

Its nice to know that its interesting project for other.
And i brought a update:

The outlet of the water needs to be changes to center of the head due to risk of less cooling on the other side. First time i tried aluminum welding and think it came out pretty good.

Preparations:


Welding done:

And the old outlet hole is shut, and the other hole to.


Got some more things done but dont think i got any pictures of that.

Stay tuned!
 

·
Registered
Joined
·
50 Posts
Discussion Starter #19
Read the article, it was interesting. I've learned some new things about the fuel. Didn't know that the regular fuel was mixed with alcohol. But here it seams like its only 5% in the fuel generally were i live. Probably 10% in a few years. Thats a serious issue though.

So got some progress done this weekend. Got the cylinder horned up to right measurement and put most of the engine together. Now i've only got 2 big things left. The head and the pipe. After that its time to put all the plastic parts on. :) Neat.

Pipe.


stay tuned
 
1 - 20 of 43 Posts
Top