Polaris ATV Forum banner

21 - 40 of 43 Posts

·
Registered
Joined
·
50 Posts
Discussion Starter #21
Spitfire79: A few years newer boss, but still a old machine thats still need maintenance :) I believe you that it made a big difference, most of the ATV's ar probable not well taken care of.

I brought a update once again:
Started on the head,

The old combustion chamber must be shaved off.

To make room for a new.

Did this yesterday, a few hours of turning but it came out ok.


And got the pipe cut and welded to fit the chassie with the help from a buddy, and the it came out perfect in my opinion. :)



Not many things left to do before i can finally start the Boss.!

Stay tuned.
 

·
Registered
Joined
·
370 Posts
Hello J,

Man, when you decide to modify something, you just modify the living hell out of it, don't you? We can call that the Jorpe Transformation. You'll go down in history. Enjoying watching your project.

Where in Scandinavia are you from? It wasn't in your profile. I like to know stuff like that. You speak great English, so you can't be that far away. I feel for you in learning the imperial system. Learning the metric system was really easy. Everything is based on ten and factors of ten. What could be easier than that? The imperial system is based on the length of middle segment of the king of England's second finger, twelve of which make up a foot. Something like that takes a lifetime to learn. Good luck with it. I prefer the metric system, myself.

What did you do to the pipe? It looks beefier, fatter, thicker. What will it sound like? If it tones it down some and gives it a deeper, more throaty sound, I am all for it. For a good sound, it is hard to beat a Harley Davidson. I know it is a totally different genre, but I love their sound. Wish quads could sound like that.

Keep up the great work. Your photography is very instructive, in support of your story. Take lots of pictures during the re-assembly. It will be like a metamorphosis.

Later---------------------------------------->
Mick
 

·
Registered
Joined
·
1,565 Posts
Mick, that's close to the exhaust I put on mine. And no ,it's not quieter! Louder is an understatement ,but boy does it run better! I don't quite understand how that head is gonna work now, no combustion chamber,no spark plug area??? Nice to have equipment like that at hand. Fun to be able to modify this stuff. So, you've basically built a stroker motor. What is the size now?? Lots of nice work.
 

·
Registered
Joined
·
7 Posts
Check on ebay. Rims are pretty cheap and so are a lot of parts for these bike. I bought 1995 trail boss for my daughter. We been working on it for a year now. Can't get the engine to fire. O well
 

·
Registered
Joined
·
50 Posts
Discussion Starter #25 (Edited)
BigDog: Thx!
HAha, "jorpe transformation". Yes, when you do some kind of engine modification u need to do it so its more than enough. :) And its alot of fun.

I live in the northen part of Sweden, chose American forum because i like to write English. And so i dont forget so much of the language. Like the forum too.
Grew up with the metric system so its a natural choice for me hehe. Never prefer the imperial system and having a hard time learning and remember it as you say. So I rather change the inch to mm every chance i get.

The pipe is an AAEN performance pipe for Quad 400 scrambler. Copy from AAEN: "This pipe produces 48 HP at 6500 RPM"
As you can see on the dyno pull std trailboss 350 it only 500 rpm less, but the whole register is going to get wider. The pipe its going to sound a bit more, but you could build a larger silencer. I rather like the sound of an aggressive 2 stroke hehe. :)
If you want better performance you need to change the stock one. This is going to make a grate difference. But don't think I'm going to have 48hp at first. Need to do some work with the cylinder for that. Just aiming at getting the whole boss together before vacation, so dont care what the power is this first year.

Renoboy: What kind of pipe have you put on your wheeler? Yes its real nice to be able to do this kind of modifications and its alot of fun to. Improving the performance is always awesome. :)
The old bad stock combustion chamber is removed so I get room for a new better one. My brother designed a new camber for me with his own design: Stox Research. ThX!
Not a stroker engine but a BigBore engine, theres a big difference. :) The size on the engine is 425cc, and it cant get much bigger.

Cripple: Yea i've been looking on ebay for TrailBoss stuff, but not rims thou. Was it aluminum ones? Have been looking for something like that, but it gets kind of expensive. :( Good luck on getting the engine fired, guess you started a thread here for help!
 

·
Registered
Joined
·
50 Posts
Discussion Starter #26
Brought an update with me,
The new chamber. Machined this out of a soild aluminum piece.
Dont have so many pictures on this but this is what i got.

Just made the squish:

top side of the chamber:


The head in place to measure the squish clearance. But it was to much so need to fix that... 1.2mm should be 0.9mm clearance.


Stay tuned for more.!
 

·
Registered
Joined
·
7 Posts
rims

When on ebay try different search questions, rims, tires & rims, atv parts and so on. You have to look really hard sometimes to find them but they are thier.
Good luck

tim
 

·
Registered
Joined
·
50 Posts
Discussion Starter #28 (Edited)
Hey im back,

Been busy with the head, and chamber for a long time now. A lot of different issues that needed to be solved and some other little details that needed to be done on the frame.

But got it started yesterday for the first time. Wohoo! Dont know if its a astronomical change but its still a big difference in throttle response and acceleration. Got some trouble with the calibration of the carburetor and maybe the clutch setup just a notch... Going to find out more tomorrow. So ill be back with more when i find the time to do so. :)

Two pictures of the complete work of the head. And the special design of the combustion chamber is StoxResearch own.

And the backside,
 

·
Registered
Joined
·
46 Posts
WOW!! You really dig in don't ya??

Nice build. I just got a 91 350L back together. I didn't go quite as far as you did with the work tho.

I shaved the head 25 thou, cleaned up the casting imperfections in the intake, cleaned and polished the exhaust port, Boyesen reeds, but stock exhaust. This machine will be going to my brother and his wife.

The next project is a 350L 2x4, which will be rebuilt stock and then sold,
Then it's on to the machine for me: A 94 400L. It'll be massaged a little bit.

So this welding of the decompression hole. How much difference does that make? Does the engine turn over harder as a result?
 

·
Registered
Joined
·
50 Posts
Discussion Starter #30
Hello Scootertrash!

Yeah you could say so :) But when i think back at this when i got all the facts, I would just satisfy at porting the 350 and modify the head. That would have been a smoother transformation. haha.

So you shaved of the head 25 thousand of an inch for higher compression? The blueprint and boyesen mods should improve in flow. Hes a lucky one your brother to get that boss hehe :)

You have your hands full on a perfect hobby at fixing up old TrailBosses hehe. So your going to take out some more power out of the 400? Sounds cool if thats the plan!

Not to known of your expressions due to im from sweden. But think i know what you mean, it will respond better at bottom end you will gain some power, mostly for the throttle response. But it doesn't make any horsepower at full rpm, leakage is minimal at high rpm. Thats what i've heard, cant personally compare since this never runned stock. But it improve bottom, that im sure of.
 

·
Registered
Joined
·
50 Posts
Discussion Starter #31
Now that im here, i bring a little update. Dont really have anything to show, but everything haven't goon real smooth, had to change the carburetor to an 38mm Mikuni because i could not get it to run proper with the stock on. But the intake manifold broke when it got a bit stretched, the rubber already had some cracks due to its age so it was just a matter of time. Fixed that temporarily with a "new" one from ebay.

Going to manufacture one in metal after this season, but found billet ones in alu on ebay.. but cant get a hold on the seller to get it shipped to sweden.. But as the machine is running, im quite satisfied with the power. Just need to be calibrated the clutches since the rpm go over the peak power and shifts to hard and nearly clutches it self to death.



Had to cross a swamp to get to the fishing place, but never reached it because it was impossible when there were open water puddles that we could not cross. My brother got a Trailboss 250.
 

·
Registered
Joined
·
50 Posts
Discussion Starter #32
Long time since i did an update.

Need to do some fine tuning on the carb and prob. the clutch to.

Got a problem tho, need more cooling. So anyone changed the original heat exchanger or just added an extra one on the rack? Give me suggestions please!
 

·
Registered
Joined
·
50 Posts
Discussion Starter #33
And got another problem with the clutch cover, water gets by and the belt starts to loose grip.. The cover seams to be deformed. And the primary clutch started to carv a hole on the cover. I know this issue is going to drive me nuts, its probably no easy problem to fix. Suggestions?

Stay tuned.
 

·
Registered
Joined
·
50 Posts
Discussion Starter #35
Though i check in here, its been awhile since last update.

So i was looking around on ebay, and i made an observation on the clutch covers that i thought that someone can answer. I can see that the clutch cover on newer trailbosses (for example an 2006) seems that they have more room for the clutches, is this correct?

Maybe they can fit on to my 91 trailboss and i can dodge this carving issue that have occurred when i lined up the engine.

If someone knows, tell me. Thanks.
 

·
Registered
Joined
·
50 Posts
Discussion Starter #36
Just bought a new clutch cover, complete with the inner cover. Its from a newer trailboss so i will make it fit, im done with this melting plastic :p
 

·
Registered
Joined
·
50 Posts
Discussion Starter #37
Just picked up the clitch cover today. Its a cover from an 330 TrailBoss -06. Lets see if i can make it fit later on. ImageUploadedByTapatalk 21373914867.893970.jpg
 

·
Registered
Joined
·
50 Posts
Discussion Starter #38
ImageUploadedByTapatalk 21375539636.287743.jpg
This is not possible to get it to fit. Maybe with a major rebuild with the old clutch cover, cut loose and then weld them together.

But the new cover fits on the old back clutch cover. Maybe i just try to see if it works :)

Runs real good now with new porting, much smoother on idle and turn way harder then before from the bottom. ImageUploadedByTapatalk 21375540003.406195.jpg (old pic)
 

·
Registered
Joined
·
50 Posts
Discussion Starter #39 (Edited)
Will this recoil pull starter fit on the older polaris trailbosses?

It comes from a scrambler 400 1999. Like this models more. Any one that have tried this?
 
21 - 40 of 43 Posts
Top