A few upgrades for the polaris 120

[thedude306]

"It's been a show", as my wife would say! The suspension geometry changed by moving the track on the driver ahead and it threw everything off. Had to redo the rails and move the top idler wheels. Also cut and moved the bulk head in towards the engine, but then it hit the valve cover. So messed with that for a day to get it just right.

My advice, sell, sell, SELLL and buy a 200 bahahahah

Bulk head cut and bent it. Had to weld it back up solid to keep the snow out.





here it was with the track rubbing



It's hard to tell from this picture but the idler wheels are move WAY back and down. They where origanally on the shaft that the top of the coil over is attached to. I am going to try and relocate the top of that coil over to the shaft with the wheels on it. It will work WAY better angled the other way.



We've only had it down the alley so far and I think it's going to work great. Geared back up to 2.3:1 (from 2:1) and that should give us 30mph Has better low end torque as the 5 tooth driver didn't seem to pull much power from the engine?? And it's been dang cold here. -30 this morning and that's the warmest it's been in weeks. I've been sledding but the kids can't handle it. The new Cold Guaurds, hooks and Maxx hand warmers are going to help though And I bought a proper Fly 5" riser.



And then of course I was having carb issues. Pulled the engine out 5 times yesterday and cleaned the carb 5 times. Fifth time was the charm. Idle circuit had something in it. We don't run an air filters and that circuit has a port on it that draws air. I'm sure we got a piece of chaff or canola stubble in it! Idles sweet again with 3000 rpm clutch engagement. Spins the track when you pin it. Replaced the coil as well with an OEM honda coil. We got RPMs! No power up that high but pulls good to 6500 RPM under load.

 

[thedude306]

So we have 100 miles on this set up and it's pretty good for the fields and on the trail. I'm running 2.5:1 gearing with 16 tooth front 40 tooth rear. It's pretty good in all but the deep heavy snow. (it was 0c here) and does 30mph. Snow is drifted so lots of bumps. The sled is so light it spends a lot of time in the air! hahaha I am going to make up another chain for a 3:1 gearing for the deeper snow. It should get us about 25mph. The back coil over isn't doing much as the angle is all wrong. I am going to find a shorter shock/coilover and angle it the other way.

IF I was starting over I would design the skid/suspension more like a big sled and not have just the single pivot point. Maybe the design of race shock kit from Rec supply would help. There is just to much movement in an arc for my liking with the stock polaris 120 set up.

But the kid loves it.

 

[Reeb]

The Cat has lots of room. That’s an ordeal you got going on with the Polaris.

I used these on the KC. Maybe an option for you?
The wheels are mounted onto some alum I spun on the lathe. And the plastic slider is from like a 80’s Cat trail sled.

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[Reeb]

The Rec Race Kit is good for us so far. Racers say the shocks blow out but ours are fine. And they come with spare heavier springs. I did mount mine differently than how they say to. I needed to get my ride height right and it makes it better for my 8yo. They come with idlers too. Makes it easy to clean that all up but for a price....I don’t have to tell you about that.

I might shorten the back of my rails and move the bracket forward, slide the skid back a few more inches than I did. The front springs have a wicked rebound so I’m not sure I’ll achieve what I want with the current setup.

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[meathooker]

My advice, sell, sell, SELLL and buy a 200 bahahahah

love the thread. There is a ton of great info in here and your work is impressive!

we‘ve got 3 120’s. One bone stock cat, one Polaris with gov removed, and one with the Rec motor Honda, cut head, rear shock kit, 35 chain clutch kit, big bars etc.

Luckily found and picked up Yamaha 200 in December

i couldnt agree with your statement more!

 

[thedude306]

This will be the last season for this gem then it's going back to mostly stock and sold. (engine is going into a kart) Can't keep chain on it. Everything is aligned and gears are good. Just using cheap chain until today. Bought some RLV Gold on gold kart chain. It's BEEF... Hopefully it will finish off the season without issue.







Running 2.2:1 gear ratio with 4 tooth Rec motor drivers. Rider is 75LBs. Riding fields and trails. It's fast. (too fast for the short track) It's simple. It's realistically what you should do to a polaris 120 the day you get it. I've alway told guys: It's easier to make a fast machine go slow then to try and get a slow machine to go fast. If I was to do it again, I would buy the sled when my kid was 2 and do the following right away:

A mildly built 200 or 208 or 212. MAKE SURE IT'S ELECTRIC START! This honestly was the best thing ever.
bored honda carb. This thing starts EVERYTIME (or performance carb of your likeing)
get a choke on it that you can use without opening the hood
Get rid of the governor
Add a cam and and a billet connecting rod
5 tooth rec motors drivers (not the 4)
proper chain tensioner
Quick change hub and a bunch of gears

Gear low and use half throttle. It will putt putt around until your ready to go faster.

That's the start, then I highly reccomend

Wider running boards. The stock boards are SOO poor
Better handle bars. Higher and wider with warmers.
raised seat cushioning.

I'm not sold on the C&A skis on the short track for trail and field riding. On the long track they made a big diference I would NOT do the motor in stages again. I would do it all at once. It's such a PITA to take that motor in and out. I've done it hundreds of times now.

I would also buy a 120 sled lift right off the bat too. A guy on FB is making a cool electric version. It's mint. The amount of time I have lifted these darn things onto a table myself is insane. Wouldn't do that again.

 

[thedude306]

well did the final upgrade to the blue 120. It got geared down to 3:1 and nice kart chain. Rips like a mad man in this spring weather. Snow is melting fast.

This will prob be the final update on this thread. It's been fun.

We bough a pair of indy lites for the kids. One is going completely stock but rebuilt and the other is getting an xtra 10 rear 136" skid with 1.5" cobra track, pro taper bars, 7 tooth driver, dragon running boards and a few other items. Rebuilt the carbs and clutches on both already. They go like stink (for a 340.) hahahah

two very happy kids

 

[thedude306]

Well I lied. One more update. We sold the sled but thought I would post up our final mod. I fixed the suspension. Well made it 1000% better. Moved the coil over into the proper orientation and inboarded the rear bogey wheels 1/2" on either side. Coil over actually works as intended and you can run the track loose. and loose is fast with more power. My boy was cheering on the first ride then complained it was way to slow!

He loves his lite but misses being able to "throw around" his 120. Maybe should have got him a 200 but prices are nuts here right now. Get your kids on a sled. They hold there value and man do they have fun!

All cleaned up for the new owner:



Coil over

 

[OregonSledder503]

Do you have any idea if 2 charging coils could be used independently - so that one can charge the battery, and the other one can power a low watt LED headlight and low watt tail light?

 

[thedude306]

Do you have any idea if 2 charging coils could be used independently - so that one can charge the battery, and the other one can power a low watt LED headlight and low watt tail light?

It should work. My issue was always the high RPM and large voltage variances, I couldn't get a cheap voltage regulator to ever hold up to the spikes.