A few upgrades for the polaris 120

Reeb

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Took mine out for the first time yesterday. I need to put an anti-stab kit on it. The track beats the front rail caps pretty hard and makes you think it’s ratcheting but really it’s just the noise it makes.
After that it works remarkably well with my boy on it.

I haven’t swapped engines yet. Still waiting on parts(aargh) but the stock engine with the governor removed and the aggressor kit moves it along fairly well. I might regear for Boxing Day to see if I can get more speed but he’s still 15-17mph as is which I didn’t think he would hit.

I also ran out of track adjustment once the track stretched some. I thought I’d be ok but by the end of the day it could have been tightened even more. Surprising really. So I’ll drop the skid and move it back an inch or so. Then the anti-stab kit will be a must have.


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Mar 13, 2019
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Does it do it just under take off or all the time? I've got a bit of a ratcheting sounding noise on take off but I think it's the track hitting the bulk head. Loose is fast!! hahaha I didn't get pics but the kids had their cousins out so there was lots of double riding and the sleds did great. Having trouble with the charging coil running a relay for the hand warmers. I've got dual 3 amp coils and a voltage regulator coming to try and solve the issue. The electric start is a game changer. I didn't have to chase down a single sled to start it.

now we just need more snow! All lined up and the end of the ride today.

F5A3515B-B495-4AF4-AAC8-D8D07830D805 by Brad Taylor, on Flickr
 

Reeb

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Yeah I spun mine and had the nose touching the snow with the rest end up checking clearances etc. Everything looked good except the rails caps. It was hitting right where the sliders butt up against the caps. God awful noise that sounds exactly like ratcheting.
Other than that it goes good with the stock engine(mods of course) I have to gear down our other 120 tho. It flys on flat ground but put it against a hill and she’s a hurting unit. Quick gear change should fix that.


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Reeb

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So moved the skid back 1-3/8” and down an inch in the rear.
Then moved the front mounts back 1-3/8” but up half an inch. The attack angle is something fierce so I’m trying to combat that. Works good with the stock engine and Aggressor Kit. Needs to be geared down. But I won’t bother with changing the setup on this engine. The rest of the 208 parts should be here mid month and I’ll swap it out for that one and hopefully have it running well enough for our first drag race mid Feb.







And my youngest got his first ride on his Kitty Cat today too.




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Mar 13, 2019
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Looks like they are both having fun! I ordered a new straight ish pro taper bar from china today for cheap. The polaris bars have such a goofy angle to them it's uncomfortable for the kids. Might try some springs/shocks from aliexpress as well.. We put on about 4 hours on the machines today and those 208 engines just run better and better and the cold start has been great. -14 and no issues today. Still low on snow so the skis are doing just fine. I would like to see what the sleds do in some powder. They will both climb a two foot snow rigde with ease. You're going to love the extra power.
 
Mar 13, 2019
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got the light mounted and the fuel rack finished. Just need to install. Wondering about blanking off old light location or adding a flap for storage like the old skool sleds. I also started adding up the cost. Looks like about $1200CAD on top of the sled that we bought new for $3g That's making my own shaft and rails and scrounging lots of parts for free or near free. And going with electric start engine and battery

I'm going to have another $500 into it with C&A skis and more motor mods (cam, rod and other cromoly parts)

The biggest expense is the track itself. at around $500 with new driver and there's no way around it.

33B666BC-9744-43AA-8AE5-B7F3143902EF by Brad Taylor, on Flickr

B157D304-72FC-465F-A235-CB9D7C298323 by Brad Taylor, on Flickr

C13B2492-5095-4682-9CC2-8F7BE6EC5E0F by Brad Taylor, on Flickr
 

Reeb

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I cut up a Mountain Addiction Rail set and using a small 2g tank. The things we do for our kids

And more parts are showing up. I have to go thru your thread with a fine tooth comb and make sure I have everything I need to make this as seem less as I possibly can.




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Mar 13, 2019
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Another good day on the sleds. Kids had about 4 hours on them today. My son hasn't figured out he doesn't have to squeeze so hard to hang on, his hands are sore after 10 min of riding.... stops, shakes hands, continues. really kills the ride, hahaha Oh, and bigger running boards are an absolute must IMO. Gotta GOMA next week and get them done.

Also, I'm having issues with the starter not engaging all the time. It looks like the ring gear is out of round or coming off. It's a press fit on the chinese fly wheel. No available option to keep the charging system and go with AL flywheel. You can get an ARC AL flywheel with ring gear, but no poles for charging. Not sure what's going on yet. When my cams arrive I will pull the engines and inspect.

Also, the indy is outperforming the XCR which is strange. The indy has a 4* key and governor is still hooked up. XCR has no governor and an 8* key. Timing might be too advanced but I don't think so. Will swap carbs to make sure that's not it. Only other difference is mufflers. Both geared the same too.




 
Mar 13, 2019
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Ya, me too. He's such a natural rider. He's going to be better then his old man pretty soon....

Not happy with the fuel can holder. I shouldn't have knocked the sides out of the angle. Makes it look too busy IMO.

BUT the running boards are going to rock! They came off a polaris tunnel, no idea what model. Cold front moving through this week (-30s ) so hopefully will get these done. They are talking 5" of snow tomorrow, that would be very welcome.





 

Reeb

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Dragon boards! Those look really good!
I just have the Skinz plastic cleats on the outer edge of ours. I was thinking of punching a few holes but I like your idea a lot!


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Mar 13, 2019
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had a bit of a smash up yesterday. Friend came over and his 8 year old ran the hills backwards to what the kids are used to and had a head on at the crest of a hill. Nobody got hurt but a good lesson for sure! My 5 year old was pretty shook up. Crumpled nosepan, one broken ski and some twisted metal. Good opportunity to beef up some known weaknesses. I should have taken the belly pan off to install the dragon running boards in the first place. I have now ran the outer tube up to the trailing arm mount. Stiffened up everything nicely. Also added a stiffener to the bulk head.

guess I'm getting those C&A skis sooner rather then later. Nice thing is the nose pan is cheap (thankfully the hood was untouched) Oh, and a box full of NR racing parts showed up...

The other 120 fared worse with a cracked hood and more twisted metal. Parts are ordered for both, they should be up and running before this cold snap ends.





 
Mar 13, 2019
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some go fast parts. Mild cam upgrade for the XCR and a bit more lumpy cam and other shiny bits for the indy. Saw some nice Pro R decals on a 120 that I might track down for the Indy. Boy wants to be like his dad!

 

Reeb

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Oh now you're going all out! I like it! How about that stock flywheel tho? Is it going to be ok with the added performance? I still haven't taken my engine out of the box, been too busy getting other sleds ready.

I hope both boys are ok and learn from that, sounds like it could have been scary. I've been thinking a cam but not sure if it's worth it. That billet rod means you're getting serious tho! I like it!
 
Mar 13, 2019
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Ya, it was a scary moment. Both kids made sure each other was ok before they started crying over sleds. I didn't get a picture as emotions were running pretty high but it was a mess and looked way worse then it was. Big kid stayed on his sled and jack went over the handle bars. He said he was never going on a sled again but we had him on his sisters XCR 20 min later. Today the only thing hurting is his pride and my piggy bank!

hahaha yup. I was humming and hawing over waiting for that new artic cat blast to come out and upgrading to it. or the Evo but the reality is that I don't want my kid on that big of sled. And he's only 5. This long track worked out WAY better then expected, and with the running boards and a bit of an upgrade to the front shocks and handle bars I think the sled size is going to be about perfect up to a 100lbs rider. I dunno, I guess we will see.

The XCR gets the mild cam with no other internals changed. I think it was $45. Worth it to just get rid of the plastic gear and get a few more revs. With that and the bored carb and HD springs I think it will be great.

The the only problem is power and clutching. We aren't racing and the cheapo upgraded maxtorque clutch is holding up really well. I did machine the inside of the drum, and I will keep an eye on the shoes to make sure they are wearing evenly. Even with the two kids on it (over 100lbs) it works great, so I figured I would bite the bullet and go all in on the motor. BIG cam, billet rod, cromo rockers etc. I'll do some head work and it should be good. Then next year I might try one of those fancy hillard clutches.

I am worried about the flywheel. I got my hands on a genuine honda with ring gear but I don't know if it will work yet. It should be better. I'll get it balanced and hope for the best.
 
Mar 13, 2019
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So I found out today that the stock muffler is robbing power. SOOO it's race can time for both sleds! Jack's is the smaller one I made first. It's LOUD. Made the other today a little different with a baffle inside and a bigger can. Hope it's a little quieter. or not ;-) Also order up new skis.

Hope to start on the engines again tomorrow. Port and polish and cam for the XCR. I'll try to take better pics along the way.

 
Mar 13, 2019
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Got a nice picture of the clutch and chain with tensioner. The OEM Polaris part is a chunk of plastic that slides up and down vertically in the slot. It's OK but produces a lot of friction. The solution is the cog gear seen hear. It normally just goes on the OEM bolt and slides up and down, but with my motor placement and gears I wasn't able to tension the chain properly. So to solve the issue I put the gear on an arm that pivots on the OEM bolt. LOTS of room for adjustment. I am hoping to be able to run two set of gears with the same chain. 3.3:1 for the powder and 2.5:1 for the drags.

Pictured is the maxtorque 7 clutch with a 12 tooth drive sprocket and #35 chain to a 36 tooth sprocket. This set up has about 30 hours on it. The key is proper alignment with all three gears and only 1/4" slack on the top chain. I also chamfered the teeth on all gears with a bastard file. I will be going to a 18 tooth drive sprocket with corresponding gears for better chain performance.

 
Mar 13, 2019
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Got the 208 pulled and added a set of dual 3 amp charging coils. The single OEM unit is about 1 amps. Hope this works better. It will go to a DC-DC rectifier and then voltage regulator



I also installed this new cam on the right. It sure is different with the bigger lobes. It will be interesting to see how it runs. All other internals are stock except for the valve springs. Old cam had a plastic gear. NO signs of wear on the plastic but I feel better with a metal replacement (the added RPM and power will be nice to)



I also started on the head. I was actually very surprised at how good the casting is on this head. There are no real "problem" areas at all. No real rough spots or poor seams ect. On the first motor I was going to use you could have cut your finger on the ridges inside the intake and exhaust ports. Oh, and the ports are perfectly matched to the carb and exhaust. Also not the case on the old 196cc engine. I have about two hours on this and will do I little more clean up before install. It's really hard to tell with the pictures but basically you round over any hard edges and try to smooth out the port. I am not so picky on the exhaust side. I then polish as much as I can on the intake side.

The roughest part of the casting. A quick hit with 240 then 400 grit sand paper. You can also see the sharp edge around the valve guide on the intake side.



It's not polished but it's smoother. Also notice the intake side again, that lip is rounded over. You remove a lot more material then what I was able to take a picture of...



Here I was trying to show the edge just under the valve seat and along the sides. You want to round all these over and make them smooth to the touch



It's hard to tell but the OEM finish was pretty good. Way better then lots of engines I've seen. I spent the most time on the intake. You can't tell but it's polished to an almost mirror surface.



 
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