A few upgrades for the polaris 120

Mar 13, 2019
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yup.

@Reeb find yourself a mild cam. I put in this one. http://www.nrracing.com/product-p/dynomod2.htm?1=1&CartID=0

From what I saw today this would be my recommendation for a GREAT back yard engine build:

upgrade carb with intake
upgrade valve springs to 22lbs
upgrade cam
remove governor

I only ran the engine for about 20 minutes and I haven't had it on the snow yet but I can tell you it revs WAY higher (couldn't get my tach working) and is WAY smoother and there is almost zero backfiring like the stock unit. And it is snappy. Like REALLY snappy. Should be fun. 😆 Not sure if I will put all the race parts in the other sled or wait til next season...


I also added a pair of 3 amp charging coils. The stock princess auto unit is only about an amp it wasn't cutting it. Got about 30 volts out of them so I am also adding a dc-dc regulator. pic to follow.
 
Mar 13, 2019
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dang it bugs me I can't edit old posts....

Here are the charging coils. Pretty basic. I will have the lead go into the DC-DC converter (silver box) with the output from that going into a diode to prevent back feeding from the battery before it goes to the fuse block. It should work great. FYI I was getting a full day of riding with the hand warmers on high. I do need to track down warmers for the throttles.



 
Mar 13, 2019
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So our little crash did more damage then I thought. Cracked the fly wheel. Kinda scary. Glad I found it before we hit the snow again. New one is on it's way. I suspect a casting flaw as well but the ign coil did hit the fly wheel too. I will make sure and torque all coils to spec and have lock tight on them as well.

Make sure you lap your flywheel and torque to spec, 55ft-lbs Use a rope in the sparkplug hole to prevent the engine from turning to reach spec.





The good news is skis are on there way and improvements have been made to the bulk head and running boards.

For reference, the 208 pro point runs a 1.180" crankshaft and a .716" wrist pin in standard length of 3.308"



I also got the charging figured out. I added those dual three amp charging coils but you have to add diodes to each coil to prevent back charging... I also added a diode to the output of the DC-DC regulator. Everything is working nicely. The fly wheel has me a bit freaked out so I added some belting to the top of the shroud. I did some testing with high velocity projectiles and was happy with the results.

 
Mar 13, 2019
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so Kimpex screwed up and sent me two PAIRs of mini skis. I had only bought one pair to replace the broken skis from the crash. They didn't send out the install kits.

They look significantly better then the OEM skis.... Might have to keep both sets. Damn these minis are $$$$$$$$

I am def considering modding the keels on the bottom to match the rec supply race modifications.



 
Mar 13, 2019
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Well the lights aren't working again. Not sure if it's the charge coil or the DC-DC or what. Might be time to say forget it on the charging system and just go with charging the battery after the rides. PITA .

Got the wear bars made for the new skis as well. A little time with the welder and grinder and I have two sets made for a couple bux each. Hope to have the install kit here this weak. I think I have enough parts to make one kit except for the rubber.

oh, and Jack got a early birthday present:

 
Mar 13, 2019
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Nothing worse then waiting on parts. New flywheel still not here and dealer that I bought the skis from has gone MIA and no install kits for them. We have races on the 22nd. Hope they get some seat time before then.... Not sure who is more frustrated, me or the kids! haha

pictures just cuz.







 
Mar 13, 2019
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HOLY MOLY. Geared the XCR down to 2.5:1 It hauls A$$ seriously fast. 6800rpm max. It's going to be fun.

Also got the skis on, they sure did feel "heavy" but with a kid on the sled no one complained.

Picked up a pair of used Powermad Star handguards with a polaris mount. I hope they really cut down the wind on the little ones hands. I didn't like the width of the pro tapers for the kids so ordered a set of Moose Mini bars.



 
Mar 13, 2019
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Well, I am going to have to do something about the steering. After an hour out today Jack is complaining his arms are sore and the sled is hard to turn. Might be the angle of the handle bars too. Handguards worked great. Just need some fresh snow, it's pretty bumpy out there.

I can never get him to do the cool stuff for the camera...

 

Reeb

Modding mini's
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The Rec motors mod helped to the skis. Doesn't take long and while I didn't notice a difference, my then 12yo said it helped. My 7yo doesn't care, he rides till he damn near falls off the sled from being so tired. My 3yo literally tries to make deals with me to sleep on his Kitty Cat. Crazy kids....
 
Mar 13, 2019
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I did the front part of the keel but I will do the back as well. I think my runners were too long so I cut those back as well. I put the old skis back on today and it turns easy. BUT, I think a bigger problem was/is the spindles are not perpendicular to the ground. I am not sure if he bent them yesterday doing jumps or if they were bent before and I just never noticed. The skis almost looked like a kid wearing skates that weren't tied up tight enough. Could be sloppy bushings too. I think I am going to make the top arm adjustable just cuz. I thought about widening the suspension but I really don't think it's needed for the riding we do. The sled is 20 years old and been in a crash or too so I am not surprised something bent... Didn't get a picture as sleds are in different shops.

I did put them on the Indy and they turn fine on the cement. (they didn't on the XCR) And as you can see the spindle is straight up and down and ski is level side to side.



I also started on the steering adapter to go to a proper riser and the pro taper bars. It should be sweet

 
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Mar 13, 2019
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getting closer. Engine tune up tomorrow morning and some electrical work then off on holidays! Coming back a day earlier to get sleds ready for the drags. The things we do for our kids ( I love it)




 
Mar 13, 2019
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And he's rolling. Beautiful day today but really showed the weaknesses of the the clutches. -1* C and the snow is sticky. One foot rise and the Indy bogs out and won't spin the track. Black soot out the exhaust from running so rich. These are a -10 C or colder machines. Jack loves the pro taper bars and the skis. Emma digs the handguards too. I am going to talk with Rec Motors about clutch options for next year. Not sure if a $200 clutch will help VS the $45 rotor tiller max torques we are using now. hahaha Off to the drags this afternoon!




 
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