A few upgrades for the polaris 120

[thedude306]

used rmk axys bumper for cheap. Should work sweat. Just need to bend up some AL for the tunnel extension. Started on the rails for the skid today. Should work well. Camso racing track is going back, it's meant to be spiked for oval track or ice drags.

It's going to need new running boards by the end of the year. I have a feeling the OEM boards are going to be too short once he figures out that standing up is way better then sitting.

4D3B77FB-3F16-4DF9-B368-9D5DD1FD2983 by Brad Taylor, on Flickr

 

[Reeb]

As soon as I’m back in town I’ll throw a tape on it and address your other posts I keep trying to circle back to.
I’m sending the head down to Morelli Motorsports to get helped out. He does a lot of carting stuff. I told him I just wanted a reliable 13-15hp engine so he’s keeping it simple. Mikuni carb and a long tube header to exit out the mag side and the torque should be similar to the hp gains too which is the important part. Until I have the engine swap parts all together we’ll ride with the stock engine. It’ll be a good comparison for the Christmas holidays.

I really don’t want to but I’m almost at the point where I have to buy an expensive clutch and learn how these work because I’m not going to Jr. belt drive this thing. Lol.


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[thedude306]

Nice, I would think we are in the 10hp + range. The porting and using a thinner head gasket has to help. And the carbs. These engines are soooo lean in stock form to meet emissions. Next item for me is going to be a new cam. These engines have a plastic cam gear that I suspect will wear pretty quick at higher RPMs. I think the kids will out grow the sleds before the engines give us any trouble

I think clutching is going to be the problem on these little sleds. I've been looking at "Chinese" option on ali express. Prices come way down but I don't know about quality etc. It's the problem of wanting to have it geared low for the powder but then geared high for the trail.

Found a good price on the track today and have the OEM unit coming for thursday.

 

[thedude306]

got some work on the skid done today. I am going to hold off on doing the cut outs for the rear wheals and adj mechanism until I have the track in hand. A little heat with the torch and some bending and they came out really close. Stock one beside it for reference. It is also a full inch wider. Had to remake all the lower bars.

I went 12" longer. 93" - 69" = 24" divided by 2

0C5AFCB4-793A-4EC2-8C01-82A102C8ADEE by Brad Taylor, on Flickr

08FE84A0-F897-4744-B1FD-ED57E2BCF2DC by Brad Taylor, on Flickr

862B7D29-0F00-4574-9794-2F465E029B70 by Brad Taylor, on Flickr

 

[thedude306]

box of parts. Scott and Alex at Rec Motors have been super to deal with

8E1E4BE4-5856-4345-90F3-048147C25795 by Brad Taylor, on Flickr

 

[thedude306]

well I started adding up receipts on these darn modifications. Hhhmmmm It's something you're NEVER supposed to do....

I'll break it down once I get everything together but it will be interesting to see if the cost is close to the Arctic Cat ZR200 and what the performance will be versus that sled. It won't be quite apples to apples but it will be close.

Sure like this new track driver for the polaris track. old vs new


EE556BA9-DC68-4667-8AC9-0BA9DEC2E1E5_1_201_a by Brad Taylor, on Flickr

 

[thedude306]

picked up the proper track got my igrip studs for the short track. Did a 2-2-2-3 pattern down the center. It's going to hook up nice on the trail. Phone died and I didn't get pics. I have to pull the motor again as I think I installed the cam 180 degrees out, silly mistake. And this is my 5 year old pondering when it's going to snow again....

BEA9C339-E52B-43FF-B86E-FD198138ED00 by Brad Taylor, on Flickr

F06B2783-598B-4E68-A60F-28DC17E9DC94 by Brad Taylor, on Flickr

B9A280E5-FD1D-487C-9A6C-72F6DB23B2F8 by Brad Taylor, on Flickr

 

[thedude306]

couple guys asked for this in PMs

bored out honda carb with intake.

275EABAC-DCA4-4A6E-B0C1-501CE2924083 by Brad Taylor, on Flickr

starter solenoid relocated and OEM fuel tank stand off removed for steering clearance.

279DF7C3-591A-46E5-A424-9F3B796408F4 by Brad Taylor, on Flickr

OEM spring on left, 28lbs version on right. Any higher and you need rocker arms and push rods. Prob go that route with a cam upgrade for next year.

9D693ED7-03D4-4BEF-89E3-4A72CFCAC672 by Brad Taylor, on Flickr

motor template. Bolts are in OEM position.

68755598-C9EA-4FBD-931F-F65A8663EE51 by Brad Taylor, on Flickr

 

[thedude306]

igrip screw in studs. wicked on the hard pack in the yard. 2-2-2-3 pattern

44E65DFF-418D-49AB-9C7A-331593ED158C by Brad Taylor, on Flickr

1B444A33-CE07-49E1-9AE0-A2F9A44BBC4E by Brad Taylor, on Flickr

and finally got the new drive shaft machined and the rear bogey wheel shaft done. I should have the long track in this week.

E719AFDF-BC50-4867-9093-ED10010E9AB9_1_201_a by Brad Taylor, on Flickr

 

[Ztank]

Where did you get the upgrade for the drivers?

 

[Ztank]

Also where did you get the rear schlock from and do you have a part number?

 

[thedude306]

here is the write up from another forum member. It has part numbers. I got the drivers from http://recmotor.com/

POLARIS 120 REAR SHOCK KIT

PARTS NEEDED Start with a 77-78 Arctic Cat front ski shock, KIMPEX part # 08-114-14. approx $25.00 from mail order houses, Keep in mind that it's an oil shock, skinny shaft UP (fat body down) in order for it to work. (1) 10.82" long 5/8" diameter steel shaft, threaded for 5/16" on the ends...

www.snowest.com

 

[thedude306]

couple more days and I should get the first test run in with the long track and new motor. Test fitting for the tunnel extension and rear bumper. Need to do some AL welding on the rails and clean them up. Very happy so far. This is the track these sleds should come with!

-32C here tonight. Hope it warms up and we get some more snow

9F8A4E10-981D-4D02-845F-042079511008 by Brad Taylor, on Flickr

93F6FE81-CA29-454A-B48D-AF1AEA15ADFF by Brad Taylor, on Flickr

 

[Reeb]

Looks great! Our whole family has been down and out with the flu and I haven't even thought about driving out to our shop to work on sleds through it all. And we don't have any snow down low either so a shakedown run isn't going to happen unless it either snows or Boxing Day when we go for a family ride in the hills.

I have the engine now, haven't cracked it open. What did you do for throttle linkage and pipe?
I need to remove the governor gear right away and disconnect the low oil level switch. Add a extended dipstick and get the head figured out.
Instead of boring out the stock carb, the Mikuni upgrade isn't much more and seems worthwhile to me. What did you do for a fuel pump and tank?

 

[thedude306]

I moved the throttle swivel and cut up the plate that it came with, added a spring and drilled a few holes. I thought I had a pic of the finished product but I don't, I'll get one.

I should have got the extended dip stick, i'll fight it for now.

As for a pipe, I made my own. Loud AF. Jack loves it, Emma hated it. It's anoyoing as all get out puts a grin on my face everytime I hear it. Also hacked/modified the stock muffler. It does the job.

IMG_5704 by Brad Taylor, on Flickr

07D21AC2-9303-4663-8DE1-A0E98911FA35 by Brad Taylor, on Flickr

I think I shoulda went with the Mikuna as well. I have a modified Honda carb and it's pretty good too. I'm running stock fuel tank and NO pump. Gravity feed to the carb. So far so good. Not sure at what HP you need to look at fuel pumps. I am looking at these guys though. No return on my carb so I am not sure if it's worth the trouble.

12V Electric Fuel Pump Solid State Cube | Princess Auto

12V Electric Fuel Pump Solid State Cube

www.princessauto.com

 

[thedude306]

here are the two throttle linkages. One is with the governor removed and the other with it. You have to add a spring and loosen the throttle lever bolt on both set ups. I also took the grinder and cut off wheel to it but I don't have a pic of the original set up.

Notice the spring zip tied for the governor. Also a few options for governor spring placement.

B7A13F18-2525-45A9-9822-A7E72958E3C8_1_201_a by Brad Taylor, on Flickr

With the honda carb you need to drill the throttle lever and bend a piece of stiff wire. The reason for the the three holes is to get the max stoke possible. (trial and error) I do notice with this set up that the throttle lever has more movement then the thumb throttle. That makes the throttle pretty sensitive and if the driver doesn't have good throttle control, it could be an issue. I am guessing I am using 80% of the thumb throttle stroke to achieve full throttle on the carb.

F63BDF3F-A957-4C8B-B70D-2689230D18BC by Brad Taylor, on Flickr

That starter is so close to the bulk head. The biggest head ache is the steering clearances. I think the Cat will be much simpler. I also went to a bigger battery, up from a 12 aH to a 18 aH. I needed to heat up and mold the plastic a bit where it sits so they would fit.


849C3575-1379-488F-9E82-FE17DD487402_1_201_a by Brad Taylor, on Flickr

 

[thedude306]

I haven't got the tunnel ext finished but it's time to go for a rip. Should have video tonight. Kids and I are heading out after school.

3BC636DD-589F-420E-A43E-A37A72E81BDE by Brad Taylor, on Flickr

I also solved the saggy 20 year old spring on the XCR. Made a set of spacers out of uhmwp. Made a big difference.

AF0B764E-7D70-4055-B5EB-C48DD37C3E1A by Brad Taylor, on Flickr

 

[thedude306]

going to see if youtube video works better. Sleds RIP! I still need to tweek the indy. Clutch is slipping on take off but I think it's because the chain and track are WAY too tight. Might have to upgrade to a dominator clutch, Both geared at 3:1 no rev limiter on the XCR The blue indy long track does about 22mph and the red XCR does about 26mph. As fast as both those kids want to go for now.

 

[thedude306]

Jack is a little unsure of all the new power!! Skis dart like crazy,

 

[thedude306]

this is turning out great. Bumper needs paint and I am going to make a fuel can holder. Next up is running boards. I am also making new gears so that the clutch gear is 16 tooth. Both these sets are the same ratio but the larger set has better rolling resistance. I also fully clipped the track. made a BIG difference

Kids are loving them, I will order C&A skis for the long track in the new year.

341B60ED-F041-4278-B9AD-2D5CC9316243 by Brad Taylor, on Flickr

D44AFDF7-60BF-4523-8850-E9D7BBF80E3D by Brad Taylor, on Flickr

2E3B00A3-1B21-4D1E-9685-A43CD8E4FAAC by Brad Taylor, on Flickr

09A59872-397D-4AFB-A2F4-F55008E1DBBE_1_201_a by Brad Taylor, on Flickr