Nyper build thread

[Nikolai]

That’s a great tip, I’ll do that!

 

[Nikolai]

Took a shock apart tonight, not much to them.

The shaft is 1.125 solid aluminum, 7” long and weighs 0.77 lbs. I was going to make 0.60” spacers to go over the shaft to shorten the shocks but I’m going to call around and see what a machine shop will charge to just cut 0.60” off the end and drill the hole a little deeper so I can tap some more threads. The bolt that holds the valve stack is 3/8-24 threads. I really wish I had the ability to drill the shaft out somehow, there’s no reason that needs to be solid aluminum, you could get the shock weight way down.

 

[Nikolai]

I cut the shafts down with my bandsaw and was able to crudely rig them in my small lathe and turn them down to the correct length. Not the most accurate but it saves me some money at the machine shop. Dropping them off at a local machine shop tomorrow to have them faced flat and the holes drilled 0.50” deeper so I can tap additional threads.

 

[Nikolai]

Back of secondary sheave when open. Hub flush with sheave.

Clearance is tight with correct offset but it does clear.

About .010 clearance to the flange

Only part I’m not happy with is having to use the Yamaha steel flanges on the jackshaft but it is what it is. I wanted to use a nice aluminum one but they are all too large and stick into the tunnel too far that my track would hit them. Thought about using standard triangle flanges (52 MSTR) but they use the spherical bearings and that doesn’t seem as strong to me as using Yamaha’s cylindrical bearing and squared flanges.

Any input on the flanges? Are the triangle flanges and spherical bearings just as good?

 

[Thunder Products]

Had an extra 10mm anodized shaft I used for my spindle axles. Made the spacers out of my leftover 7075. I offset the skis inward to try and get the stance close to 35”. Each axle w/ spacers was only 0.12 lbs.
View attachment 166622
View attachment 166623

Got my clutch sheave back from @Thunder Products. Can’t say enough good about Terry, great service and price. 5mm was removed the back and 9mm of internal splines were removed.
View attachment 166624
View attachment 166625

My nitrogen needle adapter from Schmidty Racing arrived as well so I have everything I need to take apart the shocks.

Lots to do!

Anytime bud!

 

[Nikolai]

Got the jackshaft jigged in place. Yamaha center to center spec is 267-270mm. I double checked my tool I made and it was 269mm so I ovaled the hole just a fuzz and machined a tight fitting washer to weld on so the center to center is right in the middle at 268.5mm. Ready now to start doing the plating for the bearing flanges and brake caliper.

With the secondary machined the chaincase can be against the frame tubing.

 

[cannondale27]

I cut the shafts down with my bandsaw and was able to crudely rig them in my small lathe and turn them down to the correct length. Not the most accurate but it saves me some money at the machine shop. Dropping them off at a local machine shop tomorrow to have them faced flat and the holes drilled 0.50” deeper so I can tap additional threads.
View attachment 166651

Here are specs you will need for doing those shocks. Since you shortened them you will have to experiment with amount of oil to add. It will be less than the 200cc shown. I would do them for you for free if you want. I have learned alot from your builds and am looking forward to doing a Turbo Phazer build with Cat front geometry some day. Your Posts will be invaluable. Just need to learn how to TIG weld better myself! Hope this helps.

Ski
Shock Part #	IFP Depth	Nit Pres (PSI)	Service Kit	Rebuild Kit
7041255 (F)	1.700"	200	10-02001	11-02004
7041266 (F)	2.000"	200	10-02001	11-02004
7041291 (F)	0.728"	200	10-02001	11-02004
7041292 (F)	0.728"	200	10-02001	11-02004
7041346 (F)	0.728"	200	10-02001	11-02004
7041349 (F)	0.616"	200	10-02001	11-02004
7041385 (F)	1.142"	200	10-02001	11-02004
7041401 (F)	1.139"	200	10-02001	11-02004
7041474 (F)	0.728"	200	10-02001	11-02004
7041490 (F)	0.600"	200	10-02001	11-02004
7041494 (F)	1.000"	200	10-02001	11-02004
7041536 (F)	1.000"	200	10-02001	11-02004
7041537 (F)	2.000"	200	10-02001	11-02004
7041540 (F)	1.000"	200	10-02001	11-02004
7041545 (F)	0.675"	200	10-02001	11-02004
7041593 (F)	1.000"	200	10-02001	11-02004
7041612 (F)	1.000"	200	10-02001	11-02004
7041692 (F)	1.000"	200	10-02001	11-02004
7041697 (F)	1.000"	200	10-02001	11-02004
7041747 (F)	0.950"	200	10-02001	11-02004
7041801 (F)	1.110"	200	10-02001	11-02004
7041803 (F)	0.900"	200	10-02001	11-02004
7041811 (F)	1.100"	200	10-02001	11-02004
7041838 (F)	1.150"	200	10-02001	11-02004
7041848 (F)	1.050"	200	10-02001	11-02004
7041881 (F)	0.800"	200	10-02001	11-02004
7041926 (F)	1.050"	200	10-02001	11-02004
7041971(R)	2.100"		10-03002	11-03002
7041972(R)	2.100"		10-03002	11-03002
7041976 (R)	6.560"	280	10-03001	11-03004
7041978 (R)	6.520"		10-03001	11-03004
7041990 (R)	6.780"	200	10-03001	11-03004
7042059 (R)	7.460"		10-03001	11-03004
7042072 (W)	2.500"	200	10-27006	11-27006
7042109 (R)	6.360"	200	10-03004	11-03006
7042111 (R)	1.900"		10-03002	11-03002
7042112 (R)	1.900"		10-03002	11-03002
7042126 (R)	6.840"	200	10-03001	11-03004
7042146 (R)	6.570"	200	10-03004	11-03006
7042147 (R)	7.960"		10-03001	11-03004
7042180 (W)	2.000"	200	10-27006	11-27006
7042183 (R)	6.950"	200	525083-040	11-03006
7042211 (R)	5.510"		10-03004	11-03006
7042215 (R)	6.210"	200	10-03004	11-03006
7042249 (R)	6.510"		10-03004	11-03006
7042258 (R)	6.920"	200	525083-040	11-03007
7042280 (W)	2.000"	200	10-27006	11-27006
7042293 (W)	2.000"	200	10-27002	11-27004
7042296 (W)	2.000"	200	10-27006	11-27006
7043082 (R)	6.270"	280	525083-040	11-03007
7043083 (R)	7.770"		525083-040	11-03007
7043090 (R)	6.540"	200	525083-040	11-03007
7043095 (W)	2.250"	200	10-27006	11-27006
7043102 (W)	2.250"	200	10-27006	11-27006
7043103(W)	2.250"	200	10-27006	11-27006
7043141 (F)	1.420"	200	10-02016	11-02025
7043194 (W)	2.250"	200	10-27006	11-27006
7043206 (W)	2.250"	200	10-27006	11-27006
7043233 (W)	95 cc	215	10-27004
7043245 (R)	6.920"	200	525083-040
7043268(F)	2.550"	200
7043269 (F)	2.550"	200
7043315 (R)	5.750"		11-03014	11-03014
7043345 (W)		200	10-27001	11-27003
7043357 (R)	5.750"		11-03014	11-03014
7043364 (W)	95 cc	220	10-27004
7043404 (W)	200 cc	(225psi main, 325psi res.)		10-27004
7043429 (W)	6.875"	200	10-27003
7043436 (W)	2.000"	200
7043446 (R)	5.750"		11-03014	11-03014
7043447 (R)	5.750"		11-03014	11-03014
7043452 (W)	2.125"		10-27001	11-27005
7043490 (W)	95 cc	225	10-27004
7043534 (W)	2.000"		10-27001	11-27003
7043568 (W)	2.000"	200	10-27001	11-27003
7043599 (W)	2.000"		10-27001	11-27003
7043631 (F)	1.750"	200	10-02016	11-02025
7043636 (W)	2.000"	200	10-27001	11-27003
7043650 (W)	2.000"	200	10-27001	11-27003
7043725 (F)	1.070"	200	10-02016	11-02025
7043730 (W)	2.250"	200	10-27001	11-27003
7043731 (W)	2.00"	200	10-27001	11-27003
7043749 (W)	2.00"	200	10-27001	11-27003
7043757 (W)	2.00"	200	10-27001	11-27003
7043827 (W)	2.00"	200	10-27001	11-27003
7043835 (W)	7.000"	200	10-27003
7043861 (F)	6.650"	200
7044009 (W)	2.250"		10-27009	11-27010
7044120 (W)	2.000"	200	10-27001	11-27003
7044137 (W)	2.000"	200	10-27005	11-27005
7044224 (W)	2.250"	200	10-27009	11-27010
7044288 (W)	2.000"	200	10-27001	11-27003
7044384 (W)	2.000"	200	10-27005	11-27005
7044388 (F)	2.300"	150
7044298 (W)	6.800"	200	10-27003
7044302 (W)	2.000"	200	10-27007	11-27007
7044343 (W)	2.000"	200	10-27005	11-27005
7044388 (F)	2.300"	150
7044518 (F)	7.250"	200
7044564 (w)	2.000"	200	10-27005	11-27007

 

[Nikolai]

Thanks, I have the Polaris chart and I spoke with Fastrax Motorsports before I tore them apart, they did the original rebuild on them years ago and have a lot of experience with the WE air shocks. They told me the same thing, start with 95cc of 3wt oil and 225 psi nitrogen. If shocks are too soft then add 1cc of oil at a time, if too stiff then subtract 1cc of oil at a time. Luckily these are super fast to work on compared to my RZR shocks, no IFP or resi to mess with. I’m guessing I’ll have to play around them a few times to get them setup correctly.

I wrote down the valve stacks as well in case I need to make valving changes. I’ve read that sometime around 2008 Polaris used a different(better) piston, I have no idea if I have those or not. If you saw a picture would you be able to tell?

 

[Nikolai]

I realized something really stupid today that I did years ago. I had cut off the end of jackshaft and cut a groove to retain the gear with snap ring. But over the last few years it never occurred to me until yesterday that the Jack shaft would just lose all the chaincase fluid out the clutch side since it’s hollow. Definitely felt like an idiot last night. Thought about plugging it with a rubber plug. Then measured the ID and it’s .503 which is the perfect size for an M14x1.5 tap which is the same threads as the clutch bolt. So I’m thinking at this point I’ll just tap the jackshaft and retain the upper gear with an M14-1.5x30 bolt and use thread sealant on the bolt threads.

 

[cannondale27]

I realized something really stupid today that I did years ago. I had cut off the end of jackshaft and cut a groove to retain the gear with snap ring. But over the last few years it never occurred to me until yesterday that the Jack shaft would just lose all the chaincase fluid out the clutch side since it’s hollow. Definitely felt like an idiot last night. Thought about plugging it with a rubber plug. Then measured the ID and it’s .503 which is the perfect size for an M14x1.5 tap which is the same threads as the clutch bolt. So I’m thinking at this point I’ll just tap the jackshaft and retain the upper gear with an M14-1.5x30 bolt and use thread sealant on the bolt threads.
View attachment 166848

Couldnt you just push a Aluminum plug into there? Lighter and Snapring works so.

 

[Nikolai]

I could, that’s a good idea and easy to do. I’ve been wondering the last few days if the snap ring would be strong enough? I don’t think there should be much lateral force on the snap ring. Shouldn’t be any from the gear, maybe only from the secondary clutch opening?

 

[74Nitro]

This is jackshaft from 97-04 two strokes.

 

[74Nitro]

This is jackshaft from 97-04 two strokes.

Part number for that rubber fitting is 82M-17699-00-00

 

[Nikolai]

Part number for that rubber fitting is 82M-17699-00-00

Thanks! That’s an easy fix.

 

[Nikolai]

My bent 3/4 frame tube is not vertical and made the drivetrain plate slightly more difficult. I drilled & tapped some holes in the jig and bolted a couple pieces of 1” angle to it for my drivetrain plate to rest against. I put a straight edge across the lower frame tubes and then a square on top of that, and then shimmed behind the bottom of the 1” angle pieces until they were square with the lower frame tubes. Now when I go to fit the drivetrain plate I can clamp it to the angle for welding and it will be vertical.

Had to make a paper copy of the brake caliper to get the mounting bolt locations for proper template.

Drivetrain plate will be a single piece of .090 4130 plate that both flanges and the brake caliper bolt to.

I’m unsure at this point how rigid a flat piece of plate will be. 0.090 is fairly thick and once it get welded and shrinks it should be stiff. If it does flex then I’ll weld some additional tube or plate in to stiffen it up but I want to wait and see. Trying to come in under 1.25 lbs for the plating on this side. That gives me .75 lbs for the chaincase side.