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133 x 2.5 is becoming a reality

chumbilly1

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So I just got my new Ice Age 130" custom rails yesterday. They look great. Have the steeper approach angle in the front like the 15 kits, since I will be using 6 tooth Avid extroverts to turn my modified 2.5" flexedge track. I will be using in conjunction with the new Ice Age +3 sidepanels. The combination will move my drive axle forward 3+" and shorten wheelbase by about 6-7". I think this is going to be a real good track set-up on my 300 based build. I am going to need some gearing advise from some of you experts soon.
 
U
Sep 12, 2010
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Oh boy this should be great! I'm looking forward to the ride reports.

I can tell you that I have no regrets on my 146×2.5.
 

chumbilly1

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The motor is a 300sx built off of a 250sx close ratio five speed. last year I used an xc six speed but felt I shifted too often. I was using 13/17/19 gearing with the chaincase stock last year.(17/20 I believe) This year I want to go slightly higher again. I am thinking 13/19/19 over 17/20 or maybe 13/19/20 over 17/20. Does this sound realistic? The 300 is ported and has 230# compression and runs on minimum50% 110/50%92. I wil be running the Bill's pipe and silencer and I am having crankworks balance a sx crank for high rpm use as I type his. With the sx crank and ignition it will have more snap and it should rev out real well with the crank tuned for high rpm. I have ridden the 300sx with the 250sx lower end in the dirt and they are a handful. Nothing like my xc based 300sx that I race and ride in the dirt. Input is welcome!
 
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I've seen the Iceage side plates but can't find them on their website, what are they charging for those?

M5
 

dirtrebel

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Nov 26, 2008
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Bozeman, MT
The motor is a 300sx built off of a 250sx close ratio five speed. last year I used an xc six speed but felt I shifted too often. I was using 13/17/19 gearing with the chaincase stock last year.(17/20 I believe) This year I want to go slightly higher again. I am thinking 13/19/19 over 17/20 or maybe 13/19/20 over 17/20. Does this sound realistic? The 300 is ported and has 230# compression and runs on minimum50% 110/50%92. I wil be running the Bill's pipe and silencer and I am having crankworks balance a sx crank for high rpm use as I type his. With the sx crank and ignition it will have more snap and it should rev out real well with the crank tuned for high rpm. I have ridden the 300sx with the 250sx lower end in the dirt and they are a handful. Nothing like my xc based 300sx that I race and ride in the dirt. Input is welcome!

the new kits are 1 to 1 in the chain case to account for the 6 tooth drivers. 17 tooth top and bottom, in the chain case. you probly knew that but just in case.
 
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mxracer299

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Nov 24, 2010
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Sounds like a fun build! I'm doing the same thing, 250 bottom end with a 300 Sx top and running a 15 SX LT kit on it and plan on doing a 2.3. I haven't balanced the crank though as I'm going to see how it runs and stuff the cases and do a stroker crank if I don't think it has enough power...
 

chumbilly1

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The iceage side panels were on the site. I have a feeling they may have become a very limited build. They only work with pds supposedly, however I would not be afraid to either commit a frame to snowbike (ie. cut off linkage tabs) or notch track to clear linkage tabs.

As for the balanced crank, I have found 300 to vibrate worse, and snowbike seemed to amplify this due to WFO type of riding. Have had it explained to me that the sx crank is already stuffed and it is set up for 250 not 300 as in that the 300 piston weighs more and throws off the balance. I only want it smooth at peak rpm so realistically it will be balanced for like 7000-9000rpm.

I am excited, should be a great ride!
 

chumbilly1

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Sounds like a fun build! I'm doing the same thing, 250 bottom end with a 300 Sx top and running a 15 SX LT kit on it and plan on doing a 2.3. I haven't balanced the crank though as I'm going to see how it runs and stuff the cases and do a stroker crank if I don't think it has enough power...

Don't you think a stroker will slow down the revs too much? The way I understand stroked engines don't rev as high and are torquier. IMHO of course
 

chumbilly1

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I think I need some pics to satisfy my curiosity.

I will post pics when I start assembly. Need to dry fit the track before she goes to vulcanization process. When you trimthe flexedge it starts to look like a powder claw. Giant center paddles with small paddles on the edges. I am thinking I will go with 11.5" wide.
 

chumbilly1

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So I started cutting track tonight. This is way easier than folks make it sound! I used a Bigfoot 10 1/4" beam saw with an old $hitty blade. Wear safety glasses but not bad. Went 11 1/2" wide. Sure does make a nice lightweight easy moving track compared to fullsize sled tracks. Cant wait to weigh it compared to my stock 137. a little birdy told me that the next gen timbersled tracks will be narrower than 12.5", supposedly they handle much better. I think the 2.5" track is going to be a sweet upgrade!
 

chumbilly1

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Probably going with carroltech in NY. I had found a place in Spokane but now cant find info. Still lookin though. Seems in the west the best vulcanization specialists work in the mining industry doing conveyor repairs. I may bolt together or use alligator clips initially just for testing purposes and to not wast $$$ on the vulcanization process until I decide on track.

If you multiply the square inches of track by paddle height it is pretty easy to see where the increased paddle height should outweigh the length. In my hillbilly theory anyway.
 
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