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Discussion Starter · #1 ·
As most of you know from all these posts I've been putting up, I'm just really getting into this 03 Pro-X 8 121. Here are my questions:

-Right now my gears are 25/40. From another post one opinion was 21/43 & another 21/40, any other opinions or do one of these sound good? (Will have: CPI twins/10-66 weights/Tempa-flow/gutted airbox/flow rites/VF2/121X1 studded or 1.5 un-studded)

-Can you guys fill me in about the BB upgrade? Best place to get the bearings, Do I need any special tools, will I only need bearings & gaskets?

-I have heard studs can be hard on chain cases, is this true? I know a guy with a 1.5 track, apparently it's like new w/ no missing lugs & he only wants $250 for it. Studded 1" or un-studded 1.5"?

-I ordered some CPI twins, will I need to take out the stock support for the can to make room for the silencer? The picture wasn't good enough to see if they were the dual silencer, if they are it looks like I will. Just want to know so I can start looking for a cutting wheel now.

-My valves are aluminum, what do SS valves go for & where can I get some?

-Is the SLP air horn still beneficial if the air box is gutted & have SLP flow rites?

Thank you.

Slowly but surely
2010522541783_2812.jpg
 

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I highly recomend Curtis at Fast trax motorsports / Union Bay Racing.
Have him do the good bottom end and port / case port it for your application.
He's really good and will help with clutching for the set up, everything.
Your machine will absolutely rip.
go here:
http://ftxmotorsports.com/
Tell Curtis that I sent you.
 

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the stainless valves are about $84 each from partsland http://partsland.com/index.cgi?N=1274640874-20317&P=SM-2003-600-PRO-X-CYLINDER-800

You would lose a lot of top end speed going to 21/43 gears. I think you'd end up with about an 85mph top speed.

the crank bearing upgrade gets done differently by different places. SLP just puts a wider bearing on and it's cheap if you disassemble your motor and just send them the crank. other places modify the case http://www.snowtechmagazine.com/articles/2004/allsprtcrank.php

you definitely want to stud it. as long as you maintain your chaincase you shouldn't have issues there.

twin pipes are a pain in the rear in my opinion.
 

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Go with the 1.5" track if you ride powder conditions, studded 1" if you ride rivers and lakes alot(hard pack and ice). Gear it to 24/41 or 23/41, don't go too low otherwise you'll lose out on speed. Drop the lower front arm mounting position about 7/8"-1", your suspension will react much better and it will work better in the powder and overall.
Run non-synthetic oil or the Blue/Syn blend and don't worry too much about the crank until it gives. Why rebuild it if it isn't broke yet is what I say? Run the 719 helix, this will wake it up even more as well.
 

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Discussion Starter · #7 ·
Customized89Trail said:
the stainless valves are about $84 each from partsland http://partsland.com/index.cgi?N=1274640874-20317&P=SM-2003-600-PRO-X-CYLINDER-800

You would lose a lot of top end speed going to 21/43 gears. I think you'd end up with about an 85mph top speed.

the crank bearing upgrade gets done differently by different places. SLP just puts a wider bearing on and it's cheap if you disassemble your motor and just send them the crank. other places modify the case http://www.snowtechmagazine.com/articles/2004/allsprtcrank.php

you definitely want to stud it. as long as you maintain your chaincase you shouldn't have issues there.

twin pipes are a pain in the rear in my opinion.
Damage! I know some fanatics around town so I'll see if I can get them locally.

Well first priority is top end, thats why I upgraded but I don't want it to be shit off the line either. What's a good compromise?

I'll price it out but I already know its not going to be cheap especially with shipping so it'll be on the back burner for a while.

I was thinking the same thing but I might get the track anyway just to have it in case.

I know they were on my 97 SKS 7, I became a pro at jetting it (eventually bought dial-a-jets) but I'm hoping the tempa flow will take care of this one.
 

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MXZ700SKS700 said:
As most of you know from all these posts I've been putting up, I'm just really getting into this 03 Pro-X 8 121. Here are my questions:

-Right now my gears are 25/40. From another post one opinion was 21/43 & another 21/40, any other opinions or do one of these sound good? (Will have: CPI twins/10-66 weights/Tempa-flow/gutted airbox/flow rites/VF2/121X1 studded or 1.5 un-studded)

24/41, or 23/40. [/color=red]

Run the 1.5" track, and throw 96 1.6" Woody's megabites in it. Better all-around track.[/color=red]

-Can you guys fill me in about the BB upgrade? Best place to get the bearings, Do I need any special tools, will I only need bearings & gaskets?

The BB upgrade is when the put a larger PTO side crank bearing in. When you have the crank out, get the crank welded, indexed, and blueprinted. BIKEMAN performance does that, as well as SLP, or somewhere like flannery, or custom motor shops. [/color=red]

-I have heard studs can be hard on chain cases, is this true? I know a guy with a 1.5 track, apparently it's like new w/ no missing lugs & he only wants $250 for it. Studded 1" or un-studded 1.5"?

-I ordered some CPI twins, will I need to take out the stock support for the can to make room for the silencer? The picture wasn't good enough to see if they were the dual silencer, if they are it looks like I will. Just want to know so I can start looking for a cutting wheel now.

-My valves are aluminum, what do SS valves go for & where can I get some?

They around $80 a piece, and great upgrade.[/color=red]

-Is the SLP air horn still beneficial if the air box is gutted & have SLP flow rites?

You can make a SLP airhorn homemade in 5 minutes. Flowrites, arent that great, but add a little airflow, buy them if the money is burning a hole in your pocket.[/color=red]

Thank you.

Slowly but surely
2010522541783_2812.jpg


 

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Discussion Starter · #9 ·
-Is the SLP air horn still beneficial if the air box is gutted & have SLP flow rites?

You can make a SLP airhorn homemade in 5 minutes. Flowrites, arent that great, but add a little airflow, buy them if the money is burning a hole in your pocket.[/color=red]


Would it consist of taking the shelf out & cutting a large hole in the top of the box? If not, please elaborate. Thanks.


24/41, or 23/40, I'm looking to keep a decent bottom end but more interested in top end, will either of these get me there? Thanks.
 

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1.5 with no studs. yeah u could put studs in the track but the studs have a higher chance of breaking and bending. but supposedly if u get the nuts that go up the stud farther it greatly reduces the chance of breaking and bending
 

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23-41 or 42. 719 helix, red/blue sec spring for topend.
 

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MXZ700SKS700 said:
-Is the SLP air horn still beneficial if the air box is gutted & have SLP flow rites?

You can make a SLP airhorn homemade in 5 minutes. Flowrites, arent that great, but add a little airflow, buy them if the money is burning a hole in your pocket.[/color=red]


Would it consist of taking the shelf out & cutting a large hole in the top of the box? If not, please elaborate. Thanks.


24/41, or 23/40, I'm looking to keep a decent bottom end but more interested in top end, will either of these get me there? Thanks.


http://www.snowmobilefanatics.com/forum/topic/52500/display.aspx
 

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Discussion Starter · #13 ·
jesse500 said:
MXZ700SKS700 said:
-Is the SLP air horn still beneficial if the air box is gutted & have SLP flow rites?

You can make a SLP airhorn homemade in 5 minutes. Flowrites, arent that great, but add a little airflow, buy them if the money is burning a hole in your pocket.[/color=red]


Would it consist of taking the shelf out & cutting a large hole in the top of the box? If not, please elaborate. Thanks.


24/41, or 23/40, I'm looking to keep a decent bottom end but more interested in top end, will either of these get me there? Thanks.


http://www.snowmobilefanatics.com/forum/topic/52500/display.aspx


Wow, that just confused me more. The directions are straight forward so I could take care of it but it seems like the general consensus is not to do it. Has anyone else done this? If so, what did you think? Thanks for the link Jesse.
 

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MXZ700SKS700 said:
jesse500 said:
MXZ700SKS700 said:
-Is the SLP air horn still beneficial if the air box is gutted & have SLP flow rites?

You can make a SLP airhorn homemade in 5 minutes. Flowrites, arent that great, but add a little airflow, buy them if the money is burning a hole in your pocket.[/color=red]


Would it consist of taking the shelf out & cutting a large hole in the top of the box? If not, please elaborate. Thanks.


24/41, or 23/40, I'm looking to keep a decent bottom end but more interested in top end, will either of these get me there? Thanks.


http://www.snowmobilefanatics.com/forum/topic/52500/display.aspx


Wow, that just confused me more. The directions are straight forward so I could take care of it but it seems like the general consensus is not to do it. Has anyone else done this? If so, what did you think? Thanks for the link Jesse.


Alot of people dont want to do it because they think it allows alot of junk into the airbox (sticks, water, etc`..) and it allows a little bit of it into the carbs. Which i think is not true, the hood keeps most of the particles out, and some simple screen pre-filters fix that.
 
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