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Discussion Starter · #1 ·
Should i run with the stock 380/50 set up? I have no idea what altitude i'm in. I live in southern upper michigan, northren wisconsin. area. any ideas out there? Looking for the best set up for my 97 ultra spx. Its in a 96 xcr 600 body.. Thx again.
 

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what jetting have you been running? how does the wash look on the old pistons.

go to partsland.com and look up jetting for a spx ultra.
 

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And go to Wunderground.com and type in your zip...you will get weather, elevation....etc.
 

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Discussion Starter · #4 ·
I think the guy who put the motor in it, (the last owner) used the 600 xcr carbs, I ran it last year and it had 340, 35s in it. It looks like it ran lean. the pistons are messed up on the exhaust port side, also a wrist pin came out or he forgot to put it in which messed up one jug, The wash seemed ok on two cylinders but the middle where the wrist pin came out it was blackend completely. The stock jetting was 680 50. Was wondering if running that low of jetting on a sled that calls for 680's may had something to do with it..... Also I was just in the garage taring it apart some more, Putting a new seat on it and just going over everthing, I checked the gearing and its set up 21/35.. What kind of set up is that? From what I've gathered from browseing this site, 20/39 is the perfered set up. Do U think that had something to do with it too? I'll go check those sites out too, thanks.
 

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stock 97 SPX main jets are 380s with a #50 pilot jet. Stock gears are 21/39.
 

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Discussion Starter · #6 ·
Yeah Thats what I learned too, think I'm gonna try the 20/39 set up with the stock carbs. Thats on a fresh rebuild of course. We'll see how everything turns out.
 
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