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Just curious as I have a 79 Centurion 500,with some minor improvements but no port work done.I,m thinking of triple piping it as I,ve heard it can really wake up these polaris triples.I,ve heard some guys going up to 38mm carbs after installing the pipes.Is it really necessary or just something to squeeze out a few more hp?Any help would be appreciated.I know some veterans must have run a few of these in there day.
 

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More air = more power and the pipes will require rejetting anyway.
 

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I remember someone telling me that the cranks were good on stock engines, but didn't hold up with mods. Just ride that old girl a little easy. Don't hold the loud handle to the bar too long, and she'll probly hold up.
 

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notsure if those came stock with the 34mm or 38's, i know the txl 340 came with 38's. but if stock is 34mm, i cant see where a 38 would hurt, just have to play with the jetting some. i know the old 600 indys came with the 38's on them and stock mains was a 260. been awhile since my centurion had stock carbs on it, since it has a 650 kevin hanson race motor in it, the carbs are 40 mm bored to 42.5 mm. kind of a wild little ride down the 1,000 foot track. (nasty to be exact) strictly a speed run sled. let us know what you do . am interested especially what kind of pipes you put on it.
 

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Rainman56 said:
Just curious as I have a 79 Centurion 500,with some minor improvements but no port work done.I,m thinking of triple piping it as I,ve heard it can really wake up these polaris triples.I,ve heard some guys going up to 38mm carbs after installing the pipes.Is it really necessary or just something to squeeze out a few more hp?Any help would be appreciated.I know some veterans must have run a few of these in there day.
Nope. If you have bored and ported the engine,yeah, but just for pipes your 34mm carbs can be easily adjusted for better performance. By installing bigger carbs you'll just pour more fuel through the engine. Ultimately decreasing performance and wasting fuel and money. Hope it helps
 

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I had a 81 Centurion Indy 500, had dg trip pipes and stock carbs. That sled hauled serious mail. Just rejetted and she was fine. In my old girl, she hated NGKs ans would foul them within 20 miles, put ol Champions in her and they would last a whole season. Dont know why, but thats how the blue bitch was. Them DGs were loud and had the goofy can/silencer set up of theres, not a big fan, but what you gonna do when they were free. Stick with stock carbs and rejet. Ran premium gas with a 40:1 mix and she loved it and ran perfect. On the Rock River i didnt get embarassed much at all if ever. Shocked a lotta folks also. Just memories and my advice.
 

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if you want some real advice on how to wake these sleds up give me a email. i have 1 imp stock, 1 mod, and another pro stock i just built out of centurions. 38"s made a 4.5 mph difference on our imp stocker.
 

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keep the stock carbs and rejet. i have a centurion 500 in my indy 650 chassis and it flies pretty damn good. if you have pipes just rejet them carbs to spec my the pipe manufacturer. pretty easy
 

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depends what you want to do with it. you can tune around a 38 and make up for any short falls to gain the top hp. in a side by side drag race between the two carbs it would be a toss up as they both have there plus sides.
 

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34's are a little quicker on the bottom end but with a 38 dialed in right it will be almost as quick off the bottom end and will have a better top end.
 

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the centurion motor is pretty much a Tx-L 340 with an extra cylinder, get 3 carbs from that, and it should give you a good starting point, those are 38's
 

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polarisorbust^^^^ you are correct they are the same. i can take 2 centurion cyl and heads and stuff them on a txl (i am actually making one right now). we just raced our 2 centurions at the wautoma, wi grass drags and we have 38's and we toke vintage open. im actually thinking about putting 44's on mine. who knows
 

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polaris650freak said:
polarisorbust^^^^ you are correct they are the same. i can take 2 centurion cyl and heads and stuff them on a txl (i am actually making one right now). we just raced our 2 centurions at the wautoma, wi grass drags and we have 38's and we toke vintage open. im actually thinking about putting 44's on mine. who knows
^^ realy i just raced my sled at the wautoma drags too! [thumb] the turn out wasnt very good this year..
 

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What sled did you race? and i agree the turn out wasnt the best but it was still fun. Its all those yamaha's that are getting the handicap like the nytro's being allowed to race in 500 imp???? that is no fair when im sitting there with a 1979 500 centurion and im doing all i can to even get 100 horse out of it and they can plug in a lap top and double the horse and torque that i could ever think about having.
 

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polaris650freak said:
polarisorbust^^^^ you are correct they are the same. i can take 2 centurion cyl and heads and stuff them on a txl (i am actually making one right now). we just raced our 2 centurions at the wautoma, wi grass drags and we have 38's and we toke vintage open. im actually thinking about putting 44's on mine. who knows
the Tx-L's were a mono block, the jugs from the 500 wont fit.
 

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^^^^that does not matter, everything lines up. water jackets, sleeve, bolt pattern, everything. i have one sitting in my bedroom if you want me to take a picture and post it on here, i have talked to flannery about this and he has made many of these motors, he even had the wonderful idea of putting 650 cylinders and heads on a tx-l, they fit right on but the port's need a little stretching to match the piston and stroke, but 500 cylinders and heads work perfectly.
 

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polaris650freak said:
^^^^that does not matter, everything lines up. water jackets, sleeve, bolt pattern, everything. i have one sitting in my bedroom if you want me to take a picture and post it on here, i have talked to flannery about this and he has made many of these motors, he even had the wonderful idea of putting 650 cylinders and heads on a tx-l, they fit right on but the port's need a little stretching to match the piston and stroke, but 500 cylinders and heads work perfectly.
WOW, that would be a sweet little motor. I never thought it would work. must have to do a custom water manifold for the top of the heads?
 

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all you do is take triple water rails and cut one end off so you have a twin water rail and weld on a lip so the hose doesnt slide off.
 

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polaris650freak said:
What sled did you race? and i agree the turn out wasnt the best but it was still fun. Its all those yamaha's that are getting the handicap like the nytro's being allowed to race in 500 imp???? that is no fair when im sitting there with a 1979 500 centurion and im doing all i can to even get 100 horse out of it and they can plug in a lap top and double the horse and torque that i could ever think about having.
i raced my pro x2 600. i had my tent in the pits over by the tree line. but yah i know the yammys had such a huge handicap!!! it was unfair..
 
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