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Discussion Starter · #1 ·
Got the following build coming but will be several weeks before I can report as I am 4 weeks away from being back in the US and having the kit:

Thumper Racing 570 Kit w/ Wiseco 12.5:1 Piston w/ Total Seal Rings (Piston 7 grams heavier than stock)
807 Cam with CrowerPower grind
Will port w/ + 1mm valves
Ceramic Coated Head & Piston
Taper Bore Carb FCR 43mm from Sredrum (Chris)
HMF Full System
K&N w/ Outerwear
Will Open Air Box
Pump Gas

Hope this all works out - should be able to stay up with the Raptors
 

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Premium Member
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1,477 Posts
Got the following build coming but will be several weeks before I can report as I am 4 weeks away from being back in the US and having the kit:

Thumper Racing 570 Kit w/ Wiseco
12:1 Piston (CP doesn't have a 99mm) w/ Total Seal Rings (Piston 7 grams heavier than stock)
833 Cam
Will port w/ + 1mm valves
Taper Bore Carb FCR 42mm
HMF Full System
K&N w/ Outerwear
Will Open Air Box

Hope this all works out - should be able to stay up with the Raptors
cole,
i have a few questions or concerns about the thumper racing 570 kit. maybe you can answer them or get them to thumper racing to be answered.

being that the biggest piston we can use is a 97mm before the cases must be machined to accept the larger sleeve. so with that said, does this kit require the cases to be machined or are they machining the skirt to fit the stock cases. i must say that if they are modifiying the sleeve to fit in the cases without being machined is quite scary to me... also after doing the math it will really only be a 554cc (72mmx99mm).

I am not sure about you, but I know that the extra 22cc's that you gain with the Thumper Racing 570 kit over the ktm 540 kit is not worth the chance you take by using a aftermarket sleeve, etc.

I am not trying to rain on your build, just save you possble future headaches...
 

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Premium Member
Joined
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630 Posts
Discussion Starter · #4 ·
cole,
i have a few questions or concerns about the thumper racing 570 kit. maybe you can answer them or get them to thumper racing to be answered.

being that the biggest piston we can use is a 97mm before the cases must be machined to accept the larger sleeve. so with that said, does this kit require the cases to be machined or are they machining the skirt to fit the stock cases. i must say that if they are modifiying the sleeve to fit in the cases without being machined is quite scary to me... also after doing the math it will really only be a 554cc (72mmx99mm).

I am not sure about you, but I know that the extra 22cc's that you gain with the Thumper Racing 570 kit over the ktm 540 kit is not worth the chance you take by using a aftermarket sleeve, etc.

I am not trying to rain on your build, just save you possble future headaches...
http://www.thumperracing.net/525xc.php
http://www.roughhousecycle.com/KTM_BIG_BOR...ore_kit_520.htm
http://www.totalseal.com/TechPage.aspx#trGaplessPistRings
http://ktmtalk.com/index.php?showtopic=260421
Give Travis a call Bronson he knows these engines well and is a pleasure to talk to...very helpful...let me know what you think...the kit is actually a good price...he bought Thumper Racing moving it out to Californy...I'm basing my build off off the power my LTZ470 makes and the 67.2mm Stroke X 94mm Bore...I think I'll see the over rev and won't lose a lot of low end with the 41mm but will send the 39mm for taper bore to 42mm just in case I run out of fuel on the top end with the 41mm
They are reliable...one that is already built is at 60hp at 8100 rpm and 45 ft/lbs torque at 5100 rpm with custom Hot Cam grind and Port w/ +1mm Valves with 41mm Carb...we are trying for a custom 12.5:1 Piston also with Total Seal Gapless rings...and then we'll go with the 8/07 cam
I've got my 41mm Carb w/ TPS off a 2003 525MXC...
If it all works out 61-62hp with 47-48 ft/lbs torque

Thanks for the input!....
 

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you know, now that i think about it... i think that pwr requires a pre-payment for 10 radiators to get them to make one; or atleast that is how many had to be paid forbefore they would make a oversized radiator for the ltr. it only took abour 6-8 weeks to get...
 
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