any one with a thumper racing 520 Kit

[KAWGRN]

any one with a KTM 520 kit on their 450SX! need to replace crank bearing so as long as Im in there thinking about the BB ,wondering if there is enough power increase to warrant the change?

 

[M5-]

It's a good upgrade for dirt because it is best at low rpms it really has a lot of roll on power, they don't like to be revved for long periods of time. Mine blew up a brand new KTM con rod in nothing flat snow biking so back to Thumper racing it went for a second rebuild, Travis treated me very fairly but it still cost a fortune. I like it on the dirt which is where it lives now for snow biking I'd never do one again.

M5

 

[KAWGRN]

I was wondering about holding it open for a long Pull!! I guess I will just rebuild the stock motor? any one else with experience out there, I'm told he sends a lot of them to Canada?

 

[Wheel House Motorsports]

Rode with a fresh 15 ktm with a 520 setup against a piped 2014 yz450 with 150 hrs, same kits, TSS, riders switched bikes and raced back and forth. The 450 was pulling it on top every time. Not saying its the end all decision making, but I wasn't very impressed and we did our best to make a straight comparison. Also the 520 vibrates noticeably more.

 

[DenverSnowBike]

Keep it stock and freshen everything up. You won't really notice a difference, and for $700+ not worth it in my book.

 

[sierraclimber]

Took my 2004 525 MXC to a 540 with Thumper Racing and carb bore. Very noticeable increase in power on low to mid rpm. That's where these motors are happier running. It revs up just as quickly as before ( I heard they were slower to rev but maybe that's true with the 570's) I would do it again with Thumper, they fixed a lot of other stuff in the trans while they were in there too. Wish I had them throw in a lower 1st gear when it was split apart.