close/wide ratio gearing turbo questions

[skippy]

First off, I'm very new to snowbikes and have never even had a chance to ride one yet. I have watched every video that pertains to the mountainhorse and have seen a couple in action about three weeks ago in Cooke city and was instantly sold on getting one no matter what, so I'm quickly trying to learn everything I can about the bikes/ kits before the snow check expires...
Through all the post readings on here It seems like more people lean towards the mx (close ratio) bikes then the wide ratio bikes. I haven't picked a bike to go with yet but I do know that I plan on putting a turbo on the bike i do get at some point and was wondering if going with a wider gear ratio would be better fit for a turbo application. To me it seems that you wouldn't be able to shift fast enough to keep up with the turbo spooling and quick power burst with a close ratio bike. What does everyone think? Thanks

 

[powderzone]

short answer

KTM 450sx-f with 520 bore kit with turbo.
It's the weapon!

 

[nilsmountain]

KTM 450sx-f with 520 bore kit with turbo.
It's the weapon!

Which company sells 520 bore kit for sxf 450?

 

[Rush44]

KTM 450sx-f with 520 bore kit with turbo.
It's the weapon!

I'm sure it is when you have an extra $25,000 laying around. How about the rest of us with jobs and families? Hard to explain that purchase and not feel like a total jerkoff. I'm sure it's a total kick in the pants on somedays... but that is a bunch of cash for sure.

I don't know if I would worry about the trans as much as I would worry about the motor. Most wide ratio bikes, if I'm not mistaken, have lower rev limiters vs. close ratio bikes. I'm sure there are exceptions out there, but the thing you want with that turbo is a high rev limiter so you have a larger turbo window. What amazes me about the turbo is just how quickly the revs come on... it's not just power it's the entire bike going batsh*t crazy in an instant. Those extra 3,000RPM vs. a Husie or an XCW make more of a difference than the transmission. Of course, in a perfect world, the wide ratio tranny with a 12,000RPM motor would be awesome.

 

[skippy]

Thanks Rush44! That's a very good point about the revlimiter, I would have overlooked that for sure... I keep leaning towards getting a dual purpose bike thinking I will use it equally in the summer months, but when it really comes down to it, i could careless about the summer part as winter performance will trump summer by a long shot.

Does anyone know if you can raise the the revlimiter on the dual purpose bikes?

Here's the list of bikes I keep going back and forth on. Open for suggestions to please.

KTM 500EXC
KTM 450SXF
WR 450F
YZ 450
Found a brand new Husqvarna Te511 for under $6000, but concerned about not being able to use the timbersled kit on any other bikes besides the Huskys. Plus nobody has a turbo kit yet that I know of... thanks

 

[Rush44]

KX450F or 450SXF. They are probably your best choices for race bikes. The only reason I am partial to the 450SXF is because I believe the air forks on the KX and CR are a weak link. You will find plenty of people who say that the air forks aren't a problem... but coming from a guy who's now seen it happen on 5 bikes you can believe me that you DON'T want it to happen to you. Rebuilding or replacing those forks are not cheap. My buddy loaned out his KX to a friend to "demo" for a day and the air forks went out. The guy riding it stroked through the fork clamps, spindle, and bent the tubes. $1600 in damage for a friends loaner ride.

Both the KX and SXF have great motors.

 

[tdorval]

Does anyone know if the gytr competition ecu and power tuner can raise the rev limiter on the wr450 or does the wr450 12+ already rev high?

 

[powderzone]

Rush44 nailed it. The rev limiter is key. The 450sxf limit is around 11,500 rpm whereas the 500XC-W is (I think around 8,000 to 8,500). The 520 bore kit for the ktm 450 is available through your KTM dealer.
My preference is to run NOS with or without the bore kit. It's so fun.
I think if the OP is looking to run a snow bike without a turbo kit for a while the 450 will make a better bike.

 

[skippy]

The rev limiter is key. The 450sxf limit is around 11,500 rpm whereas the 500XC-W is (I think around 8,000 to 8,500).
I think if the OP is looking to run a snow bike without a turbo kit for a while the 450 will make a better bike.

Wow... didn't realize that the 500 rpm were that low or that much spread apart from the 450 rpm. That will for surely lean me towards the 450 over the 500. I will be keeping the bike stock, till I can replenish the fun fund back up to purchase the turbo. But who knows, maybe after riding the bike for the first time, it will be fun enough the way it is, and i won't need the turbo. Thanks

 

[mnsnowhawk]

Anyone use one of these. Could you get the revs higher or is the engine not designed for it? http://www.amazon.com/gp/aw/d/B00B7IRDBS?pc_redir=1395550957&robot_redir=1