4speed DOHC vs 5speed SOHC

Been looking at the specs for the 450 SX and the 505 XC-F

and noticed that the 450SX has the same final drive ratio as the 505XC-F.

Is this correct and is so are both bikes suitable for open desert and desert baja racing, because at fisrt I thought the SX was a track bike, more comparable with the Honda 450R.

Both the 450 SX and the 505 XC-F are DOHC. The 5 speed tranny in the 505 would be much better suited for desert riding than the very limiting 4 speed in the 450.

Both the 450 SX and the 505 XC-F are DOHC. The 5 speed tranny in the 505 would be much better suited for desert riding than the very limiting 4 speed in the 450.

But on the KTM spec sheet it states the final drive gearbox ratio is the same?

But on the KTM spec sheet it states the final drive gearbox ratio is the same?

I believe KTM removed the 1st gear from the SX, putting 2nd in its spot, cause people start off in 2nd for tracks

the 505 xc-f can hit 98mph stock, and has a DOHC motor

98mph stock! so I guess the only different between the sx and xcf would be the suspension then. I would assume the 505xcf is better suited to the desert as I have read in som other posts.

Cheers

The transimissions in the two are actually COMPLETELY different. It is NOT just first gear removed as many think. There are almost no interchangeable parts (other than one shift rail, some gear retaining clips, and a few bearings) between the two transmissions.

Different design: the four speed is a single shift rail (potentially stronger design), the five speed is a conventional twin rail.

The ratios are as follows; you can see that they are completely different for each model:

SXF: First 17:32, Second 19:30, Third 21:28, Fourth 23:26

XCF: First 16:34, Second 19:31, Third 20:26, Fourth 23:25, Fifth 26:24

With the 505, stock gearing (14/48) is okay for the dez. The 450 SXF has stock gearing of 14/52 (the same as the XCFs) which is a little low IMO for the four speed. You still get 80+ mph top speed on the 505. Yes, a XR650R (or XCF) will blow by you on the dry lake bed, but there aren't too many of them included in a desert race anymore. The biggest issue is going UP hills. You are basically stuck with what would be second gear on any other bike. As long as the hill in front of you is devoid of spodes scattered all over it so you have a clean run, you are all right. But if you screw up once you don't have that "granny low" gear to drop back to. So you have a good chance of smoking a clutch if you don't go back and get a new run at the hill. If you are a really good rider (going up) the four speed won't hurt you. Remember that when Ty Davis and his team started racing with Yamahas way back when, they had to run their WRs with the four speed YZF tranny at the time because the five speed WR tranny would always break. David Pearson won the H&H title with a four speed, so it can be done in the dez with only four cogs. It just takes a little more commitment!

I've raced my 4spd in the dez, and it wasn't the bike holding me back from finishing well. It was my riding like a little girl that made me finish poorly.

i just sold my 04 sx because i would run out of gears on the open sections. yeah it would hit 80mph...but as to how long you want to run the bike that hard for long periods is the question. i upgraded to the 450 xcrw and what a difference. i can cruz comfortably at 70mph forever without winding the piss out of the motor. this means longer life, less fuel consumption, and comfort. the xcrw dosen't have that super agressive first gear of the sx. but the sx was much harder to control in technical situations. over all: sx much better on track and wont hang on long rides. xcrw long distance desert machine!!

xcf has more power but no kickstarter. something to consider depending on how far you wander in the desert!!! xcrw is green sticker if you live in cali. major bonus

Another major bonus of the XC-W is the wide ratio 6 speed tranny.

Another major bonus of the XC-W is the wide ratio 6 speed tranny.

This is key for desert riding/racing!

This is key for desert riding/racing!

my bike has a key

The Baja 1000 gets won by a 5 speed every year. the extra gear just makes it that much nicer

my bike has a key

The Baja 1000 gets won by a 5 speed every year. the extra gear just makes it that much nicer

Yeah but those are full blown Honda efforts, who knows what in their. And they run those bikes for 650-1200 miles then get a complete teardown, I think the 6 speed in our, or at least my bike should extend the life when running at WFO as compared to a 5 speed.

Yeah but those are full blown Honda efforts, who knows what in their. And they run those bikes for 650-1200 miles then get a complete teardown, I think the 6 speed in our, or at least my bike should extend the life when running at WFO as compared to a 5 speed.

I was just saying you don't need a 6th speed unless your johnny campbell and fly down a beach at 110mph.

the 6th gear adds ton's of comfort, and allows our bikes to run a lower 1st and have a better overall spread

but there is also nothing wrong with a 5 speed, they seem to handle there own quite well as it would seem

just adding to the discussion, i love my 6 speed, and never find that i need another gear :p

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