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Author Topic: 4T or 2T?  (Read 66875 times)

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trevo

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Re: 4T or 2T?
« Reply #100 on: December 23, 2013, 01:59:44 pm »
I support you,got hold of one earlier this year for 21K 08 model
 

Offline wolf skaap

Re: 4T or 2T?
« Reply #101 on: December 31, 2013, 08:51:32 am »
I always thought that the 2T weighs a lot less than a 4T but it seems that a KTM 200 weighs in at 95kg. A CRF250 weighs in at 98.6kg. Thats a 3.6kg weight difference without any fluids.
Add twice as much fuel to the 200 and the crf is dangerously close to weighing less.

For the WFO season, I'm thinking strongly about getting a CRF250r 2nd hand for 20K, having suspension done by Hilton Hayward and adding a recluse.
It's gonna be a weapon for sure.

In order to improve the reliability of the CRF, I will have to do the SS intake valve conversion. Note that there is, at the moment, a 2008 CRF250 WITH SS valve conversion for sale in the Cape for 23K! That's bloody cheap!
« Last Edit: December 31, 2013, 08:56:37 am by wolf skaap »
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Offline LoopSoosStroop

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Re: 4T or 2T?
« Reply #102 on: December 31, 2013, 09:15:33 am »
A CRF250 weighs in at 98.6kg

Sure about that?

Does not sound right.
 

Offline wolf skaap

Re: 4T or 2T?
« Reply #103 on: December 31, 2013, 09:26:05 am »
A CRF250 weighs in at 98.6kg

Sure about that?

Does not sound right.
Yep. http://motocrossactionmag.com/Main/News/4148.aspx
MXA spent $10 000 to drop its weight by 17lbs to 200lbs.
98.6 = 217lbs  ;)
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Offline LoopSoosStroop

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Re: 4T or 2T?
« Reply #104 on: December 31, 2013, 09:51:13 am »
A CRF250 weighs in at 98.6kg

Sure about that?

Does not sound right.
Yep. http://motocrossactionmag.com/Main/News/4148.aspx
MXA spent $10 000 to drop its weight by 17lbs to 200lbs.
98.6 = 217lbs  ;)

That is the R obviously, but still quite amazing! How suited is this for enduro?

What is the dry weight of a X?
 

Offline wolf skaap

Re: 4T or 2T?
« Reply #105 on: December 31, 2013, 10:38:17 am »
That is the R obviously, but still quite amazing! How suited is this for enduro?

What is the dry weight of a X?
My thoughts exactly :)

Hilton Hayward suspension + flywheel weight + recluse is what I believe will sort it out.

250x is a no go for me: it's 12kg's heavier and costs quite a bit more 2nd hand. You can have an enduro prepped R for less than a 250x it seems
« Last Edit: December 31, 2013, 10:53:00 am by wolf skaap »
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Offline Rough Rider

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Re: 4T or 2T?
« Reply #106 on: December 31, 2013, 11:42:41 am »
That is the R obviously, but still quite amazing! How suited is this for enduro?

What is the dry weight of a X?
My thoughts exactly :)

Hilton Hayward suspension + flywheel weight + recluse is what I believe will sort it out.

250x is a no go for me: it's 12kg's heavier and costs quite a bit more 2nd hand. You can have an enduro prepped R for less than a 250x it seems

You have obviously never ridden a MX bike in an enduro. It does not matter what you do to the suspension it remains a MX bike due to frame geometry.

In Cape Town the majority of riding is done in soft sand which kills 250 4t's   
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Offline wolf skaap

Re: 4T or 2T?
« Reply #107 on: December 31, 2013, 11:47:39 am »
That is the R obviously, but still quite amazing! How suited is this for enduro?

What is the dry weight of a X?
My thoughts exactly :)

Hilton Hayward suspension + flywheel weight + recluse is what I believe will sort it out.

250x is a no go for me: it's 12kg's heavier and costs quite a bit more 2nd hand. You can have an enduro prepped R for less than a 250x it seems

You have obviously never ridden a MX bike in an enduro. It does not matter what you do to the suspension it remains a MX bike due to frame geometry.

In Cape Town the majority of riding is done in soft sand which kills 250 4t's  
I wonder how those guys on the WR converted YZ250's manage to stay competitive in enduro races?
If memory serves, Gray Dick was SA enduro champ on a YZ426. Jade Gudzeit was enduro champ on a YZ450F. Mahoney raced a YZ450F in the enduro class too.
And then there is the 2012 Roof winner on a YZ250F.  :biggrin:
Their MX frames must have been replaced with KTM enduro steel frames... cant be the suspension!

As for thick sand, the 250 2T is not the right tool either. Even my 300 didn't come close to a 450 in thick sand.

KX250's bottom end left much to be desired as an RM would too. I'm sure you love your RM and yes RC won many SX titles on one but that was then and this is now. The 250 2T's would not clear many of the SX jumps in the AMA championship any more. They simply lack the grip and bottom/mid range, which is what I'm looking for  ;)
« Last Edit: December 31, 2013, 01:21:04 pm by wolf skaap »
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Offline Kenisis

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Re: 4T or 2T?
« Reply #108 on: December 31, 2013, 01:06:27 pm »
Very interesting comments guys thanks. I think I'm going to have to give one of these a try myself one of these days. The Mrs. is a 450 fan and she hates the whining of a 2T (she says it whines like a sick girl, Danie ;D) , but I think a lighter bike might give her more confidence too.

What do you guys reckon? Powerband maybe too much for girl who rode a 450 without wringing its neck very hard?

Be careflu with a 2T I have a YS 250 2T and it is a blast to ride until i get tired. When on an MX track and it gets physical and really interesting with a couple of bikes thrown into the Mix and as soon as your concentration slips the 2T bites.

Please do not get me wrong 2T`s are great fun  but a 250 2T is just as powerful if not more powerful than a 450.

i have come to realize that i am not clever enough any more to race/ride a 2T  ???
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Offline wolf skaap

Re: 4T or 2T?
« Reply #109 on: December 31, 2013, 01:24:56 pm »
Be careflu with a 2T I have a YS 250 2T and it is a blast to ride until i get tired. When on an MX track and it gets physical and really interesting with a couple of bikes thrown into the Mix and as soon as your concentration slips the 2T bites.

Please do not get me wrong 2T`s are great fun  but a 250 2T is just as powerful if not more powerful than a 450.

i have come to realize that i am not clever enough any more to race/ride a 2T  ???
Agreed however, the 250 2T's are not exactly on par with today's 450's any more (regarding hp). KXF, KTM make almost 10 more hp in 2014. 55hp on rear wheel  :thumleft:
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Offline 2StrokeDan

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Re: 4T or 2T?
« Reply #110 on: January 04, 2014, 10:02:30 pm »
Be careflu with a 2T I have a YS 250 2T and it is a blast to ride until i get tired. When on an MX track and it gets physical and really interesting with a couple of bikes thrown into the Mix and as soon as your concentration slips the 2T bites.

Please do not get me wrong 2T`s are great fun  but a 250 2T is just as powerful if not more powerful than a 450.

i have come to realize that i am not clever enough any more to race/ride a 2T  ???
Agreed however, the 250 2T's are not exactly on par with today's 450's any more (regarding hp). KXF, KTM make almost 10 more hp in 2014. 55hp on rear wheel  :thumleft:

Well, it would be shameful if a bike 200cc's , or almost twice the engine size, does not make considerably more power than just 10% more.
 

Offline wolf skaap

Re: 4T or 2T?
« Reply #111 on: January 04, 2014, 10:39:32 pm »
Well, it would be shameful if a bike 200cc's , or almost twice the engine size, does not make considerably more power than just 10% more.

I hear you but kindly remember that peak hp is not where it's at.

Same Dyno and only 100cc difference between 250 2T and 350 4T:
YZ250 (Heavily modded. Ported head, race fuel et. etc. http://www.motorcycle-usa.com/277/9600/Motorcycle-Article/2011-Yamaha-YZ250-Project-Bike.aspx)


KTM 350sx-f (stock)

350 produces the 2T's max power throughout 40% of its entire rev range. That's quite a difference.

Having said that, the biggest reason for not going 2T is the fuel consumption; some of my tracks would not be possible with a 2T as the distance between filling stations are ~170km.
For a 2T to be "most" efficient, it has to be "on the pipe" as the least amount of un-burnt fuel escapes out the exhaust. This means you have to let it scream all the time which is rather unpleasant if you are doing longer rides.
« Last Edit: January 04, 2014, 11:25:17 pm by wolf skaap »
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Offline wolf skaap

Re: 4T or 2T?
« Reply #112 on: January 04, 2014, 11:14:13 pm »
My point is that for some folks, the 4T might serve a better purpose.
For instance, I can ride the 450 in the same places as I did the 300 (in fact, I did more insane stuff with the 450), but I can also do 1000km multi-day rides with the same 450.
I attempted one outride with the 300 and never again.

In my case, the 450 4T is just a better all-rounder and if you are fit and strong enough, you can make it work anywhere.
 ;)
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Offline sidetrack

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Re: 4T or 2T?
« Reply #113 on: January 04, 2014, 11:29:38 pm »
I do not think any R&D has gone into the YZ in at least 10 years engine wise. The KTM is brand new technology. Too bad since I think 2T still has potential. I also prefer the 4T's especially after seeing that Motul 2T oil is R300 a liter ! However talk to just about any enduro / WFO rider and they would take a 2T over a 4T any day of the week (enduro not cross country and other high speed mielie field races). The 2T enduros have a very forgiving power curve and better suited suspension plus the weight savings do add up. I rode a YZ 250 2T with WR gearbox and it was now where as nice as a Gas Gas 300 I then rode a month later. Then a KTM 300 which was even better. I would do some regional enduros first before going the WFO route. Trust me when I say I saw experienced riders on a KZN WFO head out that took a whole day just to finish one lap, half not even finishing. The terrain is rough !
« Last Edit: January 04, 2014, 11:33:43 pm by sidetrack »
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Offline sidetrack

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Re: 4T or 2T?
« Reply #114 on: January 04, 2014, 11:41:16 pm »
My point is that for some folks, the 4T might serve a better purpose.
:thumleft:
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Offline sidetrack

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Re: 4T or 2T?
« Reply #115 on: January 04, 2014, 11:58:45 pm »
That is the R obviously, but still quite amazing! How suited is this for enduro?

What is the dry weight of a X?
My thoughts exactly :)

Hilton Hayward suspension + flywheel weight + recluse is what I believe will sort it out.

250x is a no go for me: it's 12kg's heavier and costs quite a bit more 2nd hand. You can have an enduro prepped R for less than a 250x it seems
The enduro fundi's reckon you will need a 18 inch rear wheel as well  :biggrin:
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Offline wolf skaap

Re: 4T or 2T?
« Reply #116 on: January 05, 2014, 12:00:16 am »
I do not think any R&D has gone into the YZ in at least 10 years engine wise. The KTM is brand new technology. Too bad since I think 2T still has potential. I also prefer the 4T's especially after seeing that Motul 2T oil is R300 a liter ! However talk to just about any enduro / WFO rider and they would take a 2T over a 4T any day of the week (enduro not cross country and other high speed mielie field races). The 2T enduros have a very forgiving power curve and better suited suspension plus the weight savings do add up. I rode a YZ 250 2T with WR gearbox and it was now where as nice as a Gas Gas 300 I then rode a month later. Then a KTM 300 which was even better. I would do some regional enduros first before going the WFO route. Trust me when I say I saw experienced riders on a KZN WFO head out that took a whole day just to finish one lap, half not even finishing. The terrain is rough !
Whats this thing about 2T's being lighter? It was the case 10 years ago.
350 4T and 250 2T actually weighs the exact same.
250 is 218lbs. Wet weight is 231lbs: http://www.motorcycle-usa.com/276/1865/Motorcycle-Article/2009-Yamaha-YZ250-2-Stroke-Bike-Test.aspx
350 wet is 231lbs: http://www.motorcycle-usa.com/27341/Buyers-Guide-Specifications/2013-KTM-350-SX-F.aspx

I had a very long chat with Altus de Wet at the 2012 roof. For him, the 350 is the ultimate. look at his results too. Not sure about 2013 (as i was not there) but in 2012, top 2 positions were 4T and only 2 riders in the top 5 were on 2T's. All I know is, Jarvis won the roof on a 4T Husqvarna in 2013 and I don't believe just about any rider will pick a 2T for enduro. Many of the pro's actually don't (and still win)

As for suspension, if you are at all serious about racing, you should have it reworked anyway, so starting off with an MX setup is really a moot point.
« Last Edit: January 05, 2014, 12:19:06 am by wolf skaap »
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Offline wolf skaap

Re: 4T or 2T?
« Reply #117 on: January 05, 2014, 12:23:40 am »
Look, some riders will always prefer a 2T for its gutless (read forgiving) bottom/midrange, where other simply won't.
There's really no answer to this thread, only that everyone's different and so are their choices in bikes.
 ;)

Don't you have a couple of nuts to go tighten on that forgiving Husky of yours?
 :biggrin:
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Offline BlueBull2007

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Re: 4T or 2T?
« Reply #118 on: January 05, 2014, 03:34:17 am »
This is very interesting, thank you. Im a 4T guy, but only because I have never ridden a 2T. Maybe I should just get better on it.
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Offline 2StrokeDan

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Re: 4T or 2T?
« Reply #119 on: January 07, 2014, 09:18:44 pm »
Wolfskaap, your graphs also efficiently shows why the two-strokes are easier and cheaper to maintain, with revs running 30% lower on the strokers.

While the 2stroke engine operates at it's most efficient in the powerband, it is still a lot lighter on fuel trundling out of the powerband.

The one area where 2strokes still saw some development till recently was the 125cc GP bikes, now replaced by 250 4stroke singles. And yes. the 125cc 2strokes of 2 years ago are still quicker in both lap times and top end than the 4strokes double their size.

You cannot bring an engine that misfires once every 2 revolutions to brag with! :imaposer: