2011 KTM380sx

[Boo]

Yes very valid points, but if you look at a late model 450, and there power delivery, and the power delivery of a big bore 2t they dont match. All frames now days are built to handle that type of power. When faced with any big bore 2t, the frames can't handle the hard hitting power. I think not handle is too harsh a word but do you get what I'm saying. Therefore any conversation where a 2t is put into a late model frame will not handle as well due to stresses and flex not originally spcified in the frame. I don't won't to put your build down and many would not know have the ability to ride the bike to that level. I've been contempllating the issue for awhile. To really have a bike with such a conversation, some thought must be taken into consideration where by the motor has a more linear power delvery. Porting could possibily help achieve this, while still retaining the 2t reliabilty and character they have.

[CHOPPA]

Yes very valid points, but if you look at a late model 450, and there power delivery, and the power delivery of a big bore 2t they dont match. All frames now days are built to handle that type of power. When faced with any big bore 2t, the frames can't handle the hard hitting power. I think not handle is too harsh a word but do you get what I'm saying. Therefore any conversation where a 2t is put into a late model frame will not handle as well due to stresses and flex not originally spcified in the frame. I don't won't to put your build down and many would not know have the ability to ride the bike to that level. I've been contempllating the issue for awhile. To really have a bike with such a conversation, some thought must be taken into consideration where by the motor has a more linear power delvery. Porting could possibily help achieve this, while still retaining the 2t reliabilty and character they have.

I know you have done several CR500AFs so your talking from experience but the KTM is a bit different to the hondas as they still develop 2 strokes and they use the same frames and it shows by just how easy it was to put this engine in and everything lines up perfectly as if it were made to fit. The power is the same as a 450 so there is certainly not too much power to overcome the frame.

There is no way that a 2 stroke is going to create extra stress in a frame designed for a 4 stroke, there is no hit on a 500 2 stroke its just like a big 4 stroke but they dont rev out.

The modern frames are far stiffer than anything that a 500cc every came out in

[takitimu]

Do you think the vibration of the 2T vs 4T is a factor in the frames cracking ?, mates CR500 transplant has cracked the frame.

[doddzee]

Do you think the vibration of the 2T vs 4T is a factor in the frames cracking ?, mates CR500 transplant has cracked the frame.

Would say vibration would be one of the contributers, more so in an alloy frame due to the way aluminum fatigues.

Another big bore in a KTM frame http://ktmtalk.com/index.php?showtopic=442105&st=120

Awesome build Choppa.

[CHOPPA]

Would say vibration would be one of the contributers, more so in an alloy frame due to the way aluminum fatigues.

Another big bore in a KTM frame http://ktmtalk.com/index.php?showtopic=442105&st=120

Awesome build Choppa.

Cheers mate! That looks good but I dont think I could bastardise a bike by putting a honda engine in a KTM just seems wrong!

[Flicks]

The frame should be fine as KTM still use steel frames so less flex then aluminium.

[Jay GTI]

Please don't sully this thread by making it yet another bloody 2T vs 4T debate.

This bike is awesome, simply because it's awesome.

[Stylo]

Please don't sully this thread by making it yet another bloody 2T vs 4T debate.

This bike is awesome, simply because it's awesome.

Don't think the 2T vs 4T debate is going to end anytime soon mate , it's healthy and helps keep these threads alive .

[Jay GTI]

Don't think the 2T vs 4T debate is going to end anytime soon mate , it's healthy and helps keep these threads alive .

True, it will never end... but I really want to read about this bike, not why a 500 2T in a Honda alloy frame is/isn't a good idea.

[CHOPPA]

Just bolted a few more things on

[Crasherfromwayback]

Bet my 30 year old YZ465 is faster in a straight line!

At the first corner, the bet stops!

[CHOPPA]

Bet my 30 year old YZ465 is faster in a straight line!

At the first corner, the bet stops!

I dont know man, with those clunky old gearboxes ill give you a shot!

[Crasherfromwayback]

I dont know man, with those clunky old gearboxes ill give you a shot!

I'll start in 3rd. Only need a gear change or two to roost in your face.











Maybe.

[F5 Dave]

One end of Kent Terrace to the other? Basin on knobblies could be interesting.

[Boo]

When you sat the motor in the frame and lined up the front and rear sprockets, where did the motor sit with the bottom rails. Did you put the engine mounts on the the rails to lift the motor enough to reach the air box without mods.
The motor looks to be clocked forward, did this allow enough room to put the chamber though the Y. I would be careful with that as you may have problems fitting the pipe as it will turn the pipe down and it may run lower under the bottom rails.
Did you try to sit it in the frame lower, it looks as though the kicker would hit where the swing arm bolt and frame bolt on. I ran a set of 20mm triples on my build and needed to pay attention to if there was clearance when the fork bottomed out. Man thats a big clutch the piston looks small in comparsion.