Two stroke V four stroke

[RustyAs]

I may be a bit Rusty on a road bike, but there arn't to many dirt bikes I havn't ridden, and blowin smoke outta my own arse, rode bloody well.

In my youth I think at some stage, I've owned every brand of known, and some not so well known, of dirt bike available at the time.

The 400 s strokes were the ultimate adrenalin rush and it took some balls to ride them in anger.

And as discussed elsewhere, If and when we had to, we could pull them down by torch light and put it back together with out any problems.

Kids today are being duped into buying these modern four strokes, either brand new with the prospect of expensive and ongoing maintanence, or used with a rebuild.

Funny how just about every add for a used dirt bike has " just spent $2500, on recent rebuild" in it

Bring em back and watch them fly out of the showrooms

Cheers

[Six Addict]

They don't race them because thy can't sell them because of new emissions laws... And yes Honda put paid to 500cc gp bikes, because they didn't sell any other 2 strokes anymore... I'm sure they played a part in mx as well

[Gosling1]

real engines don't use poppet valves.

real MX bikes need pre-mix !!

I have been reading headlines that say "2 Strokes are Dead" now, since about 1978 *yawns* what a crock. Best bang for your buck. 4T MX bikes that need new top-ends every 50 hours are a fucken joke.

[Jonno]

Direct injection is meeting emissions.

[Gosling1]

Exactly ! they have been using direct injection in the big V6 and V8 outboard 2T motors for years now - these motors provide the very best response in dicey situations out at sea - far better than the best 4T outboards can muster.

You can lay the blame for the loss of 2T road bikes squarely at the feet of Honda. This was the end result of the bitter model wars that played out between Honda & Yamaha in the early 80's - where Yamaha declared open war on Honda and aimed for #1 manufacturer in the world.

It was never going to happen, Honda hated the race success that Yamaha had for a decade or more with the mighty TZ 2-banger in every capacity you can think of. Yamaha had far more race wins across the globe with 2-strokes than Honda could have possibly dream of.

This galled Honda so much that they moved heaven and earth to remove 2T bikes from the GP world, despite their own success with the NSR500. I fucken hate Honda for what they have done to motorcycles and motorcycle racing - they have pushed their own agenda at the expense of every other manufacturer out there and it sucks fucken donkey balls.

rant over

[bonester]

People whinge that 2 strokes pollute more so than 4- however the 4 stroke requires constant oil changes that the 2 stroke does not- causing extra pollution- what to do with the used oil.
BTW KLX450 is due for new piston and rings at 1500km- have a look in the service manual. Done around 5000km on my shitty old DT200R 2 stroke and haven't touched the engine yet.

[Blurr]

New piston and rings at 1500kms

Something wrong there dude.

[bonester]

Yep that is what recommended. Not much of a skirt on the piston.

http://www.dirtbikeworld.net/forum/show ... hp?t=53488

[Jonno]

It wasnt the punters that turned their noses up at 2strokes but we all bought the spiel of the environmental shite of the day and that racing was heading towards 4 stroke for some reason with rules that excluded 2t's.
If they made more 2t's for the market they would be out the door in a flash (KTM300 2t's are everywhere), i detest the latest "handgrenade" 4t's, they have made them to rev hard to be competitive and they break easy costing big $$$$ and keeping the dealers happy.

After riding my new (old skool) toy the CR500 the other weekend I really want to offload both the 4T's and we are talking about a 20 year old 2t engine that will outlast any modern 4t engine, out power it, easier and way cheaper to fix/maintain and even in its 1994 frame weighs in dry at 101kg I think, that is about 10kg lighter than my 2011 TE511 it easily out powered all the big bangers in the sand and it is a lot of bike to handle but it is ten times the fun.

I am hunting down a CRF250 frame to drop the CR5 engine into it, surprisingly there are quite a lot of these with blown 4t engines in them, who would have thought that! Apparently its a common simple transplant

So how good is this going to be, big bore power in a super light alloy frame that handles great with the latest suspension and brakes

It is that good I might start a new thread on the build

[Gosling1]

Great idea mate. I love my YZ500 even though it scares the shit out of me every time I ride it it was 101.5kg stock weight in 1984, even with the extra sub-frame and some lighting, mine still only weighs 104kg dry.

And it will hold its own against any modern 4T bike (as long as the 4T is upwards of 500c !!)

Looking forward to *this* build story

[Wattie]

Most powerful engines being built in the world today are 2T.
But they run on diesel...

Supertanker engines.

[Six Addict]

And do about 8rpm

[Wattie]

And do about 8rpm

Yeah

But they don't need top end rebuilds as often.

[Gosling1]

22-102 rpm. 2T turbo diesel. 300 ton crank !!!

[steve086]

http://www.ebay.com.au/itm/cr500-af-crf ... 2ebeba8b6f jono here is what you need to make your cr500 awesome