A modern, updated air cooled two stroke bike

Just did a top end rebuild on my 02' Yamaha PW80 today (which has a two stroke air cooled engine) and the simplicity just amazed me.

 

Four, and I repeat, FOUR 10mm nuts to unscrew, and bam! The cylinder head and cylinder slide right off and the piston is exposed.

 

Took me a total of 25 minutes to do the whole job. Got it all back together and it ran awesome.

 

So, it got me thinking, how many of you would enjoy a lineup of air cooled two stroke bikes in modern, lightweight frames with great suspension?

 

They would be the perfect bike for casual riders, for riders on a budget, or for people that just like to have fun on bikes and not worry about boiling over, valve adjustments, etc. etc.

 

Honda made CR's that were air cooled, I believe they were 125, 250, and 480, and I'm sure they weren't slow by any means. It would be cool to see somebody shove a CR480 motor in one of Honda's updated chassis.

 

What do you guys think?

I think it should be a 5-valve design with titanium valves.

I think it should be a 5-valve design with titanium valves.

Sounds like my buddy's yz450f that recently blew the bottom end :o :o

You're right, better to have a two stroke than a blown bottom end.

You're right, better to have a two stroke than a blown bottom end.

Hey, thats your opinion, not mine.

Meh, takes me 25min to do a YZ 125 top-end.....

Air cooled is noisier and can't make as much power, but could be great for a trail bike.

+1,  ever run sound check on aircooled twostroke? LOL.     I'd still love to see an aircooled jug and head kit for a modern bottom end. I asked here years ago about interest in a yz250 or cr250 aircooled enduro ported topend kit. Didn't get much reply. Everybody thinks they need 50hp and radiators to ride trails.

Edited by highmarker

My it 200 is really all the trail power you need and so simple, installing a air cooled engine in a modern chassis now that would be a good trail bike, which has been done many times. Just too bad the mfg's don't make simple bikes for trailriders looking for simple dependable bikes that anyone with a screw driver and pliers could fix.

Air cooled is noisier and can't make as much power, but could be great for a trail bike.

 

 

?????????????????? I can guess you never came across a yz490...

To get power out of the 125s in order to make them competitive, the bikes have to run so hard that they would overheat all the time.  Intro water cooling--ran much better!  I'm not sure the year or models, I was born in '85, but I've heard from older guys that bikes ran much cooler, cleaner, and thus harder having water cooling systems.

But for trail bikes or kids bikes, makes little difference.  Air cooling is a simple system!

Not entirely modern but check out the s1 maicos from maicosonly

In general, big bore air cooled 2 strokes were very ornary bikes to ride and tough to jet. Having been a teen in the early 80's I can tell you the jump to liquid cooling made a magical difference in the way bikes ran. For me, I keep an IT200 in the garage for the few times a year I get to ride. I never worry about corrosion, acelerator pumps,air in the hyd lines etc. My biggest concern is mice in the airbox!

google, ATK 406

 

having raced those old aircooled twosmokers back in the day the only thing you are giving up is amazing suspension,on modern bikes,you kiddies really are spoiled...

You gotta have a new gen frame or you will just have an old-school handing bike

The older bikes had slack head angles (no steering dampers and flexy forks had to be comensated for)

 

I think a Husky CR390 motor in a CRF250X frame would be awesome.

Honda also made an air cooled CR 500 in 84! I agree some of my old air cooled bikes were fast vibrated atrociously but my YZ 490 make a great desert racer never had to worry about sagebrush tearing a hose or busting a water pump cover rock hitting the radiator. Sucks to break down like that 50+ miles from a pit or check

Honda also made an air cooled CR 500 in 84! I agree some of my old air cooled bikes were fast vibrated atrociously but my YZ 490 make a great desert racer never had to worry about sagebrush tearing a hose or busting a water pump cover rock hitting the radiator. Sucks to break down like that 50+ miles from a pit or check

Yeah, but that thing is in the top 5 of the world's worst dirtbikes of all time!

When you could start it, it detonated so bad it would destroy spark plugs.

The frame flexed so badly that it was no good for desert, and the handling had so much understeer, it was no good for track.

The '82's and 3's were Honda's attempt at making a Japanese Maico, and they were a few steps off, until Honda HRC pulled the plug and they went to the 500's conventional design.

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