A Modern Road Legal 2 Stroke

[Skub]

The Langen.

https://www.bikebound.com/2022/06/17/langen/

120kgs 76bhp.

[Le_Fromage_Grande]

I had a 45bhp 2 stroke 250, it wasn't the nicest thing to ride, a 76 bhp one is going to make a horrible road bike.

[MingtheMerciless]

That’s lovely. I’d have one.

[Yorick]

The headlight is shit . Like one off a CD175

[porter_jamie]

76horse. I call bullshit

[Yorick]

76horse. I call bullshit

Ha ha. I missed the engine size.
250 is a poor choice. And 76 gee gees is a joke.

[mangocrazy]

Why limit yourself to 250cc? If it really does make 76bhp out of a quarter litre, it will be peaky as hell. A twin cylinder 2T in the 350 - 400cc range making that amount of power would be a much, much more pleasant bike to ride and still wouldn't stress the running gear.

[Le_Fromage_Grande]

Genuine 60bhp 350 power valves aren't very nice to ride, for 76bhp a 500 would be better, but then you'd have to admit you're making the same power as a 1984 RD500.

[Supermofo]

MCN tested it on the road a while back

https://www.motorcyclenews.com/bike-rev ... roke/2022/

Oh yeah it's 30k too

[DefTrap]

All 2stroke enthusiasts are of a certain age and bang on about Yam RDs and LCs, so you'd think a modern 2stroke would visually play up to that somewhat.

This is just a horrible mess. What's going on with that frame ffs!?

[Le_Fromage_Grande]

All 2stroke enthusiasts are of a certain age and bang on about Yam RDs and LCs, so you'd think a modern 2stroke would visually play up to that somewhat.

This is just a horrible mess. What's going on with that frame ffs!?

And we're all a bit rose tinted specs about them, LCs are huge fun to ride, but they're pretty horrible compared to modern bikes.

[The Spin Doctor]

Interestingly, Langen are now working on an electric bike with an interesting modular battery

[porter_jamie]

How much power does a late tz250 make (ie real measured), and how often does it need a piston rod and crank. And plugs?

[Le_Fromage_Grande]

That's a difficult question as Yamaha never gave any power figures for TZs, the last works two stroke 250s were putting out about 100bhp (according to Honda), crank and piston life was one race, not the whole race weekend, I know someone with an ex Kato NSR250 that he won't start because it'll shorten the engine life measurably.

The reverse cylinder TZ250U was about 70bhp, but it never had a reputation for long engine life, a mate has a TZ250E and it's pistons will last a weekend and the crank about twice that.

I had a YZ125E that would eat a piston ring in 20 minutes, I doubt if it was making 36bhp.

[porter_jamie]

I reckon a v twin made just over 70.
A road engine making 76, even with years of development just seems unlikely. Maybe the mcn one was in a higher state of tune for the test but something stinks.

[mangocrazy]

I reckon a v twin made just over 70.
A road engine making 76, even with years of development just seems unlikely. Maybe the mcn one was in a higher state of tune for the test but something stinks.

They're not referred to as stinkwheels for nothing, you know...

[mangocrazy]

So how is it that four strokes have nearly doubled their output since the 80s, but we still expect two-strokes to make roughly the same power they did 30 years ago? Apply modern electronics, advanced lubricants, increased knowledge of pressure waves etc etc and I'd be very surprised if a 350 - 400cc 2T couldn't be made to be reliable and still produce 85-90 bhp with a decent midrange. Using modern chassis, suspension and wheel technology and you'd have something weighing no more than 130 kg. I'd take that any day over a 200bhp 1000cc IL4.

[Skub]

So how is it that four strokes have nearly doubled their output since the 80s, but we still expect two-strokes to make roughly the same power they did 30 years ago? Apply modern electronics, advanced lubricants, increased knowledge of pressure waves etc etc and I'd be very surprised if a 350 - 400cc 2T couldn't be made to be reliable and still produce 85-90 bhp with a decent midrange. Using modern chassis, suspension and wheel technology and you'd have something weighing no more than 130 kg. I'd take that any day over a 200bhp 1000cc IL4.

Development,I'd reckon. The emphasis has been on 4 strokes for decades now.

[mangocrazy]

Agreed, but there are still people developing two strokes.

[Le_Fromage_Grande]

Because there's nowhere for the 2 stroke to go, 500 GP bikes were making 200bhp in the mid 90s, 10 years later they were still making 200bhp.