Older 2 stroke fans, anyone remember these tuners?

[BroadsRS6]

On a wider note i think it's a real shame 2 strokes were largely killed off. They have such basic advantages to their design, a bit like the rotary motorcycle never carried on very long either.
My RE5 was a great bike in many ways, but too heavy, too complicated. It may have only had 3 moving parts but the carb was incredibly complex, it had 5 throttle cables IIRC and it was a swine to work on, as well as running incredibly hot, to the point that even the exhausts themselves were cooled. The Gen 2 model i had was slightly better with only one set of points, for example, but was still a nightmare to upkeep. The sound was incredible. Like a British twin on tickover someone once said but then so smooth as the revs rose.
But 2 strokes could have been so good if they'd solved the emissions issues. I just love how they sound and go. Imagine a 750cc 2 stroke V4 or IL4 now. Easy 150 bhp. 150 kgs. 4 spannies yowling.

[LukeBrown66]

when you look at what has happened to the diesel market in the last 10 years, it is astounding. Two strokes are remarkably efficient, less moving parts, simple design.

but they did sound awful to some, made a lot of smoke and injecting them for clean running proved very difficult.

[ddom]

The omnivore that Lotus built was interesting.

[rigga]

Still some two stroke development ongoing, this limited run bike uses a v twin injected engine

https://langenmotorcycles.co.uk

[Steve Bass]

KTM and Husky sell 2T's by the ship load.
The advent of Transfer Port Injection has transformed the emissions of the bikes.
Would be interesting to see someone translate that to a road bike with something like a triple configuration.
500cc water cooled, transfer port injected,power valve equipped 2T with around 130 bhp would be stupendous.

[Rob 131 Sport]

Steve Bass said:

KTM and Husky sell 2T's by the ship load.
The advent of Transfer Port Injection has transformed the emissions of the bikes.
Would be interesting to see someone translate that to a road bike with something like a triple configuration.
500cc water cooled, transfer port injected,power valve equipped 2T with around 130 bhp would be stupendous.

For the 3 Cylinder it’s called a highly tuned Honda NS400R and for 4 Cylinders an RG500. You wouldn’t get near to 130BHP, however a well tuned RG should be nearing 100BHP.

[Red9zero]

I had a Stan Stephens stage 3 tuned YPVS back in the day. He used it to develop his pipes and had it in his PB ad at the time. If you were in the mood it absolutely flew, but with a powerband between 9-11k it was a struggle round town. I sold it after it developed a death rattle 50 miles after its 3rd rebuild.

[BroadsRS6]

The link above looks good. 250cc. 75 BHP. With effort a road bike could be 120 kgs. All the ingredients for a great road and track bike.

[Steve Bass]

Rob 131 Sport said:

For the 3 Cylinder it’s called a highly tuned Honda NS400R and for 4 Cylinders an RG500. You wouldn’t get near to 130BHP, however a well tuned RG should be nearing 100BHP.

No, I'm referring to a modern iteration. Not a revamp of the older versions. A triple is the sweet spot for torque and rpm vs a 4x 125cc motor.
And fwiw, a well tuned RG550 will make circa 125bhp (95 standard) and the Suter MMX makes 195 from 576cc.
So 130 from a 500(ish) triple with injection and a decent ecu will be easily achievable.
Suter have shown what is possible with 2T engineering, now if someone could make it road legal using modern tech I reckon they would sell a fair few.

[Rob 131 Sport]

Steve Bass said:

Rob 131 Sport said:

For the 3 Cylinder it’s called a highly tuned Honda NS400R and for 4 Cylinders an RG500. You wouldn’t get near to 130BHP, however a well tuned RG should be nearing 100BHP.

No, I'm referring to a modern iteration. Not a revamp of the older versions. A triple is the sweet spot for torque and rpm vs a 4x 125cc motor.
And fwiw, a well tuned RG550 will make circa 125bhp (95 standard) and the Suter MMX makes 195 from 576cc.
So 130 from a 500(ish) triple with injection and a decent ecu will be easily achievable.
Suter have shown what is possible with 2T engineering, now if someone could make it road legal using modern tech I reckon they would sell a fair few.

Whilst a stock RG500 was quoted at 95BHP, as I can recall within the contemporary motorcycle press the real figure was less with the tuned versions producing around 100 BHP.

Perhaps some of the owners and /or tuners could clarify this based on dyno readings.

[Tango13]

It's well known that the road test RG500s were 'fettled' prior to being given to the journalists, see also E Type Jaguar...

[Rob 131 Sport]

Tango13 said:

It's well known that the road test RG500s were 'fettled' prior to being given to the journalists, see also E Type Jaguar...

The question is by how much. We look forward to some of the expert opinions

Whatever the power, I still absolutely love them and on balance is probably my all time favourite bike. IMO the Skoal Bandit colours were the best

[ddom]

Rob 131 Sport said:

The question is by how much. We look forward to some of the expert opinions

Whatever the power, I still absolutely love them and on balance is probably my all time favourite bike. IMO the Skoal Bandit colours were the best

Rumour was 100HP at the launch. IIRC they had head gasket issues with some on the day?

Mark Dent’s 570cc 130hp+

[Tango13]

Rob 131 Sport said:

Tango13 said:

It's well known that the road test RG500s were 'fettled' prior to being given to the journalists, see also E Type Jaguar...

The question is by how much. We look forward to some of the expert opinions

Whatever the power, I still absolutely love them and on balance is probably my all time favourite bike. IMO the Skoal Bandit colours were the best

Iirc Skoal Bandit colours were worth 5~10bhp depending on the dyno used

[lazybike]

https://brcracing.ca/ One of these engines in a 125/300 rolling chassis (road) would be fun.

[Steve Bass]

Rob 131 Sport said:

Steve Bass said:

Rob 131 Sport said:

For the 3 Cylinder it’s called a highly tuned Honda NS400R and for 4 Cylinders an RG500. You wouldn’t get near to 130BHP, however a well tuned RG should be nearing 100BHP.

No, I'm referring to a modern iteration. Not a revamp of the older versions. A triple is the sweet spot for torque and rpm vs a 4x 125cc motor.
And fwiw, a well tuned RG550 will make circa 125bhp (95 standard) and the Suter MMX makes 195 from 576cc.
So 130 from a 500(ish) triple with injection and a decent ecu will be easily achievable.
Suter have shown what is possible with 2T engineering, now if someone could make it road legal using modern tech I reckon they would sell a fair few.

Whilst a stock RG500 was quoted at 95BHP, as I can recall within the contemporary motorcycle press the real figure was less with the tuned versions producing around 100 BHP.

Perhaps some of the owners and /or tuners could clarify this based on dyno readings.

The road bikes produced by Mark dent with the 550 (?) engine were regularly showing circa 125/130 on the dyno. Never more as there were many inherent restrictions in the engine. I know a guy who grafted RGV barrels and heads onto an RG50 bottom end for the inclusion of power valves etc and again, made about 130 bhp but with decent low end torque once we programmed the PV controller and ignition curves for the lower rpms.
But bear in mind there's a lot more to the bigger cc motors, things like bored carbs, re-profiled disc valve timing etc. Then things like improving the CR (standard was a woeful 7:1) and decent ignition timing curves from a PDCI unit or similar make substantial improvements.
For reference, my RS250 with a PDCI, different pipes and a Kit Spec engine in making 65 bhp at the last check. Given the RG is 2 x that the 125 bhp figure is reasonable considering the additional losses etc. of the bigger engine.
The limiting factor on the RG engine is the port timing, original CR and the poor electronics. The last 2 can be improved however the port timing is a compromise but can be teased sufficiently to make reasonable power, especially on the disc valve inlet side....

[Steve Bass]

Rob 131 Sport said:

Tango13 said:

It's well known that the road test RG500s were 'fettled' prior to being given to the journalists, see also E Type Jaguar...

The question is by how much. We look forward to some of the expert opinions

Whatever the power, I still absolutely love them and on balance is probably my all time favourite bike. IMO the Skoal Bandit colours were the best

Yes, there was a difference between the official figures and the actual but that was easily remedied by a decent and detailed blueprinting of the motor.
However, the fettling only achieved what was already available in the engine rather than a wholesale change of components. That's a significant point which seems to get lost in comprehension.....

And unless you've ridden one for a while, best keep the rose tinted glasses firmly attached
It's not for good reason Mark Dent builds the motor into a decent chassis like the Aprilia RS or Suzi RGV. The RG's were pretty crap and today i'm not sure many would want to ride one in anger once they've tasted what a denet chassis and tyre combo can serve up.
Even the motor is a bit meh in truth, but still stellar compared to the dog Yamaha produced in the RD/RZ 500 engine......

[graham22]

Steve Bass said:

Yes, there was a difference between the official figures and the actual but that was easily remedied by a decent and detailed blueprinting of the motor.
However, the fettling only achieved what was already available in the engine rather than a wholesale change of components. That's a significant point which seems to get lost in comprehension.....

And unless you've ridden one for a while, best keep the rose tinted glasses firmly attached
It's not for good reason Mark Dent builds the motor into a decent chassis like the Aprilia RS or Suzi RGV. The RG's were pretty crap and today i'm not sure many would want to ride one in anger once they've tasted what a denet chassis and tyre combo can serve up.
Even the motor is a bit meh in truth, but still stellar compared to the dog Yamaha produced in the RD/RZ 500 engine......

My argument when someone tells me a RG500 is still a GSXR1000 killer.

Happy to have owned my RG back in 1989 when it was a match for bigger bikes of the time - a CBR600 soon became faster and was already better tyred and braked.

[graham22]

Steve Bass said:

KTM and Husky sell 2T's by the ship load.
The advent of Transfer Port Injection has transformed the emissions of the bikes.
Would be interesting to see someone translate that to a road bike with something like a triple configuration.
500cc water cooled, transfer port injected,power valve equipped 2T with around 130 bhp would be stupendous.

Would have been nice if that Langden was built as a V-Twin 500/600 using KTM/Husky TPI barrels - think the current motor is already obsolete.

[Rob 131 Sport]

Steve Bass said:

Rob 131 Sport said:

Tango13 said:

It's well known that the road test RG500s were 'fettled' prior to being given to the journalists, see also E Type Jaguar...

The question is by how much. We look forward to some of the expert opinions

Whatever the power, I still absolutely love them and on balance is probably my all time favourite bike. IMO the Skoal Bandit colours were the best

Yes, there was a difference between the official figures and the actual but that was easily remedied by a decent and detailed blueprinting of the motor.
However, the fettling only achieved what was already available in the engine rather than a wholesale change of components. That's a significant point which seems to get lost in comprehension.....

And unless you've ridden one for a while, best keep the rose tinted glasses firmly attached
It's not for good reason Mark Dent builds the motor into a decent chassis like the Aprilia RS or Suzi RGV. The RG's were pretty crap and today i'm not sure many would want to ride one in anger once they've tasted what a denet chassis and tyre combo can serve up.
Even the motor is a bit meh in truth, but still stellar compared to the dog Yamaha produced in the RD/RZ 500 engine......

I’ve never ridden an RG500 and in view of the prices (stable around the £20k mark) unlikely to do so. I did look at riding one (prior to Covid) on a bike provided by a company in Tuscany that rents them out.

I was never keen on the RD500, are they much different to the RG500.