Engine-braking is important ?

acotrel

acotrel

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I found this video interesting because of Terry Rymer's ride on the Norton rotary. It appears the bike's only weakness was it's lack of engine-braking ? Perhaps there should be a section on this forum for the Norton rotaries, they are rare but still probably important ? I know a guy who bought an ex-police rotary from the UK and had ridden it in historic races after converting it.

 
Why should it be? You don’t need engine breaking on a racing a bike around the track on tarmac at least-it’s all in the mind you can get along without it if you are good enough to adapt to the bikes characterises. You are either full on the throttle or breaking hard, anything between you are for want of a better term "sandbagging" !
I myself came off twice in one damp afternoon around Brands Hatch on the same corner, the bike demolishing a straw bale each time, all because I lost my bottle going into the corner (on a damp track) after the hairpin and closed the throttle and as I was going downhill the weight of the bike was transferred to the front wheel which then overloaded the front tyre- giving me no indication of my impending doom. I eventfully caught on and started to counter steer when I shut off the throttle. sometimes engine breaking can be a hindrance to your well being!

The Norton Rotaries were winning races almost from the word go, by riders like Steve Spray winning the IOM TT and other races first time out.

https://www.hemmings.com/blog/article/nortons-wankel-rotary-588s/


https://www.motorcyclenews.com/news/2016/october/whatever-happened-to-the-jps-norton-team/
 
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acotrel said:
I found this video interesting because of Terry Rymer's ride on the Norton rotary. It appears the bike's only weakness was it's lack of engine-braking ? Perhaps there should be a section on this forum for the Norton rotaries, they are rare but still probably important ? I know a guy who bought an ex-police rotary from the UK and had ridden it in historic races after converting it.

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Great race! Love seeing those Nortons out there. Fast bikes!
 
Lack of engine braking never stopped any 2-strokes from winning races.
 
Danno said:
Lack of engine braking never stopped any 2-strokes from winning races.
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No they did not, but a two-stroke handles very differently from a four-stroke. With an early two stroke, it was always point and squirt. The extra power and the lighter weight then came into play. The bike Terry Rymer is riding needs to be smooth coming into corners, the other bikes in the race were conspicuously better. Have you seen any of the Wiz Norton racing ? The rotaries look like guided missiles to me.

 
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Although the rotary is it's own classification of engine, it's much closer to a 2-stroke in terms of firing, heat and lack of engine braking, not to mention emissions. Also it's 660cc swept displacement should put it in a 1200cc or unlimited class. Pitting it against 600 4-strokes is patently unfair.
 
acotrel said:
No they did not, but a two-stroke handles very differently from a four-stroke. With an early two stroke, it was always point and squirt. The extra power and the lighter weight then came into play. The bike Terry Rymer is riding needs to be smooth coming into corners, the other bikes in the race were conspicuously better. Have you seen any of the Wiz Norton racing ? The rotaries look like guided missiles to me.
This year, I saw the Wizz Nortons racing at Spa in the Classic weekend in July. Their rider is used to smaller two strokes, and said it was quite similar, in it’s lightish weight. When there was a gap in the traffic, he said it wizzed past most of the opposition.
However, they had several problems: ignition, centre rotor bearing being two. Even when Hislop won at the TT, someone who worked for the team told me they were on the edge of rotor bearing performance/reliability, and nothing has changed much since, as I understand it. Location of bearing means temperature is a major factor.
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I think it is much more difficult to be smooth, if you need to use the rear brake to steady the bike. With my Seeley 850, I rarely ever use the back brake. With short stroke Ducatis, they use a slipper clutch to stop from over-revving the motor. That might come at a cost to smooth riding. When you race most of the speed is about being smooth - smooth is faster than ragged. If you watch that video about Terry Rymer, he approaches the corners at very high speed, then gets out of shape. Normally engine braking would keep the back of the bike in place.
 
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