Honda may sell RCV Replicas to privateers by 2014

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Keshav

Keshav

Joined
Aug 27, 2007
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Accd to M. Oxley Honda in reaction to the CRTs is planning to sell RCV replicas with spring valves - not pneumatic

ones. Can't write more now - just came from hand surgery and sore as hell.
 
Keshav said:
Accd to M. Oxley Honda in reaction to the CRTs is planning to sell RCV replicas with spring valves - not pneumatic

ones. Can't write more now - just came from hand surgery and sore as hell.
Click to expand...



Why the surgery ? Spending to much time in the shop alone...on the internet
 
I have had dupuytren's contracture for some years but it just got really bad in the last 8 months. Could hardly get my motorcycle glove on my left hand 'cause my was turning into a claw. Some doctors say it is a result of heavy boozing in my youthful days.
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http://www.youtube.com/watch?v=2YV_BZfdG-g
 
Keshav said:
Accd to M. Oxley Honda in reaction to the CRTs is planning to sell RCV replicas with spring valves - not pneumatic

ones. Can't write more now - just came from hand surgery and sore as hell.
Click to expand...

If they go to the 15- 16k rev limit, is there much benefit to having pneumatic valve train ?
 
povol said:
If they go to the 15- 16k rev limit, is there much benefit to having pneumatic valve train ?
Click to expand...



AFAIK...



In general, yes. At higher revs, the mass of the steel spring starts to become a liability, and the spring itself can start to flutter and oscillate. Even if these motions are not critical, they can cause uneven valve pressure, which can cause floating off the cams just past full lift, or seat bounce when then slam closed. Looking at this from the other direction, at any given RPM, pneumatics let you get away with more aggressive cam profiles.



OTOH, steel springs at 15K are well understood and would be cheaper than air.



[media]http://www.youtube.com/watch?v=_REQ1PUM0rY[/media]
 
Specifically: http://www.profblair...ings_Vs_Gas.zip



Including some good dope on the 2006 Honda 990.



6. Summary



Before 2007, Honda HRC raced a 990 cm3 V5 engine with a valvetrain which included bucket tappets and a single coil spring per valve. This engine, if paddock rumour is to be believed, produced some 240 hp at 16,000 rpm, reinforcing the conclusion already expressed that 200 hp can be achieved at 16,000 rpm by a fourcylinder

800 cm3 engine with such a conventional valvetrain. What is also known, perhaps rumoured is again the better word, is that trying to run this same HRC 990 cm3 engine above 16,000 rpm resulted in some valvetrain problems. Hence, as rumour is always a dangerous commodity, the &ldquo;contention&rdquo; expressed in the Abstract did need to be examined as did the &ldquo;contention&rdquo; that 200 hp at 16,000 rpm could be theoretically attained.



What is established here is that a valvetrain using coil springs will become unstable at some point in the speed range and that a gas spring control of that same valvetrain will operate to a higher engine speed than with the coil springs, simply because of the reduction in mass being oscillated. All spring systems will ultimately become unstable at some engine speed, but as the gas spring is the lightest spring and most of such designs, but not all, also behave as a spring damper system, its ability to control the sudden catastrophic bouncing at speeds marginally above stability is considerable (see Fig.27).



Further, it appears from Fig.27 that coil spring control of a finger follower valvetrain for a 800 cm3 engine four-cylinder engine could be stable at engine speeds approaching 18,000 rpm. However, it is shown that this is only possible with careful design and selection of the valve lift profile to be employed. Although it has not been examined here, it seems unlikely that the heavier bucket tappet design could be similarly successful as the bucket tappet must weigh at least 25% more than a finger follower and its inertia could well be 30% more at the very least.
Click to expand...



I don't know the bore of Nicky's V5 990. I'm guessing it's close to the current 81mm spec. (??) If Ezzy gets his 15/16K limit, steel springs should be 'good enough.'
 
They'll keep the pnuematics, the engines still need to last a long time and the pnuematics can handle more aggressive cams.
 
Speaking of engines. I read the other day where Lorenzo is already using engine # 5. It didnt say how much it has been used, but if they were to lose an engine at this point, it would be catastrophic. As it stands, #5 already has wear and there is 6 races left. It would interesting to see where the other teams are, especially Honda. Last year Krop kept us up to date on the engines, how about some info there old buddy
 
The manufacturers, mainly Honda are at fault for ....... up the sport. Instead of sending the bikes to the crusher at the end of the season they use to hand them down/sell to sat or private teams..or hell at least the engines, Team KR and the Honda 990 for example.
 
Geonerd said:
In general, yes. At higher revs, the mass of the steel spring starts to become a liability, and the spring itself can start to flutter and oscillate.
Click to expand...



The other thing pneumatics give you is a reduction in mechanical losses due to friction. The strength of the spring in racing engines is greater than that in your average road vehicle. This increases friction and also, at the F1/GP/LM level requires more massive cams and the lightest poppet valves you can get away with. All of that takes away from power at the crank.



The holy grail is computer-actuated solenoids - no cam, camchain/gear drive, timing chest, just electronics. This would bring a huge reduction in mechanical complexity and weight. Then you would have true VVT - variable valve timing.



The solenoid technology is there, the sustainability and software aren't. In a race the solenoid will activate around a million times. The heat generated by a solenoid actuating at more than 250 times a second and the electric power required to do that for an hour presents the biggest hurdle - on an M1 there are 16 of those little suckers all needing a bunch of electric and a way to dump heat.



The first four-stroke design using solenoids was made in 1935... it isn't a new idea, but the obstacle is like so many other cool technologies, the ability to store and release electricity in large quantity and light weight.
 
With the spec ECU coming I think Honda will leave MotoGP as a Factory Prototype Racer. This will render Yamaha and Ducati's Factory Prototype efforts useless because there is no point in spending all that money to beat no-one. That then sets the scene for Honda's domination of MotoGP.



If they produce a CRT spec RCV that blows away all the other CRT's then everyone will try to buy and race one. No other race team would try and develop a bike because the Honda is too good. Teams will leave and we will have MotoHonda.



The law of unintended consequences keeps biting Dorna in the arse. The above is the way I see it playing out over the next 4 or less seasons due to Dorna's continued manipulation of the rules and disrespect for Honda.
 
Mental Anarchist said:
With the spec ECU coming I think Honda will leave MotoGP as a Factory Prototype Racer. This will render Yamaha and Ducati's Factory Prototype efforts useless because there is no point in spending all that money to beat no-one. That then sets the scene for Honda's domination of MotoGP.



If they produce a CRT spec RCV that blows away all the other CRT's then everyone will try to buy and race one. No other race team would try and develop a bike because the Honda is too good. Teams will leave and we will have MotoHonda.



The law of unintended consequences keeps biting Dorna in the arse. The above is the way I see it playing out over the next 4 or less seasons due to Dorna's continued manipulation of the rules and disrespect for Honda.
Click to expand...



Makes sense what u say, but are Yamaha and Honda not spending millions to beat no one at the moment?
 
xx CURVE xx said:
The manufacturers, mainly Honda are at fault for ....... up the sport. Instead of sending the bikes to the crusher at the end of the season they use to hand them down/sell to sat or private teams..or hell at least the engines, Team KR and the Honda 990 for example.
Click to expand...

Last I heard, including from kropotkin's site, honda have no engine durability problems at all, and the factory hondas have used way fewer engines than yamaha have.
 
What I don't get is the RC-166 red lined at 18k (19k some sources) in 1966. That was with steel springs and 60's metallurgy. Why is 16k the limit nowadays with steel springs? Was it the size of the 990's ?
 

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