I just dont understand what Honda has against dual overhead cam engines!? There unicam design on the 450r really needs to be scrapped to compete with the yfz450.
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I just dont understand what Honda has against dual overhead cam engines!? There unicam design on the 450r really needs to be scrapped to compete with the yfz450.
Just Too Addicted
Arm chair racerJust too addicted
All there cars are DOHC aren't they? They probably think its uneccesary in smaller engines?
Twinkle Toes
The day begins with 3WW
the 350x is DOHC, but I get what you are saying about newer machines. The 450r isnt DOHC? That is weird.
Last edited by Tri-ZNate; 12-16-2005 at 07:45 AM.
Nate
The Myth, The MAN, The Legend
R.I.P HRR
Originally Posted by honda250sx
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I'm glad the 450-R does'nt have dual cams. When it comes time to buy 1 cam you spend half the money. I don't see where the 450-R or the crf 450 is lacking one bit because of only having one cam. It's pretty smart on hondas part to build a motor with a single over head cam, that can STOMP motors with dual cams. The 450's have a roller tipped rocker on the exhaust side. The 450-R has lightning quick throttle response, there is no need for the second cam. Thanks honda, now when I get my 450-R I will be able to afford to put A camshaft in it, unlike If I owned a YFZ (NOT).
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The 350X is a single cam engine. With the yamaha yfz450''s you dont need to buy aftermarket cams because yamaha gives the customer high performance ones right from the factory installed on the bike. Just retard the exhaust cam one tooth (a free mod) and you have the same cam and specs as the wr450f! With Honda you have to buy the power up kit which comes with a cam and other components. Dual cams are superior to a single design for the reason that you get a motor that revs much quicker. Also add that the yamaha motor is a 5 valve motor and not 4 valves like the honda.
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Its to hard for honda to put to cams in there "sideways" ass motors that they put on most everything. I think that the 450r should be a DOHC though. SOHC is simpler for the average person to fool with. Try adjusting the Valves on a DOHC like, say, a Kawasaki Mojave, pain in the ass!!!
1985 Honda ATC 350X
2003 Yamaha Banshee
2003 Polaris Sportsman 500
There are 3 kinds of people in this world, Those who make things happen, those who watch things happen and those who wonder what the hell happend.
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I agree. For the recreation and utility machines a single cam would be better and more user friendly not having to use shims to adjust the valves. But the flagship 450r should have a dual design.
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Explain why having two is an advantage? you can have a single cam doing exactly the same job and as said when it comes to upgrade time its cheaper
85 Tri-Z "Rumble Bee"
85 250R "Red Rocket"
83 200X "Flat Tracker"
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With two cams you can run more valves per cylinder as well as having more radical cam timing. You would never have to upgrade the stock cams in the yfz, they are the same cams that you get in the dirt bike. Yamaha put a ton of design and engineering in them. You just have have to retard the exhaust cam one tooth (yamaha bike specs) and you are set to scream!
Within Arms Reach Of The Master
Arm chair racerLord of the trike
There's sizable advantages to changing the cams in a yfz. A single cam can run 4 vavles per cylinder with ease. Are you saying they're missing the boat not running 5 valves?
'02 Honda 416ex - A seasoned blend of 11 herbs and spices
'04 Honda Recon - The yard machine and snow plow
'88 Honda CR250R - Another chapter in my torrid all terrain affair
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RUBBISH! we have a lancia engine here that is a V4 and it has ONE camshaft per bank. Its a hemi head aswell Theres no loss. You could run 5 valves off one cam easily More radical cam timing? thats purely to do with how it has been ground and how its been setup. On my old 70 we check the stock 3 bolt no adjustment cam timing. It was 4 degrees out as they are nver all the same. Instead of looking at twin cam engines they should be looking at having fully adjustable cam timing, so you can set it for your specific engine.
85 Tri-Z "Rumble Bee"
85 250R "Red Rocket"
83 200X "Flat Tracker"
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The Honda 450r is a great bike. Honda always has and will build top notch vehicles. But from a "pure performance aspect"' you want to get as much fuel/air through the motor as possible to make hp. Every roadracing factory team kawasaki, suzuki, yamaha, and yes honda uses dual cams in there motorcycles. Same with performance cars like ferrari, lamorguini?sp, etc uses the dual setup. When you get a very aggresive single cam setup in a 4 valve arrangement the idle and operation of the machine becomes erratic at low rpm. I do think a reason behind the unicam design was partially for weight savings in there 450 dirtbike lineup. Dirtbikers are CRAZY about weight savings!
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Its only done to have less complicated valve gear, less moving parts at high RPM the better. There would be no wieght advantage as the valve gear probably weighs as much as another cam
85 Tri-Z "Rumble Bee"
85 250R "Red Rocket"
83 200X "Flat Tracker"
Within Arms Reach Of The Master
Arm chair racerLord of the trike
You get the same air flow with a single cam pushing 4 valves as a twin cam.
'02 Honda 416ex - A seasoned blend of 11 herbs and spices
'04 Honda Recon - The yard machine and snow plow
'88 Honda CR250R - Another chapter in my torrid all terrain affair
At The Back Of The Pack
Arm chair racerAt the back of the pack
I am not sure of the exact specific differences, but I do know that the guys hopping up Honda Civics use primarily DOHC motors because they can produce more hp from them than the SOHC motors.... There are a few hard nosed underdogs getting high power out of the SOHC motors, but there is always a DOHC that is making more.... Once again, not quite sure exactly why, maybe I will research it....
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