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Author Topic:   Yamaha F70 Information

tedious posted 11-24-2009 05:55 PM ET (US)
I'd like to split this thread off from the general "Yamaha Game Changer" thread here: http://continuouswave.com/ubb/Forum1/HTML/018698.html

My thinking is to have this thread capture interesting information on the new F70, and only on the F70, not the bass boat or offshore motors. I'm particularly interested in specifications and pictures. Here are some links to start:
http://www.sportfishingmag.com/article.jsp?ID=1000078590& cmpid=enews112009
http://www.chattanoogan.com/articles/article_163331.asp
http://www.marinebusiness-world.com/index.cfm?nid=63641
http://www.versuscountry.com/hunting-and-fishing-blogs/pennazs-pointers/More-on-Yamahas-2010-Product-Launches.aspx
From these articles, it seems that the F70 is the F60 short block updated with 4-valve heads, running off a single camshaft, giving a redline of 6300 RPM. Weight is 260 pounds, and MSRP is $8745. The Versus article reports a boat of ~2500 pounds cruising at 4000 RPM, 18.1 MPH, 2.5 GPH for 7.24 MPG.
Thanks for additional contributions of factual information regarding the F70, and links.
Tim
Peter posted 11-24-2009 06:25 PM ET (US)
One of the articles answered my question: What is the displacement of the F70? Answer: Same as the F60 -- 996cc. The picture of the F70 suggests it uses their bigfoot 2.33:1 gearcase. Weight is 12 lbs more than the T60 and probably due to the different head.
My guess is that its power curve would be similar to a T60 from 0 to 6000 RPM and the extra 10 HP is developed between 6000 and 6300 RPM. Basically, the F70 appears to be a modified T60.
jimh posted 11-25-2009 12:09 AM ET (US)
[Sorry, but a completely unrelated sidebar discussion encroached on this discussion of the new Yamaha F70 and factual information related to it. It has been deleted.--jimh]
jimh posted 11-25-2009 12:43 AM ET (US)
It would be interesting to see a detail of how a single camshaft operates four valves in one cylinder. I believe that is somewhat unusual.
number9 posted 11-25-2009 01:20 AM ET (US)
Here is one example, 1987 Honda CRX.
http://wpcontent.answers.com/wikipedia/commons/thumb/f/f2/Head_D15A3. JPG/250px-Head_D15A3.JPG
tedious posted 11-25-2009 08:52 AM ET (US)
Another picture seems to confirm that the F70 has the larger, 2.33:1 gearcase: [Link required user to register to view.]
fishgutz posted 11-25-2009 09:38 AM ET (US)

quote:
The Versus article reports a boat of ~2500 pounds cruising at 4000 RPM, 18.1 MPH, 2.5 GPH for 7.24 MPG.

An Alumacraft Dominator 165CS weighs 1100 pounds. So the combined weight of boat, motor, fuel and 2 guys probably comes to the 1995 pound weight that the article states.
Just to clarify.
Peter posted 11-25-2009 09:44 AM ET (US)
U.S. Patent No. 4,561,391, issued in 1985, shows a single overhead cam, four valve per cylinder design.
Perry posted 11-25-2009 12:37 PM ET (US)
Mercury and Honda both have 1 liter 60 HP EFI 4 strokes weighing in at around 250 lbs. I'm wondering if they will also go the same route as Yamaha and tweak another 10 HP out of them to compete in the same market segment?
Peter posted 11-25-2009 01:26 PM ET (US)
The Honda already has 4 valves per cylinder (3 cylinders) driven by a single overhead cam. So the hardware looks like its already there. It would seem that they just need to spin it faster and use different lobe profiles for the cam.

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Author	Topic: Yamaha F70 Information
tedious	posted 11-24-2009 05:55 PM ET (US) I'd like to split this thread off from the general "Yamaha Game Changer" thread here: http://continuouswave.com/ubb/Forum1/HTML/018698.html My thinking is to have this thread capture interesting information on the new F70, and only on the F70, not the bass boat or offshore motors. I'm particularly interested in specifications and pictures. Here are some links to start: http://www.sportfishingmag.com/article.jsp?ID=1000078590& cmpid=enews112009 http://www.chattanoogan.com/articles/article_163331.asp http://www.marinebusiness-world.com/index.cfm?nid=63641 http://www.versuscountry.com/hunting-and-fishing-blogs/pennazs-pointers/More-on-Yamahas-2010-Product-Launches.aspx From these articles, it seems that the F70 is the F60 short block updated with 4-valve heads, running off a single camshaft, giving a redline of 6300 RPM. Weight is 260 pounds, and MSRP is $8745. The Versus article reports a boat of ~2500 pounds cruising at 4000 RPM, 18.1 MPH, 2.5 GPH for 7.24 MPG. Thanks for additional contributions of factual information regarding the F70, and links. Tim
Peter	posted 11-24-2009 06:25 PM ET (US) One of the articles answered my question: What is the displacement of the F70? Answer: Same as the F60 -- 996cc. The picture of the F70 suggests it uses their bigfoot 2.33:1 gearcase. Weight is 12 lbs more than the T60 and probably due to the different head. My guess is that its power curve would be similar to a T60 from 0 to 6000 RPM and the extra 10 HP is developed between 6000 and 6300 RPM. Basically, the F70 appears to be a modified T60.
jimh	posted 11-25-2009 12:09 AM ET (US) [Sorry, but a completely unrelated sidebar discussion encroached on this discussion of the new Yamaha F70 and factual information related to it. It has been deleted.--jimh]
jimh	posted 11-25-2009 12:43 AM ET (US) It would be interesting to see a detail of how a single camshaft operates four valves in one cylinder. I believe that is somewhat unusual.
number9	posted 11-25-2009 01:20 AM ET (US) Here is one example, 1987 Honda CRX. http://wpcontent.answers.com/wikipedia/commons/thumb/f/f2/Head_D15A3. JPG/250px-Head_D15A3.JPG
tedious	posted 11-25-2009 08:52 AM ET (US) Another picture seems to confirm that the F70 has the larger, 2.33:1 gearcase: [Link required user to register to view.]
fishgutz	posted 11-25-2009 09:38 AM ET (US) quote: The Versus article reports a boat of ~2500 pounds cruising at 4000 RPM, 18.1 MPH, 2.5 GPH for 7.24 MPG. An Alumacraft Dominator 165CS weighs 1100 pounds. So the combined weight of boat, motor, fuel and 2 guys probably comes to the 1995 pound weight that the article states. Just to clarify.
Peter	posted 11-25-2009 09:44 AM ET (US) U.S. Patent No. 4,561,391, issued in 1985, shows a single overhead cam, four valve per cylinder design.
Perry	posted 11-25-2009 12:37 PM ET (US) Mercury and Honda both have 1 liter 60 HP EFI 4 strokes weighing in at around 250 lbs. I'm wondering if they will also go the same route as Yamaha and tweak another 10 HP out of them to compete in the same market segment?
Peter	posted 11-25-2009 01:26 PM ET (US) The Honda already has 4 valves per cylinder (3 cylinders) driven by a single overhead cam. So the hardware looks like its already there. It would seem that they just need to spin it faster and use different lobe profiles for the cam.