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Old 01-15-2007, 07:32 PM   #81
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“ Quote:
Originally Posted by Speed_Demon View Post
Edit:
I found a Eunos 800M to use a Miller Cycle engine. Never heard of it.
Me either. Mazda Milena 95-99 was the one I was looking for and it was used successfully because of electronic variable valve timing worked out the bugs of the Miller cycle.

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Old 01-15-2007, 08:10 PM   #82
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“ Quote:
Originally Posted by Riverrat View Post
The power valve smoothes out the power band by restricting exhaust gasses and creating back pressure at lower? rpms.

I'll wait for the ok on this one because I'm not sure the rpm range.
Sort of. Basically creates optimal porting for both bottom and top-end. Initiation rpm varies.

You gotta ask a question after you answer.

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Old 01-15-2007, 08:18 PM   #83
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Ok I'll get it going again. No calcs on this it should be super easy if you know what your talking about.

A bike is putting out 50ft/lbs of torque at 7500rpm is putting out 71hp. The same bike putting out 50ft/lbs of torque at 15000rpm is putting out how many horsepower?

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Old 01-15-2007, 08:59 PM   #84
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let's see, same amount of torque twice as often...142hp?

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Old 01-15-2007, 09:06 PM   #85
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“ Quote:
Originally Posted by Riverrat View Post
let's see, same amount of torque twice as often...142hp?
You are correct! Now ask a damn question! Ahem... please ask a question.

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Old 01-15-2007, 09:12 PM   #86
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From: Kennewick, WA

I Ride: DRZ400SM (Dirted)
on some very large engines there is a device called an electrostatic precipiator. What is this device and why is it necessary?

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Old 01-15-2007, 09:20 PM   #87
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“ Quote:
Originally Posted by Riverrat View Post
on some very large engines there is a device called an electrostatic precipiator. What is this device and why is it necessary?
Come on thats not a motorcycle related question.

Anyways, a particle collector is used to attract stuff the EPA deems harmful to humans.

Before installing new clutch fiber plates you must do this for five hours before installing them?

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Old 01-15-2007, 09:27 PM   #88
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From: Kennewick, WA

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Yes, for the first part but they serve a different purpose on VERY large engines. They precipitate oil particles from the crankcase to prevent an explosion hazard.
ok, motorcycle question:
What is the reasoning behind left-hand kickstarters on enduro bikes?

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Old 01-15-2007, 09:34 PM   #89
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“ Quote:
Originally Posted by Riverrat View Post
Yes, for the first part but they serve a different purpose on VERY large engines. They precipitate oil particles from the crankcase to prevent an explosion hazard.
ok, motorcycle question:
What is the reasoning behind left-hand kickstarters on enduro bikes?
I would hazard to guess its so the right leg has brake control if bike stalls in a bad spot? Or if the the grade is not optimal its easier to get off the bike and kick start it with your right leg? hmm...

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Old 01-15-2007, 09:45 PM   #90
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Both are correct! your turn...this is kinda fun!

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Old 01-15-2007, 09:53 PM   #91
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“ Quote:
Originally Posted by Riverrat View Post
Both are correct! your turn...this is kinda fun!
I thought you had me on that one!

Explain how a two stroke expansion chamber works and why they can only be tuned to one rpm band at a time? For bonus brownies, how does exhaust water injection help improve performance?

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Old 01-15-2007, 10:34 PM   #92
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I Ride: DRZ400SM (Dirted)
The expansion chamber acts like a vacuum for the exhaust head pipe. As gasses flow into the larger chamber, the pressure drops and exhaust is pulled into the chamber, pulling exhaust out of the header pipe and assisting in evacuating the cylinder. The "tuning" comes into play when the exhaust gasses pressurize the chamber to the point that it no longer helps evacuate the cylinder. Larger volume chamber=more rpm's.

Bonus: Water injection flashes to gas in the header pipe, expanding rapidly into the chamber and allowing the bike to be "on the pipe" at relatively low rpm's.

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Old 01-15-2007, 10:38 PM   #93
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Most Harley Davidson bikes start with the letter designation "F" (FLST,FLHT,FXD...etc) What does the "F" stand for?

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Old 01-15-2007, 10:54 PM   #94
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“ Quote:
Originally Posted by Riverrat View Post
Most Harley Davidson bikes start with the letter designation "F" (FLST,FLHT,FXD...etc) What does the "F" stand for?
F stands for the big model with the big motor.

When increasing the stroke of an engine what is the most significant improvement in engine output?

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Old 01-15-2007, 11:19 PM   #95
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"F" originally stood for "footshift" the letter came along when they switched from the handshift on the tank.

As for the stroker, I would say the biggest improvement would be on the torque curve. Moving the rotational mass and forces applied to the crank farther from the center of rotation, it seems logical. A total guess though.

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Old 01-15-2007, 11:40 PM   #96
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“ Quote:
Originally Posted by Riverrat View Post
"F" originally stood for "footshift" the letter came along when they switched from the handshift on the tank.

As for the stroker, I would say the biggest improvement would be on the torque curve. Moving the rotational mass and forces applied to the crank farther from the center of rotation, it seems logical. A total guess though.
Torque is right. I'm going to bed... later...

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Old 01-15-2007, 11:45 PM   #97
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I'm still waiting for the CV carb/airplane answer.

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Old 01-16-2007, 07:33 AM   #98
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Joined: Feb 2005
From: West Richland

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“ Quote:
Originally Posted by Riverrat View Post
The expansion chamber acts like a vacuum for the exhaust head pipe. As gasses flow into the larger chamber, the pressure drops and exhaust is pulled into the chamber, pulling exhaust out of the header pipe and assisting in evacuating the cylinder. The "tuning" comes into play when the exhaust gasses pressurize the chamber to the point that it no longer helps evacuate the cylinder. Larger volume chamber=more rpm's.

Bonus: Water injection flashes to gas in the header pipe, expanding rapidly into the chamber and allowing the bike to be "on the pipe" at relatively low rpm's.
Actually, that is incorrect. It is harmonics (soundwaves) that make the expansion chamber work. They are tuned for RPM depending on the length between the chamber to the reflective cone at the end and the exhaust port on the engine (longer distance is better for low RPM, shorter for high RPM. The soundwave exits the port, reflects off the cone, and forces air back into the combustion chamber just before the piston goes back up and closes the exhaust port, effectively supercharging the new air/fuel mixture. Of course, expansion chamber volume also has an effect as it needs to be tuned to bleed properly depending on the tune of the reflective cone. Yes, the higher RPM pipes need a larger chamber.

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Old 01-16-2007, 10:41 AM   #99
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Joined: May 2005
From: Cheney

I Ride: slow old bikes - fast as they will go
“ Quote:
Originally Posted by Wrench View Post
Actually, that is incorrect. It is harmonics (soundwaves) that make the expansion chamber work. They are tuned for RPM depending on the length between the chamber to the reflective cone at the end and the exhaust port on the engine (longer distance is better for low RPM, shorter for high RPM. The soundwave exits the port, reflects off the cone, and forces air back into the combustion chamber just before the piston goes back up and closes the exhaust port, effectively supercharging the new air/fuel mixture. Of course, expansion chamber volume also has an effect as it needs to be tuned to bleed properly depending on the tune of the reflective cone. Yes, the higher RPM pipes need a larger chamber.
Check out Gordon Jenning's Two Stroke Tuner's Handbook (out of print, but available in used bookshops/amazon). It goes into much more depth about the mechanics of expansion chamber design. The pressure waves you speak of also work as a vacuum to help scavange the combustion chamber and assist the movement of the new charge into the chamber. The trick is to make the negative pulse arrive as the exhaust port is opening and then a positive pulse to arrive just before it closes. Port design and expansion chamber design play a part in tuning a two stroke. Because any combination of port and chamber design reaches maximum combustion chamber filling efficiency over a fairly narrrow rpm range, the power valve allows tuning for maximum efficiency over a wider rpm range by changing the characteristics of the expansion chamber with engine rpm.

Why are Earles forks better than telescopic forks for sidehacks?

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Old 01-16-2007, 10:42 AM   #100
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Originally Posted by tophyr View Post
I'm still waiting for the CV carb/airplane answer.
Me too.

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