- Joined
- Dec 10, 2008
- Messages
- 7,253
Junk yard Dawg said:Is this the crankshaft for the Dawg Chaser ? Were tuning here in Mudville also.
John Ellis
AHRMA 5X
F750
No,
not the dawg chaser - It would be the dawg catcher.....
Junk yard Dawg said:Is this the crankshaft for the Dawg Chaser ? Were tuning here in Mudville also.
John Ellis
AHRMA 5X
F750
comnoz said:Junk yard Dawg said:Is this the crankshaft for the Dawg Chaser ? Were tuning here in Mudville also.
John Ellis
AHRMA 5X
F750
No,
not the dawg chaser - It would be the dawg catcher.....
Junk yard Dawg said:You got me, question for Jim the wizard ? you running like 61 present , or higher ? Got a 360 crank here were working on. Smaller wheels as you know.
John Ellis
5X
You mean, "Yahtzee"?Holmeslice said:comnoz said:Junk yard Dawg said:Is this the crankshaft for the Dawg Chaser ? Were tuning here in Mudville also.
John Ellis
AHRMA 5X
F750
No,
not the dawg chaser - It would be the dawg catcher.....
That's it
Junk yard Dawg said:Yes Jim, 61 percent or ? Just curious , as there are many opinions out there.
John Ellis
5X
fiatfan said:Jim, as a novice on these things, I just wonder about the 1200 rpm, why those revs?
Tommy
acotrel said:I suggest that with the shorter stroke the rod length and piston mass become more critical. Your motor will probably need to peak at more than 10,000 RPM and use more than a 4 speed transmission to make sense in a race bike. Also the exhaust system becomes more critical, it determines how much bottom end torque you have to make the bike rideable. What you are doing is great in theory, however you won't know until you try to use the crank, what will happen in practice. There is nothing worse than a savage motor which requires heaps of revs to get going, and has no bottom end. I spent my childhood road-racing a bike like that and I can still feel the pain and the anxiety.
I really like your crankshaft, it is very exciting.
comnoz said:The reduction of stroke is mostly to reduce the amount of power given up to friction -which in a longstroke motor is a major loss at 8500 rpm.
Paddy_SP said:comnoz said:The reduction of stroke is mostly to reduce the amount of power given up to friction -which in a longstroke motor is a major loss at 8500 rpm.
You may well find that the heads work better at those rpm too - I've not done the harmonic calculations for a Commando yet, but on the Harley big twins they don't start working properly until the motor is doing 7,500 rpm. Which is a shame, as on the stock stroke they run out of piston speed at 6,500 rpm...
comnoz said:That is true for a 32mm port Norton also if your just looking at port size.
Of course when you look at the small valve on the end of that 32mm port -nothing works.
comnoz said:Paddy_SP said:comnoz said:The reduction of stroke is mostly to reduce the amount of power given up to friction -which in a longstroke motor is a major loss at 8500 rpm.
You may well find that the heads work better at those rpm too - I've not done the harmonic calculations for a Commando yet, but on the Harley big twins they don't start working properly until the motor is doing 7,500 rpm. Which is a shame, as on the stock stroke they run out of piston speed at 6,500 rpm...
That is true for a 32mm port Norton also if your just looking at port size.
Of course when you look at the small valve on the end of that 32mm port -nothing works.
Kvinnhering said:What stroke did you use Paddy?
Paddy_SP said:Kvinnhering said:What stroke did you use Paddy?
I apologise if I've confused matters - I was referring to my HD sprint-hillclimb racer: http://www.foxonic.com/harley.htm which has a 3.812" stroke using Cosworth DFL pistons.
comnoz said:Paddy_SP said:Kvinnhering said:What stroke did you use Paddy?
I apologise if I've confused matters - I was referring to my HD sprint-hillclimb racer: http://www.foxonic.com/harley.htm which has a 3.812" stroke using Cosworth DFL pistons.
Nice, that looks mean and fun.
Reminds me of the Ecosse TI I was involved in without the excess bling....