Author Topic: R.P.M @ 60 (55)  (Read 9144 times)

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cyrusb

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on: March 10, 2008, 07:12:26 pm
Has anyone tached out their classic at 60 mph (indicated) ? Looking for a ballpark figure, stock (17t) sprocket. Thanks.
2005E Fixed and or Replaced: ignition, fenders,chainguard,wires,carb,headlight,seat,tailight,sprockets,chain,shock springs,fork springs, exhaust system, horn,shifter,clutch arm, trafficators,crankcase vent.


fredgold52

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Reply #1 on: March 11, 2008, 08:08:46 pm
I wanted to bump this back up - I'm interested in knowing what RPM's we are turning at various speeds too.  I know this is sort of a lazy engine and that's one of the reasons I like it so well.  But still, RPM's would be nice to know.
2006 '65' and a 200cc Stella, Indian all the way


cyrusb

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Reply #2 on: March 11, 2008, 08:28:35 pm
I cant believe no ones done it yet! I guess I'll have to dig up an old dwell meter or the like. Haven't seen any of those old tuneup tools in 20 years. I'm going to take a guess at 3800 and hope I'm wrong.
2005E Fixed and or Replaced: ignition, fenders,chainguard,wires,carb,headlight,seat,tailight,sprockets,chain,shock springs,fork springs, exhaust system, horn,shifter,clutch arm, trafficators,crankcase vent.


Foggy_Auggie

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Reply #3 on: March 12, 2008, 12:37:41 am
Transmission ratio in 5th gear.

Sprocket ratio = rear sprocket / front sprocket

Engine rotation / km = trans ratio * sprocket ratio * wheel rotation / km

Engine rpm = engine rotation / km * bike speed / 60

One mile = 1.609 km

Wheel rotation travel found by using a string to measure the distance traveled in one rear tire rotation.  Can be performed on the center stand with a helper.  Measure in inches - convert to millimeters - convert to three decimal points of meters.
(example only:  wheel travels 65.25 inches in one rotation - this equals 1658 mm = 1.658 meters).
Diagonally parked in a parallel universe.

Fortiter Et Fideliter


baird4444

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Reply #4 on: March 12, 2008, 01:36:17 am
                                       FOUND IT!
Below is a post from "DWM" Dave was the builder of Hanuman in the members
rides. What he didn't know he figured out and shared.   - Mike
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
I wanted to know my RPMs at different speeds, so got this little tach;
http://www.tinytach.com/tinytach/gasoline.php
Not bad for $37 US, being digital, it's useless for shifting. but, if you need
a
tach to shift a
RE, you're stone deaf, and yer butt has gone to sleep. Also has a 2 second lag.

Anyway, here are speeds/RPMs, with a 19T countershaft sprocket on the five
speed.
(XT- extrapolated.interpolated)

50MPH-2870 RPM
55MPH XT - 3146 RPM
60 MPH - 3450 RPM
65 MPH XT- -3737 RPM
70 MPH - 4025 RPM
75MPH XT - 4312 RPM
80MPH - 4600 RPM
85MPH XT- 4887 RPM
Theoretical;
90 MPH XT - 5175 RPM
MAX RPM-5500 - 95MPH

The speeds above are from a GPS corrected speedo, and I think they're pretty
tight
numbers.
I don't think the bike would do 95 MPH if you pushed it off the Sinny Arbor
Bridge, but it
touches 85 with my 220 lb on board, so I think a lighter rider would see 90.
(535cc, 8.5:1. 34mm Mikuni, short Brit exhaust, K&N)
More importantly, it means my "75 MPH all day, 80 to pass only," are usable
limits. I just
can't see that motor objecting to 4300 RPM. It sure sounds relaxed.
Below are extrapolated numbers for 19 and 18 tooth sprockets;
18T (19/18ths of above RPM)
50MPH-3029 RPM
60MPH-3642 RPM
70MPH-4249 RPM
80MPH-4855 RPM

17T (stock, 19/17ths of 19T readings)
50MPH-3207 RPM
60MPH-3855 RPM
70MPH-4498 RPM
80MPH-5141 RPM

BTW, I installed the black bar-end mirrors from CMW on "Lady Triumphantes", the
$15
ones, and they have been fine. Of course, the Trumpet vibrates a bit less.
Best,
DWM
'My dear you are ugly,
 but tomorrow I shall be sober and you will still be ugly'
 - Winston Churchill


jdrouin

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Reply #5 on: March 12, 2008, 01:50:01 am
Wow! Cyrusb's guess of 3800 rpm on a 17T countershaft sprocket is pretty much dead on, balls accurate.

Jeff
« Last Edit: March 12, 2008, 01:51:32 am by jdrouin »


cyrusb

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Reply #6 on: March 12, 2008, 04:52:36 pm
Thanks baird444, I printed that out. I had a feeling the revs were in the high 3000's but didn't think my guess was that close!
2005E Fixed and or Replaced: ignition, fenders,chainguard,wires,carb,headlight,seat,tailight,sprockets,chain,shock springs,fork springs, exhaust system, horn,shifter,clutch arm, trafficators,crankcase vent.


Bankerdanny

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Reply #7 on: March 12, 2008, 06:53:07 pm
dead on, balls accurate?
Endeavor To Persevere

Current: '75 Honda CB550F, '76 Honda CB750F. Previous:  2007 Yamaha Vino 125, '75 Harley FXE Superglide, '77 GL1000 Goldwing, '77 Honda CB550K, '02 Royal Enfield Bullet 500ES, '68 Suzuki K11, '68 Yamaha YR2, '69 BMW R69S, '71 Honda SL175


luoma

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Reply #8 on: March 12, 2008, 11:10:04 pm
Appreciate the info. My bike has a 19-tooth also. It feels pretty tight at 75, but I guess it's not.


jdrouin

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Reply #9 on: March 12, 2008, 11:43:40 pm
dead on, balls accurate?

That's Marisa Tomei's line in My Cousin Vinny. She's the daughter of a mechanic who clinches the mystery of an armed robbery at the end of a lost-cause trial.

http://www.youtube.com/watch?v=DhL5exi_avE

Jeff


LotusSevenMan

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Reply #10 on: March 13, 2008, 12:33:03 am
I have never seen that film Jeff but I liked the clip!!!!  ;D
If it ain't broke-------------------------- fix it 'till it is!

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Honda VTR FireStorm (SuperHawk) 996cc 'V' twin
Kawasaki KR1 250cc twin 'stroker
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jdrouin

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Reply #11 on: March 13, 2008, 02:10:36 am
Actually, I sent the wrong one. It's in this clip, from about 1:15 to 2:15. For some reason I thought the line was repeated later as a clincher in the trial, but it wasn't. The technical humor is good in this one too, as well as certain other... ahem... aspects.

http://www.youtube.com/watch?v=M-ZyxRNCTuc

Jeff


LotusSevenMan

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Reply #12 on: March 14, 2008, 09:47:45 pm
The  new clip is "Dead on, balls accurate" !!!!  ;D
If it ain't broke-------------------------- fix it 'till it is!

Royal Enfield Miltary 500cc  (2003)
Honda VTR FireStorm (SuperHawk) 996cc 'V' twin
Kawasaki KR1 250cc twin 'stroker
Ducati 916 'L' twin


cyrusb

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Reply #13 on: March 14, 2008, 10:05:12 pm
Its an industry term!
2005E Fixed and or Replaced: ignition, fenders,chainguard,wires,carb,headlight,seat,tailight,sprockets,chain,shock springs,fork springs, exhaust system, horn,shifter,clutch arm, trafficators,crankcase vent.


LotusSevenMan

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Reply #14 on: March 15, 2008, 04:46:26 pm
Maybe I'd better not ask which 'industry' if it turns out to be the worlds oldest profession  ???  :o
If it ain't broke-------------------------- fix it 'till it is!

Royal Enfield Miltary 500cc  (2003)
Honda VTR FireStorm (SuperHawk) 996cc 'V' twin
Kawasaki KR1 250cc twin 'stroker
Ducati 916 'L' twin