Stupid Question
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Road Master
Joined: Aug 2005
Posts: 1,203
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From: Bedford , Pa
Stupid Question
I noticed that with the clutch lever pulled in and bike in gear the bike is hard to move. But with the engine running and in gear and lever pulled in it just sits there like it should. Is this something normal that I never noticed or is there something wrong with the clutch. It does jump a little if you start it in gear with the lever pulled though but not real bad.
Thanks Clap
Thanks Clap
Stellar HDF Member
Joined: Feb 2010
Posts: 3,395
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From: Southern California
On a Multiplate Wet Clutch such as our Harley's have, there is always a bit of drag even with the Clutch Lever pulled in (clutch released). Even more so when the oil is cold.
With the Engine off when you try and push the bike, with the bike in gear one set of the Clutch Plates are held stationary by the Engine (which is stopped) while you're trying to rotate the Clutch Plates that are attached to the Transmission Input Shaft because the Transmission is in Gear. The effort you feel is the drag between the Clutch Plates multiplied by the gear ratio of whatever gear you've got the Transmission in, plus the ratio of the Drive Belt (or chain). Take it out of gear and all you're trying to turn is the Transmission Output Shaft. With the Transmission in Neutral you're no longer trying to turn the Transmission Input Shaft when you rotate the Output Shaft. Since you're no longer rotating the Input Shaft with the Transmission in Neutral, you no longer have the drag of the Clutch to contend with.
The opposite takes place when you first put the Transmission in gear and you get a fairly solid thwack at the engagement of the gear, even with the Clutch disengaged. This is because the aforementioned drag of the Clutch is in fact causing the Input Shaft of the transmission to rotate (even with the Clutch Lever pulled in) while the Transmission Output Shaft is stationary, because the rear wheel isn't moving. When you engage a gear (hopefully 1st gear) this brings the Clutch Plates that are attached to the Transmission Input Shaft to a very rapid halt . . . hence the Thwack.
With the Engine off when you try and push the bike, with the bike in gear one set of the Clutch Plates are held stationary by the Engine (which is stopped) while you're trying to rotate the Clutch Plates that are attached to the Transmission Input Shaft because the Transmission is in Gear. The effort you feel is the drag between the Clutch Plates multiplied by the gear ratio of whatever gear you've got the Transmission in, plus the ratio of the Drive Belt (or chain). Take it out of gear and all you're trying to turn is the Transmission Output Shaft. With the Transmission in Neutral you're no longer trying to turn the Transmission Input Shaft when you rotate the Output Shaft. Since you're no longer rotating the Input Shaft with the Transmission in Neutral, you no longer have the drag of the Clutch to contend with.
The opposite takes place when you first put the Transmission in gear and you get a fairly solid thwack at the engagement of the gear, even with the Clutch disengaged. This is because the aforementioned drag of the Clutch is in fact causing the Input Shaft of the transmission to rotate (even with the Clutch Lever pulled in) while the Transmission Output Shaft is stationary, because the rear wheel isn't moving. When you engage a gear (hopefully 1st gear) this brings the Clutch Plates that are attached to the Transmission Input Shaft to a very rapid halt . . . hence the Thwack.
Last edited by Bluehighways; Aug 29, 2013 at 11:54 PM.
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Joined: Jul 2009
Posts: 13,870
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From: Taylortucky, MI
I noticed that with the clutch lever pulled in and bike in gear the bike is hard to move. But with the engine running and in gear and lever pulled in it just sits there like it should. Is this something normal that I never noticed or is there something wrong with the clutch. It does jump a little if you start it in gear with the lever pulled though but not real bad.
Thanks Clap
Thanks Clap
Extreme HDF Member
Joined: Feb 2008
Posts: 13,422
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From: Las Cruces, NM
Very informative response, thanks!
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Outstanding HDF Member
Joined: Apr 2013
Posts: 3,369
Likes: 472
From: CC TX
Another factoid, oil viscosity is a contributor, oil tends to be sticky-er when cold.
Even dry clutch's will have drag.
Even dry clutch's will have drag.
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