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TOPIC: E-Start sprag blow ups research.

E-Start sprag blow ups research. 17 May 2019 08:40 #7

  • commando6868
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My original sprag clutch lasted just over 46K miles. Recently when I started the bike from cold, the starter, occasionally, would spin with no sprag engagement. I removed the outer primary cover and I had very black/dirty oil. I change it on a regular basis but haven't opened the case for a while. Cleaned it out, fresh oil, and it seems to be working normally now. Sprag "bones" gummed up getting hung up so that they could not grip? I didn't take the spray and inspect it this time but if it does it again I will. I will be keeping a close watch on it, checking the primary oil from time to time . Ride to the rally coming up next month, should be over 2000 miles for the entire trip.

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"THE FUTURE'S UNCERTAIN AND THE END IS ALWAYS NEAR"

E-Start sprag blow ups research. 03 Mar 2023 15:01 #8

  • dynodave
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On Tue, Apr 16, 2019 at 4:55 PM Larry Anderson <[email protected]> wrote:

Dave: This is Larry Anderson. I talked to you earlier. My address is: 246 Riverview Drive, Roswell, GA 30075. Phone: 770 634-1023.
Please send me a list of all the parts off the starter and my bike that I need to send to you and I'll get to it ASAP. Thank you.


On Wednesday, April 17, 2019, 8:13:25 AM EDT, David Comeau <[email protected]> wrote:

Hi Larry
parts off starter
2 x 4" long allen screws
aluminum mount starter end plate that plugs into primary
small stainless bracket for electric power stud mount & brass screw nuts washers

then for examination
your sprag clutch assy
the 4" diameter drive gear that rides on needle bearings on crankshaft

dave

On Tue, Apr 23, 2019 at 2:43 PM Larry Anderson <[email protected]> wrote:
Dave, did you get my parts yesterday? I'd like to hear your opinion about what I might need to purchase beside the starter. Let me know, thanks. Larry Anderson


Apr 24, 2019, 7:48 AM David Comeau <[email protected]>wrote:to Larry

Hi Larry
I should award you a prize for the most damaged drive gear race I have ever seen. There is a LOT of dimpling on the race.
The sprag is dead but the dog bone rockers do not show a lot of dragging wear. The dragging wear shows up as a flattened section on the one rounded ends that run on the small inner race. Yours did show a moderate amount of divots or spot damage from grit or metal schards getting crushed into the surface.
I'll have the starter ready to ship tomorrow.
Dave

PS
Larrys items were so contaminate with black slime, I quired to discover that fiber clutch plate were likely the source of the slime. This slime influenced my opinion as to the bad effect of undesired slime lubrication of the sprags ability to bite?

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E-Start sprag blow ups research. 04 Mar 2023 06:25 #9

  • commando6868
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I guess mine wasn’t too bad, but it needed replacement. I got over 40,000 miles from the old sprague clutch. t least it didn’t give up on some remote don’t knowwherethefuckiam road!

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"THE FUTURE'S UNCERTAIN AND THE END IS ALWAYS NEAR"

E-Start sprag blow ups research. 04 Mar 2023 06:33 #10

  • dynodave
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Your dogbone tip wear making worn flats is very notable. It makes me wonder if a use time or number of uses limit should be established. However the severity of engagement load could vary quite a bit depending on
1. engagement power and
2.Rotational resistance such as ignition advance and compression resistance and oil viscosity from (cold) ambient temperature....
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E-Start sprag blow ups research. 08 Mar 2023 09:51 #11

  • dynodave
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I will have to reaccomplish my drive and driven (engine sprocket) gears size measurents. I recall the sizes were not to the engineering spec for sprag clutches which are cousins to roller bearings .
Think of the superblend crankshaft bearing prefering C3 clearance which are to an incredibly small ( a few microns) of added clearance to fight the abnormal shrink fit mounting in .aluminum cases.
Well the sprags are run on steel components that IIRC, I measured the sizes as off (big) therefore affecting the location or angle of sprag dogbone engagement.

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