Author Topic: sprag sprague clutch easy fix diy (Read 33289 times)

Texbid · « **on:** July 20, 2014, 03:31:25 PM »

berts explanation of the sprag clutch is the lets analyze the principle behind a starter mechanism pdf at the bottom of this post...

this is texbids excellent post...

dreaded sprag cluch issue. If you dont know what this is then search the forums. This is my super cheap fix and done in about 40 minutes includes 20 minutes with flusihin oil and engine running..

parts needed
12mm drill
1/4 bsp plug with o ring (see below for the item i bought)
http://www.ebay.co.uk/itm/111268478093?var=410275065095&ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649
flushing oil
http://www.ebay.co.uk/itm/231095282248?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649
two oil filters
http://www.ebay.co.uk/itm/270776992221?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

drill hole as per pictures.
move gear through the window to align the flushing hole on the sparag clutch
you should see the hole as in the second picture.
spray into hole with wd-40
and it now works.

i then ran flushing oil in the engine until the fan turned on.
changed oil and no problems.

cap the hole with the bsp plug. no need to thread it.

wmax351 · « **Reply #1 on:** July 20, 2014, 04:50:12 PM »

Interesting. How did you deal with swarf from the drill?

Seafoam Spray would be a lot better than WD40 for this application.

WayneDW · « **Reply #2 on:** July 20, 2014, 09:34:18 PM »

welcome.
great idea, thanks.

Texbid · « **Reply #3 on:** July 21, 2014, 12:43:11 AM »

Wmax,

The key was to use a very sharp drill. Then drill slowly and blow the swarf away with a compressor. IMO you don't need the compressor but it helps. The case material is soft so im small particles got into the engine it should be fine. They are bulletproof aren't they :).

beachcomber · « **Reply #4 on:** July 21, 2014, 04:38:26 AM »

Quote from: Texbid on July 21, 2014, 12:43:11 AM

Wmax,

The key was to use a very sharp drill. Then drill slowly and blow the swarf away with a compressor. IMO you don't need the compressor but it helps. The case material is soft so im small particles got into the engine it should be fine. They are bulletproof aren't they :).

I came to the same fix about 5 years ago ....... I used a blob of silicone gasket goo to drill through - that entangled all the swarf ! Good fix.

Tiny97 · « **Reply #5 on:** July 22, 2014, 07:53:25 PM »

Texbid any chance we could get a point of reference shot a lil further away from the hole? I'm not in front of my bike but I'm having a hard time visualizing exactly where the hole you drilled is.

Texbid · « **Reply #6 on:** July 23, 2014, 01:03:22 AM »

Tiny97

I have been doing a few things to the bike in order to resurect it. Water-oil pump rebuild, wiring harness replacement, etcetc.

The image needs to be rotated 90CW to be correctly orinted. There is no airbox on the bike either so it may be misguiding.

Once rotated yYou will see the outline of the right hand side engine cover, the one with BMW embossed. The hole is directly above the back top corner of the engine cover. Hope that helps.

TimTyler · « **Reply #7 on:** July 23, 2014, 04:52:35 PM »

Is the right?

Texbid · « **Reply #8 on:** July 23, 2014, 06:32:25 PM »

Exactly correct. Thanks for the. Assist.

Tiny97 · « **Reply #9 on:** July 23, 2014, 07:59:51 PM »

Wow thank you so much I was thinking it was a top down shot before. I've spent so much on oil changes every few hundred miles trying to fix this, this is a big help. I may be setting about to working on this this weekend. is the 1/4 bsp plug something I could find in a local hardware store or maybe auto parts store?

Texbid · « **Reply #10 on:** July 24, 2014, 12:48:16 AM »

I got mine from ebay. Check local plumbing supplies or maybe even home depot or BQ (depends what side of the Atlantic you are on)

See link above. You could put anything into the hole. Even a regular bolt. Its not load bearing or pressure containing. It merely keeps the oil from splashing out.

Hope it works out for you..

wmax351 · « **Reply #11 on:** July 24, 2014, 03:28:18 PM »

A 3/8 (might be a smaller NPT size, though) npt tap comes with one of the cheap Harbor Freight tap/die sets. NPT is a tapered thread, and self sealing, especially with a little (carefully applied) teflon tape. Would be ideal for this location. You could even make the plug too, out of Aluminium rod: the matching die comes with the kit.

Texbid · « **Reply #12 on:** July 25, 2014, 10:20:47 AM »

I think the 3/8 hole will be too small. If the clutch oil hole, as shown through the hole in my case and between the gears on the photo below , is not aligned with the case hole the only way to make it align is by manually rotating the gear seen on the right hand side of the hole. You can rotate this with a aluminium rod(must be softer than the gear to avoid tooth damage)

Inge K. · « **Reply #13 on:** July 25, 2014, 10:48:50 AM »

Quote from: Texbid on July 25, 2014, 10:20:47 AM

the only way to make it align is by manually rotating the gear seen on the right hand side of the hole. You can rotate this with a aluminium rod(must be softer than the gear to avoid tooth damage)

I would guess it could be difficult, you also at the same time must turn the crank, cam, intermediate and gearbox input shafts.
It would be easier to turn the rear wheel, or remove the cover at the hall sensors and turn the crankshaft...
is my opinion.

TimTyler · « **Reply #14 on:** July 25, 2014, 11:32:53 AM »

Are the sticky sprags inside that smooth ring between the gears?

That hole is the only way oil gets in and out?

Texbid · « **Reply #15 on:** July 25, 2014, 11:36:48 AM »

Yes the sprags are inside the smooth part. Oil gets in by splashing action inside the case.

Texbid · « **Reply #16 on:** October 09, 2014, 04:33:26 PM »

Months later the fix still works.

johnny · « **Reply #17 on:** October 09, 2014, 07:38:27 PM »

greetings texbid...

highly sought after information... thanks for doing the leg work and posting up... this will come in handy for sure...

gonna getts this in the lieberry... and you will be world famous...

j o

racinrich · « **Reply #18 on:** October 12, 2014, 01:24:26 PM »

2 questions what is the symptom of a sticky sprag and is this motor specific ie k75 or does this apply to all motors :dunno

Texbid · « **Reply #19 on:** October 12, 2014, 01:29:03 PM »

Upon pressing the start button the starter spins but the engine does not. Its a whine that drives shivers down the back of all K bike owners as the entire motorcycle was built around the sprag clutch (sic).

racinrich · « **Reply #20 on:** October 12, 2014, 01:41:11 PM »

thanks

joolx · « **Reply #21 on:** May 22, 2015, 07:28:54 AM »

I followed this post to the letter only to find that my starter clutch is the 3 roller type so after drilling the hole in the bell housing found no small hole in which to squirt the seafoam etc. However I did my best to cover as much of the exposed innards as I could with the solvent and left it over night....Next day same issue
Then I thought about trying to vibrate it free so I took a bit holder, turned it the wrong way round and inserted it into my cordless drill. I set the mode to masonary so it would vibrate and as the tip is now just a smooth hexagonal shaft of metal it wouldn't do any damage. I then carefully placed the end against the exposed smooth starter clutch through the hole I'd drilled through the bell housing and gave it half a second of power.......Tried the starter button and hey presto it burst into life..
I will now follow the rest of the instructions...flush the engine...put in new Mobil 1 fully synth 15W50, new filter etc. I've had to buy a tap to cut a thread for the 1/4 bsp plug but thats no problem

Many Many thanks for saving me a lot of trouble

Texbid · « **Reply #22 on:** May 22, 2015, 08:14:19 AM »

glad to see that the fix has helped somebody else. I haven't had any problems with mine since i implemented the fix.

On another note. I don't think that the brick will benefit from fully synth oil IMO.

Btw. A few pics of my bike.

Chaos · « **Reply #23 on:** May 22, 2015, 08:33:34 AM »

Quote from: Texbid on May 22, 2015, 08:14:19 AM

Btw. A few pics of my bike.

:mbird

Conrad325i · « **Reply #24 on:** March 11, 2016, 01:40:30 AM »

I did this with a 3/8 npt and a pipe plug... worked like a charm. I sprayed wd40 in the little hole and then hit it with a hammer and punch.

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Author Topic: sprag sprague clutch easy fix diy (Read 33289 times)