Sprague Clutch not catching to turn over engine- What 2 Dooo?

[skyrocket]

Just purchased a 95 K-1100RSA with 39K. Bike was in storage for a year when I saw it. Known fuel pump problem was bought knowingly, and I can repair that. It started easily in the storage garage. But now the starter motor will spin strongly, but the Sprague clutch does not bind to turn over the 4 cylinder motor. Is cleaning with special oil treatments a possibility? Can the springs and whatever inside it be cleaned via removing the starter motor and spraying contact cleaner into the gear area? The bike otherwise looks clean and well cared for.

[Bruce C]

Just purchased a 95 K-1100RSA with 39K. Bike was in storage for a year when I saw it. Known fuel pump problem was bought knowingly, and I can repair that. It started easily in the storage garage. But now the starter motor will spin strongly, but the Sprague clutch does not bind to turn over the 4 cylinder motor. Is cleaning with special oil treatments a possibility? Can the springs and whatever inside it be cleaned via removing the starter motor and spraying contact cleaner into the gear area? The bike otherwise looks clean and well cared for.

 

Save the contact cleaner for cleaning contacts! You can't access the sprag clutch it-self by removing the starter.

 

A sticking sprag clutch was a well known problem to the early K100's.

 

The only cure that I know works(SOMETIME) is to add a pint of Rislone Engine Treatment to the oil, bump start it and ride the bike for a couple of hundred miles. That might free up the sprag clutch rollers. If it does, change to fresh oil, filter and you should be good to go.

 

If you have to replace the sprag clutch, it's a major deal. Best to look through a Clymer manual than have me explain it.

 

You can also look over on: www.ibmwr.org/ktech.shtml under"engine".

[bmwmick]

sky,

The most common cause of the sprague clutch failing is infrequent oil changes. The deposits from old oil cause the teeth to stick and not engage the outer sprague wheel.

You can learn more about it over on the K11OG.ORG forums:

http://k11og.org/forum/viewtopic.php?t=3292&highlight=sprague+clutch

There 'were' a couple of updates to the assembly over the years but it is basically unchanged since 1983.

The best way to prevent this problem is the constant use of synthetic oil. I have never seen a failure on a bike with synthetic oil. Very frequent oil changes with regular dino oil would prevent it too.

 

Mick

[steptoe]

Add some ATF ( auto transmision fluid )to the engine oil, push start the bike, let it run for 15 minutes. Drain the old oil, add the new oil, and your bike will be back to normal.

 

Works every time.

[duckbubbles]

To get it to start normally, at least the next time-

Engine off, put tranny in 2nd gear.

Sitting on bike, roll it backward with the clutch lever pulled. A slight downhill helps.

When going a couple of mph, release the clutch rapidly.

You should hear an "rrrrrrr" sound. That is the starter turning backward through the sprague clutch.

If that happens, put it in neutral and do an ordinary start.

What you have done is clean off the grunge that is in the outer area of the inner sprague. It may start normally several times until the next time you have to do this.

This is not a fix, but will get you going when you need it.

 

Frank

[skyrocket]

Hi:

What are the risks (besides falling over) of jumping the motor into reverse?

What goes up comes down. Turn one way and then the other. But the sprague must have some inner springs that object to this treatment?

I don't know the mechanism; Is there a picture of the part exploded somewhere?

Thanks for the unique solution. Sky

[bmwmick]

Here is a pretty good picture: http://tinyurl.com/nrojo OR

http://www.realoem.com/bmw/showparts.do?...hg=11&fg=10

 

Rolling it backwards won't hurt it (unless you fall over).

 

Mick

[skyrocket]

Here is an update: NAPA "CRC" brand FAST MOTOR FLUSH was applied in the following manner. Existing oil was dirty so I just dropped the oil but not the filter. Put in 2 quarts 15W40 cheap oil-- and the full quart of Fast Motor Flush. Push started motor and ran it for about 8-9minutes (label says only run 5 for an automobile engine-but they don't have sprague clutches) and then shut it off.(to drain) The motor did get very hot; enough to start the fan on the radiator.

Tried to start it and at first it just spun. On about the third push on the starter button the sprague locked in and it started.

Just to play safe I ran it another 4-5 minutes, without riding or racing the engine. (The additive is very thin.)

Since then it have been starting AOK.

I dropped the new but now old oil with the additive and added the 20W50. It is still starting so far.

Add NAPA "CRC-Fast Motor Flush" to the home-based Sprague Remedies until someone says I have just blown my seals with the solvents in it. ($4.39 @ automotive parts shop.)

PS-I was too tired to start the cycle when I put the new oil and additive in; the machine sat overnight with the cleaner in the pan, but not circulated. That bike is heavy to push up the grass lawn three times to get it going.

Thanks, Sky

[Bruce C]

Great news!!!

 

You might want to think about adding some "motor flush" just before your next couple of oil changes.

[skyrocket]

The adding of additional cleaner may be a regular thing for the first few oil changes. Maybe in 500 or 700 miles I will change this oil and add a little cleaner for a few minutes of running. However, it seems the sprague is engaging reliably now. Why take the chance thought?

Thanks for all the assistance. Sky