k100 starter

phonetrouble · 11-03-2009, 01:36 PM

I looked through the forums and can't find an answer to this one, but here goes...

I have acquired this 1985 K100, it is a build and learn experience so far. I got all ready to start it up after changing all the fluids and such, new battery, everything back in place as best I can tell.
I left the plugs out, and put it in gear, rotated the rear wheel to make sure the thing was free and not froze, as it hasn't been running in about 5 years. It has been in a garage, so no visible damage from the weather.
I turn on the key, all the indicators lights light up, neutral and so forth. I hit the starter, and it spins, but doesn't engage. I can see that the alternator is turning and the rear wheel, creeps a little, but the gears don't engage.
Am I gonna have to take the engine out of the frame to get to the gears to free them up? Or is there an easier way to do all this.
Also, I don't hear the fuel pump running in the tank with about 1/4 tank of gas...

deilenberger · 11-03-2009, 02:21 PM

When you say you can see the rear wheel turning, that indicates to me that the starter IS connecting to the engine and is turning it over.

If you're expecting a gear-solenoid-bendix sort of noise, you won't get it on a K brick engine. The starter is a high speed motor that engages through a one-way centrifical clutch called a "sprag clutch" - located inside the engine. If you just get a high-speed whine - and the pistons aren't moving - then you're correct - the starter isn't connecting to the engine.

See: http://www.realoem.com/bmw/showparts...82&hg=11&fg=10 - the part they call "ring" and "free wheel cage" are the bits that make up the sprag clutch. The clutch may not engage if it has (1) gotten gunked up from use of inferior oil or not changing the oil (2) been sitting for a long time and rusted up.

People have reported being able to squirt some cleaner into the clutch assembly and free it up fixing #1. I suspect that won't be the case for yours, but we can hope. I rather suspect sitting for 5 years may have allowed all the oil to drain off the clutch "dogs" and they may have rusted up just from moisture in the air.

You can remove the intermediate housing from the engine block with the engine in the bike (after removing the transmission and driveline) - but I suspect it would be much simpler to do with the engine out of the bike (actually - the bike removed from the engine is how it's usually done.)

It's also not too big a surprise to hear the fuel pump isn't operating. I'm guessing the bike was left with fuel in the tank? After 5 years - it turned the fuel pump mount to sludge, and probably the fuel pump to junk. Rather common problem with K bikes that sit too long.

For lots of good K bike tech - I'd suggest the IBMWR website (www.ibmwr.org) and look under K-tech section. There are some postings addressing starter problems and possible fixes.

Good luck and let us know how you make out with it.

BTW - I'm going to remove your other posting on this problem from the other thread so people don't get confused..

phonetrouble · 11-03-2009, 02:36 PM

I suspected the fuel pump would be toast, as I got a bunch of bad gas out of it. I have the chilton manual so will be using that to disassemble and proceed!

hhshort · 11-03-2009, 07:12 PM

If the alternater is turning. The engine is turning, the starter is working.

deilenberger · 11-03-2009, 09:41 PM

Quote:

Originally Posted by hhshort

If the alternater is turning. The engine is turning, the starter is working.

That was my immediate thought also - why I asked if the pistons were moving in-out (and certainly the rear wheel turning is a large clue that the starter is probably working.)

phonetrouble · 11-09-2009, 04:23 AM

The movement of the rear wheel is similar to a sympathetic movement, there is no solid momentum. I can gently hold my hand on it and it stops.
I have the plugs out, and put a dowel rod in the cylinders and none of them move.

I can rotate the rear wheel by hand and transmission in 5th gear, the engine turns over, so I know it isn't locked up.

I had the thought that once the fuel pump is back in order, I will push start the bike and hope that motor oil will get to the starter clutch and lube it up enough to allow it to break free.

roncooper · 11-09-2009, 07:03 AM

Put it in gear and turn the wheel backwards. This might free the starter clutch up.

deilenberger · 11-10-2009, 06:11 PM

Quote:

Originally Posted by phonetrouble

I had the thought that once the fuel pump is back in order, I will push start the bike and hope that motor oil will get to the starter clutch and lube it up enough to allow it to break free.

A reasonable thing to try - I've done it. Visit your friendly auto parts place, and look for either Rislone engine treatment (Paul G's fav) or CD-2 Oil DETERGENT (my favorite.) Also fill up the fuel tank.

Since your sprag is stuck - dump the whole can in (and don't worry about getting the oil level too high - even an extra pint or so isn't going to harm anything..)

Then bump start the engine (and it can be done - BTDT).. hit the starter button as you're bumped since that gives a richer mix for easier starting even if the starter doesn't engage the engine.

Once started - don't stop it. Run though the entire tank of fuel. Go for a LONG ride. Plan on a 150-180 mile ride. Make sure the end of the ride is back in your garage.

That MIGHT free it up if it's gummed up. If the sprag-dogs have rusted, not so likely, but certainly worth the effort to try.

Once it goes get to working - change the oil.

PHMarvin · 11-11-2009, 02:34 PM

Quote:

Originally Posted by deilenberger

That MIGHT free it up if it's gummed up. If the sprag-dogs have rusted, not so likely, but certainly worth the effort to try.

Once it goes get to working - change the oil.

Hi, Phonetrouble,
And if I can add to Don's post, change the oil and use a good oil high in ZDDP. This does NOT mean Castrol GTX! Use a synthetic or dino motorcycle oil, SG grade. Mobil 1, Valvoline, Spectro, Castrol, etc. make and market motorcycle oils. Once your sprag clutch is free and working properly, and does so for a few thousand miles, you might then decide to use the Mobil 1 15w50 synthetic car oil, any number of 15w40 diesel oils, etc., but first use the motorcycle oil once the sprag clutch is working, to make sure it stays working.

11-03-2009, 02:21 PM	#2
deilenberger A bozo on the bus Join Date: Mar 2003 Location: Spring Lake NJ, USA Posts: 3,840	When you say you can see the rear wheel turning, that indicates to me that the starter IS connecting to the engine and is turning it over. If you're expecting a gear-solenoid-bendix sort of noise, you won't get it on a K brick engine. The starter is a high speed motor that engages through a one-way centrifical clutch called a "sprag clutch" - located inside the engine. If you just get a high-speed whine - and the pistons aren't moving - then you're correct - the starter isn't connecting to the engine. See: http://www.realoem.com/bmw/showparts...82&hg=11&fg=10 - the part they call "ring" and "free wheel cage" are the bits that make up the sprag clutch. The clutch may not engage if it has (1) gotten gunked up from use of inferior oil or not changing the oil (2) been sitting for a long time and rusted up. People have reported being able to squirt some cleaner into the clutch assembly and free it up fixing #1. I suspect that won't be the case for yours, but we can hope. I rather suspect sitting for 5 years may have allowed all the oil to drain off the clutch "dogs" and they may have rusted up just from moisture in the air. You can remove the intermediate housing from the engine block with the engine in the bike (after removing the transmission and driveline) - but I suspect it would be much simpler to do with the engine out of the bike (actually - the bike removed from the engine is how it's usually done.) It's also not too big a surprise to hear the fuel pump isn't operating. I'm guessing the bike was left with fuel in the tank? After 5 years - it turned the fuel pump mount to sludge, and probably the fuel pump to junk. Rather common problem with K bikes that sit too long. For lots of good K bike tech - I'd suggest the IBMWR website (www.ibmwr.org) and look under K-tech section. There are some postings addressing starter problems and possible fixes. Good luck and let us know how you make out with it. BTW - I'm going to remove your other posting on this problem from the other thread so people don't get confused.. __________________ Don Eilenberger, MOA Ambassador - http://www.eilenberger.net Spring Lk Heights NJ - NJ Shore BMW Riders Ex-lotsa beemers, '07 R1200R (current ride) and some bimmers..

11-03-2009, 02:36 PM	#3
phonetrouble Registered User Join Date: Oct 2009 Posts: 5	thx for the info I suspected the fuel pump would be toast, as I got a bunch of bad gas out of it. I have the chilton manual so will be using that to disassemble and proceed!

11-03-2009, 07:12 PM	#4
hhshort Registered User Join Date: Apr 2005 Location: Kansas Posts: 90	Alternater turning? If the alternater is turning. The engine is turning, the starter is working. __________________ Harold In Kansas 1985 K100RT Bullit 1985 K100XX/EML Bemel

11-09-2009, 04:23 AM	#6
phonetrouble Registered User Join Date: Oct 2009 Posts: 5	rear wheel The movement of the rear wheel is similar to a sympathetic movement, there is no solid momentum. I can gently hold my hand on it and it stops. I have the plugs out, and put a dowel rod in the cylinders and none of them move. I can rotate the rear wheel by hand and transmission in 5th gear, the engine turns over, so I know it isn't locked up. I had the thought that once the fuel pump is back in order, I will push start the bike and hope that motor oil will get to the starter clutch and lube it up enough to allow it to break free.

11-09-2009, 07:03 AM	#7
roncooper Registered User Join Date: Mar 2008 Location: Belton Tx Posts: 108	Put it in gear and turn the wheel backwards. This might free the starter clutch up. __________________ Ron 91 K75RT

11-03-2009, 01:36 PM	#1
phonetrouble Registered User Join Date: Oct 2009 Posts: 5	k100 starter I looked through the forums and can't find an answer to this one, but here goes... I have acquired this 1985 K100, it is a build and learn experience so far. I got all ready to start it up after changing all the fluids and such, new battery, everything back in place as best I can tell. I left the plugs out, and put it in gear, rotated the rear wheel to make sure the thing was free and not froze, as it hasn't been running in about 5 years. It has been in a garage, so no visible damage from the weather. I turn on the key, all the indicators lights light up, neutral and so forth. I hit the starter, and it spins, but doesn't engage. I can see that the alternator is turning and the rear wheel, creeps a little, but the gears don't engage. Am I gonna have to take the engine out of the frame to get to the gears to free them up? Or is there an easier way to do all this. Also, I don't hear the fuel pump running in the tank with about 1/4 tank of gas...