Replacing Output Shaft Anti Backlash Sping

[Vespa no more]

How long will it take me to replace the spring?
Can I do it with the motor in the frame, bike on stand and the rear section (ie working my way in from the rear of the bike) removed?

1984 K100RT.

Have just received the spring and timing chain kit from UK (motoworks) - cheaper than Australian prices. According to local BMW dealer, the spring for this bike is not available! 3 pounds from England.
I know I can up the idle speed and maybe eliminate the noise. i know I can ignore it. However, I don't like noises in machinery if I can fix them. If done the only problem will be a non working speedo. Everything else done... brakes, rear brake disc, ALL fluids, battery, alternator rubbers (twice!) etc etc. Ready for the road after absence of 8 years.

Just the issue of the spring...

Happy riding.

Guy Francis
Wollongong NSW Australia

[The Mighty Gryphon]

I have just done mine, and didn't find the problem in the backlash gear, but in a bad alternator drive dog support bearing and in the fit of the output shaft to the idler gear. 

I don't think you can do the job without dropping the engine out of the frame.  You need to remove the bottom half of the crankcase, and then get into the shaft and the gears.  You also need to remove the intermediate housing to check the starter gears and the alternator drive.  I suppose you could get the job done in the frame, but the working conditions would make me leery of the quality of the final job.

I am still working on mine.  Next task is getting the engine back in the frame.  So far I have been working on this job for about 4 weeks on and off.  Seems I keep finding another part or two that I need to order, and I did a lot of cleaning and painting on the frame and engine parts.  I would guess that if you have everything you need at hand and can work straight through you should be able to get it done in three uninterrupted days. 

The biggest pain in the ass seems to be the fairing and the damn ABS.  Job would be pretty easy without that stuff. 

[Vespa no more]

thanks for the reply

3 days! I am hoping to get the bike on the road asap. My friend is hassling me to go riding with him. And I've got two weeks holidays without the family at home. If I can ignore it for now I will. I have the back end off and am about to receive new rear brake disc and do timing chain.

Question to anyone out there: what is the recommended replacement mileage / kms for the timing chain? (K100RT 1984 107K KMS) I've got a brand new timing chain kit on the bench and was recently in there cleaning the tensioner etc. Timing chain is not noisey but general engine noise is not insignificant (I suspect it is the anti backlash spring)

My concern is that if I drop the engine then I will be far enough "up the tree" to keeping going and do everything - including bead blasting the engine etc, painting the frame and fairings. And then it might be another year before she's back on the road.

I have removed the fairing - not that hard (one of the first things I did). I would say less than 2 hours will have it all out of the way. A lot of little screws and bolts to keep well organised and labelled. Maybe clip a Go Pro to your head and create a running narrative / commentary. I would like to keep the fairing off mine while for a few months to keep an eye on everything.

My garage is a pokey, dirty little affair and, having heard of a K100 for $500 (how do i account for that too the wife?) might get more cramped. Am impressed with your efforts - keep at it while you are still in winter (USA I assume) and are in the groove.

Ahhhh ... ignore it for now it is and "monitor progress"

Happy riding

Regards

Guy

[The Mighty Gryphon]

My K75RT has been clanking and growling for the 20,000 miles I've owned it.  All the usual fixes like the timing chain and the monkey nutz had no effect. 

As I mentioned, I found the backlash spring and the gear are perfect.  There was pretty bad wear in the starter gear teeth,  the bearing that supports the alternator drive dog was pretty rough and the shim on the countershaft was missing allowing the dog to wobble, banging around inside the alternator clutch.  Also found that the balancer shaft looked like it was loose and banging around a bit.

The only problem I had in all those miles of listening to all that cacophony was having the splines torn out of the alternator drive dog.  That causes the alternator to stop making electricity.  Took about an hour to replace the worn dog.

With winter coming, what you get of it, I would wait to tear into your brick.  For now, ride the heck out of it.

[Vespa no more]

When I likened the decision as "putting stitches in an arm versus amputation", my wife (neither mechanically minded nor interested) told me to keep going and pull it all apart.

No, I'll take your advice and get it ready to ride.

When I take it off the road this winter I will probably do the lot - respray and bead blast the aluminium (aust spelling). I've seen another owners site where they have pulled the motor apart and will copy their wooden boxes and saw horses.

Will keep a record of progress.

Regards

GF

Any idea of timing chain replacement schedule? eg 100,000 km / 60 000 miles?

[Martin]

I've got over 150,000 K's no timing chain problem, however it can depend a lot on how the bike was ridden and maintained.
Regards Martin.

[The Mighty Gryphon]

At 65,000 miles I bought a new timing chain and a full set of guides and tensioners in an attempt to quiet down the cacaphony of noise my K75 made.  Upon disassembly I found I couldn't tell the old parts from the new.  Put them in anyway and saved the old parts. 

Last winter I went into my K100 and at 110,000 miles I figured I could use the unworn parts from the K75.  Nope, the only thing that showed any wear was the chain itself which I replaced with the one from the K75.  So here I am after checking two bikes I still have a complete set of good guides and a tensioner.

Bottom line, don't spend a bunch of money on timing chain parts until you know the old ones are really worn. 

[Vespa no more]

It had to happen

Spent Sunday morning putting everything back on the bike (rear end basically). Even used the torque wrench Decided to get the unnecessary crap off the keys, cleaned up and wiped the bike down after some work. Things were going great when...

Went to turn on...Nothing. Checked the fuses and top 7.5 amp fuse was blown. Didn't have a spare. Had something to eat and drink. Went to the auto shop and the local hardware (wood for a stand for the back of the bike ... need to remove the centre stand (welded the repaired leg at the wrong angle and it hits the muffler!)).

Fuse into the bike, dielectric grease etc etc. Went to turn on and ... no key.

Looked high and low ... it's out there. Even a reward for the family didn't find it.

So will need to get new keys cut. How the hell do you remove the barrel to take it into the locksmith? I have removed the crash pad and the dashboard / instruments but can't release the clip. Any suggestions greatly appreciated. Will also post this under lost keys.

And let this be a warning to the rest of you...

[Laitch]

You're burying your problem in an unrelated thread, Vespa. You should start a thread devoted to your situation, and your situation is unclear to me. Can you not turn your key in the ignition switch or can you not disassemble your ignition switch after checking all your electrical connectors because you're trying to trace a power failure after reassembling your bike and you want to clean the ignition switch? If it's the second choice, there's an ignition switch disassembly procedure the Technical Library card catalog of the Workshop. A different problem, perhaps—I haven't had my first cup of coffee yet.

[The Mighty Gryphon]

Can you lift your seat?  If so, you can remove the seat/helmet lock.  It should be keyed the same as the ignition.   It's held in with two screws.  then you can take that to the locksmith.

Another option would be to remove the fuel tank to take the fuel cap which should also have the same key.

[Laitch]

I understand now—gremlins.

[Scott_]

I think the fuel cap would be the easiest to take to the locksmith......

[The Mighty Gryphon]

Can't get the fuel cap off without unlocking it.  Seat lock is the way I would go.  Most people don't lock it.   Especially if he has been working on the bike.

[Scott_]

Can't get the fuel cap off without unlocking it. 

Dohhh!!
Note to self, be fully awake before posting......

[The Mighty Gryphon]

Don't feel bad Scott, that was my first thought as well.  Almost hit the post button before I realized you can't get to the screws with the cap down.

[Martin]

Just a suggestion always have more than one key. When I get a new vehicle it's one of the first things I do. I have one set in the garage and a spare hidden on the bike that actually requires a screw driver to access. It can save lots of cursing and time.
Regards Martin.

[mw074]

I always Gorilla tape a spare key on the inside of the battery cover. Haven't needed it but if it wasn't there I probably would have.

[Vespa no more]

Thanks for the replies.

Have two keys ready to go - collecting tomorrow morning ... $35 via local locksmith
The BMW dealer told me two weeks from Germany if VIN was to be used.

Because I had the fairing off and the ignition was laughing at me, I took the crash pad off and released the ignition. After some phaffing around trying to lever out the barrel (from the plastic surround) I got back online and found a thread regarding replacement keys. Found the answer via a K1100 post ... in the little hole under the red paint hides a little screw. It was all so easy in hindsight - isn't everything.

So back together tomorrow and turn the new key and ... well ... we'll see. If all goes well fairing back on and off to register.

thanks again.

PS  yeah should have gone with the seat lock. But where's the challenge in that?

[Laitch]

Good work, Vnm! Calvin Coolidge would be pleased.

[Laitch]

You can always gently clean the switch while apart if it needs it. They often do.

[The Mighty Gryphon]

Excellent point Laitch!  There has been a few dirty ignition switch problems lately.  A good preventive cleaning while it's out is a good idea.  I's hate to have to do it in the parking lot at work, or worse, a couple hundred miles from home.