Bob's 85 K100 Project

[Laitch]

The electronic control holder shouldn't be resting on the battery posts. Inspect the holder; its rubber frame mounts might be missing.

A compact and secure method for attaching the positive and negative cables is to remove the post screws that protrude upward from the battery then attach L-brackets to the battery to receive the battery's ring terminals, or attach the ring terminals with screws directly into the terminal blocks but I would consider this battery ready for recycling. Do you know its history?

The battery's hold-down plate is installed upside down and reversed; that should be corrected.

[bobvans]

The electronic control holder shouldn't be resting on the battery posts. Inspect the holder; its rubber frame mounts might be missing.

A compact and secure method for attaching the positive and negative cables is to remove the post screws that protrude upward from the battery then attach L-brackets to the battery to receive the battery's ring terminals, or attach the ring terminals with screws directly into the terminal blocks but I would consider this battery ready for recycling. Do you know its history?

The battery's hold-down plate is installed upside down and reversed; that should be corrected.

Great observations, Laitch!!

The PO had told me the battery was new and that it was too short for the hold downs so he put a piece of wood underneath it. 

I’ve read of others who flipped over the battery tray because the battery was too short or too tall, can’t remember which.  I’ll get in there and sort that out.

As for the holder sitting on the terminals, that was me... I was trying to get the holder/tray out so that I could see the battery better but It was bumping into the seat support so decided to get the picture from the side.  But in moving the tray around, the round bumper stopper fell out so the tray was sitting lower when I tool the pics.  I was only able to find one of the rubber bumpers but got it back in place.  Not sure the missing one was ever there because I didn’t see that one falling out.  will look a bit more.  May need to get a replacement.

[Laitch]

Raising the battery by use of the wood platform is a better means of stabilizing it than defeating the design of the hold-down. When the moto isn't being used, the battery ground cable should be disconnected from the transmission after the battery has been fully charged; otherwise, the battery needs to be fully charged then maintained on a trickle charger. To do neither will result in a faulty battery.

[bobvans]

Raising the battery by use of the wood platform is a better means of stabilizing it than defeating the design of the hold-down. When the moto isn't being used, the battery ground cable should be disconnected from the transmission after the battery has been fully charged; otherwise, the battery needs to be fully charged then maintained on a trickle charger. To do neither will result in a faulty battery.

That's good to know... thank you!  The bike came with a trickle charger but I've never used it.  Should the moto be on the trickle charger pretty much at all times then?

[billday]

Autozone has a nice assortment of ground cables (including some roll-your-own kits) in their battery department.

Funny story. When I bought my 1985 K100, the ground strap from the battery was connected to the frame under the cross piece that the tank mounts to (again, this is an '85). Many a time I've gazed at that mounting point on the left side of the transmission and wondered what it's there for. Now I know, so thanks, Bob.

[Laitch]

  Should the moto be on the trickle charger pretty much at all times then?

If your charger is the type that shuts down when the battery is fully-charged, then you could leave it connected except when starting and running the engine for maintenance and diagnostic reasons.

[bobvans]

Autozone has a nice assortment of ground cables (including some roll-your-own kits) in their battery department.

Funny story. When I bought my 1985 K100, the ground strap from the battery was connected to the frame under the cross piece that the tank mounts to (again, this is an '85). Many a time I've gazed at that mounting point on the left side of the transmission and wondered what it's there for. Now I know, so thanks, Bob.

Glad someone was able to learn something from my trials and tribulation posts 

I'm hoping the improved ground I get will fix my speedometer problem.  The needle bounces around quite a bit.  I must say that it didn't do this until after I switched my handlebars but I don't see how the two can be related.  Actually, the other thing I did was add the heated grips but can't see how that would affect the speedometer either.  I tried cleaning the fuses and spraying with deoxit like some recommended... the fluctuations may have gotten a little smaller but it's still fluctuating.

[Martin]

Bob speedo needle bounce can be cause by a dirty speedo sensor at the final drive or a dirty connection where the sensor plugs into the harness.
Regards Martin.

[bobvans]

Bob speedo needle bounce can be cause by a dirty speedo sensor at the final drive or a dirty connection where the sensor plugs into the harness.
Regards Martin.

I'll take a look at that, thank you!  Also read cleaning the 3 pronged connection inside the instrument cluster has fixed this issue for others.  I'll try the easy things first. 

[bobvans]

I think I got the speedo fixed.  Took the sensor off the final drive and it looked fine.  Just wiped it off and put it back on.  I sprayed a little deoxit into the connector and plugged/unplugged it a few times.  Started the engine and put her in gear on the center stand.  Ran it up thru a few of the gears but the speedo was still fluctuating.  One observation was it seemed the connector mated almost too easy.  So I twisted the spade ends of the connector a bit and mated it back up.  Ran it up thru a few gears and this time the speedo was nice and steady.  Not sure why it started fluctuating to begin with other than the stacking of high resistance interconnects in the circuit.  Regardless, she's fixed!

[Martin]

 

[bobvans]

A couple of pics...


IMG_1804.JPG (68.36 kB . 768x576 - viewed 448 times)


IMG_1806.JPG (59.46 kB . 768x576 - viewed 505 times)

[bobvans]

Dang it!  Speedo is fluctuating again!  It was rock solid earlier in the day and started fluctuating again when I went for a short ride.

[Martin]

Try tweaking it again at the plug and if that works go buy a waterproof two pin plug.
Regards Martin.

[Laitch]

Considering that relic looked like it had been pulled from a moldy hay mow, consider disconnecting the plug from the speedometer itself, cleaning all the connections and checking their tightness, too.

[bobvans]

Try tweaking it again at the plug and if that works go buy a waterproof two pin plug.
Regards Martin.

Thanks, Martin... I'll give that a try this morning.  The bike did get rained on a few days ago and I drove home on wet roads.  I was also thinking that if the connection is loose that it may have just vibrated to a point where it wasn't making good contact again.  Will give an update tonight.

[bobvans]

Considering that relic looked like it had been pulled from a moldy hay mow, consider disconnecting the plug from the speedometer itself, cleaning all the connections and checking their tightness, too.

Ha ha... yea, that blue bike is in not so good shape.  It's actually been preventing me from wanting to work on it.  That and the garage has been cold.  Plus I've been wanting to ride the red bike (this is the one with the fluctuating speedo) every chance I can get.  Excuses, excuses 

[billday]

Bob, after 1985 they made some major improvements to the instrument box -- went from 7 screws to 9 holding it together, and added a couple of circular vents on the back with fabric "screens" that supposedly let moisture out but not in. Thanks to the Kafe Kraze, later-model bread boxes are available and relatively cheap. You might want to consider finding yourself a replacement.

[Laitch]

Plus I've been wanting to ride the red bike (this is the one with the fluctuating speedo) every chance I can get. \

Please put the red moto's year and model in your Profile's Bikes: list, too. Consider posting about your work on the red bike in a separate thread within Motobrick Workshop so you don't confuse the chemically/hormone distracted or elderly here. That might be just about everybody. 

[alabrew]

and added a couple of circular vents on the back with fabric "screens" that supposedly let moisture out but not in.

They were Gore-Tex. You can buy small Gore-Tex patch kits at camping stores to make new ones.

[bobvans]

Thanks, Martin... I'll give that a try this morning.  The bike did get rained on a few days ago and I drove home on wet roads.  I was also thinking that if the connection is loose that it may have just vibrated to a point where it wasn't making good contact again.  Will give an update tonight.

Tried wiggling things around but no improvement.  Took the female terminals out and crimped the ends closed a bit to better mate with the male ends.  It was a bit tough to mate the two but I'm pretty confident they're making good contact.  Still no  improvement.  Has me wondering if I have a bad wire.  I'm going to try swapping out the pick up sensor from the blue bike to see if there's any difference.  I've also read where people have fixed this by tightening the interconnect inside the cluster.  I want to calibrate the speedo so will have it open and can try that then.  In the mean time, I'll try a few other things.

[bobvans]

Please put the red moto's year and model in your Profile's Bikes: list, too. Consider posting about your work on the red bike in a separate thread within Motobrick Workshop so you don't confuse the chemically/hormone distracted or elderly here. That might be just about everybody. 

Yea, I was thinking of that myself.  I'll post more specific topics like "fluctuating Speedo" or something.  Thanks for the suggestion!

[bobvans]

Bob, after 1985 they made some major improvements to the instrument box -- went from 7 screws to 9 holding it together, and added a couple of circular vents on the back with fabric "screens" that supposedly let moisture out but not in. Thanks to the Kafe Kraze, later-model bread boxes are available and relatively cheap. You might want to consider finding yourself a replacement.

That's a really good suggestion!  I'm a big fan of changes that lead to improvements. I could even try the cluster on the blue bike.  Thanks for the idea!

[volador]

FYI some speedo units have flat pin connector and some have round pin connector

[Skunky]

Just a thought. Have you disconnected cleaned and refitted the ground cables under the tank. They tend to get mucky and a little rusty and then all sorts of weird stuff happens (like fluctuating speedos).