fatallightning said:
In reply to 03Panther :
There's a, I think, 3 wire connector thats known to vibe loose/get weird. It's the one under the tank. A lot of people replace them with trailer light connectors.
Exactly the one! I did not know that was a commonly known thing. Freaked me out the first time it happened... late at night, in the middle of nowhere on some back roads, and EVERYTHING just quit! Fortunately, I had mistakenly left the key on while I was removing stuff to get in to where I could do some real troubleshooting - and the lights cam on. Made it home, and checked till I found the culprit. Cleaned connections and assembled best able, but would still go out randomly. After about the 5 0r 6 times, I just hard wired that wire!
Ok. Lovin' the "new" triple. But now I have a really odd question, I could not ask anywhere but here...
the stock 3 cyl 740cc engine had 3 throttle body's, 3 injectors and a common fuel rail. Someone on here might be familiar enough with the Beemer K bikes to say what kinda FI it is. But I'm an old carb guy. Only thing I know about this system, is I've never needed to know anything!
From the factory, it is tuned for I think 67 or 69 hp.
Some folks have said, two up, with luggage, in the Rockys, they would have liked a little more power
I'll never need as much as it has, since I'm an old fuddy duddy these days anyway
Anybody have any thoughts on how to tune this engine for a lot better mpg - even at cost of power? At 40 - 45, it's not bad, considering the power it does have, but I've had a bunch of bikes, of many sizes, do a bunch better.
I've only managed to bother with getting all the gear on for the ride to work 5 times now, but am enjoying it when I do. I found and ordered new "hinges" for the panniers (saddle bags, to the american riders), but have not gotten them installed, yet. Its just s strip of rubber, molded in such a way to slide in a groove in each half, and flex so the bag can open. I've had one come apart in the past, so for now I just have a strap holding both lids shut. Kinda cheesy looking, but it works. The BMW latches, are typical Bavarian engineered - high tech, and kinda cool; but a bit fussy.
Was hoping for some thought on changing tuning, but I guess GRM likes their bikes stock and trouble free, so they can play with their cars. Most of the riders on here prolly ride a 'scoot cause they are fun, not because their as cheap as me!
I did find a link to RussEFI; he did a BMW K bike with his own version of megasqurit, but that has been quite some time ago.
I had a flat silver HJC helmet, but the tote with all the bike gear came off the RV on the way to a job one Sunday. By the time I got turned around and back to it, someone had stopped and adopted about a grand in bike gear for themselves. Coming through MD, we saw a HD dealer open for an event, and was able to replace most of it with stuff off their clearance rack. The flat black HJC with the HD logo, was all they had, that I could afford. I have some reflective tape on it now, since riding home at 1am! I like the jacket, with the reflective piping, better than the one it replaced, and have a lot of miles on a bunch of HD's to be allowed to have a HD logo jacket on a BMW. The old school bikers don't give a rip, the RUB's don't matter to me at all, and the BMW guys that have tried to be offensive, just get laughed at. 
Imagine, grown azz men acting a fool like that!
So a quick google search shows these ran Bosch LE-Jetronic for the fuel injection which is similar to what was used in the cars at the same time. Typically to tune these there is an Eprom chip inside the ECU that needs to be burnt (reprogrammed) with the new parameters. On the car side where I am more familiar I know earlier cars had that chip soldered onto the board so you really couldn't do anything unless you really really wanted to. A quick search for a K75S performance chip shows up a couple of results for units that wire in between sensors and the ECU, this doesn't reprogram anything but rather tricks the ECU into thinking things are different than they are so its output are different and hopefully has a performance benefit, not great. That tells me there isn't a simple way to just plug and play with a chip for these.
What can be done is to screw around with the ignition timing of the bike as well as the air flow meters and see what can be done but I'll leave that research to you. I think your time would be better spent base-lining the bike though and making sure everything is exactly in spec (valve adjustments etc.) and seeing where that gets you.
The other option is something like a megasquirt or microsquirt but that is a big project, I'd just enjoy the bike.
In reply to adam525i :
Thanks a bunch for the info.! I was/am kinda sorta familiar with some of that, from reading about the K's since I bought the first one in 03 or so. But nice to have it laid out in one consice post, with nice concise wording.
the "new" bike will not get modded at all, beyond bars/Aeroflow windscreen.
IF, and that's a big if, I decide to pull the "old" bike out of the hole in the woods it has "sank" into, it would be the one I would try to eek the most mpg I could out of. The old bike is a 1988 I bought years ago with 33 K hard life miles and neglect. The new bike is a 1987 with 53K normal miles, with adequate maintenance 
was outside, sitting on the rack on the back of the 5th wheel we traveled in, non running for 2 or three years. Then inside a dirt floor pole barn for 4 or 5, and now, out in the woods for about 2. Deteriorated more inside the pole barn (damp floor and humidity) than outside. While at barn I had started taking it apart, to do some mods to the tank to add a petcock, and external fuel pump, but someone came in that, apparently thought they needed the tank and other parts more than me!
So she's kinda a sad case!
The engine/trans/rear/suspension and brakes are all sound. Needs injectors, and a tank. But can buy a complete rough shape bike for the cost of just the tank!
First failure. No biggie, but inconvenient timing.
Rode to work Friday. Stopped for gas at the station near work that carries non ethanol. Due to rationing, the pump would not take my card, and I didn't have time to run inside, so I figured I'd run out during lunch. But they close at 9, and I didn't get the chance to slip out by then. We keep a can around for small engines, so I purist a bit of that in, and figured I'd stop at the place near the house, that leave the pumps on after hours.
Made it there on fumes, but, could not get tank to unlock; just spin...
Woke my wife up, came back in am and broke the lid off... Picture of parts bike shows the spare sitting there..
Was already recoverable ever the tank grew legs!
But I forgot to grab it on way out the yard. Figured I'd see if I could get cyl. out without damaging anything... Nope. Went back for spare part...only the lid! Part I need is not bolted to the inside of it.
Found a used one on the bay of fleas - will be here Fri.
Itching to ride, but it worked out ok.
Time to start a modification!
Apparently, the used one I tried to order, was the last existing one in the US! They sent an apologetic note, saying they had inadvertently re-listed it after selling it locally. Ops. Looking again... Found one in Canada, but 259.99 is a bit high. Would have to work out exchange difference if it wasn't 5 times what I'd pay, but that's high enough I won't bother!!!
A mod some distance riders have done in the past, is to put a 1" spacer under the cap assembly; raises the assembly for room for a lot more fuel.
I'll pick up an aircraft cap, Trick custom stuff, make an adaptor ring, and be set!
That's the ring a guy built to space the stock cap/lid/door up one inch, to keep the cap from being resesed into the tank so far, and add more fuel.
I figure same OD, 1/2" tall, flush screws for the 4 bolt pattern, and drill and tap the aluminum adaptor to the aircraft cap.
Since Sketchup is the only 3D modeling software I can do anything at all with, Here is the "plan" for my adaptor ring. And since all of my drafting classes were over 35 yr ago, I'm sure I didn't make my dimensioning quite correctly. And Sketchup does not do circles very well! Or, at the least, I don't know how! (100% self taught)
I exported it, opened in "paint" and added the dimensions and notes.
If anyone wants to do that as a better looking drawing I can give a local machinist, I'd love the help.
I'm gonna also post this in the recent cad thread, in case it gets better exposure there.
Sadly, I did not manage to get my revised sketch for the adaptor ring off to the friend of a friend to make for me till this am. On the good news front, the new airplane gas cap came in and it is AWESOME! Gonna look great, when the adaptor finally gets here.
Got the adaptor ring from the machinist. Still had to tap the 4 holes and modify one hole as a internal vent. And transfer and drill the Aircraft cap.
I cut a teflon gasket for it. In retrospect, I should have added an o-ring groove to it, but it was expensive enough so far as it is! The black sharpie did a decent enough job making the sides of the adaptor black, but would not darken the teflon. Any thought on how to make teflon black? The first one became the practice piece, when it didn't go well.
The bubbled paint for previous gas spills, did not hold up well to my messing with that area - no surprise. Common problem with the stock fuel cap setup. This will fill much easier. My other K had that as well, and had less than 15,000 miles on the clock when I bought her. Other than that spot, the paint the BMW Motorcycle division had paint in the 80's that was some seriously tough stuff! I planed on a black decal to apply there, and will have to draw one out for this bike. Should blend in nicely with the new black adaptor.
I will get the tank removed and cleaned out, and make sure a particular ven mod has already been done. if not, I have what I need from the old K-Bike.
Got it running, just in time for work to roll me to days for two weeks... I set in the ac for lunch on nights, but with "all" the crowds (all three of them - too many people for me) on days, I go sit in the car for lunch. Might tough it out and and deal with 'em and a ride a few days anyway.
Things got very crazy during my short stint on days; and since I wasn't there to cover problems on nights, I ended up getting called back in a lot. Haven't even gotten any honey doo's done, much less finish cleaning out the tank insides and putting it back together well new rubber hoses, filter, ect. This week back on nights, I've been called back in 1/2 hr after I clocked out twice for stuff. But I am not on call this week end, so I hope I'll get to it. Ready to be ridin' to work again!
Normally as much OT as I've had, I could put some of that extra into the bike, but we had some unplanned expenditures come up... Oh well, we'd have been in really bad shape if I had not gotten to work the OT! I have not been cutting things this fine since I was a young man, and even then, I knew I could cut back on the partys, and be ok. I can't cut anything back now. But hey! I also found out I'm getting my cost of living raise next week. That 1% will make up for the current high cost of... oh, wait....
Anyway, back to bikes, looking at her closer, she's had a respray; shame since BMW factory paint on these K's was SO tough. They did match the stock color, and did a great job, but it is showing its age.
I hope I can get a friend to bring his mini-ex over to lift my parts bike out of its hole in the woods. It has a few pieces on it I would like on my "new" one. A bit of elbow grease will prevent me from having to spend money for those bits!
Only ridden the 87 to work a few times. Put a taller Aeroflow wind screen on. It's ok, but I still want more faring. So....
after much looking, I found an RS parts bike at a price even a guy as broke as me could do!
So I left for Atlanta at 8pm, and am headed back home with her.
Ill get back (hopefully) just in time to help my wife take one of our furry kids to the vet. I'll get to sleep good Tuesday. I'm gettin' to old for this.
but some things are worth it.
"old" 88 parts bike. I found a good deal on a tank, with a good stock cap (now apparently made of unobtainium) so the cap will go on the 87 K75S, to be sold. All the red tank, faring etc. from new parts bike goes on 88, to ride to work... hiding behind a faring.
I never did get a legit offer over $1800, and non of the trades quite worked out. So looks like I'm keeping the 87 K75S. On a job only 13 miles from the house now, so I don't need more faring to hide behind... at least till winter!
I am adding a top box, so I painted one of my other tail sections that already had mounting holes. Paint doesn't quite match, so I added some black "highlights " to make it less obvious - and hide some defects.
Still gotta do a better job on the clear coat, and put it back together. After a deep cleaning!
And finish the box install
Do you have already have a top case? I have a K75 Vario top case.
In reply to fatallightning :
I sorta have two... a small givi made for an F650, and a very nice case from a newer boxer. Either requires mods to mount (but doable) but the larger box is a blue, in nice shape!
Not sure what the vario for a K75 actually looks like, but I am definitely interested. Thanks.
You would need the stock luggage rack thing, it mounts to that.
Oh yea. That's the box! Didn't know that was a vario!
I have the stock luggage rack... somewhere! It's what was on the tail I painted, before I modified a givi mount on the previous K.
No clue how much shipping for that would be these days, but as I'm in no hurry a GRM express might work, as well. How much would ya want for it?
IIRC, a full helmet will not quite fit in that one?
