ah yes my first question /story. my 86 k100rs which had not been started for almost year did not start a few weeks ago, after i finally got the front brakes refilled with fluid and holding pressure, more on that at a later date. for any of you who did not read my members intro, i'm trying to learn and understand the mechanical processes at this point, without a lot of prior experience, haha.

so it turns out i've written a short story here ,so i've decided to ask the technical questions up front to hopefully get some answers before anyone dozes off if they continue reading. the story is pretty non technical but might help those less mechanically inclined.

1. I plan to put in a Ford Bronco II fuel pump, what method should i use for any wire adjustments i need to make? Is crimping enough or crimped and soldered, or crimped and taped ? Is there electrical tape that is petrol resistant?

2. On the final drive bolts ,what is the best method for loosening them? The last time i tried to take it off, in order to grease the splines, I could not remove one bolt and did some damage to the bolt. I was using a socket/allen key combo with a breaker bar. Is a torque wrench an option back there, seems like there wasn't enough room as there is? Maybe a propane torch and penetrating oil as well? Should I get the Staburags NBU 30 since I do plan on lubing the clutch splines in the near future to or is there a good alternative for both jobs?


short story starts here. so after talking to the guy who sells me parts and reading the manual i decided to replace the brushes in the starter, put in new NGK dp8ea9r plugs , install a new fuel filter, and replace the cracked crankcase breather tube. while changing the fuel filter i noticed a lot of debris and waxy build in the tank which i cleaned out with hot water, brushes, solvent and compressed air( note i would try to do it all with a rag and solvent in the future as i now have to evaporate off a lot of contaminated water. i also inspected the bottom of the fuel pump and scraped off some thick dark goo at the bottom of the pump . the strainer at the bottom of the pump soon cracked apart at the top and has since been replaced. after getting it all back together and getting the battery charged it would not start, fun. it would turn over but that's it.

so i decided to take a look at the engine gunk that seems to have appeared after the time i bought it and had also been covering the now replaced crankcase breather tube. after some cleaning and bright light i could see one of the rubber bushings that sit above the throttle housing assembly was cracked. after a call to the parts guy this sounded like a reasonable cause of the not starting bit.

. . after cleaning all of the bushings, throttle housing assembly and areas around the intake manifolds i removed the bushings , fuel injectors and the throttle housing assembly. i discovered 3 of the 4 bushings had cracks in them. looking down into the intake manifolds i saw one valve that was not closed like the other 3 were and became worried when someone told me they were all supposed to be closed, i was pretty glad to hear that is normal as each cylinder fires at a different time. i cleaned down into the intake manifolds with a lint free rag and solvent, my shop vac with a small piece of tubing attached to it and compressed air on the 3 valves that were shut, i used the vacuum and rag on the open valve, but no compressed air.

after the new bushings, clamps , and o rings (for the fuel injectors) came i started putting it all back together. it was a tight fit pulling the air mixing chamber, bushings and throttle housing assembly off when i first started and was worried it might be a pain getting it all back on, it was. but really it shouldn't be , put the throttle housing assembly down into the intake manifolds first with the rubber bushings attached (clamps not crimped) and then the air mixing box will slide right over the bushings with minimal effort and no going in at a an angle like i thought i had to do. btw, would the screw tightened clamps work here as well, on the rubber bushings?

cleaned up the fuel injectors and put the new o rings on them and reconnected the fuel rail etc and everything else that had come off as required. went to start it and within 5 attempts, choke wide open, it started up and sounded better than it ever had! i was happy. i rode it for .5 hours and it was running really good.took a coffee break and my brother showed up. he sold it to me a few years ago was visiting during this time and was wishing he could ride it during his visit. although he wasn't prepared at that point to go for a spin he wanted to hear it run. so we go out to the bike and it does not start . it would turn over but that's all.

i started reading starting problems on this forum and decided to take a look at the fuel pump, since it had been sitting in dirty fuel and was also making a lot of noise during the test ride. after advice from the forum,tis , i disconnected the fuel filter and held my thumb over the end of the filter(still in the tank) and tried to start it for a couple sec at a time. there was fuel coming thru the filter but the pressure seemed to be higher the first couple times i tried it. so i assumed there was enough pressure to at least start and reattached the filter. i wish i would have tried to start it back up at that point, as i did three other things at the same time.

i disconnected(the negative on the battery first) the wire that comes off the fuel tank and reconnected it. also disconnected the fuel control unit?(it's right above the battery) and reconnected it. i checked all plugs for spark, and they all had a small white spark and all were white on the tips. they were new plugs with only a .5 hours of riding, should they have turned white in such sort time? all of the old bosch plugs looked normal according to a mechanic. and finally reconnected the battery. after all of that it started up, with the choke wide open.. i started it up 3 times after cutting it off myself each time but did not ride it.

during this time i had left the gas cap unscrewed to the tank and could hear quite a bit of noise coming out of there again so i took the cap off and was shocked to see fuel spraying off the top of the fuel pump, on the side(where it is crimped shut.)

is this normal? everyone i've asked seems to believe otherwise. and so after more time reading the forum about fuel pump alternatives i decided to purchase a Ford Bronco II fuel pump off of feebay and the foam adaptor that is available for 37mm pumps. i'm not sure if i'll need the adapter but i wanted it here incase. the pump has not shown up yet. is a simple crimp enough for any change of adapters i might need to do for the new fuel pump? is there any fuel resistant electrical tape or alternative to keep the fuel pump wires together? i'm hoping this fuel pump works and solves the problem ? ..

this maybe related, two summers ago after going up a steep and twisty road and then down a large hill i had the bike cut out on me and it would not start for about 20 minutes. i do remember the pump making a lot of noise after i was trying to get it started and maybe even continuing to pump after the bike cut out. i then rode it another 15 miles or so in hilly terrain with no issues, got gas rode back the same way and did not have any problems with it doing that since, although i haven't been on it too much since. . ..all for now!

The Bronco pump should be OK.
Crimp the wires in the new connectors dont solder or use any electrical tape.
Those bolts can be difficult to get out, because any long tool is at an angle I use a hex key with an extension to crack them then a ball head hex key to get them the rest of the way.
Heat may work or you may have to use a 10mm drill down the hex hole and drill the head off and replace the bolt. Allways use an antisieze compound on those bolts or any steel bolt that goes into aluminium.
Permatex antisieze is a good product to use but there are many others out there.

Rick is correct on all fronts, and NO the fuel pump should not be squirting fuel out the top around the crimp.......likely someone has been inside the pump before you got it....

The fuel squirts out the top when the O ring is dried out and needs to be replaced.
I settled on using the ford pump because it was easily replaced on the road and its cheap.

thanks guys. i put in the new pump today and will have to wait until the battery charges up before i can try to start it again. the first time i tried today i had the wires reversed(must have been the fumes) and so it did not start. i switched the wires around and confirmed that it was pumping gas(felt like a strong stream), once again with my thumb over the line in the tank but after that the battery sounded weak so i quit for the night.

when i took out the old pump toady i realized i had cut the new strainer basket for the old pump(not sure if it was when i put it in the tank or pulled it out) that goes on the bottom of the pump and that there was also debris inside of the strainer. considering i just spent a great deal of time cleaning the tank out i'm kind of surprised, maybe the debris fell out of the fuel pump? speaking of which does the fuel line that attaches to the basket and then connects to the top of the tank serve any significant purpose? should there be a line going down there even if it is not attached to the strainer basket.

i had to use the foam adapter on the ford pump and i went ahead and put the basket and fuel line on the foamadapter(with a patch for the hole in the strainer from a cut out piece of the old strainer) even though the new pump came with two different strainers, i have the metal one on now.

i have not been able to get the adapter ring to snap down into the bracket(attached to the tank) like it did with the original fuel pump. hopefully it starts tomorrow, will post pics of the new pump soon. cheers

Flip2 wrote:thanks guys. i put in the new pump today and will have to wait until the battery charges up before i can try to start it again. the first time i tried today i had the wires reversed(must have been the fumes) and so it did not start. i switched the wires around and confirmed that it was pumping gas(felt like a strong stream), once again with my thumb over the line in the tank but after that the battery sounded weak so i quit for the night.

when i took out the old pump toady i realized i had cut the new strainer basket for the old pump(not sure if it was when i put it in the tank or pulled it out) that goes on the bottom of the pump and that there was also debris inside of the strainer. considering i just spent a great deal of time cleaning the tank out i'm kind of surprised, maybe the debris fell out of the fuel pump? speaking of which does the fuel line that attaches to the basket and then connects to the top of the tank serve any significant purpose? should there be a line going down there even if it is not attached to the strainer basket.

i had to use the foam adapter on the ford pump and i went ahead and put the basket and fuel line on the foamadapter(with a patch for the hole in the strainer from a cut out piece of the old strainer) even though the new pump came with two different strainers, i have the metal one on now.

i have not been able to get the adapter ring to snap down into the bracket(attached to the tank) like it did with the original fuel pump. hopefully it starts tomorrow, will post pics of the new pump soon. cheers

Use the filter that came with the new pump, you might have to fold it to get it to fit.

If you cant get the adapter ring to snap back rotate it 180 degrees. If you look carefully you will see that one tab is larger then the other. That had me stumped for a while too!

Do you have a new rubber isolator (like the one that turned to goo)......bolted up to the bottom of the white plastic fuel pump mounting ring?
If so.....they are often almost "too" thick to compress far enough to get the second tab on the mounting ring to snap into the aluminum notch in the tank.
I don't have your set up.....because I opted for the OEM style pump and isolator with basket from Euro Motoelectrics. At any rate, I had to get the forward clip down in to the aluminum notch and then try to "roll" the back side of the bracket down in to it's notch. I could not do it with hand power reaching in through the top tank hole at the odd angle. I finally fitted up a stick of wood and wedged it in on the top of the plastic ring and popped the end of the piece of wood gently but with a heavy plastic dead blow hammer. It was enough to compress the rubber just enough to let the latch tab snap in to place. As posted above, the design is similar to the tail light plastic socket it will only go in one way.
I can't speak to the question about the basket hose. I might guess that they added that nipple to sort of "vent" a high area at the top of the basket under the ledge of the pump.......possibly to prevent an occasional cavitation issue from air under the edge of the pump. Someone else may have more accurate ideas. It could also have something to do with allowing the pump to pull up all the fuel when running near empty. My 85rs did not have the hose option.
Good luck, ibj...

The hose was fitted to prevent cavitation which was happening to the early Ks that didnt have the hose. It just goes to the vent and how it prevents the cavitation I don't know but I'm sure that some german engineer thought it absolutely imperitave.

Ok......another stunning mystery SOLVED!
My 85 does not have the hose, so I'll assume that if I ever run the fuel down near the empty place that it'll warn me by surging from cavitation before it decides to just stop altogether and send me walking for a gas can????
I've never run one out before so I have no idea if it stumbles some first or just stops all at once????
Also, My tank (85rs) still has the triangular shaped anti-overfill short extension attached to the bottom of the filler cap assy (but curiously, does not have the spring loaded trap door on it's bottom side, should it?).
Actually, I intentionally put the extension on the cap when I found it missing from the PO.
For me, I just don't need the perceived extended range I can gain by packing the tank with an extra pint of fuel.
I would be curious to know......how much fuel it takes to fill the tank up with that neck extension place from:
#1 the point the 4L light comes on (easy to find out if I just put some attention to it) and:
#2 how much it takes when it finally does run out and stop running.
My options are multiple. I can either throw a quart bottle of fuel in the saddlebag when I think it's close to empty & keep going till I find out or.....I can connect a drain hose & pump it out next time I have the fairings apart.
Tell me what your experiences are as to gallons or Liters as opposed to miles/kilos.
Thanks, ibj...

My K100 was a 1990 model and used to stop and start when very low but some say they just stop dead and others surge.
I didn't have the hose on it the hole was capped with the OEM pump and with the Ford pump it was the same.
I think it depends on the terain you are riding in as the fuel will run to the back of the tank on steep hills and slosh around in the twisties.
BMW is the only place I have heard of the pumps cavitating, they will pick up air when low but not cavitate.

you guys and gals? rock! the new fuel pump has at least enabled the bike to start up multiple times now, although i only have been out on one small test ride, a savings of multiple $$$ for sure. too bad i will have to replace the vibration damper in the future as it has started to get gooey. i think i will also replace the black absorbing pieces on the bracket- does anyone have a good idea for that? maybe a fuel hose cut in half? . . btw the foam adapter was essential to use the smaller pump. . .

i had the bike surge and stop for what seems like 5 minutes at 70mph/140km on a relatively flat highway and luckily made it to the pump :pale: , the low fuel warning light has only come on a couple times since owning the bike. and going back to my story on the steep and twisty hill, at a different time, with seemingly enough gas i had the bike start to cut out while going up said road. i became nervous and since the refueling option was only 15 minutes away i went back and refueled and then went up again with no issues. but from what i remember i did have plenty of gas at the time.

so yeah this is the same hill that the bike climbed and then cut out and wouldn't start for 20 minutes but at that time there was no surging and i was able to ride another 15 miles in hilly terrain with no issues and then got gas.

after seeing the amount of junk in my gas tank recently it's not hard to imagine a steep twisty road disturbing all the sediment and causing the pump to act up.