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"New" old K75 in the stable

GregFeeler said:
Techron rocks! I always use Chevron gas, and now Texaco has Techron. I also run a tank treated richly with the Techron additive before every oil change. I've done this on all my vehicles (cars & bikes) for many years and I just never have fuel system problems. :thumb :thumb
Click to expand...

I have wondered about who's gas has the additive...we have a large gasoline terminal east of town, and we were replacing utility poles nearby one afternoon. An Exxon, Texaco, Shell, Diamond Shamrock, then a Citgo tanker ALL pulled in to same bay as we worked. There is a large gasoline producing refinery in the Texas City complex 300 miles away that produces for several brand names. ...Trying to remember the name, Marathon maybe. It is not one of the biggies. I worked for Exxon in the early 70's, and know they also refine gas at some of their facilities as do the others, but makes you go HMMMMM?
 
Fuel Regulator Valve

Removed fuel regulator and pressure tested. It pops off at 45 - 50 psi as best as I can tell with my air compressor gauge. It seems real clean inside so it will go back on. It appears the pop off pressure is controlled by intake vacuum off the #3 TB. I'm guessing that as RPM increases, the corespondent vacuum increase tells the regulator to maintain higher fuel rail pressure. Or, I could be wrong ..... :scratch
Paul
 
DrPaul said:
Removed fuel regulator and pressure tested. It pops off at 45 - 50 psi as best as I can tell with my air compressor gauge. It seems real clean inside so it will go back on. It appears the pop off pressure is controlled by intake vacuum off the #3 TB. I'm guessing that as RPM increases, the corespondent vacuum increase tells the regulator to maintain higher fuel rail pressure. Or, I could be wrong ..... :scratch
Paul
Click to expand...

How does it test on the bike?
 
henzilla said:
I worked for Exxon in the early 70's, and know they also refine gas at some of their facilities as do the others, but makes you go HMMMMM?
Click to expand...

The Official Story is that it is the additive package that differentiates each brand. We have a major refinery in our community, and many of my neighbors work there, so I will do a little asking re this specific topic. I do know most of the tankers leaving are not brand marked.
 
It seems to me...

the vacuum port does open up the regulator to dump pressure on high vacuum I.E. snapping to idle. It is one of the ways to relieve rail pressure before service, for those who don't like VOC baths.

Did the rail/injectors test out well? Those with no hobbies want to know... <<<)))
 
Fuel Pressure Regulator

Kayseventyfive said:
How does it test on the bike?
Click to expand...
Dunno yet. The bike was parked 17 years ago with gas in the tank. When I acquired the bike, the seller had recently had the tank cleaned but nearly every fuel system component from the pump to the injector nozzels was shot. I've replaced the fuel pump, filter, in-tank lines, rail and injectors. Fortunately, I was able to get most of these parts on eBay or from Beemer Boneyard. I'm still waiting on the fuel level sending unit to arrive and then I'll be ready to put her back together. I have no reason to believe the ignition system will be a problem. In fact, I'm pretty sure it will fire up on the first touch of the starter button :whistle

Paul
 
Fuel tank leak :-(

Well, I received the last part needed to get the old K75S back together yesterday, a new fuel level sending unit. Everything went back in the tank just fine. With all the electricals hooked up, I poured about two gallons of gas in. As I did, I noticed a puddle forming on the left side of the bike due to a leak from a tiny pin hole in the tank just above the seam. :banghead Now I'll have to completely empty the tank, remove all the innards, flush every last volatile molecule from the inside and find someone who can repair the hole. Would solder work on this aluminum tank?

Another question. Before putting fuel in, I wanted to make sure my electrical connections inside the tank were working. When I turned the switch to the "run" position all lights came on but the fuel pump didn't spin until I touched the starter button. I was expecting the pump to start when the key was moved to "run" as my R1150RT does. Is there a relay that may be a problem here or is this normal? Thanks.

Paul
 
DrPaul said:
Well, I received the last part needed to get the old K75S back together yesterday, a new fuel level sending unit. Everything went back in the tank just fine. With all the electricals hooked up, I poured about two gallons of gas in. As I did, I noticed a puddle forming on the left side of the bike due to a leak from a tiny pin hole in the tank just above the seam. :banghead Now I'll have to completely empty the tank, remove all the innards, flush every last volatile molecule from the inside and find someone who can repair the hole. Would solder work on this aluminum tank?
Click to expand...
Someone might be able to heliarc weld it - but I'd suggest doing a search on gasoline resistant epoxy - there are some products made for this use. Use it on the iside of the tank and you'll get away without repainting. The reason for the leak was water in the fuel - condensed from the atmosphere. It causes corrosion in the lowest point - usually the rearmost corners by the seams.
Another question. Before putting fuel in, I wanted to make sure my electrical connections inside the tank were working. When I turned the switch to the "run" position all lights came on but the fuel pump didn't spin until I touched the starter button. I was expecting the pump to start when the key was moved to "run" as my R1150RT does. Is there a relay that may be a problem here or is this normal? Thanks.
Click to expand...
Normal. It's working correctly - the pump doesn't spin up with the ignition.. only with the starter and then when the engine is running.
Paul
Click to expand...
 
DrPaul said:
Well, I received the last part needed to get the old K75S back together yesterday, a new fuel level sending unit. Everything went back in the tank just fine. With all the electricals hooked up, I poured about two gallons of gas in. As I did, I noticed a puddle forming on the left side of the bike due to a leak from a tiny pin hole in the tank just above the seam. :banghead Now I'll have to completely empty the tank, remove all the innards, flush every last volatile molecule from the inside and find someone who can repair the hole. Would solder work on this aluminum tank?

Another question. Before putting fuel in, I wanted to make sure my electrical connections inside the tank were working. When I turned the switch to the "run" position all lights came on but the fuel pump didn't spin until I touched the starter button. I was expecting the pump to start when the key was moved to "run" as my R1150RT does. Is there a relay that may be a problem here or is this normal? Thanks.

Paul
Click to expand...

Don has a good idea about the leak. Any decent auto parts store sells a gas tank putty that is a cylinder shaped piece of goop that has an inner part and an outer part kinda like a corn dog. You cut of a slice and knead it until it is a uniform gray color. At that point it is a bit sticky and can be pressed onto the leaky spot. Clean metal works best. If you put it on from the outside eventually (2 to 5 years) fuel will seep under the paint unless you wire brush it back away from the patch. Most such leaks are pretty well hidden even of not repainted - especially if on the inside rather that the outside of the bottom seam.

And for the curious, yes, I have used it on a 1987 K75S that is at my son-in-law's house and not ridden as much as desirable. It lasted about 3 years and then I redid it because I had put the original patch over the paint. Never needed it on Old Smokey but she got ridden frequently and water in the gas and the resultant corrosion was never a problem on that bike. But the 19 year old 30K miles K75S is a different story.
 
Paul_F said:
I have just ordered a small amount of paint (POR 15) to cover some minor rust on my frame. They have a gas tank repair kit as well. I got this information from a recent airhead rust thread.
http://www.marine-paint.com/merchant.mvc?Screen=PROD&Product_Code=CTRK&Category_Code=TankSealers
Click to expand...
The POR kit really isn't suitable for a K bike tank (which has fixed lines inside the tank.. and the vent assembly.) The POR kit is a pour it in - and move the tank around so the liquid coats the entire inside of the tank. It would be good on something like an Airhead tank since there aren't fixed pipes/fittings in the tanks. Using POR on a K bike tank is very likely to plug up the vent fitting at the top of the tank.. making it useless, which will fix the problem since you'll be looking for a new tank after using it.

I'll repeat - an epoxy patch should work fine. I know of quite a few K bikes running around with one. As Paul noted - inside is better, unless you can remove all the paint in the area of the leak on the outside.
 
Gas Tank Leak

I have repaired 3 pinhole seam leaks on my '87 K100LT. I ground with a Dremmel tool to remove paint and scuff the aluminum. I used 4 minute JB Weld. This has held for 13 months, 12,000 miles with temperature extremes of 15-110 degrees.

I painted the entire bike, so the color did not matter.

Ralph Sims
 
deilenberger said:
Someone might be able to heliarc weld it - but I'd suggest doing a search on gasoline resistant epoxy - there are some products made for this use. Use it on the iside of the tank and you'll get away without repainting. The reason for the leak was water in the fuel - condensed from the atmosphere. It causes corrosion in the lowest point - usually the rearmost corners by the seams.

Normal. It's working correctly - the pump doesn't spin up with the ignition.. only with the starter and then when the engine is running.
Click to expand...
Don, thanks for the great advice. I'm glad to hear my fuel pump circuit seems to be behaving normally. I like the idea of a fuel-resistant epoxy product. I'll look into that.

Paul
 
BuddingGeezer said:
I have repaired 3 pinhole seam leaks on my '87 K100LT. I ground with a Dremmel tool to remove paint and scuff the aluminum. I used 4 minute JB Weld. This has held for 13 months, 12,000 miles with temperature extremes of 15-110 degrees.
Click to expand...
Ralph,
Did you put the JB Weld inside or outside the tank?
Paul
 
DrPaul said:
Ralph,
Did you put the JB Weld inside or outside the tank?
Paul
Click to expand...

2 of the holes were directly on each side of the other on the lower seam by the seat on the left side. The guy I bought the bike from had let it sit for 3 years on the side stand. I initially used the epoxy putty (CarGo) and I still had a leak. Then JB Weld, still wet, then Seal All, still wet. I ground all off and used JB Weld 4 minute, Still wet. I found another leak further up the seam. The paint was covering the hole.

I enlarged the holes to about a 8 penny nail in size, slightly indented the holes, ground the paint and aluminum with a Dremmel tool and applied the JB Weld. Sanded the JB Weld to conform to the tank.

The tank was empty, but not washed.

All is exterior. As I stated in earlier post, no problems, no leaks.

If the leak is at the lowest part of the tank by the seat, used only a small amount and the side cover will cover the repair, if you don't want to repaint. If someone is looking that close, tell them to get the hell away.

I had left side fairing repair and did not like the original color, so I repainted.

The putty you pinch and kneed will work, but the JB Weld will make a smoother and stronger , and bettler looking repair. Just make sure the metal is rough, even 60-100 grit, before you apply the JB Weld.

Ralph Sims
 
BuddingGeezer said:
2 of the holes were directly on each side of the other on the lower seam by the seat on the left side. The guy I bought the bike from had let it sit for 3 years on the side stand. I initially used the epoxy putty (CarGo) and I still had a leak. Then JB Weld, still wet, then Seal All, still wet. I ground all off and used JB Weld 4 minute, Still wet. I found another leak further up the seam. The paint was covering the hole.

I enlarged the holes to about a 8 penny nail in size, slightly indented the holes, ground the paint and aluminum with a Dremmel tool and applied the JB Weld. Sanded the JB Weld to conform to the tank.

The tank was empty, but not washed.

All is exterior. As I stated in earlier post, no problems, no leaks.

If the leak is at the lowest part of the tank by the seat, used only a small amount and the side cover will cover the repair, if you don't want to repaint. If someone is looking that close, tell them to get the hell away.

I had left side fairing repair and did not like the original color, so I repainted.

The putty you pinch and kneed will work, but the JB Weld will make a smoother and stronger , and bettler looking repair. Just make sure the metal is rough, even 60-100 grit, before you apply the JB Weld.

Ralph Sims
Click to expand...
Thanks, Ralph. The info is much appreciated. I plan to tackle the leak today so will post later on my results.
Paul
 
It's Alive, It's Alive!

I'm feeling a bit like Baron von Frankenstein! As you know, my fuel tank had a small perforation on the left side at the lowest point from sitting on the side stand for 17 years with 1989 gas in the tank. I followed the advice from my BMWMOA friends and used the JB WaterWeld putty on the inside of the tank and the JB Weld Quick on the outside. These products are amazing. Hard as steel and absolutely no leaking. I filled the tank with regular unleaded, hit the starter button and the old K75S fired right off as soon as the pump had loaded the injectors! Quite a bit of smoke from all the Marvel Mystery Oil I had squirted into the cylinders a few weeks back but this cleared after a few minutes. As that began to clear, I rode her about 7 miles (it's 28 degrees here) and she ran smooth as silk! I'm amazed that a motor that has sat for 17 years can run like new! Everything works! All lights, signals, gauges, no problems whatsoever. She is quick, nimble, quiet and smooth. Thanks to all who have given sage advice on this project. Now, I'll get all the Tupperware back on and wait for fair weather to ride her more! I'll get pics posted ASAP.

Paul
 
DrPaul said:
I'm feeling a bit like Baron von Frankenstein!
Click to expand...
Snippage..
I'm amazed that a motor that has sat for 17 years can run like new! Everything works! All lights, signals, gauges, no problems whatsoever. She is quick, nimble, quiet and smooth. Thanks to all who have given sage advice on this project. Now, I'll get all the Tupperware back on and wait for fair weather to ride her more! I'll get pics posted ASAP.

Paul
Click to expand...
Paul, VERY cool! :brad

I hope you yelled out "It LIVES! It LIVES!" when it came to life.. in the best FrankenCycle manner. I did many years ago when I brought an R65 that took a trip in the Atlantic Ocean back to life.. (a project I never want to even think of doing again..) :thumb :thumb :thumb
 
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