Author Topic: Luftmeister turbo k100 rs  (Read 214 times)

Offline K_grendell

  • Motobrick Curious
  • Posts: 49
Luftmeister turbo k100 rs
« on: May 30, 2020, 04:46:52 PM »
Well I’ve always lusted after a luftmeister bike before I even knew how much I’d love bricks and finally have one. It all started last winter while doing research for my sidecar turbo setup when I came across it for sale a few hours away from me. The owner didn’t know a lot about it or turbo setups and wanted to build a cafe bike but ran out of steam. He wanted too much for it and it was pretty rough so I passed on it. Fast forward a few months I sold a pristine k1100 to fund 1200rs sidecar build and regretted it. I really like the style and size of the older 2v’s and have been looking for the right 1200 to build and the pandemic hit so I held off. Thinking about a bigger turbo sidecar I reached out to the seller last week and he still had the bike with very little interest. We struck a deal for the rolling parts pile and it’s chasing me home now. I need to go throug al the documents and dig into the history but it’s got an early accel dfi injection system, inter cooled, supposedly 22% higher gear ratio and a works shock. This was supposedly one of the salt flat bikes but I have no confirmation of that and need to confirm or it’s just hear say. The paper work lists other items that may be missing now or hidden until I can open things up to confirm. I need to asses everything and see if it’s worth trying to get it going or use the parts to build a clean stock bike and make it oem+ With my ezs/California sidecar sitting in the corner waiting to be hung onto a tug... Now Pics for pleasure...
  • Worcester, MA
Current bikes:
1987 k75s
1979 Vespa px200
1969 mz es-250 trophy
1997ducati 748
2007 ducati multistrada 1100s

Offline champ7fc

  • Motobrick Curious
  • Posts: 22
Re: Luftmeister turbo k100 rs
« Reply #1 on: May 30, 2020, 07:47:59 PM »
I am interested in the leading link front end on the K75. I currently have an 85 K100RS plugged into a Vetter Terraplane. Could you tell me where the front end was sourced and approx cost. Thanks Craig
  • Staffordville, Connecticut
  • 1987 K75S, 1985K100RS

Offline K_grendell

  • Motobrick Curious
  • Posts: 49
Re: Luftmeister turbo k100 rs
« Reply #2 on: May 30, 2020, 09:54:26 PM »
Craig, I used the bike with a stock front end and a steering stabilizer for several months and it was a bear to turn and had some serious death wobble at specific speeds. I was able to buy the front end and an older elf subframe as a package off a Facebook market place for $600. Between adjusting the chair and adding that the bike is a dream to ride now. Iíd highly suggest investing in a set. Iíd try going to Claude first and if he doesnít have anything contact wasp/unit in the Uk. I was about to order the forks from wasp when that deal popped up.
  • Worcester, MA
Current bikes:
1987 k75s
1979 Vespa px200
1969 mz es-250 trophy
1997ducati 748
2007 ducati multistrada 1100s

Offline Rcgreaves

  • ^ SuperNatural Motobricker
  • Posts: 792
  • "I'd rather be flying, but this will do nicely"
Re: Luftmeister turbo k100 rs
« Reply #3 on: May 31, 2020, 11:58:59 PM »
Very cool - DMC is the only k75/100 leading link Iíve found domestically- and dear at 2800$. I turbo charged a 911 as a younger man... the idea of spooling up K bike is intriguing- plenty overengineered to handle it.

Following with interest

https://www.dmcsidecars.com/fab_custom/steering-modifications/

Stealing Kyles thunder here- lifted from your other postó

ď Yeah Baby - wow!!
  • Livingston, SW WI. USA-"With the good earth all around."
  • Newest Resto: 96 Honda Interceptor VFR750F, Also Restoring: 1995 K1100RS, 1994 K75S ,1985 Goldwing Aspencade
Doing ďbetter than I deserveĒ

Offline K_grendell

  • Motobrick Curious
  • Posts: 49
Re: Luftmeister turbo k100 rs
« Reply #4 on: June 01, 2020, 10:00:03 PM »
Well I got some time to get it up on the bench tonight for a good look over....itís a mongrel but if the accel ecu has an eprom and didnít lose its tune or have a hardware issue it might run. Iíve got compression and spark, going to swap my k75 tank with a good pump onto it to see if itíll fire. I gave it an oil change and checked the turbo over, it will need a rebuild as thereís lots of shaft play and itís spewing oil. Luckily enough the electrics all worked and it cranked right over. Started to do my homework on it tonight and luckily Iím able to get ahold of some past owners. More to come soon and a few pics.
  • Worcester, MA
Current bikes:
1987 k75s
1979 Vespa px200
1969 mz es-250 trophy
1997ducati 748
2007 ducati multistrada 1100s

Offline Arktasian

  • ^ Proficient Motobricker
  • Posts: 110
Re: Luftmeister turbo k100 rs
« Reply #5 on: June 02, 2020, 09:27:34 AM »
No doubt during your research you have located all the information and history of the Luft kits on the RB Racing site (who actually manufactured those).
Couple of things you may already be aware of:
- the solid air to air core in front of the engine radiator tended to promote overheating, which led to them changing that core into a split design with a broad opening in the middle to restore air flow into hot rad. Could be an issue with your tug.
- The low mount cartridge utilized a novel sump drainage fixture, as draining the oil from the turbo is of maximum importance and that location is far to low to leave it to gravity. There is a check valve assembly within the oil pan that utilizes the main oil pump to create suction towards the turbo drain, while also drawing up oil for general lube duties. Tricky situation to balance the two suctions developed, under all rpm and slope conditions. (akin to standing on a beach ball on top of a trampoline).
Just a heads up to be cautious on that one, or the oil consumption will be a real issue.
Good luck on the build.

Offline K_grendell

  • Motobrick Curious
  • Posts: 49
Re: Luftmeister turbo k100 rs
« Reply #6 on: June 02, 2020, 01:10:33 PM »
Thanks Arktasian Iím well aware of those issues. I have several intercooler cores ready to be mocked up already. I spent a lot of time researching Rb racing when I started to build my k75 turbo setup which is getting close to done.

I suspect a big reason for the shafts to blow on some these old kits is a lack of a diverter valve and the compresser surge cooking the carden seals/shaft. Mine doesnít have an in-line  check valve that I can find but Iím going to pull the pan to check for the t assembly.
  • Worcester, MA
Current bikes:
1987 k75s
1979 Vespa px200
1969 mz es-250 trophy
1997ducati 748
2007 ducati multistrada 1100s

Offline K_grendell

  • Motobrick Curious
  • Posts: 49
Re: Luftmeister turbo k100 rs
« Reply #7 on: June 03, 2020, 06:01:36 PM »
Well I had a good amount of assessment last night...aka the system taken off and turbo sent out for a rebuild today. Iíve found a clean k100rs that this kit is going to go on when the turbo is back. Once I have everything buttoned up Iím gonna sell the black bike as a roller.

All of the crank oil seeped into the exhaust overnight so I had to empty a few quarts of oil out of the exhaust. There definitely is not a check valve. I am going to pull the pan to investigate. Has any one seen this setup? The few luft-bikes Iíve seen have the same drain line as me.

I was able to figure out a new tech flapper valve from a mini to help with off boost using the factory maf and trying to locate someone with a fifth injector kit so I can reverse engineer it.

I want to use stock fueling to keep things simple and with the old school tech theme. Atktasian have you had any experience with this? I know a Hobbs switch was used to open The extra  injector at 4psi but need to find what injector/cfm was used (Iím assuming it was a stock Bosch k100). I do need to figure out if it was wired in to pull the signal from the ecu so the duty cycle was controlled with throttle or if it was a simple on/off?

Also for any turbo guys following have you been able to source parts for the original boost guard wastegate? If not Iíll upgrade to a tial for ease or finding parts to tune.
  • Worcester, MA
Current bikes:
1987 k75s
1979 Vespa px200
1969 mz es-250 trophy
1997ducati 748
2007 ducati multistrada 1100s

Offline K_grendell

  • Motobrick Curious
  • Posts: 49
Re: Luftmeister turbo k100 rs
« Reply #8 on: June 03, 2020, 06:53:19 PM »
Had a few minutes free tonight to pull the on and investigate. The scavenging system is slick and has a secondary pickup tube the sits down inside of the welded on return line bung. Hopefully the new turbo seals with this and the appropriate oil level will keep it from smoking.
  • Worcester, MA
Current bikes:
1987 k75s
1979 Vespa px200
1969 mz es-250 trophy
1997ducati 748
2007 ducati multistrada 1100s

Offline Arktasian

  • ^ Proficient Motobricker
  • Posts: 110
Re: Luftmeister turbo k100 rs
« Reply #9 on: June 03, 2020, 09:55:24 PM »
Well I had a good amount of assessment last night...aka the system taken off and turbo sent out for a rebuild today. Iíve found a clean k100rs that this kit is going to go on when the turbo is back. Once I have everything buttoned up Iím gonna sell the black bike as a roller.

All of the crank oil seeped into the exhaust overnight so I had to empty a few quarts of oil out of the exhaust. There definitely is not a check valve. I am going to pull the pan to investigate. Has any one seen this setup? The few luft-bikes Iíve seen have the same drain line as me.

I was able to figure out a new tech flapper valve from a mini to help with off boost using the factory maf and trying to locate someone with a fifth injector kit so I can reverse engineer it.

I want to use stock fueling to keep things simple and with the old school tech theme. Atktasian have you had any experience with this? I know a Hobbs switch was used to open The extra  injector at 4psi but need to find what injector/cfm was used (Iím assuming it was a stock Bosch k100). I do need to figure out if it was wired in to pull the signal from the ecu so the duty cycle was controlled with throttle or if it was a simple on/off?

Also for any turbo guys following have you been able to source parts for the original boost guard wastegate? If not Iíll upgrade to a tial for ease or finding parts to tune.

I can answer towards several of your questions - I have researched the RB "K" bike components and control systems with several other owners. I haven't owned one, but managed to suss things out reasonably well. That is to say, going so analog with stock injection control and the add on 5th or extra injector, and no real tunable ecu control adds up to the same analogy I used previously, only more so. Ensuring you keep the proper fueling ratios under all the various engine loading states with the tack on stuff, extra widgets is akin to targeting sitting on the beach ball while it is in a swimming pool. Can be done but certainly not without gymnastics and challenges. I say this not to discourage you, but enlighten the better way of full ecu control of your bikes electronic systems (ignition which deserves better control under boost, and injection which seeks to melt your pistons when your enthralled with roll on). I have gone the affordable route of MicroSquirt, or there is Megasquirt for added options. There is a learning curve. Seems like you are very well devoted to your bikes and having a turbo - so that's my advice to do it right.
Now, if you gauge the oil level in the sump and compare to the center line of your turbo cartridge, you most likely will notice the cartridge is very close (if not slightly below level which was definitely the case on some of RB's systems) The one cardinal rule on turbos is proper feed, and drainage. The fact that yours doesn't have any check valves on the interior plumbing of the pan suggests you will continue to suffer from siphon back feeding against the cartridge seals, and the shut down heat will coke up things and rapid failure soon demands more of your cash as cartridge fails. As well, steep long downhill runs will add to the head of oil seeking to work against proper drainage. Smoke will be the least of problems.
I find RB doesn't reveal the early systems with the check valves any more, but I have a poor quality photo I can offer below:

* IMG_2962 (1).png (556.84 kB . 640x480 - viewed 11 times)
Those balance the main bell suction for engine lube, with a slightly prioritized suction on the turbo drain, as well provides anti drain back which what you photos shows will not do. Hence the exhaust full of engine sump oil.
I've dabbled with that check valve set up, but I suspect RB spent months testing different cracking pressures and relationships to get it right (at least this was how they described it). You can test this by disconnecting the drain hose and plugging. Then place a canister under the turbo and run to see how much oil is naturally draining. Don't run sump too low. Now unplug the hose to the pan and place into that same container and run again. The turbo will continue to naturally drain into that container, but the internal plumbing will attempt to "suck it up". The amount of oil being introduced must be less than the amount being sucked back to engine.  To be 100% confident, you must do this at idle, and at a relatively high rpm with hot oil to ensure it is good throughout.
I use instead a small bronze gear scavenging pump, and low crack pressure check valves on both oil inlet, and oil drainage side to ensure no drain back (no smoke on start up, mind you I've swapped my side kick stand to the right side to keep oil migration down the cylinders under control as well).
Way too long of an email, pretty technical topic and not many partakers, or those wishing to divulge they are dabbling in boost.

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