When is an R1200GS not an R1200GS?!

When is a BMW R1200GS not a BMW R1200GS?…….when it’s a Welsch GS12
Read on re the build of this bike and German legislation 😉

Frank W’s RENNKUH 1200

Full size images here

I have been riding motorcycles since I was 16 years old. I was never interested in motorbike design so I was usually riding the motorcycle that got me the most bike for the small money I had.

Starting with a Honda VT500 E, followed by a BMW R80 and a Kawasaki GT750, the cardan drive and the touring character was the only connecting element between these bikes . In 1995, I then bought a BMW R1100R. Again the one BMW model, that probably had the least sex appeal, but a lot of value for the money. I am still riding it during winter, because I once promised to never sell it, if it won’t break down. And it never has in 14 years!

But then in 2006, during a bike trip to Austria, the hotel manager offered to park my BMW in his garage. And there I saw the coolest GS 1150 I had ever seen! Very aggressive, all black with 17 inch wheels, it made a deep impression on me. Nothing at this bike looked standard and I WANTED IT! The hotel manager told me about the guy who built it and gave me the contact details to his company RENNKUH.


But looking at the website ended the dreaming quickly. I could not afford it.

But never since this day, was I interested in another bike. I just needed to wait until I had enough money.

Now you all know, this featured bike is not my creation. It is in fact not even a unique bike. Michael Welsch, the owner of RENNKUH is a professional BMW GS Tuner, building these bikes on order. He has developed this special design and is building his bikes on the basis of GS 1150 and later the GS 1200.

Today there might be 35 or more of the 1150 version and probably 10 or so of the 1200’s . When I finally had saved enough money, in October 2008, I found that he had started to build the 1200 version, which was even more appealing to me, because with the 1200 I could have all the features of the new series plus the cool design.

Lets’s come to the technical details of my bike. The main feature is definitely the modified frame. Michael is using mainly model 2004 frames, because of the more aesthetic area around the footrests and stand, compared to the 2007 model. The lower part of the rear frame is extended by a couple of inches, bringing the whole back end substantially higher.

The passenger footrests are cut off and replaced by the holders from the R1200S, where the passenger footrests can be removed by two screws. A fully stainless steel exhaust system from Bodis that is adapted to the different angle of the rear frame is mounted very snug around the engine, to give enough cornering clearance. The main stand is removed, as is the passenger seat. The luggage rack is painted black. The driver seat is a custom design, to adjust well to the different angle between the main frame and the rear frame.

The wheels are replaced by R1200ST 17 inch alloy wheels, with 120/70 ZR 17 front and 180/55 ZR 17 tires at the rear. To avoid the rear wheel running out of center, the rear drive has been trimmed to compensate the offset. The suspension is regular GS 1200 Adventure rear shock and as well an Adventure front fork and shock. The main reason for the Adventure shocks is the improved ground clearance, that compensates the smaller wheels. In addition the Adventure front fork is black anodized aluminum and matches much better with the black trim.

The engine has been modified as well to now deliver 126hp at 8100 rpm and a nice torque of 127 nm at 6200rpm. Honestly, I do not know the detailed works on the engine, but some secrets Michael may keep.

The rest is mostly visual stuff:

Custom front fender

All (and I mean all) visible screws replaced by stainless steel Inbus screws

All of the GS’ openings covered with customer made stainless steel caps

All bigger screw heads trimmed for a nicer look

Rear light shortened by 10 cm, including remodeling of the reflector to fit into it

Trimmed aluminum plug to close the lock for the rear seat

Small LED turnligts. (Will soon be preplaced by the new black Kellermann black LED’S)

HID headlight and high beam

ABM Wave Brake Disks front and rear

VarioLever brake and clutch levers

FlowJet windscreen

Technical equipment:


Heated Grips

Tire pressure Control


Alarm with GPS Location Tracker

The color trim is a BMW car color called “Night Black”. All parts of the bike have been painted black. This was possible because the bike was built from single parts, which made it possible to paint parts, that are usually not painted because they are too much work to disassemble. For example the silver parts of the original Adventure front fork, the rear drive shaft, the frame or the handlebar. The result is a fairly mean looking motorcycle, that has a fantastic engine, corners like nothing I had ridden before and still is extremely comfortable to ride.

On the downside, the full black trim requires constant cleaning and care. Dirty does not look good here!

Due to the substantial changes on the frame, the engine modifications and to be able to register the different noise emission values, compared to the stock GS, Michael Welsch is registered as well as the manufacturer of the bike. Legally it is not a “BMW R 1200 GS”, but a “Welsch GS12” now. This gives more freedom to use parts, that would not pass the German technical inspections, when mounted on a normal GS. Something where most US bikers would have no issue anyway. But Germany is Germany! Do not alter what the manufacturer has built, unless it is tested and retested!

That’s the story of the my RENNKUH. (Which translates “Racecow”). It is not my design, not my hands work and not unique like some of the bikes on this site. But still unique enough, that I did not see a similar one in the past 20.000 km’s. I rode it all over Europe in the past year. We have been all around the Alps, down to Monte Carlo, in Croatia and the Dolomites. It makes a great touring bike still, with the Touratech rear bag, that fits into the holder of the rear seat it can carry lots of stuff.

And on the racetrack it is fantastic.

Surely not powerfull enough to outrun a GSXR 1000, KTM RC8 or Fireblade, on a straight but just perfect to catch all of them in the next corner.