1. BMW Oil-Head Inlet Duct
A year and a half ago I replaced a 1994 K1100RS with an 1999 R1100S. I loved the (much) better handling, but certainly missed the top end hit I got from the K. I certainly didn’t want to take the engine apart or do anything drastic, so I tried the normal routes to getting better response: a Staintune exhaust and a K&N airfilter. These changes certainly improved the boxer’s breathing, both in and out, but still it felt lethargic compared to my friends’ ST-4s.
I then noticed a listing in the R1100S Registry from a fellow in Australia. He had made a LOT of modifications to his bike, one of which was especially interesting to me. It was called an “MBL InDuct,” and was apparently a carbon fiber intake duct. I searched the internet for “MBL”, etc. but without any success and finally e-mailed Australia to learn more information.
What I learned was very attractive; the InDuct was another bolt-on item (I admit it, I LIKE my warranty) and was designed especially for bikes with a K&N. Apparently the designer (Mark Lennon) determined that the limiting restriction in the intake system was not the airbox or the air filter, but the intake duct itself. The InDuct was designed to permit the K&N to work at optimum efficiency by removing that restriction.
After corresponding with Lennie, he was kind enough to send me one. Upon arrival I looked it over carefully. It is a beautiful piece, solidly built and very nicely finished. It is constructed at least as well as the stock front fender. And of course it weighs next to nothing. I was really excited, and brought it to my dealer to install (I admit this too, I am frankly a dilettante!). They were as impressed as I was and, 20 minutes later pulled my bike off the stand for a test.
When they returned, they took the old duct and tossed it into the garbage since they were sure I would not be using it again. And then I went out for a ride.
Wow. What a screamer. The InDuct plainly cures the remaining bottleneck in the system. It and the K&N obviously allow the cylinders to fill much better. The surfaces of the InDuct are simply smoother than the stock duct, and even better, it has a much bigger cross section. Accordingly, it is just less restrictive, and flows a lot more air to the engine. Of course the Staintune also allows everything to scavenge easier too.
Anyway, riding the bike was literally a revelation. It now picks up speed easier and quicker and is much more responsive. The InDuct makes my oilhead boxer now feel pretty much like a four valve Ducati. I have run no dyno tests, but to me the difference is mainly in responsiveness; the bike feels exactly like it has a lightened flywheel.
Larry, CBT Imports, USA
2. Riding Lennies R1100S
After developing the production BMW R1100S for the 1998 Six Hour endurance race I’d wondered about the performance potential of the bike, unhindered by the draconian impost of mass production and modern political correctness.
Our endurance racer was almost stock, save for some careful tuning and the obligatory Staintune pipe. It’s history now that “Black Bess 2” garnered 3rd in the Production Superbike class, remarkable when one looks at the weight of the bike and the modest 94hp we had to work with.
Boxer Performance had shown interest since those early days, and head honcho Mark (Lennie) Lennon, has been busy ever since, enhancing his own R11S. Cams, carbon ‘InDuct’, fuel pressure regulator, and a pipe later, he has created a Bombastic Beemer that we would have loved to have had as our race bike!
Invited to ride his yellow example, the first thing I noticed was that the bike looked completely standard, an impression that was swiftly ‘blown into the weeds’, when I cruelly opened the throttle hard at low revs in 6th gear, going up a steep hill. Expecting to be chided by an abundance of pinging, and the need for a lower gear, I was in for a rude awakening! The R11S simply boogied away, I had to hold on tight, and that’s when at 5500rpm all hell broke loose! Never have I ridden a BM with so much willing stomp! Far superior to our racer, this converted bike had a ton of midrange, no tendency to ping, and pulled extremely hard, to say nothing of the sound! Self preservation meant a little discretion was called for, this was a public road after all, but I must have this bike back at Eastern Creek Raceway with a good ‘A’ grader on it. The stopwatch will not lie, and the top end potential, which feels considerable, could be probed.
The dyno told the rest of the story, 101 HP! (uncorrected rear wheel). Congratulations Boxer Performance, you’re on a winner!
Mal Cherlin Manager Bears F1 Racing Team.
So, the secret is out – for BMW Motorcycle Performance, InDuct’s the go.