Lennies cam sprocket review.
 

Today I installed Lennies sprockets on my R1200RT, installation was simple enough with the only real difficulty being access the left side cam chain tensioner.
Anyway, after installation I took the RT for a ride and WOW what a difference, these things REALLY work, low and mid range torque are very obviously improved, it’s not a subtle improvement. The top end is not as strong but the loss is not obvious.

Adding more fuel to the standard RT with my home made FRK did next to nothing as the standard RT runs very well, however with the advanced cam timing courtesy or Lennies sprockets low to mid range cylinder filling is improved (more air in), as a result the standard fuel maps are now lean at lower rpm, adding fuel with my air temperature spooking device now does something useful and noticeably improves torque and power at low to middling rpm.

If top end HP is your thing Lennies sprockets are not appropriate, but if you want more torque below 6000rpm go for it, Lennies sprockets and extra fuel via FRK, Memjet or a simple 6.8k ohm resistor in series with the air temp sensor really work.

+10

I did not really feel the need to try the need my 12S... but I had them in my 11S (with excellent results) and now in my 12GS with fantastic results...

I think they are more suited for the likes of the GS, RT and even the whole 11XX generation... bikes that were not built for high revving applications and top end power...

But, man, the difference in my favorite rev-range....

R-e-a-c-h-i-n-g for my checkbook.

BTW as a techno ignoramus... just how do the sprockets shift the torque downward? In my mind the 259 engine was designed to deliver torque in a certain band of RPMs. How does altering the cam sprockets' tooth count(if thats even correct) shift the torque profile? Is it similar to putting a different size sprocket on the counter shaft of a chain drive?

The tooth count is identical to the OEM sprocket; however the timing is advanced 9 degrees which closes the intake valves earlier for improved low end torque, no rocket science involved.

How much Lennie, how Much?

thanks! told ya I didn't know squat.

BTW is it advisable or even possible to swap out the cam chain guides when doing the sprocket swap?

flatbutt, I just put some in my R11S too. Haven't put it out on the road yet, I also pulled the fuel injectors and had them cleaned and calibrated so it'll be next week before I get it all back together and butt tested.
You have to take the engine apart to mess with the cam chain guides. If you drop something while changing the sprockets, you'll have a very expensive bill on your hands. Then it might be worth it to change the cam chain guides....
Just take your time, and review the stuff others have put on this list. That and the Repair Manual and you're good to go. Just be patient and t a k e y o u r t i m e .

RD - I got mine from Robert Foster. Last I heard he had a few sets available.

Owen,

Thank you for the objective report as you said you would do.

Results are as claimed and expected.

I bet you have a big smile on your dial now.

As far as pricing is concerned I am finalising things with Foster Performance and will know the results with a phone call tonight.

Thanks again Owen.

can you flip flop these things and advance the valve timing, or does that get you bent valves?

shreddr,

no they cannot be flop flopped.

the timing is very specific and one way only.

No probs mate, your sprockets have given the R12RT the grunt it should have had from the start, it now feels like a 1200cc twin. BMW really should re-evaluate how they tune bikes for different markets, top end HP may be appropriate for German autobahns but for the rest of the world it’s not the most important criteria on a bike like the RT. Most people want low and mid range torque to pull a passenger and luggage around in an effortless manner, the R12 motor is capable of delivering the goods, BMW just need to tune it right.
I am not only impressed with the performance of your product but the manufacturing tolerances seem very good as well, they are a nice press fit on the cams. Good work mate. :D

I known it sounds counter intuitive but advancing cam timing improves low end, if you want better top end you need to retard cam timing.

Thanks for the objective review Owen. It has confirmed my decision not to go for the Lennies. Although they may give excellent low and mid I do like my top end. :D

Can improvements in torque be gained with stock intake, fueling, and exhaust?

Will these sprockets improve a stock bike?

Do you mean low-rpm torque (AKA grunt)?

Almost all the mods at PP (and in the minds of the original bike designers) have to do with high-rpm peak-HP torque (AKA advertized HP). I've been grousing for years that that's the least useful place for most street riders and maybe with a shift in PP membership, that will become clearer. Which brings me to your question: improvements to breathing relate to high-rpm power because no IC engine is throttled in breathing at low speeds, duh.

One exception is redesigning the breathing for resonance at lower frequencies than the stock (AKA input tuning and exhaust scavenging). Not ordinarily easy to get right.

Shifting the cam timing (all 8 (or 16) valve openings and closings) with Lennie's sprockets is a revamping of the engine design. Although I'd bet the total integrated engine power over the full band is less, the power lower down is more. Apparently that works good even if something of a gross approach.

The only low-end torque boost much discussed is "debaffling" (kind of cousin to scavenging) which Phoenixtexoma and I strongly recommend. It is also reversible. See my write-up at URL below. For a mod which is easy to do even for ham-handed beginners, invisible and doesn't mark the outside, part of normal maintenance of undoing exhaust bolts from time to time, and costs nothing but whatever cutting tool you need, hard to believe so few people have had the get-up-and-go to try it.

Yup. That's exactly what i meant to say.

With a bone stock bike, they work just fine, Andrew... I added a cat-eliminator to the setup on my 11S and it added some of the top end back... not that I spent much time in the top RPM range anyway...

From my initial dyno results I think we lost about 1.5 peak hp but gained much better mid range torque.

I my tuning is to move and improve the power where it will mostly be used in day to day riding.

Again thanks for the positive feedback.

Andrew,

They work for most states of tune and I even ran them with my reground cams with the same improvement. I had a spare set of cams reground with the 9 degrees advance.