Lennie's rocket sprockets for GS boxers

Discussion in 'Vendors' started by Dan Cãta, Jun 25, 2012.

  1. lennie

    lennie Been here awhile

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    DDT,

    I have done before and after runs but would need some time to locate the graphs as it has been over 12 years since I developed these. All but 2 or 3 have been very happy of the rides after installation.

    Ron,

    Yes I have had customers from the Pelican board install the sprockets in the HP2 enduro.
    #81
  2. DDT Rider

    DDT Rider Been here awhile

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    Thanks, Lennie!
    #82
  3. roger 04 rt

    roger 04 rt Long timer

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    Lennie,
    I'm still thinking about installing these. I'd like to see the graphs too if you can find them.

    I tend to be a skeptic so please bear with me. I read your comment about these being developed in 2000 or there abouts. I know that advancing a cam, in particular closing the intake valve earlier can add low end torque. A few questions:

    -Nine degrees advance seems like a lot, did you measure the lobe-centerline-angle for the intake? Where does it start out before adding your sprockets, how many degrees ATDC?

    -Any chance you measured the overlap and duration for intakes and exhausts? Can you tell us those numbers too?

    -At the end of this message I listed the 6 different cams for 1100,1150 and 1200 motorcycles that you've told us your sprockets work for. Since these six cams are different, I'm guessing that they have different LCAs, durations and overlaps. Why is a 9 degree advance the right number for all of them?

    -which cam part number did you do the development work on? Would it be the 340 963 cam for the R1100S?

    Thanks,
    RB


    1150 cams
    PN 340 963 for rs, rt, 1100s
    342 961 for rr, r, GS, GSA

    1100 cams
    PN 340 963 for rt, rs
    341 560 for r, GS

    1200 cams
    PN 670 068 for rt, st, r, GS, gsa
    704 528 for s
    668 723 for GS, GSA earlier years
    #83
  4. def

    def Ginger th wonder dog

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    Remember, these sprockets do NOT change valve lift, duration, cam angle rates or other aspects of the cam profile....they only move the valve timing relative to the crankshaft angle.

    Years ago, Isky and others sold offset keys installed on the camshaft drive gear to hot rodders that performed the same function. The results was moving the engines performance up or down the RPM range.

    Some of us Brit bike tuners used to fit the gear on the factory camshafts at different locations in an attempt to extract more HP. Also, a different (flatter) radius on the cam follower (tappet) would change valve duration somewhat providing several extra HP. If you want a substantial HP increase, a new cam profile with more lift and increased duration will do the job (much better than an aftermarket exhaust and likely cheaper, as well).

    Moving the valve timing relative to crankshaft angle with Lennie's sprockets will change the personality of the boxer positively without major work.
    #84
  5. roger 04 rt

    roger 04 rt Long timer

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    Out of curiosity how much did those Isky keys move the advance. I've seen numbers in the 4-6 degree range for street machines.

    Understood that all the openings and closings shift, and also understand that GENERALLY you get more low end torque with earlier closing of the intake valve. (As you advance the intake opening, exhaust closing and exhaust opening some other things happen too.) That said, with six different cams, all likely to have different lobe centerlines, overlap and duration, I'm surprised that one size (a large 9 degree shift) fits 1100, 1150 and 1200. So I'm hoping that in the good work Mark did to design these sprockets he took some data that he can share with us.
    #85
  6. roger 04 rt

    roger 04 rt Long timer

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    From an article on cam advancing (and I'm not saying nor do I have any opinion on whether 9 degrees is the right or wrong number for the boxers):

    When the cam is advanced, the intake valve will open earlier during the exhaust stroke and the exhaust valve will shut earlier during the intake stroke. If the cam is advanced too far, reversion will occur and the exhaust gasses will not be adequately scavenged. Four degrees advance is usually the most that you can safely advance a cam beyond the manufacture’s recommended LC. When the cam is retarded, cylinder pressure will be reduced but the scavenging process is increased. If you are experiencing pre-detonation, retarding the cam will help. It also has a tendency to move peak hp to a higher rpm. Again, care should be taken when changing cam timing. Another consideration when playing with cam timing is piston to valve clearance. When you change the valve events (timing), the clearances will change and should be checked.
    #86
  7. def

    def Ginger th wonder dog

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    Roger, you're correct, 5 degrees was typical. Also, I recall the performance cam manufacturers indicated that factory camshafts were rather crude in tolerance regarding drive gear keyways cut off specification and cam drives quickly loosened and provided poor valve timing as more miles wore cam drive chains. Aftermarket cam gear drive products were offered that reduced cam drive slop. I recall watching many an ignition timing mark dance around with the timing light due to worn camshaft drive chains.
    #87
  8. def

    def Ginger th wonder dog

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    Since we're in the realm of engine breathing, BMEP, VE and other engine dynamics, the OE cam profiles we find in our boxers are designed not only to provide good performance but also to satisfy the EGR needs for emissions control. Also, the starter drive and starter motor size is determined to some extent by valve timing. Even the dimples in the intake runners (think golf ball) have an influence on engine breathing, mixture homogeneity and thus engine performance. We install free flowing air filters in hopes of more power. Some boxers owners even remove the FI system and install carburetors in an effort to change engine personality and performance.

    My thoughts are that roger04rt has provided proof that his fueling adjustments improve the boxer's drivability considerably. Also, Lennie's sprockets move the HP curve into the range where most of us operate our boxer engines with an improvement in fuel mileage....what more could we ask for?

    Oh, I forgot....more noise.
    #88
  9. lennie

    lennie Been here awhile

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    Roger,

    I originally developed the sprockets for my 1998 R1100S and we used specially made vernier sprockets with 3 degree retarded, 0 degrees stock, 3,6,9 and 12 degrees advanced.

    We started with the baseline for stock and adanced to 3 degrees and tested with improvements. We then tried 6 degrees with further improvements and again at 9 degrees. While the results on the dyno were there they were not as impressive as we expected and it was not until I rode the bike home that the change was quite beneficial.

    As far as other models I researched the cam timing and decided to test the sprockets in each to find the same positive result. When the R1200xx engine was developed I had to drill the extra hole for the cam position sensor and they were tested in the USA with the same positive feedback.

    To ease the manufacture and number of products I have I decided to just use the 9 degree advance as the product I sell.

    I have had a look for the graphs and cannot locate them but try this link to Brad Black's site. http://www.bikeboy.org/ and this is a driect link to the performance data http://www.bikeboy.org/performance.html

    There are plenty of graphs for the BMWs with just cam sprockets or in combination of other parts for you to look at.
    #89
  10. roger 04 rt

    roger 04 rt Long timer

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    Lennie,
    Thanks for the description of the process that you used. It seems thorough and a reasonable way to go about it.

    I had a look at all the graphs on Brad's site and saw his comments as well. It looks like some of the graphs are with 6 degree sprockets and others with 9 degrees. All the runs that mention your sprockets are in motorcycles that use the 340 963 cams--the same one I have in my 1150. I wish the dyno runs were more conclusive.

    Since you've settled on the 9 degree sprockets, it seems that you believe it's the best fit.

    Just one more question, were you surprised that it took 9 degrees to get the results you were looking for?
    RB
    #90
  11. Hookalatch

    Hookalatch Born Under Bad Sign

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    Make sure you are making accurate comparisons about the different degrees or advance or retard for the camshaft. Normally, when quoting advance (or retard) cam timing the figure is stated in degrees of engine revolution. In Lennie's sprockets that is 9 degrees of engine rotation. That results in 4.5 degrees of camshaft rotation since it rotates at 1/2 crankshaft speed. The above quote refers to camshaft advance of 4 degrees- which is 8 engine degrees. What it amounts to on Lennie's sprockets is about 1/4 of a tooth difference on the sprocket.

    What really surprises me about the sprockets is why they haven't caught on in a big way. If you run your engine at or near redline all the time the sprockets will work against you. If you run the bike between 3000-6000 rpm most of the time the sprockets make it a much better riding machine. I have had the sprockets in my R1200GS for quite a while now and have posted my positive results before. I don't want to sound like a Lennie salesman so I won't go into it again except to say I would have to do this again if I changed bikes because I would not be happy with stock anymore.

    Chuck
    #91
  12. roger 04 rt

    roger 04 rt Long timer

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    That's a very good clarification, thank you. I had missed that he's specifying degrees of engine rotation as opposed to cam rotation.

    I've had a large/measurable boost in the 2000 to 3000 RPM range from my Wideband O2 installation and running with 6% more fuel. Now I'm wondering if advancing cam would boost further in that range or even lower.

    You feel the same about the cams as I feel about the fueling boost.

    Hopefully Lennie will confirm this cam advance vs crank advance.
    #92
  13. Ken Fritz

    Ken Fritz Long timer

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    I understand the logic behind this mod. I'd have done this sooner, but only just now stumbled across it on ADV. Mine are now on order for my 1150GS. I just wish I had known earlier so I could get them for less $$$. Lennie - ever consider a discount for ADVriders?

    In the '70's Datsun was into racing and offered different cams and sprockets for the overhead cam engines. In fact, a stock 4 cyl OHC Datsun 510 had three locating holes drilled in the stock cam sprocket - you could advance valve timing by remounting the sprocket on a different pin for the cost of a valve cover gasket (under $5) and some time.
    #93
  14. dirtsurfer

    dirtsurfer Thread killer

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    Must the valve covers be removed to do the install?
    #94
  15. The Other JC

    The Other JC Lurking since 2004..

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    Yes<BR><BR>
    #95
  16. Dan Cãta

    Dan Cãta Long timer

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    You will never see that in BMW. Apparently, their politics is "get everything new, from us".

    Yes, you need to do this in order to get the ole sprockets out and the new ones in. Also, I adjust the valves after this job, then sync the bike.

    Dan.
    #96
  17. Andrew

    Andrew Optimus Primer Super Moderator

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    Apart from removing and replacing tire valve stem caps, removing engine valve covers is probably the most frequent maintenance item on Boxer engines. No reason to shy away from it.
    #97
  18. lennie

    lennie Been here awhile

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    Roger,

    I have quoted the changes in crankshaft degrees so the cams are advance 4.5 degrees. We found that the dyno graphs are no indicative of the real gains in the bike. It was the same with the InDuct that it does not show the full benefit once on the road.

    I have left the dyno many times disappointed until I twisted the throttle.

    Hookalatch,

    You are not a sleasman for me but simply a satisfied customer.

    Yes I am amazed that the sprockets have not taken off and that the sales are a slow steady. That is ok as it is just a sideline for me and I hope that it can pay for more development on my next bike. I am considering a R1200GS watercooled later in the year and possibly a F850R for road so more work to do.

    Ken,

    I will post your sprockets this morning Eovernight express so they will be there tomorrow.
    #98
  19. roger 04 rt

    roger 04 rt Long timer

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    Thanks for the further clarification.

    I've noticed generally that many dyno charts don't appear to have reliable data at low RPMs--the area where your sprockets should show gains. Some charts don't seem to kick in until 2500-3000 RPM. (The AFR data on many charts I've seen looks wrong, in some cases even at 4000 RPM. Below is an example of clearly wrong afr data below 4000 rpm; no way is it 15:1 at WOT between 3000 and 3500 rpm.) I have no reason to doubt your sprockets work; so if there is a gain, there must be something that is measurable.

    [​IMG]
    #99
  20. Hookalatch

    Hookalatch Born Under Bad Sign

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    I had already established that I was not a salesman for you.
    Good to know you don't consider me a sleasman either, although there may be some who would disagree.<label for="rb_iconid_27">:wink:</label>

    Chuck