F800GS 15 Tooth CS Impressions & Questions

Discussion in 'Parallel Universe' started by Desert Dave, Apr 24, 2009.

  1. GSThor

    GSThor Down & Dirty

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    Aug 12, 2007
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    Marin County, Northern California
    Great - my TT 15t is in the mail.
  2. gofast1320

    gofast1320 Been here awhile

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    Apr 22, 2010
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    811
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    Middle Tennessee
    Bought my 2009 with 1100 miles on it the end of May. I've put about 2500 miles on it in the past 2 months since I got it. The previous owner probably had a 28-29" inseam and balanced on the balls of his feet when on the bike. He rode trails a lot and I'm thinking slipped the clutch a bunch. The clutch catches way at the end of the release and I've let all the tension off. Transmission shifts smoothly but in 4th on up I can goose it and you can hear the clutch slip a bit. Probably need one in the near future. Any suggestions on a vendor with a better than OEM clutch? Anybody actually changed one of these out? I'm fairly handy mechanically and have a buddy whose a frickin mechanical genuis. I'm thinking he could take two washing machines, a 500 gallon propane tank, twelve luminous watch dials, a trolling motor and 2 dozen lead pencils and build a one man nuclear powered submersible.
    Looking forward to hearing from the gallery on this.
  3. Wildman

    Wildman In my castle

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    Clutch discussion here or here please.
  4. MoToad

    MoToad Been here awhile

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    925
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    Nelson BC, fer now.
    I put on the 15 to abate throttle jerk. It did a pretty good job at this but I noticed the highway difference in performance. Including a mileage difference. Got the chain recall and had them reinstall the new stock "freebee". I was glad to have it back. Solved the throttle jerk with the Booster Plug.
  5. HighFive

    HighFive Never Tap-Out

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    Okiehoma
    I put a 15cs on this past weekend. Very nice improvement.

    But, still needs lower gearing yet....for my preference in the woods & creeks. And, I kind of like the original gearing on the street. Since the counter sprocket swap is so quick & easy on this bike, I think I'll setup for a better combo for rapid swapping.

    I'm going from:

    Stock gearing: 42/16 combo = 2.63 ratio
    With CS change: 42/15 combo = 2.80 ratio

    To this combination:

    Street: 45/17 = 2.65 ratio
    Woods: 45/15 = 3.00 ratio

    That will let me make the "long haul" at gearing very similar to stock, and give me a much better creek crawler when I make it to base camp. Again, the swap is simply a breeze on this bike....easiest I've ever done. I like the results Wildman is getting on his 45 combo. I think its a great idea, and I'm just taking it a step farther for more versatility.

    BUT....what chain length will be needed? Wildman says 116 links works for 45/15 combo. But what about 45/17 combo? I'm wondering if I need a longer chain....say 117 or 118 links?

    Wildman, what position is your adjuster sitting in the axle slot with the 116 link on 45/15 combo?

    HF :ear

    p.s. What about a "Case Saver" on this bike? Sure seems it needs one. I posted this in my "Stupid Questions" thread also...
  6. Gangplank

    Gangplank Advenchaintourer

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  7. Wildman

    Wildman In my castle

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    Couldn't tell you off the top of my head and away from home for the week. I'll try to get back to you at the weekend.
  8. Y E T I

    Y E T I Unpossible

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    I do that all the time. In fact, I did it when we rode Jawbone while you were busy stuffing ear plugs up your nose for "dust abatement." :augie

    [​IMG]



    :hide
  9. Trout

    Trout Been here awhile

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    I was just thinking to myself - how funny! A guy with a clown nose on! Oh wait - that's me!!! And that's not a clown nose... :huh
  10. Lounge

    Lounge Been here awhile

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    Jul 2, 2010
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    COS
    I have a 46/16 currently with a stock length chain and have the adjusters bottomed making the chain slightly loose. Have a 17t CS on it's way and I think (just by eyeballing it) 46/17 will be just about the most sprocket I can use for the stock chain. We'll see when I bolt it up and give her a shake.

    I'll keep you guys posted.
  11. Sutherngintelmen

    Sutherngintelmen around the bend

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    Here's a good resource for academically evaluating gearing changes on bikes (including our beloved 8gs.) Site will accommodate customizations including 18" rear. Units default to kmh so set mph if that is your local.

    http://www.gearingcommander.com/

    As many have pointed out counter sprocket is a quick and easy change - cheap too. So, run the 15 with TKC's and 17 with Anakees for best of all possible worlds.
  12. thatnumber5

    thatnumber5 Delicately Aged

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    Here is my plan:

    change front sprocket to 17T and back to 41T for commuting/touring/getting to the trailhead. When I get to place where I will go off-road for a bit, change the front to 15T. Sounds like it can be done in 30 minutes or so.

    Sounds good in theory, best of both worlds on one bike (Good top speed for the open highway, good low end for the back roads). But how about in practice? Do I have to change the size of the chain or just adjust it after I change the sprocket?

    Am I missing something?
  13. OrcasKen

    OrcasKen Beastly Adventurer

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    Yes, changing the CS sprocket shouldn't take you more than 30 minutes. Loosen the rear wheel, slack the chain, remove the nut securing the CS sprocket, slide it off and reverse.

    HOWEVER, why do this at the trailhead to save a few hundred RPM on your ride to the trail? You'll need to carry the extra sprocket (oily), probably won't have a torque wrench with you (bulky) and then there's the spending time wrenching instead of riding. In the dirt.

    If you spend most of your time riding highway, then swap the CS sprocket back over before you head out in the comfort of your garage. If you go back and forth regularly, pick your compromise (higher RPMs on the highway or less low-speed ability on the trails with better fuel economy). I'm just saying...
  14. Sutherngintelmen

    Sutherngintelmen around the bend

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    +1

    I'd consider this swap if say mostly commuting then spending 10 days in dirt or swapping wheel sets in the shop. Don't believe it'd be worth it at trail heads.
  15. thatnumber5

    thatnumber5 Delicately Aged

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    Great point. Thanks a lot.
  16. Y E T I

    Y E T I Unpossible

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    I've done it a couple of times where I've slabbed it a few hours to get to the dirt and camped over night. Well worth it then. Otherwise, not so much.
  17. bodhizafa

    bodhizafa How hard can it be?

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    DId this work out? I'd like to pick up a 45 rear SuperSprox and use the stock chain and stock counter sprocket. Just want to make sure it will fit.

    :ear
  18. Snowy

    Snowy Long timer

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    Same.

    The 17 wont deliver better consumption per se.

    But if you open the airbox, open the exhaust and run Irridium plugs the boost all around in performance means it'll run the taller gearing without any ill effects on consumption.

    I took my tuneable exhaust and opened it right up. Not noisier, but deeper note. Big fat burble. Fit the 17 and it get's slightly better consumption with solo rider, but not so much that I'd write home about it. Haven't done a decent pillion run yet.

    It delivers better performance than it did with the standard engine and standard gearing. Has improved rideability around town as I can stretch the gears a little and let the engines torque work.

    Short shift and twist the throttle and it rides sooooooo nice. I'll see how it goes long term.



    Trail riding solo I had a lot of problems initially with the F8s habit of stalling when I'd got the front wheel up onto a log or similar. Instead of going for lower gearing long term, I went for better low end engine responce. It is now a lot harder to stall, and it picks up from idle with a full load effortlessly.

    Basically for riding off road with a pillion, if I can't get up there with the gearing it has, I probably shouldn't be trying to get it up there with a pillion anyway. I get the wife to dismount and walk up anything really nasty. Ever since both she and the bike landed on me it has seemed like the wise thing to do.

    I had her dismount knee deep mid river once to push when I got bogged....she only fell for that once. Funny but.
  19. daveo987

    daveo987 n00b

    Joined:
    Feb 24, 2012
    Oddometer:
    7
    1 after 3k+ on an (new to me ) 2010 GS
    2 normal dirt roads riding OVER 15 mph ok.
    3 nasty stuff, off camber loose rock side of mountain twisty & more loose rock... 1st gear sucks.
    4 1st gear is way to high for technical riding 2nd gear should be slightly lower & rest are ok.
    5 If you want to burn clutch all day the gs800 with stock sprockets is the bike for tech riding.
    Seems like the sweet spot on this machine is 3k rpm & up, does not work well at 5mph in a 30% grade in loose rock with a hairpin ( more loose rock) at the top. Add throttle snatch & its even worse.

    I need to drop the front sprocket size. The other issue, is getting to these "neat" places require riding 100+ miles & fuel burn at over 75+ mph really stinks.. & requires carrying extra fuel.

    Looking for suggestions on sprockets. I've dropped this bike (stalled) in nasty stuff more times than in any race I every ran in the last 40 yrs.
  20. itsatdm

    itsatdm Long timer

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    Nor Ca.
    You may be riding in technical stuff way above my pay grade, so maybe you need the low gearing. I have the 15, 2 of them in fact. I also have the 17 tooth. I am back to running stock.

    I can do that because I addressed the very lean fueling on the bike at low rpm. I did it after looking at the air fuel ratio on a 800 on a dyno. 17 to 1 at idle. It does not make a decent ratio until it spools up passed 2,200rpm.

    Trying to trail ride the bike at low rpm, due to the high gearing, is almost impossible, because it makes no power down low. The jerky throttle is caused by going from super lean fueling to adequate in the course of about 1,000 rpm.

    Power commanders, accelerator modules, Booster plugs and High Tech Coon Ass module are all solutions to one degree or other.

    If you address the low rpm fueling on the bike you can actually lug the motor. I can accelerate from 1800rpm in 6th gear. In the bottom 4 at 2,000rpm, I can accelerate briskly away to various degrees. At idle, using the brake, I can bring it down to 800rpm without stalling. None of that is a good idea, but gives you an idea of the improvement.

    May not be good enough for you, but a definite improvement and certainly makes the bike easier to ride.

    As for the mileage, you are right, the faster you go, the more gas you burn. I get 56mpg at 65 and around 45 at 75. My only advice is slow down.