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Old 05-14-2012, 07:44 AM   #121
grndzr0
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Quote:
Originally Posted by daveo987 View Post
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.
I am Running a 15/43 for the trail, and a 17/43 for the highway. I have done a couple 2 hour highway stints with the 15, wont do them again. Horrible gas mileage, and pretty buzzy. It only takes about 10 minutes if you are slow to change the front sprocket and readjust the chain.

I have not tried one of the fuel controllers yet, but plan on getting one this summer. So maybe I wont need to be swapping gears out all the time.

Ryan
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Old 05-14-2012, 11:32 AM   #122
JRWooden
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Quote:
Originally Posted by itsatdm View Post
... Power commanders, accelerator modules, Booster plugs and High Tech Coon Ass module are all solutions to one degree or other....
Gary:
Which are you running?
I have the IICE cool, but just recently installed it and have not had chance to hit the trails with it yet,
on the street is seems more "tractable" at low RPM...
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Old 05-14-2012, 11:44 AM   #123
Romano
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Can you share where to purchase this 15T from sprocket

Just want to know a good reliable source to put one on my bike.



Quote:
Originally Posted by Desert Dave View Post
****YES, I did search and checked the index for this topic and only found a number of references on the subject. If I missed a major thread go ahead an merge this in...if not, post your experiences here so others can make an educated descision.****


Many have noted the tall first gear on the 800, while others say it's fine. If you're in the "fine" category, good for you, go on to fixing the suspension, or seat or whatever. For me 1st is fine most of the time, until I get into 1st gear, feet paddling rock step ups that the stock suspension simply won't allow me to just gas it an hang on like I would a lighter dirt bike. So I end up with both feet off the pegs, doing a balancing act, at less then walking speeds, hoping I just slide on the skid plate and don't get hung up on it (as both feet are often airborne now), all the while I'm smoking the clutch and thinking of the thousands of miles of street use I may of just burned up . I need a lower 1st. Truthfully I really don't enjoy that kind of riding, but it's often necessary to get through. I'll leave the hero stuff for trials riders if I see an easier route.

Many of the fire roads I ride turn into creekbeds or are just rutted so bad from runoff and jeep tracks that could swallow a bike that I often find myself wanting a gear between 1st an 2nd. I really enjoy this sort of riding, but first is to low as I'd be screaming the tach into grenade territory , and having to watch throttle response. 2nd works well as the speeds keep the Rs' under redline, and makes throttle response much easier to control. However, I often need to chop the throttle for a rut and the R's drop so low, around 2K, that there isn't any instant snap for clearing an object, so again I'm playing the clutch hard (two stroke style) in this sort of stuff, as a downshift to first isn't practical. I'm amazed at from how low the twin will pull clean, but I don't like asking this much from the motor to often. A slightly lower second would be perfect for the more technical fire roads/trails.

A 15 tooth CS should solve that, my only concern is what happens on top out on long highway hauls. To test before I commited I tried a number of highway rides using only 5th gear. With stock gearing at 70 mph (GPS) 6th gear was around 4700 rpm and 5th was about 5100, these numbers are close as it's hard to see 100s of rpms accurately with just the tach needle. I figured with the new gearing my rpms would be right inbetween, so if I could deal with 5th on the highway, then 6th with the new gearing would be no problem. I found it it quite doable, an liked the increased passing power, even if I missed the overdrive a bit, try it yourself an see what you think. Most important was my fuel mileage didn't change out of the range I normally got on the highway. So no major downside.

So I finally got around to putting on the 15 tooth sprocket (and new chain). Took her for a 300+ mile test ride yesterday, of which over 90 miles of that was dirt. Mostly 2nd/3rd gear dirt (the stuff I like) with a little high speed stuff thrown in for good measure . My first impression was the gearing did just what I wanted, an works much better for dirt. I was able to lug second like I did before with much better response and it's now excellent for rutted climbs, with little clutching an by the time I shift to 3rd that means the trail has opened up enough to sustain speed. 1st became a MUCH better rock crawling gear as I had a few sections of very washed out trail to try it on (still not sure how I kept balance in some of that stuff, an no my shorts aren't clean ) and was nicer on regular starts on a hill. Other than that I no longer spend any time in 1st. On both dirt and street the easier to access power on tap is nice, although I find myself short shifting if I don't want that much compression braking .....pretty much exactley what you'd expect from this sort of gearing change.

On open highway 6th was doing as I expected, turning just a hair under 5K rpm at 70 mph. I'd prefer the higher sixth but this was worth the trade-off for me in the dirt. The crusing rpm is fine but I really don't prefer the added compression for slight throttle adjustments, and you can't short shift above 6th. Don't get me started on how much I wish BMW made this more of a WR transmission, but I'll have to deal with the cards as they're dealt.

So here's the down side, as well as my questions. My mileage took an absolute dump, I'm talking like 5 mpg or more. Now I did only test three tank fill ups so far, resetting the MPG computer an checking with a calculator, and there was one really windy section so I'm going to ride more and get more results to make sure that ride wasn't a fluke before I cast judgement.

Here's where I'm confused. When I tested highway MPG with stock gearing riding in 5th gear, I noticed no major changes, and that was slightly lower overall gearing than what I have now with the new gearing and riding in 6th.

So I'm wondering if it's possible if the ECU is doing something different with fuel delivery. I understand most maps are based on gear and rpm (I know, throttle position, an other sensors as well) If the ECU "knows" the gear and rpm speed is a given, but knowing the way BMW engineers is it possible the computer sees a different speed (from the speedo sensor) and it doesn't match what gear/rpm are telling it? And this causes it to react differently? Or does actual speed play a part at all in the fuel map?

For those that have done a gearing change what have your experiences been regarding mileage?

For that matter chime in with your 2 cents on how you ride and how the gearing worked (or didn't) for you.
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Old 05-14-2012, 02:35 PM   #124
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Quote:
Originally Posted by JRWooden View Post
Gary:
Which are you running?
I have the IICE cool, but just recently installed it and have not had chance to hit the trails with it yet,
on the street is seems more "tractable" at low RPM...
I am back to 16. I bought the 15 tooth before the fuel modules and the G2 throttle tube. That will allow you more rpm at the same speed and gets you into a richer part of the rpm band. I did not like it too well because that little snappy throttle was still there and if you found it, it really jerked, because more HP was doing the jerking.

I ran a 17 for a year with the module and the G2. It smoothed the engine vibes and has enough torque to ride almost any forest service road where I ride.


But I have a couple of roads in the hood that sound like what the OP is talking about. So I replaced the 17 with stock. Did a ride last week with the 16 tooth. This road has some steep portions with a couple of switch backs. Somebody had done some 'improvements" They dozed the packed dirt and rock with a few sections of loose shale, to get rid of the water erosion . It now had long stretches of fist size broken rock and about 20 water bars, not all where I would prefer them.


I wish I had taken pics to see if this is what the OP is talking about. I had no problems. I could modulate the power to prevent wheel spin and had enough hp to pull the steep portions. (Grant Ridge DD)

When you do these mods you really look at the whole bike. IMO they really are not a stand alone solution. Part of the reason it works for me is I have also upgraded the suspension. I can travel over terrain faster than I could stock. The shock of hard impacts is not getting transmitted to my throttle hand.


In all honesty I have come to the conclusion I am not as good as I used to be. I see no point in taking a 500lb bike into places I do not feel comfortable riding it there, when I have a perfectly good thumper that easily will do 100miles of pavement. I can't really bad mouth BMW about the gearing when I do the same gear reduction on my KLX 680.
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Old 05-15-2012, 06:01 AM   #125
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Originally Posted by itsatdm View Post
... In all honesty I have come to the conclusion I am not as good as I used to be. I see no point in taking a 500lb bike into places I do not feel comfortable riding it there, when I have a perfectly good thumper that easily will do 100miles of pavement. I can't really bad mouth BMW about the gearing when I do the same gear reduction on my KLX 680.
Thanks! and yeah... I'm pretty much at the same point
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Old 05-15-2012, 08:25 AM   #126
grndzr0
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Quote:
Originally Posted by Romano View Post
Just want to know a good reliable source to put one on my bike.
http://www.sprocketcenter.com/

They are the bomb. Very helpful, and great prices!!!


They helped me pick out the correct ratios, and select a good chain
at the right length.

Ryan
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Old 05-15-2012, 12:59 PM   #127
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Originally Posted by grndzr0 View Post
I am Running a 15/43 for the trail, and a 17/43 for the highway. I have done a couple 2 hour highway stints with the 15, wont do them again. Horrible gas mileage, and pretty buzzy. It only takes about 10 minutes if you are slow to change the front sprocket and readjust the chain.

I have not tried one of the fuel controllers yet, but plan on getting one this summer. So maybe I wont need to be swapping gears out all the time.

Ryan
I installed the Power Booster for last "fire road" ride, my impression is : it does seem to help on bottom end, but definately NOT a "fix" , seems to make top end feel "soft", like there was a pwr loss at freeway speeds. Had my friend try my GS ( he also has a GS800) His impressions were about the same as mine.
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Old 05-15-2012, 03:43 PM   #128
grndzr0
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Quote:
Originally Posted by daveo987 View Post
I installed the Power Booster for last "fire road" ride, my impression is : it does seem to help on bottom end, but definately NOT a "fix" , seems to make top end feel "soft", like there was a pwr loss at freeway speeds. Had my friend try my GS ( he also has a GS800) His impressions were about the same as mine.

Which one were you using?

Ryan
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Old 05-15-2012, 04:12 PM   #129
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Quote:
Originally Posted by daveo987 View Post
I installed the Power Booster for last "fire road" ride, my impression is : it does seem to help on bottom end, but definately NOT a "fix" , seems to make top end feel "soft", like there was a pwr loss at freeway speeds. Had my friend try my GS ( he also has a GS800) His impressions were about the same as mine.

Do you understand all that open loop/closed loop business? It only works when you crack the throttle and put load on the engine. When the oxygen sensor denotes less load on the engine by way of reading exhaust, it starts reverting back to stock mapping.

I think it feels it is little soft sometimes during hot weather or high altitude, but it always feels better when first cracking the throttle. I really only notice it when shifting. Even then I think the bike accelerates better but the throttle feels a little mushy. Just like a carb'd bike.

It should not require this, but it seemed to go through a learning cycle. I remember thinking the bike running soft for the first few tanks.

It is a bandaid. If you want crisp throttle, a power commander can be dialed in for that. But beside the cost you will either lose the oxygen sensor and run in open loop all the time or you will need a wide band oxygen sensor.

I bought it to deal with the abrupt low rpm throttle caused by the high gearing off road. The rest is a bonus.
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itsatdm screwed with this post 05-15-2012 at 09:25 PM
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Old 05-17-2012, 12:07 PM   #130
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Only read this thread back a few pages. Still no joy on a 43 tooth rear? Saw it listed on Sprocket Center, but their site isn't coming up now to check.
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Old 05-22-2012, 02:09 AM   #131
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I am running the 15t front and stock back and it works much better off road than the stock 16t front (for my riding style at least). (The only other modification I have made, that matters for riding, is changing to the the pivot pegs which is the best invention since sliced bread )

However... as itsatdm has pointed out the bike will still suffer from low power in the low RPM range and this is my main issue with the bike at the moment.

So now I wonder which method is best (and cheapest) to solve the issue of the low power/torque at low rpms (below 3k).

I mainly have the issue on really slow sections where I have to use the first gear and find my self having to run with the clutch slipping all the time, so to say. This is however pretty ok since it doesn't happen that often.

The other scenario, which is more common, is when riding twisty segments on 2nd gear below 4k rpm. All is fine and dandy until I want to help the bike turn quicker by sliding the rear wheel and there is simply not enough power to do this so I just accelerate. Friends riding the orange 690 don't seem to suffer the same problem.......
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Old 05-22-2012, 09:47 AM   #132
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Originally Posted by Mark5PA View Post
Only read this thread back a few pages. Still no joy on a 43 tooth rear? Saw it listed on Sprocket Center, but their site isn't coming up now to check.
I just put a 43 on from sprocket center, It is a lot heavier built that the stock sprocket. I am running a 15/43 for the trail, Probably as low as I want to go, It runs pretty hard on the faster gravel sections...

And 17/43 for the street. This is a tad higher than stock. I like the set up pretty well. I got a longer chain at 118 links when I did the swap. I have plenty of room with this setup to put on an 18T front as well if I wanted.

Ryan
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Old 09-13-2012, 08:25 PM   #133
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Eek 15 tooth sprocket splines not fitting!

I was disappointed when my new 15 tooth sprocket, bought from TT, wouldn't fit on the splines of the output shaft. The stock 16 tooth slid right off and back on. I tried a few times, lining it up very precisely and just couldn't get it to drop on. I even tried a couple of light taps with a dead blow and still couldn't get it on. It is the more expensive TT option with the "lightening" holes. Seems like the splines are just to fat on the sprocket. Anyone else have this issue on an aftermarket sprocket? I'm thinking of trying the Renthal one.
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Old 09-14-2012, 08:12 AM   #134
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TT makes 2 sprockets. My 15 tooth was the cheap version, it looks like it was as cast. I have the the same problem. The 17 tooth was the high end version and appears to have been bead blasted. It fits as it should.
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Old 09-14-2012, 09:49 AM   #135
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TT makes 2 sprockets. My 15 tooth was the cheap version, it looks like it was as cast. I have the the same problem. The 17 tooth was the high end version and appears to have been bead blasted. It fits as it should.
Did you have any trouble getting a refund out of TT USA? I need to send the offending sprocket back to them in the next few days.
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