The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: Jon_P on August 15, 2007, 12:57:27 AM
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ok so the one guy at the show got me thinking, do i have the right final drive and is that why she likes to buzz and drink plenty.
so where do i look to see what ratio i have and what is stock, i cant find it in my books??
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It is stamped in the final drive. Look near the fill hole for the driveshaft oil. On my bike, I would have to wipe away a little dirt to read them easily.
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For your model it's 9/31.
Bill................;-)
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the only numbers i can find stamped on the final drive are stamped on the inside of the unit so ou have to look throught the tire. they are 8 and a 56 but are not stamped together or with a /, in fact the 8 is sideways.
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boy oh boy my local dealer service manager is a 100% jerk! i have a feeling if he doesnt know the answer to the question this is how he acts. all he said was be happy that it goes down the road!
now i havent ridden it much with the gps to know how many miles i get from a tank of fuel but its not many, and i wonder if it is cuz this final drive? could that cause some of mine low mpg??? it has all kinds of low gearing grunt but when she gets in four and fifth there is not much there without a running start. or am i asking to much?
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Without knowing the rear end ratio, it's hard to say. This is a crude method on determining the answer, but you could pull back the boot over the universal joint, and count the revolutions of the drive shaft to rear wheel revolutions to be absolute sure what you've got. But it sounds like you may have an other than standard rear end.
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Okay, outside of going to an R80, what kind of final drive can I put on Blue to keep gears 1-3 close to the same, but let 'er run 4000 rpm at 75 mph?
Is this asking too much?
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Okay, outside of going to an R80, what kind of final drive can I put on Blue to keep gears 1-3 close to the same, but let 'er run 4000 rpm at 75 mph?
Is this asking too much?
Yes
At least, it it will not happen by swapping R.E. ratios.
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Thanks Rob, that's kinda what I thought, unfortunately, but figured maybe I'd missed something somewhere.
Sounds like it's time to go back to the 2 Bike Theory...
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There is a place in Germany that has alternative 5th gears, to do what you may want. I have never wanted for anything different than what I have.
Sometimes I get on the I'state in a hurry and look for a 6th gear accidentally. I guess that is what you might mean. But when I am out for the weekend on the slab, 5th gear at 75mph is fine - as long as I can stand the wind!
I'm beginning to get a 2nd bike bug... thinkin' RS...
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Sometimes I get on the I'state in a hurry and look for a 6th gear accidentally. I guess that is what you might mean. But when I am out for the weekend on the slab, 5th gear at 75mph is fine - as long as I can stand the wind!
I'm beginning to get a 2nd bike bug... thinkin' RS...
yeah [smiley=thumbsup.gif], thatswhati'mtalkinabout...
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I would like some taller gearing for the wide open spaces myself. I came across an unofficial listing of ratios / models here: http://tinyurl.com/32vve5 Think I'll tuck it in my pocket for my next bone yard / swap meet visit. I have no Idea how interchangeable these rears are. Probably not at all is my guess. If your bike is really thirsty / buzzy I wonder if you have an r45 gear set. Grab the GPS and watch the speed/ RPM it would be interesting.
rich
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Geeze, how fast are you guys going? 90 in top gear feels nice, smooth, and easy on my R65. I'm more worried about the aerodynamic effects from my saddle bags than anything else. Well, tickets aka freedom tax.
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well its not how fast i am going, more that how fast i would like to go ;D
i will try this weekend to take a longer look at it, i will pull the boot and take a grease pen and make a mark on the drive shaft and tire and start counting, think that is about the only way i will know for sure. then i will know what i need to do or not do.
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[size=12]Anymore, interstate hwy speeds between cities are 70 mph [113 kmh], which equates to 75 [121] cruise ::)
When I talk about how fast I am going, I am talking in GPS figures, not Motometer.
I used to think 85 mph [137 kmh] (indicated) was a nice cruising speed, and I was impressed that the 'little' 650 could do that.
Then I got a GPS receiver and found out the truth!
I've never really written it down, but that 85 mph [137 kmh] is really about 73 [117]...
100 mph [161 kmh] indicated is about 85 [137], I think.
The only time I am going these speeds is when the bike is loaded with gear. That is usually two saddlebags loaded to capacity, a sleeping bag on the rear rack, and a tent/pad/chair on the seat behind me.
That limits my top stable cruising speed to 80 mph [129] Anything above that, and the front end starts getting spooky. I really need to rebuild the forks.
The good news is, I don't have to worry about getting busted on the interstate.
It is always those NON-interstate highways that LOOK like interstates (new bypasses around towns) but have lower speed limits, like 55? [88?] where I get busted... :-[[/size]
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Ah, you have one of the pre-Carter speedometers. Mine only reads to 85 and according to Snowbum they are very accurate. I was calculating my speeds over that based on the tachometer; I can cruise quite happily at 6500 rpms but I will get a ticket, maybe even on our interstates which is insane.
As for GPS accuracy, I run with a few people who carry those things. We run the same 10? mile loop every Tuesday, and their distance varies from just under 10 to almost 11 miles for the same route. I tell them it depends on the side of the road they run on.... ;D
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Around here, actual Interstate speeds run 75-85 mph, and the cops rarely ticket for speeding as long as you're riding/driving smoothly & sanely. I have an 80 mile daily highway commute and often lock in with other vehicles running 85-90 mph, well spaced apart and flowing smoothly, for 15-20 miles at a stretch.
When done properly, by good drivers, I honestly believe this is much less dangerous than the chaos, frustration and "road rage" created by the idiots who park themselves in the left lane at 64 (or 94, doesn't matter) mph and refuse to move or let anyone by. These same a**holes will let 20 miles of traffic get jammed up behind them on a 2-lane Interstate stretch, yet move into the middle lanes and actually speed up when a 3-4 lane section approaches!.
Even the big trucks have taken to driving like this. Is it not still taught in drivers ed that the left lane in a passing lane, and that slower traffic should always stay to the right?
If I'm ever crowned the King of the Highway Patrol, there'll be some big changes, by golly! ;)
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I'd vote for you.
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how can you have a pre-carter speedo? the first year of our beloved r65 was late 78? right? he would have been in office for a couple years????
i dint get to my bike this weekend liked i hope. worked on the "new" home all weekend. i finally got the floors ready to seal, got the first two coats on and it looks nice.
so back to subject at hand i havent figured out what ratio i have.
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You are sure it is a BMW final drive?? Everyone I have seen look like this:
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fwww.pbase.com%2Ftomfarr%2Fimage%2F84175721%2Fmedium.jpg&hash=adc5c5e0f247276399dad391359d3b564061dd90) (http://www.pbase.com/tomfarr/image/84175721/large)
click for a different size
Of course, there is no guarantee that the gear set has not been changed from what was originally stamped on at the factory.
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ok now i found it. looked to be sanded, polished or gound? down alot. took a peice of paper and a pencil and did a rub to see it. it tells me it is a 31/9. with a quick removal of the boot and some tire chaulk i started counting and it came out to 31 to 9.
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If one wanted to alter the gear ratio of the rear drive to suit their particular riding style, would it be possible to replace ring or pinion gears ? Are the parts interchangeable between different ratio rear drives, or are they specific to a particular rear drive ?
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i was thinking the same thing, i have a feeling it would be better to do it in the tranny. do something with 5th! and while i am there maybe 4th it could use a little more. or save my pennies and go get a big brother to the r65 :o and keep this for playing around town.
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I am about 95% sure (pure assumption :P) that the gear sets are interchangeable for similar years.
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When I get my '81 R65 out on rural interstate cruising around 85 mph indicated, the tachometer is indicating about 5600 rpm ( it really doesn't sound like a happy engine at that rpm). My R1150R at 85 mph is indicating about 3500 rpm, and getting about 60 mpg while doing it ! It sounds like I need a sixth gear/ overdrive to get the rpm's down and increased fuel mileage.
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My chart from January when Steve wanted to know how fast he was going:
(these are speeds indicated on my Garmin GPSr)
3rd gear
30 mph (48.27 kph) = 3000
35 mph (56.30 kph) = 3500
40 mph (64.36 kph) = 4000
4th gear
45 mph (72.40 kph) = 3750
50 mph (80.45 kph) = 4000
55 mph (88.50 kph) = 4750
5th gear
55 mph (88.50 kph) = 4000
60 mph (96.54 kph) = 4500
65 mph (104.59 kph) = 5000
70 mph (112.63 kph) = 5500
75 mph (120.68 kph) = 6000
Above figures are on a 31/9 final drive ratio.
Someone mentioned they don't think a GPS receiver can be very accurate as a speedometer. True, it depends on clear sky for optimal sensitivity, but I have ridden past those automated radar signs that the police park alongside the roadway. Coming home from work at 1 AM with no other vehicles around. I even turned around and came back on it a 2nd time just to verify. It was a 40 MPH zone. I was indicating 40 on the GPSr, and the radar showed me at 39. I can live with that.
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I go past one of those "INFO" only speed indicators put out by Phoenix police , at the entrance to Phoenix Skyharbor Airport, and both the R65 and R1150R speedometers indicate 1 mph faster than the radar indicator, from 30 mph up to 75 mph.
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When I get my '81 R65 out on rural interstate cruising around 85 mph indicated, the tachometer is indicating about 5600 rpm ( it really doesn't sound like a happy engine at that rpm). My R1150R at 85 mph is indicating about 3500 rpm, and getting about 60 mpg while doing it ! It sounds like I need a sixth gear/ overdrive to get the rpm's down and increased fuel mileage.
Yep Bob, you're helping to reinforce my 2 Bike (minimum)Theory: thanks [smiley=thumbsup.gif]
Although 5-8 bikes would be ideal, we should all have at least our R65s for around town work, short hauls, and fun in the corners, and a higher hp/taller geared ride for highway work.
I've been counting my pennies carefully, and I think I'm just about to have enough to pick up a nice low-miles R100, or maybe an R1150R, sometime before next Spring... ;)
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Mine will definitely be another airhead. Definitely an RS. Probably a mono-shock. My only concession to progress... ;)
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I've gone in a different direction....
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fi201.photobucket.com%2Falbums%2Faa12%2FSemper_Gumby%2FMy1969BSAFirebirdScramblerLH.jpg&hash=00fb6769a19b9a09cc0feb932bea370284ce9040)
Oo La la!
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I didn't know you had high pipes on that; for some reason I thought it was a Lightening. Cool! A dual sport, sort of!