SBBXX Posted October 10, 2006 Share Posted October 10, 2006 Thanks for the help BTW. So far, I really like it. I do believe I'm another convert. I just have to watch my speeds now. I think the speedo error has saved my ass more than once. marty Quote Link to comment Share on other sites More sharing options...
Guest rockmeupto125 Posted October 10, 2006 Share Posted October 10, 2006 Yeah, you should be spot on with that. It gives me a good feeling...I like a gauge that's accurate. I recently switched to oversize tires on my car, cuz they were $12 cheaper............ding! Speedo is dead accurate, and the odo records 20 miles for every 21 actual. (gotta remember to factor that in when I check my gas mileage) Quote Link to comment Share on other sites More sharing options...
Warchild Posted October 10, 2006 Share Posted October 10, 2006 What a timely subject... I have a ride next year where I will be extremely interested in lowering my RPM's at typical Nevada speeds.... Couple a quick questions for those who have gone to 18T: 1) How bad was the impact to accelleration? Noticable, but not too bad? Or are you finding you really need to wind it up when you're coming off the line? How about uber-tight twisties.... are finding you need to take some of the tighter, slower corners in a lower gear than before? 2) In 6th gear at highway/desert speeds, what kind of drop in RPMs are you seeing with 18T at, say, 70mph? 100mph? 3) I assume you'all are scoring a good, quality 18T steel countersprocket.... what brand are y'all using? TIA, gentlemen.... Quote Link to comment Share on other sites More sharing options...
Tempest Posted October 10, 2006 Share Posted October 10, 2006 This is interesting.......... So we're actually going UP on the front sprocket size? Makes a difference, cos normally people only talk about going down on the front to improve acceleration. On my Firestorm for example I've dropped 1 tooth at the front and added 2 teeth to the rear sprockets, and it accelerates like mad So, with the Blackbird we're actually going the other way to slow acceleration down? Quote Link to comment Share on other sites More sharing options...
Warchild Posted October 10, 2006 Share Posted October 10, 2006 So, with the Blackbird we're actually going the other way to slow acceleration down? No.... I am strictly interested in this mod for MPG issues only. In fact, I will use the 18T front sprocket solely for this event I am doing next year, then I'll go back to the stock countersprocket after the ride. I use my XX primarily for Endurance Riding nowadays. In the vast desolate Nevada outback, the speeds we travel at - all day long - often yield MPG figures in the low-mid 20's. Even carrying 11.5 gallons of fuel, this still means I only have about a 220-240 mile range before my low fuel light start to glow steady... I really need something more on the order of at least 30 mpg for the event in question. Too, I am toying with the idea of a PC-IIusb and purposely lean out the mixture to try to squeeze an extra couple MPG, if its doable. Obviously, I need to be very careful going that direction. I can't lean it out too much, because I don't want to burn up the exhaust valves traveling at 130+mph in too lean a condition for many days in a row. Too, every Power Commander I've installed over the years almost always results in a loss of a couple MPG (which is pretty much expected, since the vast majority of the time you are enrichening the mixture from stock). But if I purposely program the PC-III a bit lean, the motor will run very, very hot, similar to the way the FJR1300 runs right out of the crate. Even busting along at 120+ mph on the FJR, I can still get 31-33 mpg all day long. I need to mimic that 30+ MPG (at mega-high speed) on the XX for this event next year.... :icon_shhh: Quote Link to comment Share on other sites More sharing options...
bartonmd Posted October 10, 2006 Share Posted October 10, 2006 Dale, Acceleration is virtually untouched... In fact, because it's easier to launch, my 1/4 mile time went down a hair... I'm just using an AFAM from WBR... In 6th gear, the stock speedo is correct, right on the dot... so 8% lower rpm at speed compared to the stock setup... Mileage went up by about 10%... On my '97, even with ethenol additive fuel, with the cruise set at 80mph, I typically get ~48-49mpg with the top GIVI on... Mike Quote Link to comment Share on other sites More sharing options...
R1000 Posted October 10, 2006 Share Posted October 10, 2006 Dale, Acceleration is virtually untouched... In fact, because it's easier to launch, my 1/4 mile time went down a hair... I'm just using an AFAM from WBR... In 6th gear, the stock speedo is correct, right on the dot... so 8% lower rpm at speed compared to the stock setup... Mileage went up by about 10%... On my '97, even with ethenol additive fuel, with the cruise set at 80mph, I typically get ~48-49mpg with the top GIVI on... Mike 17/18 is about 5.5% lower rpm compared to stock setup Quote Link to comment Share on other sites More sharing options...
SBBXX Posted October 10, 2006 Author Share Posted October 10, 2006 Dale, Acceleration is virtually untouched... Mike Haven't had it on long but so far, this is what I'm finding as well. 6th gear was more of an overdrive for me anyway and I would only use it mostly on the expressway. Haven't had it in the twisties yet but I was always in 3rd/4th going through them and I thought it was reving a tad too high most of the time. I'm hoping this will fix that up. The speedo and Tach don't change, but my actual speed is now closer to what the speedo says it is, instead of the 8% less for the speedo error. The gearspreadsheet is great. Just plug in 18 instead of 17 for the "front teeth" value and bob's your uncle. Quote Link to comment Share on other sites More sharing options...
ironmike Posted October 10, 2006 Share Posted October 10, 2006 This is beginning to sound like a very pragmatic mod... Does the increase of one tooth on the front sprocket have any impact on the required chain length/link count..? :icon_think: Quote Link to comment Share on other sites More sharing options...
SBBXX Posted October 10, 2006 Author Share Posted October 10, 2006 This is beginning to sound like a very pragmatic mod... Does the increase of one tooth on the front sprocket have any impact on the required chain length/link count..? :icon_think: That's the beauty of it. No. Same count. Quote Link to comment Share on other sites More sharing options...
bartonmd Posted October 10, 2006 Share Posted October 10, 2006 Dale, Acceleration is virtually untouched... In fact, because it's easier to launch, my 1/4 mile time went down a hair... I'm just using an AFAM from WBR... In 6th gear, the stock speedo is correct, right on the dot... so 8% lower rpm at speed compared to the stock setup... Mileage went up by about 10%... On my '97, even with ethenol additive fuel, with the cruise set at 80mph, I typically get ~48-49mpg with the top GIVI on... Mike 17/18 is about 5.5% lower rpm compared to stock setup I realize what the spreadsheet says, and what the ratio difference is, and I didn't have GPS when I had the 17T, but the side of the road speed signs always said 8% lower than my speedo did (standard blackbird speedo mis-calibration), and now with the 18T, GPS at 100mph is dead on what the speedo is reading... that's on level ground with the cruise control set... IronMike: No, it still takes a 110tooth, but is just a bit closer to the hugger with a new chain... mine doesn't rub the hugger, but any gravel on the tire when going slow in the rain does rub... SBBXX: I was the same way... third was too high of a ratio, 4th was too low... Now, third is about right for almost everything around here... I do downshift to second for the L turns though... Mike Quote Link to comment Share on other sites More sharing options...
willxx23 Posted October 10, 2006 Share Posted October 10, 2006 The gearspreadsheet is great. Just plug in 18 instead of 17 for the "front teeth" value and bob's your uncle. Where's Kmwhateverthefuck, you plug 18 in there and the top speed @10,800 rpm goes to 191.5mph. :icon_duh: Quote Link to comment Share on other sites More sharing options...
Guest rockmeupto125 Posted October 10, 2006 Share Posted October 10, 2006 Launches are fine whether I'm alone or with a passenger. I do okay at the drags for an old fat guy. Its a little more relaxed on the highway, and the speedo is right on. Twisties you have to remember to get down a gear a little earlier. This year at SeXXT I was caught too many times with an uphill starting midcorner or immediately after the corner and no powerband in sight of the gear that I was in. And yes, stock chain length, which means it shortens the wheelbase a bit for those that know about that sort of thing. Quote Link to comment Share on other sites More sharing options...
Warchild Posted October 10, 2006 Share Posted October 10, 2006 And yes, stock chain length, which means it shortens the wheelbase a bit for those that know about that sort of thing. ACK.... I hadn't thought of that till you mentioned it.... Since installing the Wilbers shock (with it's built-in ride-height increase), the steering is now so fast, it made the Avons feel almost twitchy. So much so, I went back to Pilot Roads to counteract that sensation. Shortening the wheelbase should also quicken the steering to some degree..... which might not be the optimum situation for what I need the bike to do. Maybe I will take a look at 111 links on the chain, ASSuming that leaves sufficient travel left on the chain's rear adjustment mechanism to allow for chain stretch over time.... :icon_think: Quote Link to comment Share on other sites More sharing options...
JB4XX Posted October 10, 2006 Share Posted October 10, 2006 I swapped out to a JT 18 tooth the night before Nexxt. When leaving nexxt, I filled up at the intersection of 220 and 180, then didnt stop until almost the PA/OH border, 225 miles of 80mph. My bike is a jetted 97 model and got 52mpg of constant cruising. I only stopped for fuel one more time on the 650 mile ride home. Saved plenty of time doing 700 miles in only 10.5 hours. You do have to watch the speed because you actual ARE DOING 80+mph when it says it. I have forgotten to hit 6th gear a couple times. Stays at 4000 rpm at 78mph in 6th with stock rear gear. Quote Link to comment Share on other sites More sharing options...
Venus97 Posted October 11, 2006 Share Posted October 11, 2006 These results mentioned in this thread are based on 18T Front and leaving rear the same (45T), correct? Quote Link to comment Share on other sites More sharing options...
JB4XX Posted October 11, 2006 Share Posted October 11, 2006 These results mentioned in this thread are based on 18T Front and leaving rear the same (45T), correct? Yeppers! Quote Link to comment Share on other sites More sharing options...
CALCXX Posted October 11, 2006 Share Posted October 11, 2006 I have been running with the 18T all summer. Don't see any reason to go back. No noticable differance in acceleration. Speedo is dead accurate now according to my GPS. I'm not finding any mileage improvement though unless you factor in the 8% error from the 17 tooth then, I must be getting 8 % better mileage? I have no complaints in the corners with the taller gear since my gps reads 74.9 mph in 1st gear and 104.4 mph in second gear. That covers about any corners around here. Could be my imagination but, 6th seems pretty tall. Packin double is still no problem making high gear passes. Quote Link to comment Share on other sites More sharing options...
blackhawkxx Posted October 11, 2006 Share Posted October 11, 2006 And yes, stock chain length, which means it shortens the wheelbase a bit for those that know about that sort of thing. I have often thought about this. You any of you felt any difference in handling due to wheelbase change while changing gears size? Quote Link to comment Share on other sites More sharing options...
bartonmd Posted October 11, 2006 Share Posted October 11, 2006 And yes, stock chain length, which means it shortens the wheelbase a bit for those that know about that sort of thing. I have often thought about this. You any of you felt any difference in handling due to wheelbase change while changing gears size? no. Quote Link to comment Share on other sites More sharing options...
Keith Posted October 11, 2006 Share Posted October 11, 2006 Couple a quick questions for those who have gone to 18T: 1) How bad was the impact to accelleration? Noticable, but not too bad? Or are you finding you really need to wind it up when you're coming off the line? How about uber-tight twisties.... are finding you need to take some of the tighter, slower corners in a lower gear than before? 2) In 6th gear at highway/desert speeds, what kind of drop in RPMs are you seeing with 18T at, say, 70mph? 100mph? 3) I assume you'all are scoring a good, quality 18T steel countersprocket.... what brand are y'all using? I put an 18T on about three or four months ago. So far, I'm very happy with the change for my riding location and style. To answer your questions: 1) I haven't noticed any impact on acceleration, but I'm not one to go WFO all the time. The 'bird always had more than enough acceleration for me and that remains. I really like the larger sprocket in the twisties up here in the Sierra Nevada; in many places where the twists are tight (like in the switch backs on the east side of the Sierra on highway 4 - Ebbetts Pass), the taller gearing allows me to stay in first without winding out the RPMs. With the 17T, I seemed to always be hunting back and forth between first and second gear. 2) I never really checked out the drop in RPMs, but the difference should be around 6%, no? I rarely spend any time at 100MPH (like, almost never), so certainly can't tell you the drop at that speed. 3) I purchased my sprocket from White Buffalo Racing and is, I believe, and AFAM sprocket. It's a good quality steel sprocket, in any case. Hope that's helpful. I have often thought about this. You any of you felt any difference in handling due to wheelbase change while changing gears size? I've observed absolutely no change in handling due to the larger sprocket. Quote Link to comment Share on other sites More sharing options...
Mikesblackbird Posted October 12, 2006 Share Posted October 12, 2006 3) I purchased my sprocket from White Buffalo Racing and is, I believe, and AFAM sprocket. It's a good quality steel sprocket, in any case. Is this the correct part number? Sounds like a mod I need to make: http://www.whitebuffaloracing.com/shopexd.asp?id=683 Thanks. Mike Quote Link to comment Share on other sites More sharing options...
Pete in PA Posted October 12, 2006 Share Posted October 12, 2006 I'm happy with mine (JT) RPM's feel just right now. I used to be looking for a 7th gear on the highway. Quote Link to comment Share on other sites More sharing options...
Keith Posted October 12, 2006 Share Posted October 12, 2006 Is this the correct part number? Sounds like a mod I need to make: http://www.whitebuffaloracing.com/shopexd.asp?id=683 Thanks. Mike I don't think so. I don't have the sales receipt anymore, but if I go through their web page selection process, I come up with 20602, not 20504. You are talking about a sprocket for the Blackbird, right? Quote Link to comment Share on other sites More sharing options...
Mikesblackbird Posted October 12, 2006 Share Posted October 12, 2006 Is this the correct part number? Sounds like a mod I need to make: http://www.whitebuffaloracing.com/shopexd.asp?id=683 Thanks. Mike I don't think so. I don't have the sales receipt anymore, but if I go through their web page selection process, I come up with 20602, not 20504. You are talking about a sprocket for the Blackbird, right? Keith, I had trouble working through their site and now I have it. Thanks for saving me from dealing with a return on an $18.00 part. Mike Quote Link to comment Share on other sites More sharing options...
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