The spreadsheet uses rolling distance, which is the distance that your bike moves with one revolution of the rear wheel. It is impossible to calculate the number of revolution that the rear tire makes per mile using rim size, tire size, tire circumference etc. because of the circular cross section of a motorcycle tire, which is also influenced by tire pressure, tread pattern, wear and rubber composition.
To measure your rolling distance:
1. Mark the sidewall of the tire where it contacts the ground. 2. Mark the ground at that point as well. 3. Roll the bike forward for one revolution of the rear tire when the mark on the sidewall is again at the point of contact with the ground. 4. Mark that point on the ground. 5. Measure the distance between the two marks on the ground. That is you rolling distance.
1. Click on the Rolling distance cell in the spreadsheet to reveal a pull down of rolling distances from 75 to 85 inches. 2. Select your rolling distance 3. Click on the sprocket cells to reveal a selection of sprocket choices. 4. Select your combination of sprockets.
Read the RPM's vs MPH on the chart.
Last Edit: Nov 8, 2008 21:14:38 GMT -5 by pamcopete
GOOD AFTERNOON ALL, WHAT IS THE BEST COMBO FOR SPROCKETTS FOR HWY SPEEDS. I STILL HAVE THE ORIGINALS ON MY 81 650 SPECIAL SO WINDS UP A LIL HIGH FOR LONG HIGHWAY RUNS. ANY SUGGESTIONS VERY MUCH APPRECIATED. JORAY KEEPIN IT IN THE WIND!!
A lot of guys use the 18/30 but they must live in flat country it dont work so good in Mt. OK once you get moving but hard on the clutch. I dont worry about it myself, I have other bikes for the interstat. I might try an 18/30 combo. The spread sheet is the nuts, nice job on it Pete
WHAT IS THE BEST COMBO FOR SPROCKETTS FOR HWY SPEEDS.
I'm real happy just swapping the front to an 18 tooth on my '83 Heritage and leaving the 34 rear alone. That drops the RPM a couple hundred and takes the buzz out of bopping along the two lane. Still using the OEM length 104 link chain too.
Can't tell you about freeways - I don' do da freeways, eh.
** Keep in mind you need to lose that silly case protector thingie if you go bigger on the front sprocket. Simple enough, and no problems as long as you keep the chain adjusted properly.
How is it the MikesXS 5th gear can be used without a matching gear? Am I missing something? My understanding of gearboxes is that if a tooth is added to one gear, it would have to be removed from it's mate.
They reshaped the teeth and made them smaller to get an extra tooth on there.
75 XS650B with 79 forks and dual disc, braided lines, disc brake on back, Pamco ignition, Pamcopete's reg/rec mods, kill switch relay, home made harness, all LED turn, brake and tail lights, tapered head bearings, bronze bushes in swing arm, soon to get shock and fork upgrades
r80rt: :)This is a splendid write up, THANK YOU!!!!
Dec 26, 2015 16:54:05 GMT -5
mashermoto: What the what is this shoutbox for? Or should I shout, WHAT THE WHAT IS THIS SHOUTBOX FOR!
May 12, 2016 22:22:21 GMT -5
motormike: Good Day ...just a FYI.. Wild Cat is this Labor Day weekend. Still go'n on. A few 650's still make the scene. Various rides at different skill levels each day.. awards dinner sunday eve. BS in the park'n lot after dinner.
Aug 23, 2016 7:57:01 GMT -5
lsettle: First post in over 6 years!
Aug 28, 2016 19:45:17 GMT -5
kardon: Wow quiet here, where did they all go.
Oct 7, 2016 2:18:13 GMT -5
gggGary: XS650.com LOL
Feb 16, 2017 20:49:02 GMT -5
buell88: Anybody have any idea who built the xs650 tracker used in the Draggin Jeans Ad on Pipeburn?
May 16, 2017 16:24:09 GMT -5
joshua: The regulator/rectifier unit I got from Mikes PMA has closer hole spacing than original. Are we supposed to mill the holes to fit?
Jun 7, 2017 19:25:58 GMT -5
joshua: My bad. I found the bracket they supplied to mount the rectifier/regulator... Uh oh. How is this meant to work? Which way is it meant to mount? Looks like I have to use some spacers or something. Good instructions would be nice.
Jun 7, 2017 22:09:52 GMT -5
craig8johnson: Not sure if this is the right spot or not but oh well...
Jul 11, 2017 18:04:15 GMT -5
craig8johnson: I'm checking the charging system. I'm afraid I might have fried the last battery. With the solid state regulator (after market) what should it be charging at. The book says, I think, 15 volts. I'm hitting 17 when revved. Is that too high?
Jul 11, 2017 18:06:19 GMT -5
gggGary: Yes 17 volts is too high, about 14 volts is max, sounds like you don't have the right regulator or it's wired wrong.
Jul 13, 2017 6:54:33 GMT -5
dean: Just saying Hello, new member who is going to fix up a 79 XS650 that has seen its better days. I will definitely have lots of questions coming up.
Jun 23, 2018 16:45:32 GMT -5
tt650: Trying to breathe life into a 1980 that's been stored (indoors) for 25 yrs. Air filters are dry rotted. Have cleaned carbs but she only runs briefly on choke then stops. Need jet setting info and other ideas that might help her idle and rev.
Jul 3, 2018 19:15:19 GMT -5
trix13: Hey everyone! New to the forum and am fighting those gremlins!! New charging system, ignition switch, coil and fuse box. Resistance is higher than normal on the ignition pick up so I'm trying to find one. No such luck yet.
Aug 16, 2018 8:50:48 GMT -5
trix13: Also, even though all of my connections are clean, I cannot seem to find out why , when at higher rpms, I hit the signals and the rpms pulse with the signals...hahah. same with the brake light. I appreciate all input!!
Aug 16, 2018 8:55:08 GMT -5
bob99: how do I post a question. I am new to the forum
Jun 6, 2019 10:52:10 GMT -5
adlpc: Hello all! Been enjoying your edifying posts and discussions - and as a fan of the XS650 since my early teenage years happy that I now own a 1980 Special which I plan to turn into a vintage half faired racer. Thank you all for being here!
Oct 1, 2019 0:58:56 GMT -5
jimothyj: Hello everyone, I just joined & wish would have known about this site in 2014 when I brought my 1974 TX650A back from the grave. I have spent a good deal of $$ and alot of time on it. Just painted it and working on electrical, I will post pics soon,
Apr 10, 2021 2:14:13 GMT -5
louisvan: trix13 - I had a problem with my 1975 SX650. When I got to highway speeds, the engine lost power. The problem was in the connectors. At a certain vibration and the wind pushing on the wiring loom, the connector lost continuity. A bad crimp to the wire.
May 20, 2021 1:19:09 GMT -5