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Trying hard not to be a wet blanket here but don't get to carried away with this thing, remember ying and yang - for every action there's an equal and opposite reaction and all that.. After thousands of miles experimenting(chain) on various gear ratios, my opinion is 3250 revs @ 60mph is TOO LOW for the eleven, and full throttle in first gear is gonna destroy 1st gear quick smart! Believe me, try a few dragstrip style launches and the cogs in the gearbox are gonna spin like a childs rattle toy - only the rattle will sound like a .50 cal machine gun! If you do the 750 mod, be prepared to be restricted to relatively slow soft takeoffs - a bit of a bummer when some spotty faced kid in a souped up cage can whip your ass from the traffic lights...
Once the bike's up and running in the higher gears, no problem, no need to hold back on the gas.
I found the best ratio for performance, reliability and economy is 3600 - 3700 revs @ 60mph. As far as improved economy with a taller 5th gear, you're still gonna need good riding conditions and you're still gonna need to be taking it easy on the throttle to get a consistently noticible improvement, otherwise the economy difference is negligible, there won't be any improvement at all on hilly twisty roads or constant headwinds. All in all, that extra tall gear ratio is suitable only for relaxed touring-type riding.
Originally posted by pggg Trying hard not to be a wet blanket here ...............
Well you are ...
SO GO AWAY!
But seriously,
As far as 3250 at 60 being too low...It may be for you but not me. Especially with 95 hp and 70 ft-lbs at the rear wheel.
Dragstrip launches??? If you read the opening statement of this modification procedure I said... ''I am so utterly please with this modification I would recommend it highly to any Eleven owner that is not pre-occupied with ¼ mile times.
I submit to you a stock geared Eleven ...with a stock engine....will destroy first gear if you don't treat it right. I've seen it happen too many times.
The Eleven is a poor excuse for a 1/4 mile machine. Oh yes people do it...but it certainly wouldn't be my first choice. That is exactly why the old GS1100E is still drag racing to this day...even Pro-stock... and not the Eleven. The transmission on the Eleven is not designed for continous drag racing.
However it is durable if treated right.
Tell ya what pggg, sit tight for about 3 or 4 months. By then I'll have 10 or 12,000 miles on Zilla. If it doesn't work you'll be the first to know.
As a matter of fact I retract my previous statements! I DON'T recommend this mod now. Just keep your bikes all geared higher than a cat's back in a street fight. I'll suffer the rpm benefits ...eh er consequences all by my little slef. Hehehehehe...
Man, thanks for the great presentation. It's looks easy to do, I'm looking tomorrow for a XS850 final drive to see if it has the
1J7YO # to make the swap. A guy just afew miles from my house has one. Again thanks for the spacer mod idea and that washer trick is so cool. I want to use a modern lower profile rear tire on my 17" wheel so I think I"ll need the lower gear ratio to match?
Cheers, 50gary
Ok Chop....there's no need to lie. I mean it's cool mod and everything but it won't fix the dogs on my second gear!
Now to the WAHOOO part.
I could stand it no longer. I was going to test the fuel economy tomorrow but curiosity got the best of me. Topped the tank couple hours agoand rode the turnpike toward Tulsee (that's Tulsa for you non-rednecks). I averaged about 80 mph. Normally I would get about 32 to 33. Tonight I went 114 miles on 3.1 gallons.
We've discussed this at length (I and some other XSives) and am convinced coupling a 17" wheel with this mod would probably be too much.
Gear reduction calculations predict the bike would be revving about 3700 at 70 instead of the OEM setup of 4500. That's a huge step. I fear first gear lauches would be a chore to say the least.
I think you are on the right track by trying to find a very low profile tire to couple wiht this drive. As a matter of fact you might even want to go with a 16" special rim.
Couldn't resist the tease. I just went out to the garage and measured my XS110 rear tire circumference. It's 83" (5.10 x 17") My XS650 has a sportbike rear (160/60/17"), it's only 78.25" circumference that's 94.27% roughly 6% smaller.
The XS750 VS. the XS11 FD ratio is 2.92/3.30= 88% that's 12% difference, therefore even with the 750 FD I should see a net gain of 6%. By your numbers 4500 VS 3700 rpm = 800 rpm difference. I should see half that or 4100rpm at 70mph?
Cheers, 50gary
Your presentation get's an A+ and the results speaks for itself,very solid engineering.The Eleven came out when the speed limits were 55 mph on the Interstates and was geared to cruise at 60 mph at about 3750 to 3900 depending on whether it was a standard or special.The gear ratio was the one thing I have always complained about.Cruising along at 5000 rpm serves up only 75 mph to 80 mph with the 130-90x16 tire.I am putting a 17 inch wheel with a 26.4 inch diameter tire on my special which will give me 3 mph more@ 5000 rpm than I have now,not much but every little bit helps.Someone was talking about putting a 16 inch special wheel on a standard and this might not work as the right swing arm on a standard is different (narrower) than a special as I have discovered while figuring out a way to put the standard wheel on the special.You now have the perfect combination for those smokin trip's to Albuquerque,hammer down and watch for smokey in a plain wrapper. [/B][/QUOTE]
81 Black "1179" Xcessively trick Super Special. One owner (me).
I'd be careful with that backlash thing, if you guys know how to dial in those bevel gears in perfectly, even with the same shims as previous, BMW's strip their pinion gears, worn at the bottom of the pinion teeth - usually caused by owners stripping the driveshaft the wrong way.
Maximan, that's true 16" is smaller than 17" but that's the wheel dia. The O.D. of the tires is way different, the sportbike tire is only 60 series compared to the old 90 series tire I measured carefully, the difference is a whopping 4.75" in "roll-out" (circumference.) Having said all that, I know I can't get the 160 tire in the swinwarm so I have to go to a narrower tire. Probably 140/80/17" Sorry if this is all old news.
Cheers, 50gary
All things being equal a 17 inch 130/90 is always taller than a 130-/90 16.
I have never seen any thing wider than a 140 on an Eleven because generally it won't clear the shaft housing. If you know of some tire that is XSeptionally wide that will fit please inform. It would be interesting to know.
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