Who owns the fastest XS11?

[Snow]

If I ever spun my XS to 10k in top gear (if even enough power exists), I would first get a very hefty insurance policy... both life and dismemberment...

[MAXIMAN]

Re: 10k redline

Originally posted by xschop
at 10k rpm it is possible. Can the xs11 do 10k?

That was the point. In a word...NO. Valve spring wire would have be the daimeter as your index finger to keep the valves from floating...but even then it's no practical short of radical mods with a corresponding drop in engine life span.

I like the look of my 16" rear tire with the 19" front tire. If I put the 18" on, it would kinda be an xs11 cafe-chopper. I am not trying to break land speeds, just trying to lower cruising rpm at 70-80mph. My 17" is @#$%STILL(&%#@!!! at the machine shop. So what's the tallest tire you can put on the 17" and what would be the rpm's at 70mph?

Tallest 17" tire that would clear the drive shaft is a Bridgestone S11 Spitfire 130 90 17. It stands at 26.4 inches.

Run the numbers on that tire and you're looking at 140 mph at redline of 8500. At 70 mph the Eleven would be spinning at a calculated 4242 rpm with that tire.

[MAXIMAN]

Chop

If you're gonna do it to lower RPM at cruising speed then the 18" wheel is the ticket.

A stock Eleven with a 130 90 16 at 70 mph is revving about 4350

with the tallest 17" at 70 it's spinning about 4250

with the tallest available 18" (which is 27.4 inches) about 4100. So if yer gonna do it. the gains are minimal between the 17 and 16.

The drawback to the 18" wheel is the fact the wheel is narrow. The 130/90 18 would be really stretched across the bead of the wheel. It might affect handling. I dunno but I'm gonna find out in a few weeks once I get Zilla off the dyno.

I bought a 18" tubeless wheel for an XS750. I understand it is literally a bolt on operation. I'm going to thry the 27.4 inch tire just to see what happens.

[xschop]

thanks for the info

So what would be the rpm at 70mph on the 18"? Also while were on the subject, I would gestimate that there is a gear combination from some factory bike/bikes from Yamaha. to make 5th gear taller. Someone on this green earth knows!!!

[xschop]

you are correct

hey maxi, I have found that there are two diff. widths of the 18" make sure you get the widest one....chop

[MAXIMAN]

Yeah I found a 130/90 18 that is 27.4 inches tall. I just don't know how the thing will handle. The recommended rim width for that tire is 3-3.5 and the rim of this XS750 18" is only 2.15 wide.

[xschop]

width

ther is a 4 inch wide 18 wheel for the xs750. I would personally go with that one....

[MAXIMAN]

For those wondering how we calculate this:

MPH = (RPM x Tire ODinches )/(Final ratio x 336.1)

In this case:

MPH = (4087 x 27.4) / (4.76 x 336.1) = 69.997 mph

to solve for RPM at any given MPH just re-arrange and:

RPM = (MPH x 336.1 x final drive ratio) / (OD of tire)

[MAXIMAN]

Re: width

Originally posted by xschop
ther is a 4 inch wide 18 wheel for the xs750. I would personally go with that one....

WHERE?!?!?

Point me forthwith my friend.

[xschop]

where else

check ebay, search "xs750 rear wheel". make sure you see 18x4.00. There was one there last week. I can get one from a friend that works at yamaha cycle shop for @40 bucks, In good shape of course....chop

[xschop]

where in okie land

where are you in oklahoma? maybe we can meet up. I've got two other friends with xs's. we always get the most stares/questions because nobody can figure out what kind of bikes these are at first.

[webbcraft2150]

Like the t-shirt says "the older I get, the faster I was". "But officer, I could not of possibly been going 111, my speedo only goes to 85"

Sidenote;
Biggest speeding ticket, 1979, I-25, 30 miles south of Albuquerque, 143mph in a 65. Very verified by radar. Weapon of choice at that time was a '78 Laverda 1000 Jota. Reduced fine of $300 + court costs + driver "improvement" school.

[Dan Hodges]

Speed

Of course one could use titanium valves,retainers and killer valve springs in a radically welded and ported head and a cam with .500 lift and 275 degrees of duration@.040 lift.Next would be a set of Venolia pistons hooked to Crower titanium rods via titanium wrist pins mated to a light weight profiled Crower billet crank.A reworked oiling system,some exacting machine work and some transmission modification's and yes 10,000 rpm would be reasonable but you would have a pro/stock type motor that would not be competive in pro/stock and you could not ride it around so what's the point of it all unless someone just had lot's of money and wanted to do it because he could.Maybe Maximan could put this motor in his XJ and an 18'' rear wheel and make the Turner Turnpike look like Hallet Raceway park. A 10,000 rpm XS,diffulcult yes,impossible no,insane,very much so.

[xschop]

sweeeeeeeeeeeeet

yeah, I agree Dan, but I still like improving the xs however I can, according to the laws of economics!

[xschop]

always improving

I am going to let the cat out of the bag. I am very anxious to get my wheels back.I am getting the 17" rear and fronts done this way. Here"s a peek at what they'll look like......what ya think?