fd swap?

[650mark]

a couple of my riding friends owned xs1100's years ago and both highly recommend that i swap my stock final drive unit for one from an xs750 or 850 my all stock '80 special runs perfectly, gets 40 mpg all the time, and cruises on the freeway very comfortably at 75-85mph @5000rpm. am i missing something or what would be the advantage in doing that swap? thanks

[Tat2demon]

I believe better mileage.

[James England]

This one has been discussed here a lot over the years. I've done the swap (then swapped back for local use). There are pros and cons. The use of the 750/850FD gives the illusion of the missing '6th gear' on the XS1100. It lowers the top end revs in 5th gear quite significantly and leads to the engine sounding much less frantic when cruising. The engine sounds like it feels happier when travelling at, say, 70mph. It does feel like it was made for the bike and there is a theory that the ratios were, in fact, originally intended for the XS1100 but changed in order to produce better standing quarter times and race performance (it worked).

The downside is that you get less acceleration and need to shift gears more. Whilst it's nice to have a stress-free sounding engine at cruising/touring speeds, I did feel like my XS1100 had been transformed from a powerful stallion to a tractable gelding.

Because the swap is so easy to do, and completely reversible, I would say that it's a good mod for those people that need it. If I were using my XS1100 for a long tour, then I'd fit the 750FD. But, for local low mileage fun riding, I'd keep the OEM FD on.

There has been soime debate about whether the 750/850FD's can take the strain long-term. They are certainly a bit less robust in many respects but, then again, there are loads of people who've done lots of miels on them.

I must say, after doing the swap and enthusing about how great it was, I did begin to find the bike just a little too......civilised.... and that's not really where it's at for me, as far as XS1100's go.....

[Tat2demon]

I like being able to destroy bikes and cars that want to "embarrass the relic" too much to want to change out the FD.

[natemoen]

I believe better mileage.

Nope.......

Maybe 1or 2 but nothing much, most don't see any.

[James England]

Nope.......

Maybe 1or 2 but nothing much, most don't see any.

Correct. In fact, it might even be worse, with all those extra gearchanges and higher revving in lower gears.....

[motoman]

a couple of my riding friends owned xs1100's years ago and both highly recommend that i swap my stock final drive unit for one from an xs750 or 850 my all stock '80 special runs perfectly, gets 40 mpg all the time, and cruises on the freeway very comfortably at 75-85mph @5000rpm. am i missing something or what would be the advantage in doing that swap? thanks

Your choice, but these motors are 'happy' runnin all day 4500-5000rpm. By design internally these motors were not designed to be lugged around. They'll sure do just fine all day long, but were not intended to be. The lower geared rear-end IMO was intentional to match up with what these motors were designed to consistantly run at. It all just worked out for Yamaha cause at that time, here we had the 'JimmyCarter' legal speed limit of 55mph, and I would run five over on trips runnin' at 4000rpm. The quarter mile thing, IMO is just an urban myth that worked out to be a plus for those that believe that, as I again believe Yammy's intent was to design it all to work together, which obviously it did. Braggin' rights were just a bonus, IMO. Obviously, this also gave mileage me in the 46-49mpg range with the help of the more efficient burning fuels back then, even though they were headed towards what they have become today. Those numbers can be had today with these bikes, but at a cost of ventilating a few pistons, so not reccomended. Betting your mileage numbers will drop as the motor will always have a load and be 'working' more instead of runnin' more freely havin' the load a bit removed with the stock gearing. In other words a little more throttle will be applied (more manifold vacuum causing jet needles to raise a bit more out of main jets) to get it to do the same work. True enough less revolutions over the life of the motor, but not sure that would would actually reduce its 'running life' much that one would notice since these motors were performance built with forged one piece cranks(Kaw.KZ 1000's were two piece pinned cranks for example), fordged pistons and shot-peened chanfered rods, high volume oil pumps and windage tray, uncommon 'extras' for the day associated with scoots. With that, high performance and durability were 'built-in' which was a plus and is why so many of these are still liscenced and run hard today. Some is just my opinion and some is fact. Hope some of it helps with whatever choice you make.

[jetmechmarty]

650Mark,

If you read back your own comment and take in what Motoman has to say, I would say the swap is likely not for you. I am usually running mountain roads, therefore, I would not consider the swap myself. That and I wouldn't want to neuter my bike.

[BA80]

650Mark,

I wouldn't want to neuter my bike.

The 850 FD is no different than a 17" wheel on the rear. Harry with his standard w/17" wheel and me with the 850 FD run the same exact RPMs on the highway.

We'll see how "neutered" Tod and I's bikes are with the higher geared FD here in about 10 days.

[trbig]

I don't get the "More gear changes" with the 850 final drive. I ride with my son a lot with him on a stock 81 XS and he has to shift much more than me, and I go much further/faster in 1st than he can. Original first on these bikes is like a granny gear on a 4wd and you run out of gear very quickly. With the 850 final drive on my bike, I can run through school zones at 20-25mph in 5th and acelerate out of them just fine. After @ 10mph, the final drive difference becomes a non-existant point other than cruising rpm in 5th. I can still do wheelies off the line and pop the front up again when I hit 2nd. If you're cruising locally, 4th with the FD swap is almost EXACTLY the same gearing as stock 5th, so ride it in 4th if you like a revving motor. Only downfalls I see of the swap are if you take off from a stop going uphill with 2 up or if you have a sidecar.

I hear a lot of opinions on the final drive made up with some B/S theories. "You'll burn up the clutches" etc. I've got over 100k miles on the final drives, with several years of riding the heck out of them. Still have the same clutches, and they're still in spec. I just had to look around for better springs until I found the Barnetts and have advised them to everyone since. Yes, the stock final drive will launch you better off the start, but if I lost even 2 tenths of a second in a quarter mile with the swap, I'd be absolutely amazed, and I'd hardly call that neutered. I've beaten many stock xs11's simply due to the less shifting, and many times I beat them on their very early shift to 2nd. So as I said.. the stock FD will beat the swapped bike to 10mph by a couple mph.. after that it's more a toss up to tuning, not the FD. Just my 2 cents.

[650mark]

it does sound like the swap is not in my best interest. i like the bike the way it is and have no complaints about mpg's or speeds through the gears. and since the shifting is cluncky, though better with the new synthetic oil, shifting less with the stock gearing is a good thing for me. thanks for some lucid and usable input. now, if somebody would just come up with a reverse gear for this thing....

[Bigfoot]

I have the stock final drive on my 79 standard, 750 drive on the midnight special. It definitely does not "neuter" the bike. I did not see any increase in mileage, just don't always think i need to shift while cruising at highway speeds.

Has anyone ever done the final drive swap on a standard with the 17" rear wheel? I would be interested in knowing how that performed.

[BA80]

About time you rejoined us Harry.

Let's just do it and see what happens. If it's too tall geared put a 16" wheel on it and you'll be back where you started only with a much better selection of tires that will fit the 16" wheel.

[Bigfoot]

Russ and i have been talking about giving it a shot. It is easy enough, if it doesn't work out well, just put the stock FD back on.

[skids]

a couple of my riding friends owned xs1100's years ago and both highly recommend that i swap my stock final drive unit for one from an xs750 or 850 my all stock '80 special runs perfectly, gets 40 mpg all the time, and cruises on the freeway very comfortably at 75-85mph @5000rpm. am i missing something or what would be the advantage in doing that swap? thanks

I have two running xs11s without and one with. I think highway trips are better with the FD swap because of the lower rpms, but that is just me. If you are happy with what you have, don't change it!