Final drive swap

[Poprock]

It's less strain than carrying even a small passenger. One of those won't break your bike, will it?

[jetmechmarty]

Do it. But, if you're doing it to add longevity to your bike, I think it is a mistake.

Marty (in Korea)

[cywelchjr]

Do it. But, if you're doing it to add longevity to your bike, I think it is a mistake.

Marty (in Korea)

I don't think anyone has claimed the mod for longevity, but rather for the change in the character of the bike that it provides, along with the minor increase in mileage that some have seen. There MIGHT be a very small decrease in wear in the engine on the pre-transmission side of things, and I doubt there is any difference in wear in the transmission one way or the other, the only difference is what what gear you run in, frankly you actually go a little further for the same number of revolutions than before.

[jetmechmarty]

I believe the opposite to be true. You may realize some increased fuel economy, but only under certain conditions. The engineers that set the bike up knew what they were doing. I don't see this mod as an improvement. If you do, that's fine, go ahead with it.

Somebody has to be the contrarian. I guess that falls on my shoulders.

Marty (in Korea)

[natemoen]

I believe the opposite to be true. You may realize some increased fuel economy, but only under certain conditions. The engineers that set the bike up knew what they were doing. I don't see this mod as an improvement. If you do, that's fine, go ahead with it.

Somebody has to be the contrarian. I guess that falls on my shoulders.

Marty (in Korea)

I would be willing to bet that yamaha originally planned to use the same FD as the 750/850, why make new expensive parts when we alreasy have the tools and all set up for this one, and then decided they wanted it faster so they changed the gearing, easier than changing something else.

So I don't thing it matters what FD you use, both were intended for the 1100. Also as someone else stated it is no different than changing the gears in the rear end of a vehicle, there isn't any extra wear on other parts there either.

[bikerphil]

Just somthing to compare this to, these guys with sport bikes change their sprockets to different amount of teeth (ratio) all the time to suit their riding style.

[natemoen]

Just somthing to compare this to, these guys with sport bikes change their sprockets to different amount of teeth (ratio) all the time to suit their riding style.

That is an even better, motorcycle specific example.

[cowboybob998]

As long as it dont lug the motor down it aint hurt'n nothing.

[Bonz]

I have changed the gearing on most of the other bikes I've owned or currently owned at one time or another by simply changing sprockets.

This is the first shaft drive bike I've changed gearing on, and is probably one of the only shaft drive bikes in existence that gearing CAN be changed at all...

The same principles that have applied and be PROVEN to work without ill-effect with changing sprockets apply here as well, it's just a shaft in our case.

Any fears of extra wear and tear on the bike, with all respect, are founded in nothing more than conjecture. This wonderful bike has a transmission, and no matter what FD is on the bike, the right gear for the job at hand has to be used, period.

Whether the tranny is in 4th gear at 60 mph with the FD swap or 5th gear with the stock FD, the bike knows nothing different than it is going 60 mph at about the same rpm. Then, put this wonderful bike on the open road where speed limits are in most cases 10-20 mph higher than when the bike was made and show me how lower rpm is going to hurt ANYTHING, unless some goof lugs the crap out of it ('cause they are stubborn and don't want to shift or don't know what a tranny is for!).

With the NMSL (National Mandated Speed Limit) being 55 mph when this bike was designed, running 4000 rpm in 5th gear (at 60 mph, 5 mph over the limit) for the Special or a couple hundred rpm lower with the Standard, was what the bike was set up for (as well as being undeniably geared for the 1/4 mile). I'm gonna go out on a limb here and say Yamaha potentailly sacrificed long-term higher rpm engine life in their desire to get into the 11 second bracket in the 1/4 mile. It was about making money for them, not giving a hoot about practicality.

With speed limits being higher now, the FD swap puts the bike in the same rpm range , just at 6-8 mph higher speed depending whether you have a Special or Standard. OR by the same logic, at legal interstate or open road speeds, this keeps it from going as far above the normal rpm range relative to the day and age the bike was designed for.

Show me on a 600# bike with 60-odd ft/lbs of torque that running at the same rpm it ran back in the day but a 6-8 mph higher road speed is going to do anything negative for the long term.

Same thing applies for the pundits that say it puts extra wear and tear on the clutch/bearings, whatever, when pulling away from a stop with the FD swap. This bike has no problem pulling away from a stop at idle using normal clutch release with the stock FD or a swapped FD, I can actually speak to that as I have done the swap. So that is a non-starter.

As well, the FD housing temp is lower with the swap (go ahead, feel the FD housing on a stock bike vs. a swapped bike) after high speed running, so show me how a lower temp is causing wear and tear.

I've stayed away from this, but given the choice to swap or not to swap, bikes running at 5200 rpm+/- at 75 mph (or higher rpm if you ride 5 mph over) are going outside the "normal" rpm range the bike was set up for (given the speed limits at the time the bike was made for) and those bikes are being subject to unneccessary abuse. So, I did the FD swap to keep from abusing my bike in the riding I do.

The reality seems to be the owners that have done the swap and report no ill-effects are the ones to listen to for what actually happens, vs. the ones who theorize doom and gloom and thus won't/don't/haven't swapped.

[cywelchjr]

I believe the opposite to be true. You may realize some increased fuel economy, but only under certain conditions. The engineers that set the bike up knew what they were doing. I don't see this mod as an improvement. If you do, that's fine, go ahead with it.

Somebody has to be the contrarian. I guess that falls on my shoulders.

Marty (in Korea)

IIRC it was a quote from XS11 heaven where it's mentioned that the 11 was intended to have the same final drive ratio as the 750 and 850 until the last moment when it was decided (probably rightly from a marketing standpoint) that they needed it to break into the 11's in the quarter mile. So they changed the final drive ratio. I doubt they redid the drive ratios of the transmission at the same time either, that would have added a LOT of time to the entire picture and they needed to get to market.

The point is, they turned it into a drag racer and race machine, and made it not a very good touring machine, it runs way too high in the RPM range to good comfort at normal touring speeds. This is NOT about longivity, not about any of that, this is about the use the bike is put to. It's common on those who do touring riding to change the final ratio (for those with chain or similar drive) to change the ratio to lower engine speed at cruising speed, it makes the ride more comfy. It's not always as easy with shaft drive, and when it is, it's often very expensive (it's doable in some cases though just like on a car if you are willing to through enough money at it) and it doesn't hurt the vehicle one little bit.

There are guys who have been running this mod longer than I have been on this board, and that's been like over two years now? And not one reported issue with it not related to them doing something wrong in the installation or having defective parts. So, is it going to harm anything? The evidence and common sense says since this is a common procedure done to vehicles the world over for decades with no harm done, and it actually returning the bike to the final drive ratio that it was designed for initially (and from the feel riding with it you can tell, it just FEELS right, it doesn't feel like a hot rod anymore it feels like a touring machine now) the answer is no, it's not going to hurt anything. Is it going to help anything? I think the answer is pretty likely except under certain limited conditions, no (those conditions would be touring conditions where you could take advantage of staying in more efficient RPM ranges at cruising speeds gaining a couple of MPG, I have seen on average a 2 MPG increase from the mod).

Should everybody do the mod? No, not everybody should do the mod. Those who are comfortable with their bike the way it is should stick with it that way. I notice that you make a big deal about how infallible the engineers were, but you put gold emulators in your forks. We all know while they got a lot right, they didn't get everything right for what everybody needs and everybody wants. For you the final drive ratio is right. That's cool, and frankly I thought that was the case for me too. But I was semi pushed into it, I had my left rear bearing eat my FD, and was able to find a 750 FD cheaper and faster than an 11 FD. That made me consider the swap. I figured if I didn't like it, I would switch back. After a couple of months, I'm not even considering going back. The bike is so much more even tempered, runs through the gears more smoothly and all. It's like it was setup for this drive ratio from the beginning. It's like the old Ford Galaxy my dad had. When he got it there was some really low gear rear end in it. Like the engine was racing like crazy even in high gear, and first gear was almost useless. I would pull almost anything, and if you could shift fast enough was pretty fast, but was no fun on the highway. Eventually we replaced the rear end on it. It was a different car. Nice to drive, first gear was actually usable. It made it a joy to drive. Not sure what reason the gears that were in the rear end were put in for, but they didn't work for us. This is the same thing here.

[Bonz]

Cy, you bring up a good point that I should have addressed more specifically in these later posts as well, and that is the feel of the bike is vastly improved, even when tooling around town.

I cannot say how much better it feels on the road, despite already being the smoothest inline 4 cylinder engine I've owned, it only feels better with 500 rpm less churning away underneath.

I was speaking to the reliability aspects, as that was where the skepticism was coming from. Just showing beyond a doubt that the swap won't INCREASE wear and tear (the skepticism), but very well COULD increase longevity beyond the great reliability we already know exists.

My initial mileage checks concur with you and others, I have seen a 2 mpg improvement in the same riding vs. the stock FD.

I'd be interested to see how much "slower" the FD swap makes the 1100 in the 1/4 mile, or if any of you out there have ridden side by side together and compared the real-world performance. My seat of the pants says it won't make much of a difference at all.

[cowboybob998]

epa guide lines

I beleave the only reason they went with the lower gear is so they could stay within the epa guide lines and still gain speed, they could not up the carbs, to much emishions, that motor will last alot longer with FD swap, its comen sence, the more times the motor turns over the more wear, it boils down to numbers, the more times you rub two peices of steal togeather the faster it is going to wear out.

[cowboybob998]

.

I'd be interested to see how much "slower" the FD swap makes the 1100 in the 1/4 mile, or if any of you out there have ridden side by side together and compared the real-world performance. My seat of the pants says it won't make much of a difference at all.[/QUOTE]

I would bet that with the right carbs you could make FD swap faster than the stock setup.

[James England]

I must say, having read all the posts, and ridden the XS1100 for years, I personally believe that Yamaha deliberately compromised on the top rev level in order to make it a monster fast bike. It was billed at the time as "the fastest production bike in the world". It wasn't at first hailed as a mile eating tourer. In fact the two concepts are mutually-exclusive, I'd say. And, let's face it.... the engine doesn't feel as happy at 75mph as it does at 60mph does it? It feels a bit hectic, a little over-revved and just dying for a gearchange to simmer things down a bit. I've always thought that and, it would seem, so have loads of other people. Our speed limit here is 70 and I really think the bike is over-revving at that speed... I mean, it's supposed to do 135mph....the same gear from 70 through to 135 seems a bit much to ask.

Well, I went ahead today and bought an FD from an eBay seller in Germany. It cost 24 Euros which is about £21 or $34 in proper currencies. Plus about $20 in shipping. So, a not too expensive, fully reversible modification which many people praise highly. If I fancy some monster acceleration, I'll drop a gear. I'm looking forward to a reduced rev level at 70mph, I really am!

I fail to understand how anyone could believe it might increase engine wear. Add a heavy passenger, a load of luggage, go uphill and it still makes no difference, so I doubt that a rev-reducing modification (which was originally conceived by Yamaha anyway) will cause a 1.1 litre engine pulling about 300kg to be damaged. I'll let you know if I'm wrong!

[Bonz]

Cowboy,

I recall reading in one of the road tests from back in the day (It's one of the articles stored on this forum) that they changed a few things in the top end for 1980 for emissions reasons and in anticipation of more emissions regulations if they chose to keep the same basic motor. Correct me if I'm wrong, but I believe the introduction of the YICS in later years was just for that reason, to help emissions with the older motor design.

Here's that portion about the engine changes for 1980 copied below. With that said, since the XS was introduced a few years before this, and it had the short FD gearing even at that point, I would guess that emissions didn't play as big a role, if any, compared to the performance Yamaha wanted in acceleration.

"Take the motor, for instance. The big dohc inline Four stays essentially the same. Bore and stroke remain 71.5 x 68.6mm. There's still inductive electronic ignition, still with a vacuum advance and with the same settings. The compression ratio has been dropped to 9.0:1, the pistons and head have been changed so the combustion chamber is different, the better to meet more stringent 1980 emission standards. In addition, the intake valve head diameter has been increased from 36mm to 38mm and the exhaust valve size has gone from 31mm to 32mm. Given the same cam timing and profile, that should make for more horsepower, but there's more to it than that. Those four 34mm Mikuni constant vacuum carbs are jetted differently this year. There's no adjustment on the pilot jet. The needle jet is held in the leanest position. Main jets, which were a #137.5 in all carbs previously are now a #115 in carbs two and three and a #120 in the end carbs. "

For the carb changes, the internal routing of fuel or whatever was different in 1980, so the smaller jets still provided more or less the same fuel as the larger jets did in previous years from what I understand, but in the end the performance was about the same or a bit less than the original few years of the XS.