[JoelEspinoza]

I have had a Henry's Final drive for a while, just got around to installing it and wanted to give my opinion as well as a few things I found on the way.

The point of the drive is higher gear ratios, so all the gears are moved up maybe half a gear or so. First will be be between where 1-2 is on a stock bike, 5th will move up probably about halfway to where a 6th would be. Higher top gear for me was the main reason I got this drive.

Here in the rural parts of Texas the freeway and highway speed is VERY fast. Most of the freeways and highways when you get away from towns are 75mph, and doing 95mph past cops without them pulling you over is standard. The only time either my wife or I have been pulled over out here was when she was clocked doing 98mph in a 70mph zone getting close to a town, she also had an expired drivers license, which they may or may not have noticed, and was let off with a verbal warning. When I rode up to Oklahoma a few months ago I bet my average speed over the 5 hours I was in Texas was slightly over 100mph, and the first 3 hours of that I didn't even see a freeway. Taller gears are VERY welcome here.

As a side benefit first gear is suddenly much more useable and less twitchy, but still has PLENTY of power, I used to feel that first gear ran out so fast that I could actually accelerate faster just skipping it and starting in second, this is no longer the case. I did not measure it, so I might be incorrect, but with the taller new gearing I feel like I could do a slightly faster 0-60 time than with the stock gearing, either with the stock 1-2 start or stock starting in second. Also, I noticed 2nd becomes a good relaxed in city gear now, as it can easily hang from very low speeds until well past 35mph, so I find I do less shifting between second and third in town.

I didnt check it right before this swap, but I do remember checking the speedo stock with a GPS and thinking it was fairly accurate. Now when the speedo says I am doing 25 I am actually doing 30, 50 speedo = 60 reality, 75 speedo = 90 reality.

It is my opinion, that outside of very specific use cases like Goldwing tow trucks (lol), this is the gearing all these bikes and the normal 2001-2017 Goldwings and F6Bs should have left the factory with.

The downside of the drive is that they almost $1,500 and Henry is a small manufacturer, so they are often sold out. You will also need something to recalibrate your speedometer.

As far as the actual changeover itself goes, it is mostly straightforward, just make sure you have a good stable motorcycle jack, most normal hand tools, locktite, a torque wrench, a #3 phillips impact driver, and some hypoid gear oil for the rear end. Mostly the install is straight forward and covered in the manual or the instructions Henry gives you, but two things that were kinda gotchas for me were:

Dont try to remove the two #3 phillips head screws that hold the rear brake rotor onto the final drive while the assembly is on the bike. Take out the whole assembly, put the stock final drive on something solid, and give the screws a few whacks with an impact driver set to loosen, mine were VERY tight. If you strip one of those screws it turns into a HUGE pain to remove it, as the brake rotor where the screw goes in is aluminum and the screw is mild steel. A new rear brake disk is between $600-$700 from Honda. Just dont chance it. Henry recommends replacing those two screws, I reused mine.

There is something in Henry's directions about the connecting shaft into the final drive first and make sure it is seated before sliding the end of the splined shaft into the tranny output side in the tunnel. I don't really see how that would be possible, I slid the splined end into the output shaft in the tunnel first, then onto the final drive. Henry says to replace the seal and the spring clip at the end of that transfer shaft that goes into the final drive. Mine looked fine so I reused them.

Henry's drive when it first came in:

The new drive in place:

Old drive getting set aside as a spare:

Overall I am quite happy with this modification for my circumstances, but for the cost I dont think I would have budgeted this if I lived somewhere that freeway speeds were more normal.

 

[RRoy]

Great review and information. I now have a Harley with 6 gears which my 2014 Valkyrie should have had all along, Honda definately missed the boat on that one. At 70 in 6th gear it purrs like a V twin kitten with low rpms.

 

[JoelEspinoza]

Yea, but on the downside you have a Harley lol...

I didn't like how low the gearing was, but honestly it was probably fine for what Honda planned out, as I seriously doubt they intended this bike to be averaging 100+mph for days at a time, and while the engine stops making power relatively early for a Honda, I think the "redline" was more about where the powerband is than the physical limitations of the engine.

That all being said, for higher freeway speeds 6 speeds would have been nice, but I dont think that was even really required if the gearing had been spread out a bit. Close ratio with lots of gears is great for race tracks and engines with sharp peaky power bands, but these bikes have neither of those things.

In stock form it was common for me to start in 2nd, and it wasn't uncommon to skip 3rd and go straight to 4th. Bumping up the final drive to where Henry put it makes first useable, then you could just spread out each of the shifts just slightly and had 5th be a whole gear + where it was stock, and that would have been perfectly acceptable, if not actually faster than the stock gearing with the big flat torque curve of the GL1800 engine.

Even with Henry's taller final drive I was out playing with slow speed maneuvering today and just idling in first with the clutch out at 5mph was a bit too slow, I found myself still upshifting to 2nd to do around 7-8mph idling with my hand off the clutch and no gas and just riding the rear brake a bit as I needed.

 

[TheTaylorEffect]

Great info Joel. I'm really impressed with your willingness to tear down your bike like that, and you def put a lot of thought into how you wanted to set your bike up.
Genuinely curious to see if the new gearing has any impact on the MPG's

 

[JoelEspinoza]

Great info Joel. I'm really impressed with your willingness to tear down your bike like that, and you def put a lot of thought into how you wanted to set your bike up.
Genuinely curious to see if the new gearing has any impact on the MPG's

Thanks! I am new to motorcycles, but I have been working on cars my whole life, many of them Honda's. There is a LOT of knowledge overlap there, so while I have to learn some new things, most of it seems the same as what I know, or so similar it might as well be.

As far as MPG goes, I am not sure there, I never really tested it much except for a few sections of one long ride to Oklahoma and back, which was about 500 miles. I seem to remember a few fillups around 27mpg, and one around 32mpg. However, I had the huge stock Honda windshield straight up like it comes stock, an accessory windshield on top of that to cut down on the turbulence slapping the top of my head like a giant dribbling a basketball, I have a torso like a barn door and weigh over 300lbs, plus my Corbin bags were stuffed and I had a 60L bag stuffed and strapped to the pillion seat, all regularly traveling over 100mph, and often passing cars sometimes up to 120ish.

I am sure the wind resistance there, not to mention the weight, was getting pretty extreme.

Now I have bent the the stock windshield mounts quite a ways:

So the stock windshield is much closer to inline with the forks:

I assume with the new angle there is probably a smoother air profile in the front, along with less frontal area from it being angled instead of straight up and down, plus the removal of the accessory windshield, I am guessing my aerodynamics are improved quite a bit.

So hopefully improved aero and keeping it below 4k RPMs when cruising will help improve the MPG a bit.

 

[KUGO]

Thanks! I am new to motorcycles, but I have been working on cars my whole life, many of them Honda's. There is a LOT of knowledge overlap there, so while I have to learn some new things, most of it seems the same as what I know, or so similar it might as well be.

As far as MPG goes, I am not sure there, I never really tested it much except for a few sections of one long ride to Oklahoma and back, which was about 500 miles. I seem to remember a few fillups around 27mpg, and one around 32mpg. However, I had the huge stock Honda windshield straight up like it comes stock, an accessory windshield on top of that to cut down on the turbulence slapping the top of my head like a giant dribbling a basketball, I have a torso like a barn door and weigh over 300lbs, plus my Corbin bags were stuffed and I had a 60L bag stuffed and strapped to the pillion seat, all regularly traveling over 100mph, and often passing cars sometimes up to 120ish.

I am sure the wind resistance there, not to mention the weight, was getting pretty extreme.

Now I have bent the the stock windshield mounts quite a ways:
View attachment 13548


So the stock windshield is much closer to inline with the forks:
View attachment 13549

I assume with the new angle there is probably a smoother air profile in the front, along with less frontal area from it being angled instead of straight up and down, plus the removal of the accessory windshield, I am guessing my aerodynamics are improved quite a bit.

So hopefully improved aero and keeping it below 4k RPMs when cruising will help improve the MPG a bit.

Couple things. First, thanks for your detailed posts on some of your projects. I assume most, like me, will probably not do the same on our bikes, but it's informative, interesting and hopefully better (for you) than when you started and we all end up learning something while you wrench. Second, good job on the windshield. You got the cant right, and in line with your forks, as it should be. Shields can lean a bit more towards the rider past that point, think cafe "racer", but any and all that are more towards the upright (from the line of the forks - think certain "Adventure" bikes) just look goofy to me and always have. I've always hated windshields, primarily because of the way they made any bike look, plus aero issues. Then I learned how wonderful it was to have one on in the summertime in the Midwest and not be hammered by June bugs while riding rural asphalt!

 

[Richmonder]

Agreed, Kugo. I hated, and still hate, the way my tall windshield looked/looks, and initially I was looking at shorter options. But after my first long ride when the bugs were active, I realized, despite my disdain for its appearance, the tall shield is indispensable. If only there were some way to make the mount for the tall shield and the shorty universal, to enable quick disconnect and install.

Richmonder

 

[JoelEspinoza]

Thanks, I appreciate that!

Whenever I have spent a while researching something, especially like the front suspension, but this rear end too, and I just can't find a lot of info, especially if I run into some issues along the way, I like to document what I did if at all possible to make it easier for others in the future. Heck, sometimes to make it easier for myself so I can remember what I did later!

I agree on the windshields, as far as looks go, I would much rather not have them on my bike. However, between the speeds and distances here in rural Texas, its just crazy not to have one unless it is just an around town bike, and with as tiny as my town is, that would be a VERY boring machine. If I was somewhere that my normal ride was maybe a 30 minute round trip and I was staying around 65-70, with only brief sprints faster to pass someone, I doubt I would keep the windshield on my bike. But EVERYTHING is so far and so fast here! All the major cities in South Texas are 2-3 hours from me doing 90+ MPH, Dallas is 5 hours, visiting my family up in Oklahoma is 8 hours.

Heck, my doctor is talking about going to to ride the Twisted Sisters at the end of the month and that is a 4 hour ride to get to them before we actually start riding them, which is apparently about another 3 hours depending on how fast the leader is going.

 

[tngarren]

IMO pushing the bottom of the windshield out by adding a couple u-bolt plates is a better solution than bending the upper supports.

 

[JoelEspinoza]

IMO pushing the bottom of the windshield out by adding a couple u-bolt plates is a better solution than bending the upper supports.

I actually was planning on doing that, but I wanted to keep the windshield close to the light to keep the wind flowing under the windshield to a minimum, and I realized pushing out the bottom of the windshield would greatly increase that gap.

Not saying everyone should do it the way I did it, it is easy to mess up, but it did work for me.

 

[BudgetBiker]

I am a Texas rider also. Im in San Antonio and recently did a camping trip to Big Bend solo. Even with my saddle bags and a pack with camping gear and 2 nights of food I was able to reach 132mph on a few vacant roads in the desert.

The limiter felt like it was kicking in at that speed so i let off and didn't push for more. The bike was solid and stable. Power delivered all the way up.

I agree a 6th gear for cruising long haul is needed. I believe the 1st gear was made not for quick acceleration so much as for having a low gear that will pull witbout throttle to make parking lots easier to get through. I have gone from 0 to to 30mph starting in 2nd a lot due to the short 1st gear.

It seems to me the limiter is based on RPM more than speed and its probably due to limitations on the engine parts. It keeps you from throwing a cyclinder is my guess because i have squeezed more MPH out of the bike in a gear going down hill sing less rpm.

That final drive swap looks like a cool mod and if i had the money I would surely do it.

Thanks for the details. Most Honda riders want the 6th gear especially in Texas where the speed limit in a few places is 80mph. It would get better mpg for sure.

 

[JoelEspinoza]

I know the redline is 6k, but I cant remember offhand if the rev limit is 6,500 or 7k, either seem incredibly low for a 1.8L Honda engine. I would guess the majority of the engine parts and balance are actually stable to much higher than that, but since they tuned it so mildly they probably used pretty lightweight valve springs, and that is probably the comfortable limit before valve float.

I would be surprised if this engine was not capable of safely doing 9k with more aggressive cams, higher compression pistons, Rune ITB intake, beefy valve springs, a good valve job, and a standalone ecu.

I could be wrong but a limiter around 130mph with stock gearing sounds more like a speed limiter than a rev limiter. According to my gauge the bike does 90mph at 4k RPMs with the stock gearing. While the stock gauges could for sure be off a bit, that speed still seems a bit low to be the RPM limit in 5th.

6,500/4,000 = 1.625, 90mph * 1.625 = 146.25mph

Hmmmm, just not sure there, if the speedo/tach was 10% off I guess that is about the ballpark.

I ordered a speedohealer to adjust my speedometer, and it is supposed to be able to bypass speed limiters, so if I am feeling particularly daring I might try that out at some point. If 130-146MPH was the rev limiter with the stock gearing in 5th, that means the new gearing should theoretically be good for about 156-175MPH, but I SERIOUSLY doubt the aero or power is there to get up to those numbers, even if I was feeling crazy enough to try.

 

[KUGO]

Just sit down, Power Ranger, take two glasses of fine whiskey, and call me in the morning. You'll be fine.

You crack me up! I'd really be curious what this bike can actually do, but I'd also really hate to lose a friend finding out.

 

[Sixshooter]

Try a VMax, Rocket or a H2...those will give you the jolt you're looking for.

 

[JoelEspinoza]

Lol, I am not looking to hit 156-175MPH on this bike , I was just saying the gearing and RPM limiter, if it is at 6.5k, could theoretically get there with the new gearing. But that is just looking at the gearing, I dont think the aero or power are going to get it there. The speedohealer is for recalibrating the speedometer, its just as a side point that it can apparently remove the speed limiter.

Honestly I have taken this bike to ~120MPH, and that is really as fast as I need it to go, but I wouldnt mind if that ~ 85-120MPH acceleration was a bit quicker.

I wouldnt do a Rocket or an H2, MAYBE a Vmax, I would at least one to test drive on if given the chance. Honestly if I get a second sportier bike it will probably be a used ZX-14R. Everything I read says they are the most comfortable sportbike for big guys, and that their performance is frighteningly close to the H2 for a fraction of the price and basically the comfort of an EXTREMEMLY sporty sport touring bike. .

The ZX-14R have basically had the same engine performance since 2012, but I think by about 2016 most of them came with upgraded suspensions, brakes, and ABS. I have seen a few pretty low mileage examples for around $9k. Those bikes are apparently good for slightly over 200MPH if you get the ECU flashed, although they are limited to 186MPH in stock form. Which frankly cracks me up... What engineer or bean counter was like "NO, NO 200MPH IS WAY TOO FAST FOR A PRODUCTION MOTORCYCLE." "Uhh, ok... what is a reasonable limit then?" "Well, 200MPH is insane... But you know... I think 186MPH is reasonable..."

I realize the speed limiter is actually 300KPH, but still it makes me laugh to think about.

 

[sanmo]

Frankly, I was kinda surprised that someone who is fairly new to this bike and to motorcycling generally was undertaking major projects such as the front suspension and the final drive, until you mentioned your automotive engineering background. Thanks for sharing the detailed writeups about your experience. Really interesting info.
I trust your attempts at breaking the sound barrier will be confined to a good test track. From the thread title I thought you had lost a good friend. 😅

 

[JoelEspinoza]

Yea, I mean the first time I took out a transmission by myself was a Chevy Turbo 350 in a van with a 350 v8 engine from the late 70s, it was right before I turned 12. I remember my dad paid me $50 bucks to take it out and I think $75 to put it back after he had rebuilt it. I had assisted on engine and transmission R&Rs for several years before that, but that was the first time I did it completely unassisted.

I got my first motorcycle around October of 2021, and my MC license around November. The bike was a 1998 Shadow 1100 that didn't run past a very weak idle, and I got it for $750. The owner said it had stopped making any power while he was riding during his normal commute. He had rebuilt the carbs himself, then had taken it to 3 different mechanics, 2 rebuilt the carbs again, and one replaced the fuel pump, the problem persisted for almost 2 years. I took it home and removed the entire fuel system, spread it out on my table and realized the fuel pump vent tube was plugged with dried mud, so the diaphragm couldn't move as it should, replaced all the lines and put it back together and it ran like it was new around town and up to about 70mph. I think it took me less than 2 hours with a leisurely run to the parts store.

Took me a bit longer to figure out why it was falling on its face after 70mph, turned out the fuel bowl vent tube was supposed to go to a low pressure area, and the tube was completely missing, so the high air pressure near the carbs was messing with the carb bowl vent and causing issues at higher speeds. For all I know that issue could have been happening for years.

Ended up selling that 1100cc shadow for $2k and bought a pair of 3rd gen 750cc Magnas for $1,500, one of which ran but was falling apart, and the second one didnt run and was falling apart. I fixed up the first one and sold it for $2k and used the $1,250 to fund the down payment on my Valk. The second Magna runs great and is sitting in my garage that I use as a spare bike for me when I have the Valk apart or when a friend who only has a scooter wants to go riding with my wife and I.

Some of this stuff required looking up, like proper chain tension, setting sag, and I was a bit confused at first about what was happening with the Race Tech kit damping kit and why stacking the washers just so was important, as I had never actually been inside a damping device before, but it make sense when I realized the washer stack deflecting was what what was controlling how fast the oil moved through the system. But the vast majority of it seems pretty familiar.

Also anything not legal to do on the street that I have done has ALWAYS been done on a test track!

 

[sal]

I came across this thread a couple of weeks ago, and found it very tempting to get in the game. I hope he's still doing them. I emailed Henry last week but haven't received a reply as of yet. Any input on correspondence with him?

Thanks,

Bob

 

[JoelEspinoza]

I just emailed him at [email protected]. I get the impression it is just him there, so it might take some patience.

 

[JoelEspinoza]

As an update this final drive is awesome, it not only reduces the RPMs at the top end but makes the bike WAY nicer to drive at low speeds, starting and stopping, and around town. Highly recommend it if you can easily afford it, especially if you cant decide if you want to start in first or second. It is the gearing the bike should have had from the factory.