I figured I'd put this thread here as my bike is a 94 FLTP, I run a 120 Merch in the bike which has also been used in a couple of other bikes I have had.
Anyway, I decided that I would run a Baker DD6 as the stock gear set was getting noisey and I was replacing the swingarm with an 05 type and had to bore out the case to accept the new pivot bolt.
I was quite impressed with the Baker kit and the quality of the machining and such. I took the bike out and on the hwy the lower RPM at cruising speeds was a relief from what it was with the stock five speed.
The problem arises when I got off the highway and on the hills and curves around where I live and do most of my riding, eastern Ontario, Ottawa Valley. Even with the 120 Merch I was spending way too much time shifting between 5th and 6th gears to stay in the power band. With the stock transmission in 5th gear there was no problem cranking the throttle to pull up any hill or out of any curve.
I dread going into the mountains of New England ,two up with my wife, where we like to vacation. My clutch hand and wrist will be way worn out after a couple of days in that type of riding enviorment.
This is just a personal observation and had I known this I would not have changed out the gearset. I would have just replaced the gears and bearings in the stock set up expecially considering the cost. I'm going to have to swap out the stock pulleys to get the rpms up a little to easy up on the shifting.

 

On the plus side, you had enough money to put a big old engine in there. And enough to afford a high quality tranny. If your wife is "sized" right, you might find that 5th gear works just fine when two up. Mine's just over 100 pounds and she doesn't make much of a difference, but with a bunch of gear and stuff she might be just thing to force you down a gear and keep you in the power band.

No need to answer on that one and I was not trying to insult anyone - I'm just sayin'

 

Hi from Old England! I am waiting for an 07 swingarm assembly to install in my 1990 FLHS. Don't plan boring the gearbox, but using the original smaller spindle with reduced bore bushes in the swingarm.

I recently fitted an S&S 107 and decided to stay with the original 5-speed box. We toured Europe 2-up in June and did us just fine on the autobahns and in the many hilly roads we travelled. Don't feel the need for any more gears. I can remember when 3 was not quite enough....

You could consider lowering overall gearing. Easiest way is at the crankshaft. Baker make them in several sizes. Will reduce the need to keep changing. On my Dyna I replaced the original 25T with a 21T. Goes far better now in top gear!

 

32 tooth on the trans pulley, maybe a 33t with your power, alot of touring owners with six speeds crossing to the change to make 6th gear more user friendly but like you said, it took alot of money to have to make another change to get it right.

 

We put a 31 tooth pulley on our mega motor with a six speed overdrive tranny and it pulls one up loaded fine on most hills here in upstate New York. Most of our weekend riding is done in either the Adirondacks ot the Catskills on secondary and backroads. We sometimes have to down shift, but no where near as much as the others with us that didn't change the gearing. Once on the road we stuff it in sixth and forget about it until the speeds get below 45MPH. It also pretty much eliminated any tendency to ping. Hope this helps

 

John,

That's good info. Sometimes wonder if I should have gone for a bigger motor. What is a 'mega' motor in your book?!

 

With each passing ride and a slight variation from my normal riding habits, I am liking the DD6 more and more.
It shifts flawlessly, neutral is as easy to shift into as any other gear and quiet.
I should have mentioned is that I was keeping the rpm down on the shifting as I rebuilt the 120 Merch and breaking it in.

Graham, I do some work on the side for friends and take their bikes for test runs when I'm done.
All I can say is there is "No replacement for displacement" when comparing the stock power output, even in modified HD Evo's to a large displacement aftermarket motor.
Like I mentioned before the Merch I own has been in, if I can remember 2 other bikes I had, one aftermarket frame when it was new and a HD frame. Both frames were solid mounted and pulled like a frieght train. The Merch really shines in the FL, always pulling and very reliable.
The only draw back is cost and making the other components on the bike "Merch Proof" as it is hard on anything that's connected to it.
I've had the motor since new in 01 and kepted the motor, swaping out the engines from the last two bikes and selling the bikes.

 

The term "Mega Motor" depends upon which style of bike you are talking about. As almost all of our customers ride their bikes, we call an 88+" sporty a mega motor. In the big twins 127+ inches, unless its a bagger then we try to stay around 120, with 124 being the max normally. As you make these engines larger, even with improved engine blocks, cranks, rods, cylinder, heads, etc. longeviety becomes an issue. These bikes need more maintenance than an 80", so we try to fit the engine to the customers needs. Sure you can put a mega Orca in a bagger, but you will be working on it more and after the novelty wears off enjoying it less.

 

Thanks John, I guess my 107 counts! The S&S dealer over here recommended against fitting an S&S 124 in a dresser, as the low running characteristics are not very smooth, which the 107 certainly is, running very well at very low engine revs. With over 8k miles up now it is getting sweeter in the mid-range.

Tom, I first discovered Merch a few years ago and their 131 inch motor. That captured the imagination at the time, but the cost, especially of shipping to the UK, also caught the breath! Another reason for making do with my 107 is that the collateral damage was minimal!

Turning back to the original topic, of 6-speed gearboxes, one of my other bikes is a BMW, which I have today delivered to my local dealer for a service. They gave me a courtesy bike, a 6-speed GS twin. From 3rd, the up changes to 4th, 5th and 6th are all so close they are a pain! I imagine familiarity would make the whole thing more natural to ride, but all my bikes have 5 speeds, which on today's experience is enough for this bear with little brain!

 

The exact reason why I never went to a six speed,especially with big cubes.Both my machines are geared tall for highway cruising.With big cubes,5 speeds,and huge torque,getting the bikes rolling is certainly not an issue.