DD7: Direct Drive 7-Speed

 

 

The DD7 upgrades any existing 2006-later big twin 6 speed to a full 7 speed transmission.  The BAKER DD7 is more than just another gear added to the mix for the sake of one-upmanship. That 7th gear enables the motorcycle to now make full use, by way of gear ratio management, of the torque and power put out by the new 96 ci and 110 ci motors rolling off the assembly line in Milwaukee. We did not make this transmission a deep overdrive, rather we shortened 1st gear and tightened up the gears to deliver the riding experience that you were after when you bought your bike. The gear ratios leave you the rider, with the experience of smooth, crisp, continuously pulling acceleration from 1st all the way through 4th gear. Then you are able to start getting into the cruising portion of the program in gears 5th-7th. No big drops in RPM from one gear to the next or lugging the motorcycle off of a stop light, just smooth, uninhibited acceleration.

 

We did not stop at just fixing the gear ratios. We improved the smoothness and crispness of the shifting by reducing the mainshaft mass by only having 1st gear be a part of the shaft, rather than 1st-4th gears like on the stock unit. Reduction in rotating mass for shift quality is a fact that has been utilized in the automotive world for years. We ditched the stock detent arm and spring assembly from the door in favor of a Linear Detent that decreased friction while increasing smoothness when coupled with the all new shift drum design. We have tightened up the dog teeth on the gears to prevent the loud clacking noise that accompanies every shift on the factory 6 speed. Through the use of a billet bearing door, 28% wider bearings in the door, steel bearing retainer plates and full width gears, the durability and strength of our unit is a drastic improvement. By utilizing fully diamond ground, helical gears in 1st & 4th-7th we are able to deliver a much quieter riding experience. While 2nd and 3rd gears are diamond ground, spur gears to handle the peak torque that is reached in that range.

 

- Shorter first gear ratio (numerically higher) to help with the off the light get up and go, as well as slow speed maneuvering around the bar parking lot
- Fully assembled gear set and shift system. No adjustments needed for installation
- The DD7 re-uses the stock shifter pawl and includes a new main drive gear bearing and seal, door, top and side cover gaskets
- Compatible will all types of aftermarket hydraulic side covers, as well as the stock Screaming Eagle versions
- Direct slide in installation. No case modifications needed. Clears all exhaust and works with all aftermarkets clutches
- Includes a new transmission top cover that holds the linear, roller bearing mounted, shift detent
- Easy to find neutral, every time. Smooth shifting without the the stock clunks or ‘jerks’ when engaging
- Upgraded ARP 12 pt stainless steel bolts included. For transmission top and side cover as well
- Included BAKER Direct Drive 7 Speed Stock Side Cover emblem
- Backed by a 5 year limited warranty

DD7 Kit Contents

 

 

Shift System
The shift drum utilizes many of the same features we have learned over the years, and incorporated into our other designs. Make the shift drum as light as possible, close tolerance design of the drum tracks matched with specific angles of the drum tracks ‘events’; make for smooth and positive shifting. Our specifically designed neutral position on the shift drum detent clover leaf make it easy to find neutral, every time. The close tolerance drum design paired with the gearset lay out, yields tight, repeatable dog tooth gaps that are not possible with mass production, cast shift drum designs used on the stock transmission.The linear detent, a design first used in the OEM car world. We were the first to introduce it to the V-Twin world on the Torque Box transmissions, and we have used it on the DD7 as well. It produces the lowest friction possible, with the controlled nature of using a coil spring in a strictly linear manner. The amount of precise control possible with a linear detent, can not be realized with the stock scissor spring and lever wheel detent design found on the stock gearset. All of these changes along with the billet steel machined, hard chrome plated shift forks, make it the smoothest transmission we have made to date.

DD7 vs Stock Shift Drum

Linear Detent Plunger

 

Gearset

The factory 6 speed has a 1 piece mainshaft with gears 1-4 machined out of one forging. This is easier and cheaper for high volume manufacturing, but yields a mainshaft that weighs over 5 lbs. This heavy one piece design is largely responsible for the clunk heard on every shift. This heavy rotating mass crashes into the gears on every shift. The DD7 has a 1 piece mainshaft (8620 steel) that only incorporates the small diameter 1st gear and weighs 3 lbs less than the stock unit. Whereas the stock gearsets utilizes a straight cut gear for 1st, and helical for 2-6, the DD7 uses straight cut 2 and 3rd gears, with the remainder being of a helical design. The largest amount of torque is put to the ground in 2nd 3rd gear, and straight cut gears handle that power the best. There is a not a lot of cruising going on in these gears, so the strength benefit of straight cut teeth outweighs the noise reduction factor inherent with a helical tooth design. The stock gears have tooth profiles that are cut on a shaper machine after heat treat, the BAKER gears are shaper cut before heat treat then precision ground with diamond coated tooling after heat treat (58-62 Rockwell ‘C’). This extra steps ensures not only a quieter gear pair, but enables much tighter backlash control. Further enhancements have been made to the male-female dog tooth pocket interactions, the tightened up radial gap on our design reduces the on-off throttle lag time and gear clunk noise found on the stock transmission.

DD7 Gears vs Stock

DD7 Gearset Layout

 

DD7 Ratio Stock Ratio
1st Gear 3.76 1st Gear 3.34
2nd Gear 2.75 2nd Gear 2.30
3rd Gear 2.06 3rd Gear 1.71
4th Gear 1.55 4th Gear 1.41
5th Gear 1.27 5th Gear 1.18
6th Gear 1.10 6th Gear 1.00
7th Gear 1.00 7th Gear N/A

 

Bearing Door Assembly

The stock bearing door is cast aluminum, the DD7 door is machined from virgin billet 6061-T6 aluminum.  Billet is stronger and this instance is no different. The stock gearset’s cause a phenomenon we call ‘Ghost Lever’.  Starting from low RPM’s in 2nd or 3rd gear go right to WOT and then get off the throttle.  Watch the clutch lever walk in and out from the handlebar. This is the shafts in the transmission walking left and right in the case due to the flex of the bearing door and the skinny stock door bearings. We use 28% wider roller bearings in the door and used a cold rolled 1045 steel plate to hold them in place, rather than the stock snap rings. No more Ghost Lever and much more power (up to 160 ft-lbs) can be thrown at it without the bearings breaking a sweat.

DD7 vs Stock Door

DD7 vs Stock HD Door Assembly, Section View

 

PN Description Fitment
DD7A-376C DD7 Builders Kit, Chrome Door 2006-Later Dyna, 2007-Later Softail/ Touring
DD7A-376BLK DD7 Builders Kit, Wrinkle Black Door 2006-Later Dyna, 2007-Later Softail/ Touring

 

 

 Fitment Note: Cruise Control will only work in 7th gear and the Red Line will be 5200 RPM with the DD7 on Throttle-By-Wire bikes equipped with stock ECM’s. No other motorcycle functions are affected in these instances. The 6th gear indicator light will come on when the DD7 is shifted into 7th on all models and all ECM’s. Aftermarket tuners such as Daytona Twin Tec and TTS-Mastertune will allow cruise to function in all gears, like stock, on Throttle-By-Wire bikes when coupled with the DD7 gearset. Dynojet can also flash your stock ECM to adjust the cruise control the cruise and red line, while still allowing the ECM to work with piggy back units like Power Commander. Any questions on this, please give our tech line a call.

 

Recommended Upgrades

- Cruise Drive Hydraulic Side Cover

- +1 Quart Oil Pan (2007-2008 FLH/ FLT Models)

- +1.5 Quart Oil Pan (2009-Later FLH/ FLT Models)

- Inner Primary High Torque Bearing Kit (2007 Big Twin)

- Attitude Chain Adjuster Kit

- Heavy Duty Throwout Bearing Kit

- Cruise Drive Pulleys

- Cruise Drive Sprockets

- Bully Primary Cover

- Bully Derby Cover

 

Click on any of the images below to learn more

Cruise Drive Hydraulic Side Cover

+1 Quart Oil Pan

+1.5 Quart Oil Pan

High Torque Bearing Kit

Attitude Chain Adjuster

Heavy Duty Throwout Bearing Kit

Cruise Drive Pulleys

Cruise Drive Sprockets

Truss Style Shift Lever

Bully Primary Cover

Bully Derby Cover

Spectro Oil BD-75140

Recommended Fluid Level

Picking the right transmission fluid ensures the life and durability of your transmission, that’s why BAKER recommends a fully synthetic GL-5 rated gear weight oil of 75W-140. If a GL-5 rated gear lube is not available, these commonly carried viscosities (weights) will work 75W-90, 75W-140 and 85W-140. BAKER does not recommend the use of Syn3 (20W-50). For Bert’s article on ‘Oil & Spiders’ Click Here

 

BAKER DD7 Fluid Capacity Dry: 30-32fl-oz

BAKER DD7 Fluid Capacity Wet: 26-28fl-oz

 

Installation Instructions

BAKER DD7 Installation Instructions: Click Here

BAKER DD7 Installation Instructions Addendum : Click Here

BAKER DD7 Gearset Exploded Views : Click Here

Product

DD7 Installed, LSD Hydraulic Cover

DD7 Stock Cable Style Side Cover Emblem

DD7 Installed, 2008 Nightrain, Bestway Customs, Close Up

Lifestyle

DD7 Installed, 2011 Road Glide

DD7 & Hydraulic Side Cover Installed, 2007 Electra Glide Standard

DD7 & Hydraulic Side Cover Installed, 2007 Electra Glide Standard, Close Up

DD7 & Hydraulic Side Cover Installed, Custom Bagger By Huck

 

DD7 Installed, 2008 Nightrain, Bestway Customs

Testimonial from Oasis Cycle:

 

Here is a followup from a out of town customer with his recent DD7 install.

 

BAKER DD7 REVIEW:

So here is the first 1000 miles since Saturday ~
1. Awesome Gear Ratios First four are really sweet & non stop pull
2. Shifts like butter (smooth as silk if you prefer)
3. 6th gear indicator works in 7th & cruise only works in 7th
4. Why ~ because I can and plan on MoPower down the road.
5. Dyno specs remained the same before & after (of course)
6. BIKE FEELS FASTER ` seat of the pants therefore it has to be faster.

 

Purchased and installed by oasis cyscles in Brandon Mississippi ~ this is an awesome place ~ enclosed dyno room and old school mechanics that ride, build and take their time ~ these guys do it all ~ paint booth ~ engines ~ etc ~ The website is oasiscycles.com and I have personally used their Mechanics ~ (I used to live in Hattiesburg, MS) since 2006.

 

If you have an evo, shovel, pan, panshovel, twin cam, or an ole dirt bike ~ these are your guys…. If you want paint or technical work ~ they are great ~ Good deal installed on the DD7 ~ Mark is one of the volume dealers for Baker. __________________ 2012 FLTRXSE 110 Stage III Upgrade 10.5/1 Piston/Rings ~ Chopped Tour Pack, Lowers, 13″ Tinted MadStad, HD Performance Baffles & FM Ceramic 2/1/2, Daymaker LED’s, Escort Solo Radar Detector 104hp 109 tq, Fork Baffle, Pro940′s & Monotubes, Baker DD7.

 

David M Mitchell

 

This is from Bob Pyfer, Daytona 2013:

I just wanted to drop you a line to thank you for the installation job of the DD7 transmission . No leaks, adjustments all correct, and not a dirty finger print on the bike ! I like traveling on my 07 Screaming Eagle Ultra more than any bike I’ve ever owned . But after the bearing on the transmission main shaft failed twice(always one to two thousand miles from home)I started to get a little disgusted .Now with the DD7 in it I feel like I’m going to make it to where I’m going and back home. The DD7 is so much quieter I don’t have to turn the stereo up as loud, it shifts smoother, and neutral is so much easier to find. I really like the lower gear ratio for starting out and on the fourth of July I found out it’s much better in a parade ! I’m getting ready to leave for Arkansas this week to ride through the Ozark mountains and the peace of mind it gives me makes it worth every cent. Thanks again for a great job and a great USA made product! See you at the next Bike Week .

Thanks,
BOB PYFER    from Betterton ,MD.

 

Mark Boler from Oasis Cycle

 

 

 

 

 

 

 

 

 

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