Author Archives: 12991420

Slippery Performance – Propeller Design and Operational Facts

Welcome to the first of several boating set-up and discussion articles that I plan to add to this Public Service Articles platform. These are being added as a public service to readers who can’t find the odd facts and principals affecting boating performance questions. I’ve spent 50 years wondering and searching for “What/Why boats and motors do and don’t do while in the water”. I hope you’ll enjoy these and will share the links. While this is a motorcycle tools site, I have been a boating enthusiast for almost as many years as a motorcycling nut!

Slippery Performance is an article that I wrote for Bass & Walleye Boats magazine and their May 2000 issue. It was also my first paid journalism gig!

Stressing Out Your Transom – Discussion and Dynamics of Transom Stress

Stressing Out Your Transom is an article that I wrote for Bass & Walleye Boats magazine and their March 2001 issue. I defined many of the terms used in set-up and discussions about jackplates, bolts, setback, transom stress, and leverage. The research took me several evenings at the Clemson University Library along with several phone calls to bolt suppliers, boat companies, and a structural engineer for the physical properties and math behind the leverage variations. These were questions that I wanted answers for, but could not get them from the forums, magazines, or books. My mission was clear – Go find those answers for myself and others. I hope you’ll enjoy and share! Gordon

Motorcycle Gasket Sealer – The Right Stuff Explained

Engine Case Preparation And Cleaning

Motorcycle Gasket Sealer, Liquid Gasket, and Liquid Engine Sealant are the most common terms that people refer to the “Goo” that they use during the reassembly of their engine cases. Please read and shop carefully – the sealants and gasket goos that are sold at most auto stores and hardware retailers are almost always WRONG for your motorcycle engine cases where gaskets are not used.
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Motorcycle Clutch – How They Work

Motorcycle Clutch Components Seperated

The Modern, Manual Motorcycle Clutch does a lot more than the textbook definition of this word Clutch suggest. While the definition is “to Grasp, Seize, Clench, and Hold”, we think of them as quite the opposite. Mention Clutch and most of us will describe the Slipping Action that allows us to control engagement and movement from a dead stop as well as give the pause in the transmission of power for sequential Gear Changes.
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Motorcycle Transmission – How and Why It Works

6 Speed Motorcycle Transmission

Understanding The How and Why It Works

A Transmission is defined as a mechanical assembly (machine) that transmits power from the Engine to the Final Drive. The simplest transmissions can have just one, fixed ratio and no shifting. This article will expose the detailed workings of the 6-speed motorcycle transmission, but the 4 and 5 speeds work the same way.

Power is applied to the Input Shaft (pinion/drive shaft) of the transmission by the Clutch when it is engaged (plates and disc sandwiched together) and the Engine is running. The input/drive shaft turns anytime and all the time that the clutch is engaged. There is a drive/pinion gear for each ratio (gear change).

The input shaft gears mesh with their corresponding Driven Gears that ride on the Output/Driven Shaft. Motorcycles use Constant Mesh type transmissions. This name comes from the fact that the “gear pairs” are always meshed. These gear Sets/Pairs provide the gearing ratio changes that we use to go from stand-still to top speed, and in our case a high transmission ratio of 3.1:1 for our 1st gear and 0.8:1 for our 6th gear.

The 3.1:1 Ratio of 1st means that the Input Shaft must make 3.1 revolutions for every 1 revolution of the Output Shaft (shaft where the front sprocket attaches).
The 0.8:1 Ratio of 6th means that just .8 revolutions of the Input Shaft results in 1 full revolution of the Output Shaft.

1st Gear RatioNeutral Motorcycle Transmission

2nd Gear Ratio and Power Flow3rd Gear Ratio and Power Flow

4th Gear Ratio and Power Flow5th Gear Ratio and Power Flow

6th Gear Ratio and Power Flow

Some of the gears in our transmission are keyed/splined to the shafts they ride on and some spin freely. No two gear “Pairs” can be locked-in at the same time. Doing so would have disastrous results since they would each try to turn the output shaft at different speeds. The job of motorcycle gear shifting falls on the Shift Forks and Shift Drum to ensure that absolute control and placement of the splined gears be precise and properly timed.

Shift Drum Fork Control Channels

The Shift Drum has “worm channels” cast or machined into the surface. These channels provide and manage the directional control for each of the Shift Forks. As the Drum rotates, the channels hold or move the Forks right or left to engage and disengage the different splined gear sets.

The Shift Drum moves in a rotational manner, but never a full 360 degrees. The Drum is limited and rotation stopped at it’s lowest and it’s highest positions (usually 1st, but some motorcycles do have Neutral at the bottom and some at the top). Neutral is achieved when all gear pairs are unlocked and the Output/Driven shaft is not powered. Most Neutrals are now designed between 1st and 2nd.

Shifter Shaft and Drum Ratchet

The Shift Drum has the mechanical Stop for a reason. If allowed to continue rotating, the shift forks would lock-in 1st gear immediately after 5th or 6th – locking the tire, damaging the transmission, and over-speeding the engine – all of which could have catastrophic results. For that reason, Shift Drums have the rotational limits built-in. While Neutral could be designed to fall between every gear change, that function would be undesirable and a real nuisance. The choice to have it closest to and in-between the gear change/selection most used when starting off fell squarely between 1st and 2nd Gears.

Shifter Drum and Shaft Ratchet Detent Assembly

The Shift Drum is rotated forward and backward by a “ratchet” system, When your foot presses down on the shifter pedal, the Shifter Shaft is rotated and the Ratchet tooth pulls on the Shifter Drum Pins to rotate the Drum by one Detent. Only when the shifter pedal is released does the ratchet move back and is set to move the Drum again. The travel of the ratchet is limited to only 1 pin/detent move. This same ratchet action is used when the shifter pedal is pulled upward by the foot. The Ratchet tooth then pushes the Shift Drum Pins to rotate the Drum by one detent. It is this “press/release” Ratcheting action that keeps us from making more than 1 Gear Ratio Change at the time. 1-N-2-3-4-5-6 and 6-5-4-3-2-N-1.

The precise rotation and positioning of the Shift Drum is controlled by the Shift Detent Roller/Spring assembly. This spring-loaded roller rides on a cam assembly that maintains “next gear only” control and prevents the catastrophic results if 2 pairs were to be engaged at once. I think of this one device/mechanism as the single most important part of the entire engine/transmission assembly – without it, failure is immediate and certain.

Join us next time and we’ll take a detailed look at Clutch Design, the Components, and How They Work.

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Future Meets the Past Here In the Present – A Wild Helmet Story

55 to 75 Million Year Old Concretion

He Was Here – We Know It Because He Left His Helmet!

Rumors have it that Kawasaki kept pushing the envelope in performance and then in 2035, the H222 finally exceeded Warp. The daring rider who was willing to test anything with an Electron Dynamo Fusion Engine was given the nickname “Warp” and sadly never seen or heard from again. In a twist of fate, the rider was thrust back in time – 75 Million Years Back!
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Suzuki DR650 Mini Adventurer – Turning the DR Into a Mini Adventure Bike – Part 3

Stock BST40 Versus FCR40 DR650 Carburetor

Part 3 of our Suzuki DR650 Mini Adventurer

Turning the DR Into a Mini Adventure Bike series will focus on the Changes and Improvements made to my 2013 DR650 after a full Summer of testing and our full-gear TAT Trial. My mission…..still very still clear – build a purpose bike on the Cheap. This segment will spill-over into Performance and how to make your DR more enjoyable.

With a Jet Kit and tuning, the carburetor performance was improved on the stock BST vacuum carb. Improved means it would now idle and was a lot easier to start. I wanted more. Off-idle grunt and tight maneuvering response was still poor – No let’s make that Lame. The problem? That big vacuum carburetor was still delivering soggy low-end performance and it took seconds for the vacuum slide and needle jet to actually settle down and feed the “right mix” every time you whacked the throttle open.
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Suzuki DR650 Mini Adventurer – Turning the DR Into a Mini Adventure Bike – Part 2

DR650 Starting On the Transformation To Mini Adventure

Part 2 of our Suzuki DR650 Mini Adventurer – Turning the DR Into a Mini Adventure Bike series will focus on the Discoveries and Modifications made to my 2013 DR650 in preparation for and after our TAT Trial (Trans America Trail). The Electronics, Rain, Mud, Communications, and Full Gear experience would be an almost perfect shakedown of Rider, Gear, and Bike. Parts would be added and or modified based on Function and with no regard to looks or Me-Too isms. The goal was to build a purpose bike on the Cheap.

During the Summer before our TAT Trial, we spent weekends riding Fire Roads and Logging Trails in the North / South Carolinas and Tennessee to include 2 extended camping trips where we could test set-ups. The goal was to ride hard and ride fast to see where we and the machines might break.

The crash did 3 things

The Crash – Poor judgment of speed and throttle on my part resulted in a fast low-side crash on the DR in a blind right-handed turn at the top of a hill. The sand covered hard-pack dirt wasn’t going to let my tires take any bite.

Damaged DR650 Pelican Box

The right side Pelican box came up and off of the lower rack mount. The tubular rack would in fact support the weight of the Pelican box fine and did secure the boxes under normal conditions, but my crash proved that I had to limit movement upward. I have to say that I was very impressed with the Pelican box and just how well it took the impact. Same for the Wolfman Racks I use to support them. The flaw was in the way I did the bottom support. It was a simple “rest on” support and did not stop or limit upward movement. Instead, it relied on the bolts at the top of the Pelicans to do that – something they were not up to task for.

Suzuki DR650 Wolfman Rack Insert Modified To Limit Pelican Movement

The solution was to add the Aluminum Wolfman Rotopax plates to each side loop and then cut/slot reliefs that allow the bottom Pelican mounts to work as before, only now they would Prevent the bottom supports coming up during a low side impact. The “win-win-win” was that they would add loop rigidity, prevent the Pelican box movement, and provide for RotoPax mounting where/when Fuel/Water was needed – all while being very light in weight.

DR650 Hand Guards By Tusk - Cheap, Reliable, and Tough

The long skid on the hard dirt road proved that hand guards, AKA “Bark Busters” are worth their weight in gold. My bars, levers, and guards came through the crash perfectly. The ones I installed are Tusk brand and include a small plastic hand shield that does wonders for keeping brush and limbs off your fingers as well as help with cold and wet. These also have the built-in LED‘s for turn signals that do make the bike more visible on the sections of highway we have to travel to get to our favorite off-road track. I did have to modify my stock levers to fit within the travel of the hand guards which was little more than cutting and sanding the ends of the levers off.

Modified DR650 Brake Pedal

The crash demonstrated that the brake (foot) pedal was vulnerable during a drop. The bike went down and skidded on it’s right side – the brake pedal was pushed hard into the right hand crankcase, leaving a deep scratch. Had the pedal hit pavement, a root, or been hung-up by thick grass, I think the pedal could have perforated the right crankcase cover and compromised the oil supply. As was, I had a brake pedal that would not function. We had enough tools with us to pull the pedal out away from under the crankcase and allow me to use it on the limp back to camp.

The permanent fix for me was to inspect the stock case cover and determine the scratch was not a threat to long-term oil containment and to add one of the strong Stainless Steel covers available from ProCycle to the crankcase so that would never happen again. I also sourced a folding pedal from an 80’s model XR350 Honda and grafted the toe pad to a new Suzuki DR650 pedal (mine was trashed beyond service). I positioned the foot pad such that it would fold at a 45 degree angle – deflecting in either an upward (fall) or backward (forward impact), or both.

I would also add a lanyard cable between the aftermarket skidplate and the brake pedal. This lanyard serves to prevent limbs, brush, and roots from getting jammed between the frame and brake pedal and to limit the amount of travel in the event of a slide.

The long hours of riding proved that standing during those slower dirt sections was a critical part of covering the 10 hour days. I’m 6 foot in boots and the DR was too compact for me to do that comfortably. I came back from our TAT Trial and invented/built my first edition RRR Adjustable Handlebar Riser System. I also studied the ground clearance of the bike after all of the Suspension modifications and determined that the foot pegs could easily be lowered 1.5″. The combination of lowered pegs and higher bars would make those standing breaks a whole lot safer and easier. I would have more leverage (hands closer to the push-up position and I would not be slumped over trying to hold the bars).
Better yet, my RRR Adjustable Handlebar Riser System would solve the clearance problems with competitor designs.

DR650 Footpeg Cut, Welded, and Lowered Almost 2" Less Stress Too

For the foot pegs, I could not simply “lever” them down again as some of the bolt-on lowering brackets do. I wanted to remove as much of the stress (leverage) on the frame mounts as possible while achieving the lowered position – Cutting and Welding the foot pads onto a donor set of DR650 pegs purchased on eBay did that for me. I eliminated a lot of the leverage and stress and all of the height that the stock pegs place on the frame.

DR650 Navigation Tools - TAT Ready! Keep Your Eyes Where Your Wheel is Pointed

We used Roll Charts on the TAT Trial. Wow! I hadn’t done that much math since High School……. Every turn and every intersection, many of which are unmarked required a quick calculation between the odometer’s current mileage and the roll chart’s accumulating mileage for that section. Miss one calculation and you’ve lost the turn and screwed-up the consecutive turns and directions for the rest of the course. Forget GPS except to tell you where you are – they simply are not programmed to keep you on the longest, dirtiest, and off-road route possible and neither of us had one of those heavenly Enduro Counters.

All of this interaction with Odometer, Roll Chart, and the GPS made it perfectly clear – Those items needed to be immediately in front of your eyes. My RRR Adjustable Handlebar Riser would solve this need also. I would make Flat Caps and Dash Accessory mounts that could hold charge jacks and RAM Mounts so all of the navigation tools, and your camera could perch on top of the Steering Stem – thereby having the least amount of distortion and movement possible (versus out at the handlebar ends). This would keep business and the front wheel in the same direction of sight.

This will give us a stopping place for now. In the Part 3 Article, I will cover the Gear and Equipment that I’ve made/designed and purchased to “Gear Up” for Off-Road Survival.

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Suzuki DR650 Mini Adventurer – Turning the DR Into a Mini Adventure Bike

New DR650 Crate Assembly

Spring 2013, I needed a Dual Sport bike for fire roads, backwoods exploration, and camping. I have a large Street Touring bike and some vintage bikes to ride, but nothing to take me camping and into the back country. A few weeks of research led me to more than one article praising the Suzuki DR650 for Power, Reliability, and Price. A brand new DR650 would follow me home shortly after reading one particularly well written article. – 2008 Suzuki DR650SE Comparison

Day 2 – Suspension Too Soft

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Motorcycle Parts OEM Parts How to Find Them With Microfiche

Honda ST1300 Cylinder Head Microfiche

St1300 Honda Cylinder Head Assembly
Motorcycle parts fall into 2 major categories – OEM parts – (original equipment manufacturer) and those from the Aftermarket. For the OEM Parts, there are some great, Free Microfiche tools that can help us to Identify the OEM Part Numbers, their stacked Placement and orientation, and Quantity of the same Parts used in the assembly.

Whether you’re looking to make a single item repair, to make repair to multiple ST1300 Honda Left Cylinder Head Placementcomponents, or a full-on motorcycle restoration project start to finish, the Interactive Microfiche websites like the ones available through and many others are a good way to get started.

For those of us riding and maintaining Honda, Kawasaki, Suzuki, and Yamaha motorcycles made over the last 40 + years, these Microfiche tools are outstanding.

Honda CL77 305 Project
They show year and model definition details with high accuracy and the part numbers that go into making each bike. Just a heads-up about using on-line microfiche though, a listing for a motorcycle part and it’s price detail for that part Does Not mean that the OEM part is available or that one exist in the world.

I’ve seen that happen many times over the years – want OEM or NOS Honda CL77 305 Parts Inventory and AccessmentSeat Hinges for a 1965~1967 Honda CB450KO? An Exhaust System for a 1974 Suzuki GT750? Not going to happen…….

I’m a planner. I love taking projects of the worst kind and breaking them down into dozens of manageable pieces.

Microfiche pages have been a part of my process for many years.

I find the on-line microficheMicrofiche Website Page 1 that best covers the motorcycle in my project and I print out every page. I then bind those pages into a folder that I have in my workshop for constant access. During the teardown, I mark which parts I’m going to need to replace or find.

Sometimes on the older machines, OEM Parts are not available, but knowing the OEM Part number, how many are used, and exactly where they go in the assembly can help us find them through eBayPage 2 Microfiche for Motorcycle Parts and OEM Parts and other selling resources.

Using the “where used” feature of the microfiche website has led me to salvaged parts of the correct part number from different years/models that could be restored for use. As I order and later receive each part, I document that onto the microfiche page.

This same Printed Microfiche then becomes an integral part of the “Assembly Manual” where I’ll check to see that I Motorcycle Parts Page 3 Microfichehave and use all of the motorcycle parts that I intended to.

Microfiche pages are usually drawn and grouped into assemblies of related parts.

These assemblies can guide the new restorer or mechanic through each segment of the repair. As mentioned earlier, the microficheMotorcycle Parts and OEM Parts Finder Where Used Feature page is a good tool for keeping record of parts ordered, parts received, and parts used during assembly. They go from being a planning tool to an assembly tool, then onto a recorded tool for each/every bike I’ve restored.

Make friends with your favorite Microfiche website for motorcycle parts and be sure to use the OEM Parts Tool on your next motorcycle repair or motorcycle restoration project.

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