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Knees In The Breeze: Motorcycles...It’s The Sound Of The Cash Register Ringing
By Greg Bukosky
If you listen close, you can hear the approaching thunder. It’s the sound of motorcycles cruising down America’s highways in record numbers. For a growing number of engine machine shops, it’s also the sound of the cash register ringing.
By last count, the National Highway Traffic Safety Administration (NHTSA) reported that motorcycles made up roughly five percent of all registered vehicles in the U.S. This works out to about six million motorcycles on America’s roads with the largest concentrations being in California, Florida, Illinois, Iowa, New York, Ohio, Pennsylvania, Texas and Wisconsin.
Who’s working on what
By far, the majority of machine shops surveyed for this article reported that Harley-Davidson engines are the current hot tickets. The rebuild work normally goes to one of three places: the Harley-Davidson factory in Milwaukee, WI; Harley-Davidson dealers that have machine shops; or to motorcycle machine shops like Short Block Charlie’s in Tempe, AZ.
"Harley-Davidson has it’s own rebuilding facility," said Charlie Lawlor, owner. "It’s not a bad deal for $2,500. Most dealers will usually forego the mark-up as well. This option is for someone who wants a stock motor rebuilt to stock specs.
"The money for shops like mine comes from performance upgrades, unleaded fuel conversions and rebuilds of older Harley-Davidson engines like the Pan Head/Shovel Head. For some reason, the dealers don’t want to do the older stuff anymore. They’re sourcing a lot of this out to aftermarket shops. We’ve even heard that the factory has released many of their old blueprints to aftermarket manufacturers who will now make the parts for older Harleys.
"Another thing that keeps us busy is the fact that we have oxygenated gasoline here in Arizona. This will pound out the valve seats prematurely, even on the newer Harley-Davidson Evolution series engines. Our answer has been to use valve seats made for use with propane engines so durability isn’t an issue. You do have to use a valve and seat cutter machine to install them properly, but the wide selection and quick turnarounds make this still our best option. Other states including California also use oxygenated fuel, so this problem will become fairly common over the next few years."
The bad news for rebuilders, much like that on the automotive side, is that the Evolution engine has been drastically improved. Whereas 30,000 miles used to be the limit, these engines will now run well into the 100,000 mile range under normal operating conditions. The good news for rebuilders is that the Evolution is well suited to performance upgrades that the older Harley-Davidsons simply couldn’t take.
"The Harley engineers really did their homework to correct the valve geometry on the Evolution," said Ian Segedy, master engine builder at Akron, OH-based TLC Racing. "The older Shovel Heads were really hard on the valve guides. Basically they opened and shut the valves at such an angle that they wanted to take the guides out. With the Evolution, they stood everything upright.
"Word has gotten out pretty fast that there’s plenty of room to grow with these engines. In fact, we can double the horsepower without sacrificing reliability or durability one bit. The engines come in making 44 hp on our dynamometer and they leave here making 80 hp. We’re usually talking about some combination of porting, boring, honing and some piston and rod modifications. To double the horsepower, it’s a pretty good deal."
Cylinder head work is the best
Most rebuilders agreed that cylinder head work is the way to go. The lower end of most motorcycle engines is fairly reliable; plus the equipment needed to work on the cranks can be very expensive and hard to justify. Most did warn, however, of the need to upgrade the crankcase area if cubic inches are significantly increased through stroking or over-boring of the cylinders.
In terms of pricing, Short Block Charlie’s normally charges $75 for a basic valve job on an Evolution cylinder head, $90 for a performance valve job and $25-$40 each for seat installations. They also specialize in creating what they call "duel quench combustion chamber ported cylinder heads."
"We take the seats out, weld up the chambers, reshape them, drop new seats in then refine them on the flowbench and dyno," Lawlor said. "We’re getting roughly 50% more horsepower out of this process. The cost is $600 plus parts for Big Twin engines, and $350 plus parts for Evolution Sportster engines."
Lawlor also emphasized that the clearances on motorcycle engines are much tighter, and therefore, harder to achieve compared to normal automotive clearances. "For instance, you don’t ream valve guides, you hone valve guides. Harley-Davidsons are very, very sensitive when it comes to valve protrusion. If there’s one area that can really throw off the performance of the Evolution engine, this is it."
Ian Segedy of TLC Racing echoed these thoughts. "We won’t hire anyone who isn’t proficient with micrometers and verniers. You have to understand why clearances are how they are because the next application might not be the same. We get an awful lot of engines that come through here from automotive shops that thought they could wing it."
Equipment is everything
The key to success is to have the proper equipment at your disposal. Most machine equipment manufacturers either provide or plan to provide equipment that will work on most motorcycle cylinder heads.
When boring and honing, the usual rule of thumb for both two- and four-cycle motorcycle cylinders is to use a torque plate. The reason is that there can be as much as 0.003" – 0.004" distortion on four-cycle cylinders.
Cylinder surface finish requirements can vary depending on ring compositions and applications. For most standard four-cycle cylinders a 220-grit or 280-grit is recommended for a quality finish. The 220-grit will leave a surface finish of approximately 25-35 Ra. The 280-grit will leave a surface finish of approximately 15-22 Ra. Racing applications may call for a 400-grit abrasive to cut down on friction and drag.
TLC’s Ian Segedy also suggests that rebuilders use a light oil to wipe the cylinders clean after machining. "The cross-hatch finish holds dirt and other particles. We’ve tried many other options, but the light oil works the best. You’d be amazed how much debris the cylinder walls can hold."
On two-cycle engines like ATVs, the honing process is much more critical to straightness and roundness due to the fact that a large portion of the cylinder is "open" where the ports are located. For this reason rebuilders shouldn’t use standard cylinder hones with two stones and two guides, or single stone and single guide mandrel set-ups.
Instead, a softer abrasive and a keyway mandrel on smaller sizes or a keyway stone set should be used with portable hones. This will ensure that the stone and guide come in contact with as much of the cylinder’s support area (non-ported areas) as possible and avoid what is known as "washout" in the port openings.
Two-cycle cylinders also require deburring of the port edges with a plateau honing tool when they are machined to oversize. If not done, these sharp areas can cause ring chipping, premature wear or piston scuffing.
In terms of hand tools, most motorcycle engine machine shops reported that standard automotive tools are a start, but other specialized tools are a must. There are at least five Engine Rebuilders Association (AERA) member-suppliers that currently carry tools specifically designed for rebuilding motorcycle engines.
Turnaround times for complete engine rebuilds vary depending on what type of work is being done. Kevin Unger of Countryside Custom Cycle, Sauk Centre, MN, said that from the time the cycle is put on the lift to when it’s completed and tested is usually two to three weeks. Total man hours can vary from 20 to 30 hours.
"It’s very important to clean and inspect each part as you disassemble the engine," Unger said. "There are so many little clues that would normally escape the eye. It takes a little more time, but that’s what the job requires."
Randy Thompson, parts and service manager for TLC Racing also noted that unlike automotive engine repair shops, motorcycle specialists are likely to get the whole bike when rebuilding the engine. "The car guys get the block and heads. We get the whole bike in many cases so there’s a little more time to disassemble and reassemble that needs to be built into the quote. I will say that the Harley guys are pretty good about bringing us just the parts that need to be machined. They seem to work on their bikes more than others."
Parts availability also has a big impact on turnaround times. Jim Sherman, service manager for Central Valley Cycle in Eugene, OR, said that turnarounds could be as long as five to eight weeks when waiting for certain parts. For this reason, some shops like Short Block Charlie’s prefer to have customers source their own parts when undertaking jobs that aren’t typically done every day at the shop.
For instance, when a customer wanted to restore an old Indian motorcycle, most of the parts were tracked down and paid for by the customer. Most shop owners agreed that there wasn’t enough mark-up in the parts to justify the sometimes endless hours on the phone trying to track down hard-to-find parts.
TLC Racing’s Thompson agreed, but added that they still do most of the sourcing for their regular work which requires a thorough understanding of the business. "Just like the guy who works on car engines will need hands-on training to work on bike engines, the automotive parts guy will need to get up to speed on the bike parts. You can lose a lot of time and money if you don’t know what you’re doing. Understanding what the guys back in the shop are trying to accomplish is the key."
Down the road
Several new opportunities will present themselves in the coming months. Of particular note is the current trend of plating cylinders with a very hard nickel silicon carbide base. According to Short Block Charlie’s, this has been done to meet certain Environmental Protection Agency (EPA) requirements, as well as to make the blocks "non-rebuildable."
"Basically, you have to buy a new block if you can’t hone it and replate the cylinder," Lawlor said. "The problem is, there are only three places in the country that can currently do the process, and we’re talking about a two to three week turnaround. There’s a ton of work out there for people who can afford to step up to the plate with the resources to buy the honing equipment and the plating tanks. The down side is that it’s a whole new environmental hazard concern for shops to deal with."
There’s also good money to be made repairing broken cast iron cylinder head housing fins with the spray welding process according to Lawlor. "All the new stuff is aluminum, but there are a ton of bikes still out there with cast iron fins that are prone to breakage. Because of the extreme loss of powder during the repair process, we are able to charge $100 per inch to repair fins."
Most automotive engine repair shops should find it fairly easy to get into motorcycle engine repair work. Although it will take some additional training and equipment, the profit margins are definitely better than most standard automotive engine rebuilds.
The key it would seem, is to talk with your equipment representatives, as well as some shops in your area that already specialize in motorcycles. As always, the AERA is a valuable resource when striking out into unknown territory. To learn more about motorcycle engine rebuilding opportunities, or to become an AERA member, call 847-541-6550.
The point is, there are a growing number of people out there who are willing to spend good money in order to "keep their knees blowin’ in the breeze." Maybe it’s time you hopped on the two-wheeled bandwagon, yourself.