Part Three.....BEFORE YOU BUY A HARLEY-DAVIDSON MOTORCYCLE

Reprinted from: James Russell Publishing


I am not the author of the original article.
I was going to transfer the article verbatim, but after some discussions with readers, I decided to edit the content so as to be more pertinent. On the first page of the article the author states that he owns a 2012 Sportster, after which a note was posted stating that I ride a 1981 Shovelhead. I thought that might be a clue that I was not the original writer, but I guess some people missed that.


Part Three.....


Blogger's Note: It has been brought to my attention that the author of this article is not a reliable source of information as some of his claims are over exaggerated. I will leave it to the reader to decide as to the relevance of this information to their situations. I have started to edit some of the content that I figured was not relevant to the points being made.

If you read the original publication it would become evident to you that the author is set on bashing twin cams while praising sportsters. His timelines for disaster may be exaggerated, but not all are to be ignored. While some say that if one fact is wrong then the whole article is a waste of time & not to be believed, but even with the scare tactics timelines for disaster, there are some things that warrant your attention.


With that said.... Onward to Part Three.....


12. Another terrible problem all Twin-Cam engines have is the dreaded "crankshaft slip." A perfectly new bike with low miles can suddenly begin vibrating so badly it makes riding no fun anymore, even if the engine is rubber mounted. The crankshaft flywheels are pressed together to the crank pin. Without notice and without cause the flywheels will slip out of alignment and the vibration is born. What is sad is that the Harley dealers will tell you it is normal when it is not. They will not fix the problem. I have met other riders with the same problem and the same bad results. The author says his brand new Harley failed at just 3,000 miles. He also said that he traded it in for another new Harley and the crank slipped on that one too! Those were his last Harley-Davidson's. Two strikes on two brand new Twin-Cam engine bikes was enough for me. He switched to Kawasaki Vulcan 2000 with a 125 cubic inch V-twin and later to the Victory 106ci V-twin which is a superior designed and reliable motor, but dealership qualifications to perform warranty work he found, in his case, was not up to industry standards. That is a big problem if the bike you buy can't be fixed quickly, reliably and professionally. You will find this problem throughout the "power sports" industry, so beware.


13. You will notice modern motorcycle engine design eliminates the inner and outer primary case the Harley-Davidson Twin-Cam engine uses. It is an old design full of flaws and weaknesses using a sloppy chain to connect the engine to clutch and transmission. It is a source of problems mostly regarding oil leaks from the outer and inner primary gasket and seals for the crankshaft, transmission countershaft and starter motor. It is not cheap to fix these oil leaks. And to makes matters even worse that this entire primary chain case system must completely disassembled to change a drive belt, pulley or chain sprocket. Ask around for a price to do these jobs and it will open your eyes a bit wider. Your drive belt will need replacing one day and you will have to pay a dear price due to this outdated, unfriendly engine design. Of course, if you learn to do it yourself it will only cost you time and parts. Most riders do not know how to do it. For example if you look at the Victory Freedom 106ci V-twin engine none of these problems are evident. You can change a drive belt and pulleys yourself. There will be no oil leaks from seals and there is only one simple gasket for the primary system. No chains for it is totally gear driven primary system and it uses the engine oil, not a special primary case oil. Yes, this engine too has a cam chain but of a totally different design. A proven reliable design using long cam chain guides like modern car and motorcycle engines use. If the cam chain guide wears out it will not self-destruct the engine. But you have to drop the engine out of the frame to overhaul the rear cylinder whereas a Harley can be performed in the frame.


Roland Sands makes a see-through Clarity design cam plate timing cover so you can visually inspect at least the outer cam chain shoes. They also have clear covers for the transmission and rocker boxes.


14. Harley-Davidson's generally require an oil change each 5,000 miles. And it requires that three oil compartments be drained and filled each with different types of oil; engine oil, primary case and transmission oil. The author wrote a book showing you how to do it. How to Change the Oil in Your Twin-Cam Harley-Davidson. You will notice it only takes ten minutes to change the oil on a modern motorcycle like the Victory and it only has to be changed each 5,000 miles. You will also find the same information on YouTube for free with videos.


Oil changes are at the discretion of the owner unless you are under warranty, then you should adhere to the maintenance schedule laid out. Most normal changes depend on the type of oil you are using, the riding conditions, & personal preference.


15. Transmission trouble? Yes, there is a problem with the transmission 5th gear. As the 88 twin cam engine evolved to the 96 cubic inch a strain developed on the gears. In the year 2007 the inner bearing race was upgraded due to bearing failure. In the year 2010 the fifth gear was changed to a reverse-helical gear to neutralize the side load on the bearing. What does this mean to the average rider? It means if you hop up the engine on any twin-cam engine you risk a major transmission failure. So, you need to purchase and install a fifth gear and bearing/shaft update kit if you ride the bike hard (which many riders do). The race on the shaft can move, which lets the seal leak and the bearing walk/wobble more than it should accelerating wear and fail. Some riders have found this bearing failure twice in 40,000 miles. Mostly hard-ridden stock 88 and 96 will fail along with those with souped-up engines (pistons, cams including crankshaft long-stroked engines). But the new 103 cubic inch twin cam are not immune to transmission failure even though they have the updated kit installed at the factory.


16. Overheating: Harley-Davidson engines run hot. The 88 cubic inch engine ran hot and at the high limits and the 96 cubic inch engine runs hotter yet which is not good for the engine. The 110 cubic inch engines run exceedingly hotter and so much so a class-action law suit was filed against Harley-Davidson from riders being burned from the engine heat (mostly from the rear cylinder near the rider's thighs). Heat burns to the skin is not the only problem as heat is an engine killer and the hotter these big air-cooled V-twins run reliability falls drastically. Don't expect engine longevity with a 103 or 110 cubic inch air-cooled V-twin such as the Harley-Davidson design. Clean synthetic engine oil and a large external engine oil cooler is a must have accessory, but it only helps engine cooling not cure these serious excessive heat problems that self-destructs the engine.


17. The Harley-Davidson engine looks nice with all the chrome, but if you really look good you will notice the engine design is so archaic it is truly a problem to behold for there are way too many moving parts inside the engine and in the primary case to wear out and break down. The transmission is small in size and that means smaller, weaker shafts, bearings and gears are inside. Way too many moving parts each over-stressed! This is why you see so many in shops being repaired and broken down on the side of the road being towed back to the dealers. The engines also run very hot when stock and even hotter when the engine is "hopped-up" and this old engine design just can't tolerate all of that heat. Oil coolers will help, but will not shed enough heat to stop engine damage from excessive wear. Even full synthetic oil won't stop the wear due to hot spots in the engine. Even replacing a drive belt will cause you grief even if you do it yourself for it will take you hours of labor. It will be expensive for a shop to replace your drive belt. And with the cam followers going to bite you and blow up your engine you need to consider replacing those followers often like every 20,000 miles . But they can even fail quicker in some cases. The 103 cubic inch will evolve into even higher 110 cubic inch engines that will create even higher stresses and heat and reliability is going to suffer even more.
A good example is to see what Harley-Davidson should have done by redesigning their Twin-Cam engine is to look at a cut-away view of the Victory motorcycle engine. It has all the modern materials and racing valve gear, etc. Less moving parts and much stronger parts to boot. There are limits to the power output of any engine design and Harley-Davidson is tinkering with the Twin-Cam engine to stroke and bore it out to create an engine that just is overpowered for its design. What happens? You have a hot engine that self-destructs even under normal running conditions. Even water cooling a Twin-Cam engine with restrictive water channels will help, but it will not alleviate the overheating problem.
Nobody wants to admit it because there is a lot of money repair shops and dealers and after market firms are making hot-rodding these Twin-Cam engines and people are falling for it and paying the price of engine failures. Just take a look inside the repair shops and you'll see these repair bays are full of broken down Twin-Cam engines. Yes, even brand new engines!

18.  The Twin-Cam engine between the years 1999-2006 has a very weak oil pump that actually drops oil pressure near "zero" when idling which accelerates internal engine wear.  You can shim the pressure relief valve to gain more pressure, but this is still not a cure as those chain followers wear (as yours are wearing as you ride your bike) the follower debris slowly blocks or destroys the oil pump and the engine will be horribly ruined without notice catching you by surprise.  One day all is well, the next day be prepared to buy a new remanufactured engine.  Don't you trust the warranty you have will cover this failure as it likely will not and you will be stuck with the bill.  How can this be?  Excuses are many and are you  having these followers inspected each year?  Probably not and that is just one loophole that will be used to deny your warranty claim.  There is a fix for the marginal oil pump, but you have to buy an aftermarket cam-support plate.  On late 96'ci engines it will permit you to fit "real" bearings on the outer camshaft journals, where the factory plate has none, and in the earlier engines it will allow you to install a better, late-model oil pump.  The replacement plate is stronger with no flexing.  But remember, as long as you have cam chains and tiny followers pressing on those chains your engine will eventually fail catastrophically unless you solve this problem or are "very vigilant" with frequent inspections.  Those inspections are expensive and most Harley-Davidson riders are not aware of the problem in the first place to bother asking or performing these visual inspections. 

Newer Twin-Cam engines also have oil pump problems if ridden hard or the engine has been modified.  The problem is not the oil pump's pressure side, but the suction evacuation side become overwhelmed and can not remove the oil fast enough from the crankcase.  If oil accumulates in the crankcase a piston can hydraulic the oil and the motor is going to grenade.  The cure is to replace the oil pump with a higher capacity pump such as a Fueling high performance oil pump.  Specify the year of your Twin-Cam engine and modifications made to the engine and Fueling will tell you which oil pump to install.  If you see excessive oil build-up in the cylinder head breathers it is a sign you should back off the throttle and ride with less aggression or get a new oil pump.

Well that is enough for this session....

Stay tuned for Part Four.....

Happy Trails.....

Remember..... A Harley is only as good as the TLC her rider gives her!