Videos on Inspection and Repair:
Cam Chain Tensioner Shoe Video Project
Cam Gear Drive Conversion Video Project
Not an Issue with M8 Motors but here’s a Cam Swap Project video series.Cam Chain Tensioners
Twin Cams from 1999 through 2006 (expect for the 2006 Dyna) – Harley Davidson’s cam chain tensioners on their Twin Cam motors were, to say the least, a complete and utter failure. A lot of us were, and are still, scratching our heads wondering how in the world they could not be held accountable and forced to recall these motors to be repaired on their dime.
Harley, eventually offered us an expensive “upgrade” but it was really just a repair/correction of their bad design. Although some motors are ok up to 40k or 50k. It has been our experience that most cam chain tensioners need replacement between 20k and 30k. We have seen a large number of bad cam chain tensioners under 15k. Debris from these failing tensioners can cause premature failure of the oil pump and cam bearings leading to more catastrophic engine failure.
Where does this leave us?
Being that a failing tensioner cannot always be heard, we have to suggest to our customers & friends that any 2000 to 2006 Harley Davidson with spring style tensioners and 15k miles or more, have a visual inspection of the cam compartment. This is the only way to positively identify if you have good or bad tensioners. If you inspect your tensioners at 20k miles and they appear to have very little wear, it may be safe to run another 20k before another inspection. If tensioners are worn to 50% or less, we recommend upgrading to a hydraulic cam chain tensioner assembly or direct gear drive. Although it is a cheaper option, we do not recommend replacing with a new set of spring style tensioners as it is a gamble on how far they will take you.
When inside your cam compartment, it is of utmost importance that your inner cam bearings and your cam plate bearings be replaced.
Here is an example of a worse case scenario on an 88ci Twin Cam. Pics from a blown motor we previously had in the shop. One of the original inner cam bearings failed.
A few bearing needles wiped out the oil pump. The oil pump seized over the crank shaft and damaged the crank shaft.
The rest of the bearing needles dropped into the crankcase and and continued to spread throughout the engine.
This is why it is of utmost importance to upgrade inner cam bearings and cam chain tensioners on the Twin Cam engine.
Also, thoroughly clean and inspect your oil pump and lifters if they are to be reused. There are a number of options available for hydraulic or gear drive assemblies. Cost will vary significantly. Do some research to determine what assembly or combination of parts will work best for you, for your riding style and for your budget.
Here is an example of a bike that recently passed through our shop.
Motorcycle: 2003 FLTR – 35k miles
INSPECTION:
Cam Compartment:
Primary tensioner, approx 10% life
Secondary tensioner, 0% (worn thru)
REPAIR:
Fueling hydraulic cam chain tensioner kit
S&S adjustment pushrods
S&S lifters
Cam bearings (inner & plate)
Chains (primary & secondary)
Stock cams – reused
All necessary gaskets/seals & fluids
Videos on Inspection and Repair:
Cam Chain Tensioner Shoe Video Project
Project DVD Set
p>Cam Gear Drive Conversion Video Project
I have replaced cam tensioners on multiple of the affected 88s. All were replaced before catastrophic failure. The repairs usually started with replacing rocker box gaskets. They were burnt from overheating. I believe it was the overheating, sometimes more than once that destroyed the tensioner shoe. My personal experience on my bike helps support that theory. I have an 04 FLHRI. At 41,000 miles I heard noises coming from the cam area. Immediately bike was taken into garage where I assumed the cam tensioners would be toast. With 42,000 miles the shoes showed very little wear. The front inner cam bearing had blown. From the time I heard the first noise to tear down was less than 2 miles. The bearings went everywhere and the complete engine was destroyed. My Harley now is powered by an engine that is 98 ci. Approximately 84 percent S&S. ARP hardware thruout. Every fastener that I could find from ARP is in the engine. First and last Harley. I was informed by a dealer tech that when the Timkin main crank bearings were replaced with a less expensive setup the engineers also found a cheaper option for the cam bearings. My opinion Harley should have replaced my engine but even if HD agreed to do the repair I would not trust the fix and gotten rid of the bike. New engine dyno run resulted in 103 HP. 127 foot pounds of torque. Rear tire was melting on the dyno. Dyno shut itself down because it sensed the loss of traction. Fun bike to ride. And yes, when road conditions allow, this 65 year old still rides it like I stole it! Love the bike. Can’t say the same for the company that made it.
Listen, NO do what Vincent is tell you! I didn't and it cost me a rebuild on a vacation. I don't use Harley Oil anymore. I use to be faithful to the Brand on all my service but they cured me. Jeff Guynes
This sounds exactly like what happened to my 2017 M8 with a 117 Stg 4 kit. A little over 20K miles my cam chain tensioner went bad. After it was replaced a week later the oil pump went out and a week after that was replaced, the entire motor siezed up.
hi everyone I have a 2006 Deuce I bought last May it had around 15.000 now it has 21.000 I didn't know about the issues with the cam tensioners till late September that year what gets me I'am a avid biker most of my friends have the twin cam I rode sportys most of my life should of keep my ol sporty LOL !!!!! I'm going to take the cam cover off tomorrow hopefully it's already been upgraded
I have a 2008 FXSTC, is this going to be an upcoming issue for me. I'm not sure if my 96ci motor is an M8. I see you list the years from 1999-2006. My son had an issue with his 2001 Fat Boy.
I have a 2004 Dyna Wide Glide when changing oil I found metal on magnetic plug. I also found metal in the oil filter not as much .????
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Fixing to do mine
I have 2006 Electra Glide went to gear driven S &S 510 cams at 24,000 miles ain't looked back got 49,000 went to sturgis and back to N C last year with no problems!
Amen! The tensioners on my 2003 FLCS were worn completely through at 30,000 miles and the tensioners on my 2003 FLH were about 90% gone. Replaced both myself with the Harley's "upgraded" hydraulic kit along with new bearings. Expensive "owner fix" for a factory created problem.