Harley-Davidson Twin Cam Engine Guide: 88 to 110, the Tensioner Story, and Which Years to Buy
Updated: Sep 2
Quick answer: The Twin Cam powered Harley Big Twins from 1999 to 2017 in 88, 96, 103, and 110 cubic inch versions. It is a strong engine with one famous weakness: the spring-loaded cam chain tensioners used from 1999 to 2006. Buy 2007 and later, or an early bike with documented tensioner work. MGR Reliability Rating: 7.5/10 overall.
Spec | Twin Cam |
Production years | 1999 to 2017 |
Displacements | 88 (1,450cc), 96 (1,584cc), 103 (1,688cc), 110 (1,801cc CVO and select S models) |
Configuration | 45 degree OHV V-twin, two chain driven cams, 2 valves per cylinder |
Cooling | Air cooled; Twin-Cooled heads on some 2014 to 2016 touring models |
Used in | Dyna, Softail (counterbalanced B versions), Touring, CVO |
MGR Reliability Rating | 7.5/10 overall: roughly 8.5/10 for 2007 to 2017, 6.5/10 for unaddressed 1999 to 2006 engines |
What the Twin Cam is
The Twin Cam 88 replaced the Evolution Big Twin for 1999. The name comes from its two chain driven camshafts, and it brought a stiffer crankcase, better breathing, and a twin gerotor oil pump. Softail models got the counterbalanced 88B version from 2000 because the engine bolts rigidly to that frame. The 96 arrived for 2007 alongside a six speed transmission, the 103 spread across the lineup from 2011 to 2012, and the 110 served CVO and later some S model Softails. Touring models moved to the Milwaukee-Eight for 2017, and the last Twin Cam Dynas and Softails were 2017 models.
The cam chain tensioner story, told honestly
This is the part of the Twin Cam story that gets exaggerated in both directions, so here it is straight. From 1999 to 2006, the cam chains ran against spring loaded tensioner shoes faced with a plastic composite. The shoes wear. When one wears through or breaks up, the debris can be drawn toward the oil pump and starve the engine of oil pressure, and the failure gives little warning. Harley service practice called for inspection in roughly the 35,000 to 40,000 mile range, but shoe life varies widely, and some wore out far earlier.
Harley fixed it. The 2006 Dyna family debuted a new cam plate with hydraulic tensioners, and the rest of the Big Twin line got the hydraulic design with the 96 in 2007, along with a higher flow oil pump. The hydraulic system has proven durable and is not considered a problem area. For early engines there are two accepted fixes: convert to the later hydraulic tensioner setup with an updated cam plate and oil pump (roughly $500 in parts, more installed), or fit gear driven cams, which delete the chains entirely (roughly $750 in parts, often around $1,500 installed).
Other known issues
Inner cam bearings on early engines (especially 1999 to 2002) have a documented failure history and are usually upgraded to Torrington type bearings whenever the cam chest is opened.
Heat. Later 103s in touring trim run lean for emissions and can get uncomfortably hot in traffic. Annoying, not a defect.
Base gasket and cam cover seepage on high mileage examples. Normal old Harley stuff, cheap to fix.
Which years to buy
Best: 2012 to 2017 103 and 110 bikes. Mature platform, six speed, hydraulic tensioners, strongest parts support.
Very good: 2007 to 2011 96 and 103. Same fixed architecture, often cheaper.
Good value for the informed: 2006 Dyna (first hydraulic cam plate plus six speed).
Buyer beware: 1999 to 2006 anything else, unless the seller can show receipts for a hydraulic conversion or gear drive. Price the work into your offer if not.
Realistic lifespan
A Twin Cam with the tensioner question answered and honest maintenance routinely runs into six figure mileage; the touring community has plenty of documented high mile examples. The bottom end is robust. We will not quote a failure rate for the early tensioners because no reliable public statistic exists, only a well documented failure mode you can engineer out for a known cost.
Maintenance and oil notes
General guidance, not a substitute for the manual: 5,000 mile oil service with 20W-50, separate primary and transmission fluids, and on any 1999 to 2006 engine without conversion receipts, a cam chest inspection soon after purchase. Listen for top end knocking when cold and check for metal in the oil filter at the first change after you buy.
Where you will meet a Twin Cam today
Used Dynas, Softails, and touring bikes from this era are the heart of the sub $10,000 Harley market. If you are shopping the modern successors instead, see our Street Glide review and Street Bob review, both now Milwaukee-Eight powered. Our used market roundup later this month covers the best Twin Cam buys specifically.
FAQ
Which Harley Twin Cam years should I avoid?
Unmodified 1999 to 2006 engines are the risk years because of the spring loaded cam chain tensioners. They are fine to buy only if a hydraulic conversion or gear drive is documented, or if you price the work into the deal.
How long does a Twin Cam engine last?
With the tensioner issue addressed and regular oil service, six figure mileage is common and well documented in the touring community. Neglect, not design, is what kills most of them.
Is the Twin Cam a reliable engine?
From 2007 on, yes, genuinely reliable, and we would rate those years 8.5/10. The 1999 to 2006 engines are only as reliable as their tensioner service history, which is why our overall rating is 7.5/10.
What is the difference between Twin Cam 88, 96, 103, and 110?
Displacement, and the running changes that came with each: the 96 brought the six speed and hydraulic tensioners in 2007, the 103 became the standard Big Twin from around 2012, and the 110 was the CVO engine, later used in S model Softails.
How much does it cost to fix the cam chain tensioner problem?
Roughly $500 in parts for the hydraulic conversion kit or about $750 in parts for gear drive cams, with installed totals commonly landing near $1,000 to $1,500 at independent shops. Prices vary by region and parts choice.
Twin Cam or Milwaukee-Eight, which should I buy used?
If the budget reaches a 2020 or newer Milwaukee-Eight, that is the more refined and lower risk engine. A 2007 to 2017 Twin Cam is the value play and gives up little in real world durability.
Sources
Last updated: August 8, 2026. MotoGearRater is independent. We do not sell motorcycles and nobody pays for a rating.
