came across this... just passing along with no comment

goo · 2012-11-20 17:08:40

TWIN CAM TENSIONER ISSUES If you own a Harley-Davidson Twin Cam motorcycle, you should be aware of a number of issues that have come to light since the debut of the Twin Cam motor in 1999. Though Harley has made a number of modifications to the motor, beginning the first year they were produced, there are still potential problems with the cam chain tensioners, especially for motors prior to 2007. A number of private mechanics, who have been into hundreds of Twin Cam motors, have found a very significant variation in the amount of wear on tensioner shoes by the time they reach 25,000 miles. I have first-hand knowledge of shoes completely failing by 21,000 miles. Since Harley recommends that the tensioner shoes be replaced by the time they're about half worn out, it makes sense to check your tensioners at in at least 15,000 mile intervals. Some experts say check 'em every 10,000 miles. For the record, some TC motors have gone well over 50,000 miles without tensioner issues. There seems to be no definitive explanation for this, but my theory is that it has to do with quality control of the chains (not the shoes). Think about it, if the backside of the chain, the part that rubs against the shoe a zillion times a minute, has any rough spots on it, then the chain will act like a saw and begin cutting right into the shoe material. A precaution against this is for the mechanic to polish the backside of the chain, which I do, before installation. Dealerships may not be inclined to take this extra time. If you ride a Softail, then you potentially have the same issue with the counter-balance drive chain, which requires cracking the case to access. Once your tensioner wears down to the metal, then engine stoppage or failure is soon to follow. Whether or not the damage is catastrophic just depends on where the debris goes in the motor before it shuts down. Tensioner shoes are $65 apiece at Harley. This, along with the gaskets and labor, are a minimum of what it will cost you for preventative maintenance. Let it go too long and it will cost you thousands. If you doubt this, Google Twin Cam tension shoe issues. Other options are to go to the Screamin' Eagle hybrid upgrade, which includes a new cam support plate, chains and gears. This upgrade uses hydraulic tensioners instead of spring tensioners. An improved oil pump is included and highly recommended. Another option is to go with an S&S or Andrews gear drive setup. In each case the labor will be pretty much the same, whether you're replacing tensioners or going with a hybrid or gear upgrade. In the latter case you're looking at 4 to 6 hundred dollars in parts or more. Also, just as with the Evo, the inner cam INA bearings MUST be changed out with Torrington bearings, because they will fail! If you have gone with big inch modifications to your motor, you might have other issues, such as with the left side main crank bearing that Harley changed from Timkin taper bearings to straight roller bearings in '03. Just something to think about (aftermarket conversion back to Timkin taper bearings is available) additional link http://www.cycleconnections.com/articledetail.asp?TypeID=23&ID=1014

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11-20-2012, 11:08 AM

goo

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came across this... just passing along with no comment

TWIN CAM TENSIONER ISSUES

If you own a Harley-Davidson Twin Cam motorcycle, you should be aware of a number of issues that have come to light since the debut of the Twin Cam motor in 1999. Though Harley has made a number of modifications to the motor, beginning the first year they were produced, there are still potential problems with the cam chain tensioners, especially for motors prior to 2007.

A number of private mechanics, who have been into hundreds of Twin Cam motors, have found a very significant variation in the amount of wear on tensioner shoes by the time they reach 25,000 miles. I have first-hand knowledge of shoes completely failing by 21,000 miles. Since Harley recommends that the tensioner shoes be replaced by the time they're about half worn out, it makes sense to check your tensioners at in at least 15,000 mile intervals. Some experts say check 'em every 10,000 miles.

For the record, some TC motors have gone well over 50,000 miles without tensioner issues. There seems to be no definitive explanation for this, but my theory is that it has to do with quality control of the chains (not the shoes). Think about it, if the backside of the chain, the part that rubs against the shoe a zillion times a minute, has any rough spots on it, then the chain will act like a saw and begin cutting right into the shoe material. A precaution against this is for the mechanic to polish the backside of the chain, which I do, before installation. Dealerships may not be inclined to take this extra time. If you ride a Softail, then you potentially have the same issue with the counter-balance drive chain, which requires cracking the case to access.

Once your tensioner wears down to the metal, then engine stoppage or failure is soon to follow. Whether or not the damage is catastrophic just depends on where the debris goes in the motor before it shuts down.

Tensioner shoes are $65 apiece at Harley. This, along with the gaskets and labor, are a minimum of what it will cost you for preventative maintenance. Let it go too long and it will cost you thousands. If you doubt this, Google Twin Cam tension shoe issues.

Other options are to go to the Screamin' Eagle hybrid upgrade, which includes a new cam support plate, chains and gears. This upgrade uses hydraulic tensioners instead of spring tensioners. An improved oil pump is included and highly recommended. Another option is to go with an S&S or Andrews gear drive setup. In each case the labor will be pretty much the same, whether you're replacing tensioners or going with a hybrid or gear upgrade. In the latter case you're looking at 4 to 6 hundred dollars in parts or more. Also, just as with the Evo, the inner cam INA bearings MUST be changed out with Torrington bearings, because they will fail!

If you have gone with big inch modifications to your motor, you might have other issues, such as with the left side main crank bearing that Harley changed from Timkin taper bearings to straight roller bearings in '03. Just something to think about (aftermarket conversion back to Timkin taper bearings is available)