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GL1200 Timing Belt tension

7556 Views 10 Replies 5 Participants Last post by  wildfire
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Ok. So my 1985 1200 I needs new timing belts. I feel ok that I have a good understanding of what is required with one exception... Tension



While each belt has a spring operated tensioner but they could be 27 years old and might not deliver the correct tension. I have the workshop manual and it gives the range of freeplay allowed but not how or where to measure it.



I am hoping thatsomeone that has replaced the belts on their 1200I could englighten me as to how they did it.



Thanks in advance.



Tom
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You do not want the belts to be too tight and I understand that you also do not want them too loose. Use your finger to SLIGHTLY pull down the belt right next to the tensioner and tighten the tensioner as the spring moves the tensioner against the belt. When this is done, check the belt by measuring the freeplay in the middle of the long part of the belt. You should not have more than about a quarter inch ( 5 to 7 mm )of play in the belt but you should have some. Make sense? You just don't want them too tight. That will cause premature failure of your tensioner bearings. Make sure you check the tensioners pretty good that they don't have any play in bearings and they roll without slop or grinding.
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Remember that the earlier aftermarket shop manuals are wrong in how to set the tension. The correct way is to do one, then rotate the crankshaft once and do the other side. The way the book tells you to do it would have one cam pulling the belt on the tensioner side, leaving it loose. I have seen MANY that were done that way.

A good way to check the tension is if you can just about twist the belt 90* in the mid-point with your fingers you are good.


Bill
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+1 on what Bill said. Check out the how to on the goldwing workshop on right hand side of the site. It explains procedure pretty good.
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77Pinto wrote:
Remember that the earlier aftermarket shop manuals are wrong in how to set the tension. The correct way is to do one, then rotate the crankshaft once and do the other side. The way the book tells you to do it would have one cam pulling the belt on the tensioner side, leaving it loose. I have seen MANY that were done that way.

A good way to check the tension is if you can just about twist the belt 90* in the mid-point with your fingers you are good.


Bill
One belt loose while the other side has a small amount of play is how mine is set now ( i have not replaced the belts yet). Sois thatwrong? Are both belts supposed to be have equal tension at the same time regardless of where the camshaft is in rotation cycle?
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Apologies all .I should have searched the workshop area first. The guidelines in the workshop link goes in to great detail. Thanks for your help. You got to love this site.
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wildfire wrote:
Apologies all .I should have searched the workshop area first. The guidelines in the workshop link goes in to great detail. Thanks for your help. You got to love this site.
Although the GL1200 timing belt tutorial and the YouTube video at the bottom both by Steve Saunders are excellent they both fail to mention turning the crankshaft 360⚬ to set the tension on the right belt which in my opinion is essential.
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Ken Bergen wrote:
wildfire wrote:
Apologies all .I should have searched the workshop area first. The guidelines in the workshop link goes in to great detail. Thanks for your help. You got to love this site.
Although the GL1200 timing belt tutorial and the YouTube video at the bottom both by Steve Saunders are excellent they both fail to mention turning the crankshaft 360⚬ to set the tension on the right belt which in my opinion is essential.
Ken,



Can you elaborate a bit regarding rotating the crankshaft 360 and is it only required for the right belt? Does it make a difference what belt is tensioned first?
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wildfire wrote:
Can you elaborate a bit regarding rotating the crankshaft 360 and is it only required for the right belt? Does it make a difference what belt is tensioned first?
With the crankshaft timing mark set to TDC and camshaft timing marks lined up all the valve spring on the left side are relaxed and not trying to turn the camshaft so the belt can be tensioned correctly by the tensioner spring.

On the right side however the valve springs are trying to turn the camshaft which makes setting the tension correctly next to impossible.

Turning the crankshaft 360 degrees relaxes the valve springs on the right side and makes tensioning the belt using the tensioner spring possible.
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While each belt has a spring operated tensioner but they could be 27 years old and might not deliver the correct tension.

Just to say .... the springs have nothing to do with setting belt tension, they are too light and inprecise for that. You set tension by measuring deflection on the long run side while doing the whole tension drill as specified. The springs just keep the pulleys in contact while you have the bolts loose, like a third hand.

Too tight, belt will humm loudly.

Too loose, belt will slap and sound almost like a knock at idle or slow speeds.
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Ken Bergen wrote:
wildfire wrote:
Can you elaborate a bit regarding rotating the crankshaft 360 and is it only required for the right belt? Does it make a difference what belt is tensioned first?
With the crankshaft timing mark set to TDC and camshaft timing marks lined up all the valve spring on the left side are relaxed and not trying to turn the camshaft so the belt can be tensioned correctly by the tensioner spring.

On the right side however the valve springs are trying to turn the camshaft which makes setting the tension correctly next to impossible.

Turning the crankshaft 360 degrees relaxes the valve springs on the right side and makes tensioning the belt using the tensioner spring possible.
OK, now I get it so tension left belt first, rotate crankshaft 360 and tension right belt. Thanks for the clarification.
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