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Discussion Starter #1
Ok so I tension my own belts using an Allen key method. Been doing it for 6 years no problem. Put new belts on and had the CO, TPS and balance done today at the dealer. Thought I would get him to check the horizontal cylinder belt tension as it is easier to get to and would be an intersting exercise to see how close i was setting belts too.

Reading was 152Hz :eek:.....but the engine was hot. I pointed out on his board that the tension should be checked when cold. Theoretically the Hz should rise by a "X" amount if the engine is hot with the expansion of compoments due to heat tightening the belts slightly. Ahh but by how much. Watching him reset back to 110hz it seemed he moved a very very small amount to reduce by 40HZ. This I expected as I know how little movement it takes when I am trying to get correct tension with my method

Does anyone have any idea what sort of difference you would expect see in tension hot versus cold?
 

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Theoretically the Hz should rise by a "X" amount if the engine is hot with the expansion of compoments due to heat tightening the belts slightly.
Any reason why the belts won't expand and loosen with this same heat causing the HZ to drop and/or the metal parts expanding more or less? How hot? Too many variables there to make any type of profound judgement on relative tension between hot and cold. Guess that's why the tension figure is for setting when cold. Cold is cold...relatively.
 

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Discussion Starter #3
Yeah that's why I wondered why he was so intent on checking them hot. Expansion should be more or less linear with heat increase. Not sure what would haPpen to belt material with heat.
I wanted them checked as a comparison to what I thought was a good consistent method I have used but I think I am none the wiser for it.
Oh well off tO buy a microphone tomorrow and give the laptop another go.
 

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They’re checked cold. No hot tension that I know of. I mean there might be, but why? They are set to a particular tension when cold so that the belts will be at the correct running tension when the engine is hot. If your dealer set them to cold tension when the engine was hot, they are now too loose. The belts are not affected by temp. They should not stretch or contract because of engine temp. It’s the heat expansion of the engine components that make the change. Belts loosen over time, but that is likely more to do with tooth wear than the actual belt stretching.

If you have a smart phone there are guitar tuner apps that work well for this. I have a Droid and used the free gstrings app. Worked perfect.
 

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..... They are set to a particular tension when cold so that the belts will be at the correct running tension when the engine is hot. If your dealer set them to cold tension when the engine was hot, they are now too loose. .....

This ^^^^. You need to re-tension cold (the bike needs to sit overnight so engine is at ambient temp) when you get your microphone app.
 

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Discussion Starter #7
If you have a smart phone there are guitar tuner apps that work well for this. I have a Droid and used the free gstrings app. Worked perfect.
Hmm cant find the gstrings app. Thats for the iphone. So if you use the doid phone, what do use for the microphone? Do you just hold the phone close to the belt between tensioner and drive pulleys. Probably been covered here somewhere. At least I will have some interesting comment on what 110hz is from a hot motor down to cold. Will be interesting.

Something to do on the weekend
 

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I have a Droid 3. gstrings was in the free apps area when I was looking. There are other tuners if you can’t find that one. All should work well. Yes, I just use the phone's mic. No problems. I held it as close as I could. This was on the ST4s and there isn’t much room in there. I also turned off my shop radio and the overhead florescent lights to cut down on external noise.. That helps in getting a steady reading.
 

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Discussion Starter #9
I have a Droid 3. gstrings was in the free apps area when I was looking. There are other tuners if you can’t find that one. All should work well. Yes, I just use the phone's mic. No problems. I held it as close as I could. This was on the ST4s and there isn’t much room in there. I also turned off my shop radio and the overhead florescent lights to cut down on external noise.. That helps in getting a steady reading.
Cheers Dan ...maybe the fluros have stuffed my previous attempts up:think:
 
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