Belt tension

[DucNaked]

By equal I meant when adjusting you use either the same frequency or the same allen key to measure as opposed to intentionally leaving the vertical looser to account for increased expansion.

The actual tension is what it is.

He used the same frequency and the same allen would not fit by the pulleys. I assume that is because the tensioners aren't in the same exact place on the cyclinders. Or did I not understand him correcly? They had the same tension, but the tensioners themselves were in different spots so the gap wasn't the same.(my understanding)

[ducpainter]

He used the same frequency and the same allen would not fit by the pulleys. I assume that is because the tensioners aren't in the same exact place on the cyclinders. Or did I not understand him correcly? They had the same tension, but the tensioners themselves were in different spots so the gap wasn't the same.(my understanding)

We're saying the same thing I think.

Whether the actual tension is the same or not is hard for me to grasp because of the varied pulley location. All we know is the belts resonate at the same frequency.

Also keep in mind that both belts are bowstring tight when the engine warms, so as long as they're not so loose that the belt skips when cold, or so tight that it takes out a tensioner/idler bearing when hot they're right.

[DucNaked]

We're saying the same thing I think.

Whether the actual tension is the same or not is hard for me to grasp because of the varied pulley location. All we know is the belts resonate at the same frequency.

Also keep in mind that both belts are bowstring tight when the engine warms, so as long as they're not so loose that the belt skips when cold, or so tight that it takes out a tensioner/idler bearing when hot they're right.

[ungeheuer]

Also keep in mind that both belts are bowstring tight when the engine warms, so as long as they're not so loose that the belt skips when cold, or so tight that it takes out a tensioner/idler bearing when hot they're right.

^^ Sounds like a common sense approach to me and so that there is my "take-away" from this thread  .

[BG DUKE]

Hi there 
I hope you didn't miss the new belt changing tutorial from California Cycleworks. I thought it will be interesting to watch how they determine the belt tension with a software guitar tuner. It's very handy and simple method if you have a laptop or PC in the garage.
Links to the videos:
part 1:


and part 2:



The only thing I really dislike is the free software tuner they used in the video. It can't hold the peak frequency of the belt's vibration and you have to stare to notice it just for a very short part of the second. It can be caused by the low frames per second in this compressed video, but this forced me to find a better "free" software frequency analyser to do the job easily.
And I found it
This is a link, for free download, of maybee the best instrument tuner for PC ever made. It works great and the most common thing is that it filters the desired frequency and shows it's value constantly, of course with showing it's change very accurately.
Enjoy: http://www.nch.com.au/tuner/index.html

And this is a video demonstration of it's possibilities to prove my choice of software for the job: Free guitar tuner helps find that Perfect Pitch

It works really great with guitar too!!! Tested

[akmnstr]

Rock on!


Ducati sells a special tool for measuring belt tension on their 2 valve engines.  I don't know if it works on the dual spark engines.  Somewhere, about 10 years ago, I found out that the ducati tool measures the equivalent of 10lbs of tension.  So I purchased a cheap fishing scale which I used until I blew up that engine.  The scale also works on bass, salmon, reds, and pike.   

[koko64]

I use a combination of a fishing scale (saw it's use in the Haynes manual), the 5mm and 6mm Allen keys and the 45 degree twist.
By the way, how did you blow up your bike? You weren't alluding to a broken belt I hope?

[akmnstr]

I use a combination of a fishing scale (saw it's use in the Haynes manual), the 5mm and 6mm Allen keys and the 45 degree twist.
By the way, how did you blow up your bike? You weren't alluding to a broken belt I hope?

Don't know for sure what was the problem.  I'm sure it had nothing do with the belt.  Shortly before it blew up I had a valve job done and then had a dyno run done on it.  The idiot tech that did the dyno run hit a 4 grand over red line.  He may have stressed something that broke later. 

[krista]

The idiot tech that did the dyno run hit a 4 grand over red line.  He may have stressed something that broke later. 

    aw man, that sucks.

[koko64]

Don't know for sure what was the problem.  I'm sure it had nothing do with the belt.  Shortly before it blew up I had a valve job done and then had a dyno run done on it.  The idiot tech that did the dyno run hit a 4 grand over red line.  He may have stressed something that broke later.  

That would do it. 4 grand over !
That's terrible. So sorry to here that.
That's negligent.

[akmnstr]

The engine lasted about 2k miles after the dyno run so I can't go back to the shop, and the shop is in Anchorage and I now live in Texas.  It was the Harley shop in Anchorage, the dyno runs used to be done by a fellow that went to Duc training and a great guy.  My bad luck, he had moved on, when I brought the bike in for its run there was a rookie running the show. 

[He Man]

how long does it even take for you to rev it 4grand over? I've accidently gotten my M944 up to 11,000 rpm. The engine was solid.

[jwoconnor]

At least the valves wont float.

[64duc]

At least the valves wont float.

Might have been better if they had.

[akmnstr]

I can give witness that valves hitting pistons is a very bad thing.