So I’ve changed the belts on my 95 916 while also doing exiges cable upgrade at the same time. Using the Allen key method for adjusting they seem to be running very close on the horizontal cylinder,the vertical is fine. Any idea what’s up. Are the too close or are they ok. Exige was out of stock so they are genuine Ducati belts this is the first time doing this on my 916 which I only have 2 years and I didn’t think to look at the old belt position before I took them off. Now in saying that looking through old service record the previous two sets of belts were 73710031A 996B-SPS 748B-SPS 99 As the photo shows. Am I missing something or adjusting something wrong. Is there something up with the belts I’ve ordered I’ve started her and she’s running great. But I’m just a little concerned..
The belt ending in 91A is the correct part number that supersedes the ones ending in 31A, they are 95 tooth belts for 996s and 748s up to MY01
Strange that as I have sold belts recently to a well known Ducati Emporium who couldn't get the OEM belts to tension it's only happened the once.
Hmm got me thinking now I changed my belts for genuine one because exige didn’t have any and thought mine looked close, will have to go back and check them. Counted the teeth and 95 just the same
Wonder if there is a bad batch. There was the 748 that broke a new belt last week. https://www.ducatiforum.co.uk/threads/i-thought-that-sounds-bad-and-i-was-right.78094/
Here’s a pic of my 996 belts that were fitted prior to purchase. I was worried as they were so close. Geoff at Baines could not get them tensioned. He thought they were stretched (right number of teeth etc). New belts were fitted.
I wonder if the engine has ever been apart and if so the correct base gaskets fitted. I had my barrels machined to make up for shorter rods, and the belts do get a bit close when tensioned. You could always swap the belts over and see if the problem transfers to the other cylinder.
That's an interesting thought .... We all know that there are " certain countries " that can , and will , fake anything if there's money in it , and Ducati belts aren't exactly cheap . Someone wrote a book about the global counterfeiting business , and as part of his ongoing investigations he went to the Far East ..... and guess what he found ( that had been faked ) ?
When you say “Allen key method” for adjusting them, what do you mean? The Allen key method I know is for 2V bikes. The lips on the idler pulleys prevent this method, as I know it anyhow. The 4V belts were originally set using a deflection measurement between the cam pulleys and nowadays with a frequency measurement. You may have them over tightened. I’ve never had a problem hitting the correct tension. It’s noticeable on some motors the belts run closer than others, but using the right tool, I’ve always tensioned to spec.
Baines replaces the belts with new and all good. The ones taken off were supposedly new and fitted in December 2019. They were Ducati belts.
OK. I see what that’s doing.... kind of. The factory tool when used, measures 5mm deflection at that point. Are you using the key to measure deflection, or just as a fat feeler gauge between the belt at rest and the lip on the centre cover? There doesn’t appear to be any deflection in the belt in your picture.
In that video the guy marked a line on the casing on the top of the belt in the centre So when you pull down on the 5mm Allen key you have a ref point and can get a feel for 5mm deflection. If you follow me.
I had my heads skimmed 1mm, plus reduced the base slightly to get the squish. I fitted the larger (gold coloured) idler pulleys to compensate, also needed to degree the cams for the timing. My belts still run quite close but have been like that for 10+ years with no bother.
Yes, I get you. I’ve done similar in the past but in the picture, the belt doesn’t look to be deflecting. I’d double check with a steel rule behind the belt. Reference off it and then push the belt down with a finger and read off the movement. You need 5mm with light/moderate pressure. My feeling is, looking at your picture, the belt may be overtensioned. Another route would be use a phone app and set the tension to a frequency measurement.
