hi, I'm sure it's a question asked often but how tricky is a belt change on a 1992 851 please? I have done the belts on my '93 Monster and hope it's a similar kind of task? Thanks!
Hi Ian It's a slightly controversial subject and there are several schools of thought on parts of the procedure on this forum but it's quite straightforward and if you have done belts on a two valve then I am certain you can do a four valve as it is only slightly more fiddly. It seems that most people favour the frequency/app method for setting the tension but there is nothing wrong with using a mechanical tool like the affordable one by Facom etc.
I'd never changed a cam belt before but found it easy enough on my 851. The thread below might help as it covers quite a few points. http://ducatiforum.co.uk/threads/dopey-question-cam-belts.30084/ To be honest, there's more time and work in getting to the belts than changing them. I think that there's a lot of rumours that make it out to be difficult when it's quite easy if you work methodically. There's also a lot said about tools to check the tension but I just used the twist method on mine and it's been fine. I guess on more modern stuff with probably tighter tolerances then it might matter but on the older stuff it seems fine.
But watch out for the error in setting the vertical belt position....unless the video has been corrected. ;-)
Error, what error? I've followed the procedure on there and had no problems and I imagine many thousands of others around the world have as well. Could you elaborate please?
If there really was an error in the video, I think it would have surfaced a long time ago. Maybe there's something in there that someone else might do another way for some reason but an error - really???
The error relates to the setting of the position of the Vertical Cylinder for setting the tension. Basic gist: Set Horizontal Cylinder to TDC on firing (compression) stroke. Mark positions etc and trake off old belts. Put on new belts. Adjust/set Horizontal belt tension with Horizontal TDC on compression stroke. The error in the video comes next: video says "Turn crank 90deg backwards" and then do the tensioning... This does put the Vertical Cylinder to TDC BUT...Not on the compression stroke! It should instruct to turn crank 270deg forward to put the Vertical at TDC on compression stroke. See extract from 1098R Workshop manual: Not sure what the effect of turning 90deg backwards has on the tension however I thought I would do what the Ducati Manual says rather than the video. R
Just because it's different doesn't make it an error. Recent posts on here have talked about trying all sorts of positions and the tension has always been exactly the same (I've an idea it was @Mr.R ). We can all understand and see a 90 degree turn, if it makes no difference to the final result, why complicate things?
If i remember correctly each TDC gives a slightly different tension. I had this when I did my 999, there is a thread somewhere from March(ish) time. I "think" though that turning the crank backwards actually turns the engine forward. If that makes any sense. Turn the rear wheel forward in top gear and you will see the crank go backwards. So, in theory that will give the wrong TDC. If i remember correctly there was about 5mhz in it, not a lot really.
I agree, that is why I stated "Not sure what the effect of turning 90deg backwards has on the tension however I thought I would do what the Ducati Manual says rather than the video" at the bottom of my post. CR: anticlockwise rotation of the crank using the crank turning tool turns the engine in the normal direction of operation. This is "Forward". Turn the tool "backwards" means turn it clockwise i.e. opposite to the normal rotation of the engine.
My recollection is that there was a suggestion that theoretically different positions would give different tension but others disputed that and someone actually tested tension at different positions and couldn't detect any difference. As I said, I've an idea that was @Mr.R but my memory is rubbish these days...
So why describe it as an error? Chris Kelley has been fixing, servicing and modifying Ducatis most if not all of his working life, I really can't see him putting out a video with an error in it and if there were such an error it would have come to light immediately.
There is a slight difference, i remember as i couldn't get a consistent reading every time i tried s new TDC. It was only when I tried every other TDC it became consistent. As I say only about 5Mhz in it and i doubt you would notice with the other methods other than the frequency app.
Interesting... As you say though, 5Hz will make little difference. It actually says on the CCW packaging: Recommended tension: 99Hz Safe up to: 110Hz So there is a fair bit of leeway.
Hmmm. Pretty much what I remembered and it was Steve R who was sure it made no difference... Obviously, Chis Kelley agrees with him...
