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My wife’s little Monster 620 was approaching its 12,000 mile service (bought in 2004) and I needed to change the belts. I wasn’t going to take it to my local dealer so I tackled it myself. I had already adjusted the valves on it last year.

Two internet resources were really helpful to me: Rebel Packet’s How To and as always, Ducati Suite. I had ridden with Alex (Rebel Packet) before and his description and pictures made the job exceedingly easy. I really thought it was going to be a lot tougher, but the job took less than 2 hours from start to finish.

I thought I’d post up some pictures and description here too, just to supplement the other sites. In doing research on the procedure I didn’t see too much how-to on the Monster Board.

Tools You’ll Need: 6mm and 5mm allen sockets or allen wrenches, some anti-seize compound (for the re-installing the spark plugs) and two Ducati cam belts (about $100 at my local dealer).

First thing you need to do is put the bike up on a stand, prop the gas tank (make sure there’s not much gas in there), and remove the spark plugs.

This is what you’ll be looking at. The Monster has two belt covers.



Use your 5mm allen socket or wrench to remove both belt covers. It’s very easy as you don’t need to move anything out of the way.





I think the vertical cover needs to be removed first as they interlock, but I did it backwards and it was fine. Here’s what you’ll be looking at with the covers removed.



Here’s a close up of the vertical and horizontal cylinders without the covers:





While I had the covers off I inspected the belts and did a quick check of their tension. Everything was fine. The tension is checked up putting a 5mm allen wrench between the belt and the idler pulley. It should fit like a feeler gauge. DucatiSuite has a full description of the procedure here.



Okay, before you tear into it you’ve got to get the timing all lined up. Put the bike in its highest gear. You’ll need to spin the engine around to get the cylinders at Top Dead Center. (This is the same procedure you use for checking valves.) Turn the rear wheel in a forward motion until the tick mark on the flywheel lines up with the mark visible through the glass:



Double-check. Is the piston at the top of its stroke (Top Dead Center)?


If you’ve done it correctly each of the timing marks on the gears should line up to their corresponding spots on the engine block. When I first tried it they didn’t line up. The piston was not at TDC. I simply rotated the engine around again until all the marks lined up.

This is the vertical cam gear. Note how the white mark lines up with the raised section on the case:



This is the crank gear. Note the mark on the engine case:



And the horizontal cam gear. The tick mark to the right of the paint lines up on the case.

 

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Discussion Starter #2
Once all three of your marks line up it’s time to remove the belts. Take off the horizontal belt first, it’s the easiest.

To remove the belts you simply have to loosen up the two bolts that hold the idler pulley in place. Each belt has two idler pulleys: one is fixed and one is adjustable. The adjustable one has two bolts, one stationery and the other attached to a semi-circular bracket that allows for changes in tension. You need to loosen, but not remove both bolts (6mm allen socket works best). Mine were on tight.

Here I’m loosening up the horizontal idler. The bolt below it (with the yellow paint) also needs to be loosened.



This is what the vertical idler bracket looks like. Same procedure; loosen both bolts with the 6mm socket. Don’t remove them. (The adjustable idler pulley is on the right; the fixed one is on the left.)



Once the idlers are loose, it’s easy to remove the belts. Take the horizontal one off first.



The vertical belt is a little tougher to get out. Pull it away from the idlers to get some slack. Then work it off the top cam gear, then the bottom. Work it a little at a time and it will come out.



With both belts out I inspected them for missing teeth or cracking.







I was surprised. The belts still looked really good and probably could have stayed in longer. After hearing all the horror stories I was worried because they were 2.5 years old. Maybe next time I’ll let them go a bit longer.

Here are the new belts. They were labeled for a Monster 750, but they are all the same.





The hardest part of the whole procedure is dealing with the vertical cam gear. Once you remove the belt it will want to go up or down and it won’t stay on the timing mark. It’s spring loaded. It’s easier with pictures.

Here the timing mark has rotated up (10 o’clock position):



I rotated the cam gear counter-clockwise, it gave some resistance, then spun further. Here the timing mark is at 6 o’clock. It will be at either one of those positions. Don’t fight it.



It’s nothing to be concerned about. When you put on the vertical belt (which you’ll do first), you’ll have to grab the cam gear and twist it so that the timing marks line up as they did before. It’s a little bit tricky to get it just right as you are also trying to slip a new belt over the gears. It took me about 15 minutes of playing with it to finally get it. It was helpful to put the belt around the lower pulley first and then work it back and forth. Just make sure that the belt is correctly aligned between the idler pulleys.

The vertical belt was installed first.



Then the horizontal. The horizontal cam gear is not spring loaded and can move freely. I’d advise you not to touch it as you could screw up the timing of the engine.



Both installed, not yet tightened:



Okay, next it’s time to properly adjust the tension of both belts. The tension on the vertical belt should be 6mm and the horizontal one 5mm. All you do is put the corresponding allen wrench between the belt and the fixed idler pulley, push up as hard as you can on the adjustable idler pulley, and then tighten the bolts down. You can leave the allen key in position and it will hold.

This is the vertical belt. According to Lance at Ducati Suite it needs to be at 6mm, a little looser, because it runs hotter and doesn’t receive as much air.



The horizontal idler pulley is much easier to get access to.



I checked the tension several times and made some re-adjustments because I’m that anal. The worst thing you can do is make the tension too tight. Here it’s all done.





I rotated the engine (through the rear wheel) a few times to make sure nothing was binding. I left the covers off and ran the engine for a few minutes and everything worked great.

Put the sparkplugs and belt covers back on and you’re done.

This job was a lot easier than I expected, even easier than adjusting the valves. I may have to look more strongly at a Ducati when I replace the VFR as it’s great to be able to do all my own maintenance.
 

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Great Writeup. [thumbsup] Thanks for taking the time to do that.

I nominate it to a more static location on the site (ie the Routine Maint section of the FAQ thread.
 

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Discussion Starter #6
cbm900 said:
Thanks Keith, so if all the marks are lined up on all gears your at TDC no mater what ?
I would double check with the timing mark on the flywheel as well as put a flashlight in a spark plug hole, but Yes.
 

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Great and simple writeup!!! I am curious about one thing. I have read that some ducati mechanics recommend aligning the timing marks and then marking the old belts (with a marker) and also make new marks on the new belts. Is that necessary?
 

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Silver said:
Great and simple writeup!!!  I am curious about one thing.  I have read that some ducati mechanics recommend aligning the timing marks and then marking the old belts (with a marker) and also make new marks on the new belts.  Is that necessary?
No.
 

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Great write-up! Now if we could only have someone do one like this for the 4v engine?!?! Hmmm, anyone? I'm thinking of doing the next belt change myself, but I'd like to have a good reference like this one.
 

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Thanks for the write up! Now if someone will move this to a permanent position so I can find it when I change my belts next summer...
 

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Thanks for taking the time to post this. The only thing that I would add (the vision of an armchair quarterback being 20-20) is that once the belts are out it's a good idea to check and see that the tensioner and idler bearings rotate smoothly and freely. One of mine felt kind of ragged so I replaced them and although I don't recall the price I was really surprised how cheap they were.

I was surprised. The belts still looked really good and probably could have stayed in longer. After hearing all the horror stories I was worried because they were 2.5 years old. Maybe next time I�ll let them go a bit longer.
What horror stories? I spent a lot of time last year searching this forum and others for broken belt stories and I failed to find even one documented case of a belt failing due to exceeding the 2 year service time. There may have been a few that failed due to excessive miles but it seems that most of them failed from dealers tightening them too tight which caused the bearings to fail which in turn caused the belt to fail. If you know of any documented first hand cases I'd sure like to hear them. I still wouldn't suggest intentionally going past the recommended limit, but there is a safety factor.
 

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nice job! I also nominate this thread for a permanent position in the DML archives
 

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alex156 said:
in wich gear do u have to turn the engine to align the timing marks
Easiest to use the highest gear you've got, 5th or 6th depending on your transmission.
 

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Keith, that was very kind of you. You da man! My only concern is that the cams spinning a bit off of the timing marks when taking the belts off or putting them back on. I specially worry about the horizontal cam. I mean I could always line the marks back up but what if I am off by a hair and then the timing will be messed up.
 

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I agree, very nice write up. Could we save this for the future? I have to do mine this summer. July will be 3 yrs. but I have only put on 4k on the belts so far. How much do the belts run?
 

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I agree, very nice write up. Could we save this for the future? I have to do mine this summer. July will be 3 yrs. but I have only put on 4k on the belts so far. How much do the belts run?
 
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