Changed belts on bike--now barely running - Ducati Monster Forums: Ducati Monster Motorcycle Forum

marginwalker · 09-04-2008, 06:59 PM

So I changed the belts on the 2003 Monster 800i.e. and now it's barely running. Could it be that I don't have the ticking marks lined up just right? Or what else could I have screwed up?

Thanks.

Misterearl · 09-04-2008, 08:06 PM

It certainly could be that the reference marks were slightly off. As you may have noticed, the spring tension on the vertical cam gear makes alignment difficult. I'd pull the belt covers immediately and rotate the crank (however you wound up doing that) to position the crank pulley witness marks in the proper location - lined up with the casting mark on the case. Then check each cam pulley's witness mark and the relationship with the respective engine case marks/references. If it's all lined up, then something else is wrong.

It's usually helpful to re-check all the things you did, like maybe a plug boot isn't firmly pushed on?

Good luck.

swinger822000 · 09-04-2008, 08:09 PM

bump bump---

marginwalker · 09-04-2008, 09:13 PM

Well, I must have really screwed things up because now the bike won't start at all. It just makes a "click" noise and sometimes the fuel light will flash. The bike has gas in it. Plugs are both in. Is it just the timing that's screwed up now? Is there a way I can start from scratch and get all the cam gears and pulleys in synch? I'm at a loss here.

Misterearl · 09-04-2008, 10:18 PM

Please read my first post to your thread. It describes how to set your cams back to proper position.

Do you have any references for the belt change? Take a look at DucatiSuite.com, there's a good series there with photos.

What steps did you take when you changed out the belts? Did you detach the battery cables?

Until you verify/straighten out the cam timing, it would be best to not turn the engine over at all.

marginwalker · 09-04-2008, 10:45 PM

I got some misinformation from another board about finding Top Dead Center. I was told the site glass on the left side of the bike (opposite oil site glass) wasn't something I needed to be concerned about. So when I prepared to remove the belts, I rotated the rear tire until the cam cog ticking mark with lined up with the hash mark on the engine case and then I got the ticking marks on the cam pulleys as close as I could to the marks on the engine case. And then I removed the belts. But now I think I'm pretty sure I was not at Top Dead Center when i did all of this. Am I screwing up the engine because of this?

Misterearl · 09-04-2008, 11:20 PM

When you positioned the crank pulley tick mark to line up with the casting mark, AND both the cam tick marks lined up with their respective case marks, the horizontal piston was at TDC. There is NO NEED to look at or concern yourself with the sight glass. Save that for more complicated things like valve adjustments.

It sounds like you started off right on the belt change, but it's most important to get the new belts on with the 3 gears properly aligned. So each cam gear must be positioned/indexed against its case witness mark when the new belt is slid onto the gears. The horizontal belt is no problem, but as I said earlier, the vertical cam gear is under spring tension and getting the belt on with the gear held in the correct position is a pain. It may be that this gear slipped as you installed the belt.

Whatever happened, you need to pull the covers and get in there and see what the alignment is. Not to be alarmist, but there's a possibility of serious damage to the engine. So it would be best to not try and run the engine any more.

Check to be sure that the engine turns freely with the spark plugs removed. (If it doesn't, stop - you may need the services of a mechanic.) Rotate the crank to position the crank gear mark on its case mark, then see where the cam gears are. If one or both are not at their index positions, rotate the crank until they both are, or until the horizontal is. Then see how far off the vertical gear is from its mark and let us know.

Did you successfully re-tension the belts after installing them? If they were too loose, one or both could have jumped a tooth.

marginwalker · 09-04-2008, 11:30 PM

I'll get back at it in the morning. But I doubt I'll sleep much tonight after reading the words "serious engine damage". Is the non-starting timing related? How do I know that I've got the belts properly lined up at last if I don't start the bike?

I'm sure I sound like an idiot.

Misterearl · 09-04-2008, 11:41 PM

Don't worry, it's probably OK. I'm not sure about the non-starting, could be lots of things, like a coincidentally weak battery (can you charge it overnight?)

When you are confident that the belts are installed correctly, you can rotate the engine by hand to be sure that everything will mesh properly and there's no binding or resistance before firing it up.

Just take it one step at a time in the morning, and whatever's wrong should become apparent.

marginwalker · 09-04-2008, 11:51 PM

Thanks Misterearl, I've only had my bike for barely over a year and it's my baby. I hate to think of anything disastrous happening to it, especially by my own stupidity. Hopefully, I will get things straightened out in the a.m. I worked at a Ducati dealership last year and maybe should have asked one of the mechanic buddies of mine to do the belt change. But I really want to learn to do my own wrenching. I hope this turns into a positive early experience for me so that I can have the confidence to keep on.

Thanks again, I'll let you know how it goes.

Julie