Ducati Monster Forum

Moto Board => Tech => Topic started by: Cyprus Joe on January 25, 2014, 12:28:28 AM

Title: Rattle at high temp
Post by: Cyprus Joe on January 25, 2014, 12:28:28 AM
Hi guys,

I have a 99m750 with 35k miles.  Previous owner abused it terribly, riding it on a dirt track and not caring for it.  I am very slowly fixing it up.

I was at a stoplight on o hot day and a rattle started.  I revved it a little, but the rattle didn't change.  I drove a short distance and shut the bike down.  I checked it over a bit and the crankcase breather had come apart.  I ordered a new one and also changed the belts. 

Two questions:

1). Any ideas on the rattle?
2). Now the bike won't start.  I thought maybe I had the timing wrong, but triple checked it, and the three dots on the pulleys line up with the marks exactly.  Any ideas?

Out of desperation, I took off the carbs and cleaned them, but they were surpeingly clean inside and I don't think were the problem.

Thanks in advance for any help
Title: Re: Rattle at high temp
Post by: the_Journeyman on January 26, 2014, 07:14:11 AM
How hot?  Was it a valve rattle?  My 280Z got too hot one day and I started getting some valve clatter.

JM
Title: Re: Rattle at high temp
Post by: Cyprus Joe on January 26, 2014, 08:35:33 AM
I don't think it was the valves b/c it didnt change with the revs.

My brother works on restoring 280z's.  He'just finishing one that was complete frame off interior, engine.
Title: Re: Rattle at high temp
Post by: Dellikose on January 26, 2014, 11:50:53 AM
What do you mean by doesn't start?

Lights don't turn on? Just keeps spinning the starter but no firing up? Nothing at all?

Any more info in the rattle or how the bike was performing before the rattle?

It could be a lot of things, need to starting narrowing it down.
Title: Re: Rattle at high temp
Post by: Cyprus Joe on January 27, 2014, 07:39:23 AM
I checked the spark by removing the plug and taping it to the side of the engine.  It was pretty good.  When I turn it on, I get light and the starter turns over, just no fire at all.  Not even a cough.  The bikr did sit for about 6 months while saving up for belts and breather.
Title: Re: Rattle at high temp
Post by: Cyprus Joe on January 27, 2014, 07:44:11 AM
Before the rattle, the bike was running really well.  Immediate starts and smooth running with appropriate power for the bike.  The rectifier went bad, but I replaced it and checked everything associated with the charging system.  The rattle just happened the one time, but I haven't run the bike since then.
Title: Re: Rattle at high temp
Post by: Langanobob on January 28, 2014, 05:41:34 AM
Quote from: Cyprus Joe on January 26, 2014, 08:35:33 AM
I don't think it was the valves b/c it didnt change with the revs...

Interesting.  If the rattle was coming from the engine it's gonna change with the revs.  One of the first things I'd do is check the compression.  It it's good you've at least eliminated one possible problem.
Title: Re: Rattle at high temp
Post by: ducpainter on January 28, 2014, 06:00:00 AM
If the bike sat for 6 months with unstabilized fuel you may have some phase separation of the ethanol.

I'd drain the carbs and tank and add fresh fuel.
Title: Re: Rattle at high temp
Post by: Dellikose on January 28, 2014, 06:17:06 AM
I'd also add some Seafoam to the fresh gas...couldn't hurt. It would be a good idea to change the fuel filter while you are at it for some cheap insurance.