Funny Noises

[phillc]

Just today I've noticed an odd noise with my '99 750ss. Here's the scenario:

- My bike had been standing for about 4 days. Last time I rode it was last Thursday evening.
- This morning the battery was nearly dead. Bike would turn over but not fire. I needed to roll start it.
- On the way to work started to notice an odd "noise". The only way I can describe it is a "clack" and a "hiss".
- On the way home from work this evening the noise started getting lowder.
- Noticed the bike felt to be underpowered on the ride home this evening
- Noticed that on the overrun, when using the engine for breaking down through the gears, that there were a lot of "pops" like mini backfires. This has sometimes happened in the past, but not constantly.
- At idle the noise is not appreciable, but anything about 2k revs it is noticeable.

I had a bit of a look around the bike when I got home tonight. It's a half faired version so access to the engine is easy enough. I couldn't see much really.

I know it's not much of a description, but any ideas?

Just booked a service today so it'll get sorted out in a couple of weeks. But am I terminal? Should I be riding it at all over the next couple of weeks?

Thoughts appreciated.

Cheers
Phill

[Iconic944ss]

Working on the 'hiss' and loss of power descriptions I'd be looking around:

loose cylinder bolts
loose carb mountings
loose exhaust rings

as a starter.

I'm sure Nelly / someone much more knowledgeable will be along shortly!

Good Luck - Frank

[phillc]

Thanks for the hints Frank!

It's actually Nelly that I phoned earlier today to book the bike in for a service, so I'm sure it'll get sorted then. To be honest when I phoned earlier to book the service I didn't think much of the noise and hence didn't ask about it. I was half asleep riding to work this morning so it didn't register much - and I was annoyed about having to roll start it.

I think we can discard your "carbs" theory as I have an injection version.

One of the other two perhaps though......

[nelly]

all Franks suggestions could be valid. replace carb mounts for inlet manifolds.............
Only other thing that springs to mind is the tank breather?? Petrol starvation under load? weak running on over run etc. The cap was cleaned when the tank was swapped after imploding, could be something??
Is the fuel low? does it get any better on a full tank? Try lifting the filler cap after a run and listen for a "sharp intake of breath".

[phillc]

Nice one Nelly, thanks.

I'll definetely open the tank cap tomorrow morning after riding to work and see what happens and I'll check the overflow pipe for blockages.

I'd be a v. unhappy camper should my tank implode again. Infact I'm tempted to go out in the cold right now to open the cap to ensure it doesn't crumple overnight........

Phill

[nelly]

Originally posted by phillc
Infact I'm tempted to go out in the cold right now to open the cap to ensure it doesn't crumple overnight........

Phill

does it get "cold" down there then LOL;)

[phillc]

Originally posted by nelly

does it get "cold" down there then LOL;)

For an Australian, yes.........

[Edited on 8-12-2004 by phillc]

[Iconic944ss]

BE VERY CAREFUL THE AREA IS TOTALLY VENTED OR YOU MOVE THE BIKE WELL AWAY FROM ITS STORAGE AREA BEFORE STARTING.

GASEOUS PETROL IS NOT TO BE UNDERESTIMATED !!!!!!!!!!!!!!!!!!!!!!!!!

**** PLEASE BE CAREFUL - IF LEAVING TANK VENTED - OK ****

[TP]

Originally posted by phillc
- My bike had been standing for about 4 days. Last time I rode it was last Thursday evening.
- This morning the battery was nearly dead. Bike would turn over but not fire. I needed to roll start it.

Can't help you the rest mate but if you want to borrow my optimate for a bit you're more than welcome. Give that battery a charge up.

Let me know.

Cheers,

TP

[phillc]

Thanks for the warning Frank. In the end I didn't leave the tank vented overnight, just opened and closed it to make sure there was no build up of pressure.

Anyway, I think I've got this figured out.

There appears to be exhaust gases escaping from the exhaust manifold (that's what you call the bit where the exhaust joins with the rest of the engine right?). The noise kept getting worse, so I had a good close look this afternoon. Before everything got to hot, I could put my hand around the manifold and feel gases escaping from there.

This would explain:

a) The noise
b) The loss in power
c) The constant popping on overrun as air got in

So my next question is:

- What do you think has happened? I'm hoping someone knowledgeable will say that it's most likely just a seal blown.
- Will I damage anything if I keep riding like this? Service due in a couple of weeks, I can put up with the noise that long, but am I likely to do any lasting damage to the engine?

Cheers
Phill

[nelly]

Sounds like the gasket has gone Phill. Not a real problem. If you've got a spanner, try tightening the two nuts up a little......might help.
You won't do any real damage, in the short term other than make a bit of soot around the head.

[phillc]

Thanks Nelly.

I would try tightening the two nuts, but being a half faired SS that's ridden in all weathers some *ahem* corrosion may have formed and attacking those nuts looks like a job for a professional.

Have fun with the servicing in a couple of weeks!

[888heaven]

phillc
if you do get the nuts changed make sure there either stainless or brass as this will stop them coroding again,i always use copperslip on my nuts but only when the wifes not looking?:sing::sing:

[Iconic944ss]

Hmmmm, glad a culprit has been found.

Cant find a Recommended torque figure for the exhaust flange :puzzled:

Interestingly enough there appears to be spare parts catalogue for year 2000 models onwards if you want to have a mootch :devil:

Spare parts catalogues:

http://www.ducati.com/bikes/catalogs.jhtml?MY=2000

Good luck - Frank