[hechon]

another newbie question:

I came across a bike that has 16K miles. i spoke to the shop that maintained the bike and they tell me that the bike had broken valve at around 14K which were fixed (and adjusted). i didn't get a chance to ask him follow up questions, but:

- is that a common problem? does it show abuse or any other type of misuse of the bike or is it just one of those things that can happen?
- should i stay clear of this bike?

thanks in advance for your comments.

hechon

 

[mcd]

Broken valves are typically caused as a result of 1 of 4 reasons. 1) a cam belt broke; 2) the cams are not degreed properly; 3) the bike was over-reved (albeit this should not happen with a properly fuctioning rev limiter); or there is a lower end tolerance problem (not very common). What you should be concerned with is how much damage did the valve do when it broke, where did the fragments go and what internals did they affect (if any)? Unless you are dealing with a reputable shop... I'd avoid that one.

 

[pazzoduc]

Just can't stand it...

Alright... alright... I'll post....

If the valve truely did break. It was likely under a good bit of duress at the time. Meaning the bike was likely seeing some high revs.

Under those conditions, a broken valve would do some serious engine damage. I don't think a new valve and an adjustment would be fine.

Usually when a valve breaks (haven't heard much of this in the recent past) the large end separates from the stem. There is not usually enough space in the combustion chamber at TDC to avoid some sort of instant engine failure.

But, there again. I'm no engineer and it's only my severly humble opinionated self spewing again...

 

[hechon]

Unless you are dealing with a reputable shop... I'd avoid that one.

It is a Ducati dealer (which I guess does not necessarily mean it's reputable ). Anyway, this happened about 2K miles or 1 1/2 years ago. I guess I can go and talk with the service dept at the dealer and find out what kind of damage it caused, but my inclination is just to keep looking. Thanks.

 

[ward]

You don't mention what sort of bike it was. But broken valves are nasty things, and NO, definitely not common on Ducs - not something you'd expect to happen (not like the leaky clutch slave etc.).

First inclination would be nervousness, BUT why would the dealer tell you this - that's some indication of honesty isn't it? It's not like you can tell if it rides okay etc etc. I'd suggest this (might be able to haggle a bit off in the process); go for a 2 year warranty on the motor. Yeah that's a lot, but if the bikes only done 16k miles, that's absolutely nothing for a modern Duc motor. He might baulk at incorporating electrics etc., but that's okay - specify exactly the mechanical part of the motor. If a piston is chipped or a ring broken or gouged, it'll show up soon enough.

Having said that, if there were two identical bikes side by side, and one had the valve story, I'd opt for the other one (but would I know it's history?).

 

[stryder]

Valve breakage reasons could also include:

- Manufacturing defect.

- If the bike is from very cold climes, exhaust valves can snap if taken for a hot ride on a frigid day, and then parked without the exhaust being plugged up as the freezing air will be drawn in through the exhaust and rapidly cool the valves.

- worn or misaligned guide could cause a valve face to chip against the seat.

I'd seek to clarify what caused the breakage, and what type of breakage occurred.

IIRC, there was a post a couple of months ago about a 2005 ST4s with a bent, (not broken) valve replaced under warranty.

 

[hechon]

You don't mention what sort of bike it was.

My apologies. It's ST2.

First inclination would be nervousness, BUT why would the dealer tell you this - that's some indication of honesty isn't it?

I am actually buyint it from a private party and I was told the bike gets serviced at a dealer so I called them and asked if anything major was done on the bike and the service person told me that there were broken valves that were fixed. i asked him if this was common thing and he said no. I didn't get a chance to ask him if any/all damages were repaired before hanging up.

hechon

 

[ward]

Walk away. The seller didn't bother to mention it, so the trust is gone in my book.

If you're still interested, pop by and chat directly to the service guys, find out what they think caused it, and their opinion on the bike. They seem straight enough.

As it's an ST2, I can say this is the first air-cooled duc with a broken valve I've heard of, except for a mate's 900SS 25 years ago.

 

[hechon]

As it's an ST2, I can say this is the first air-cooled duc with a broken valve I've heard of, except for a mate's 900SS 25 years ago.

i was told that he changed the timing belt himself and he put it wrong - a couple of teeth off, and when he turned her over, it bent the valves, not broken. so he trucked it to the dealer and had them fix it.

just an update.

hechon

 

[ward]

Hmmm... makes it a bit of a tough call, doesn't it?

 

[sperho]

i was told that he changed the timing belt himself and he put it wrong - a couple of teeth off, and when he turned her over, it bent the valves, not broken. so he trucked it to the dealer and had them fix it.

just an update.

hechon

I would verify that the piston, valve guide, rocker arm, and cam were checked and/or replaced as well as determine what kind of warranty the dealer will give on the work. If the listed things above were good to go (especially the warranty part) and the price was right, I'd probably trust it.

 

[ward]

Hechon - you still there? Would be curious to know how the decision / process has gone...