Soft valve stems & plasticine guides?

[Guest Nogbad]

Just to set the record straight Hackingcough, my V11 was out on the road today, and will probably do a 2 up trip tomorrow, so it is used at least as much as the Buell.

 

No, the manufacturers service intervals have not been ignored, and in fact the oil has been changed more often than the book recommends.

 

OK, I didn't open the cush drive, but I didn't fancy drilling out seized torx screws or creating a whole pile of troubles where none existed before which is the guzzichondriac's chosen path.

 

So far the bike has been reliable as the coming of Christmas and is still on the original battery and Siemens relays. I think reasonable attention according to the book, and fixing whatever else needs done when you have it apart for a failure of something is all it needs, and is all it is getting. So, maybe the cush drive will become rattly at 100k miles or something, and at that point I will tear it down and fix it.

 

You can overmaintain a machine you know. Stuff beds in and when you tear it down it never goes back exactly the same. As with human surgery, there is always a risk of introducing a new problem, so it seems sensible to leave it alone if it's working well.

 

You, dearest Hacklung, are obviously a vintage bike man at heart. You should buy an exotic and fragile project bike to fiddle with. Where your V11 is concerned I fear you have left guzzichondria behind and entered the realms of Guzzhausen's syndrome by proxy.

[jtucker]

Ratchet - here's some additional details from my friend Morgan:

 

Mine became unridable at 35k but we're pretty sure it's been happening

for 15k or more. The symptoms were popping, sputter, etc as far as I

can tell. Time will tell.

 

As far as I know it's a problem with all the 1100 motors including

yours. According to Roland it happens at 20k miles.

 

Roland would be our mechanic at Spare Parts Co. in Philadelphia. Apparently, he had to replace the timing chain as well.

[big J]

Big J, if you pay attention to my leading post, this is the question I've asked. I am most certainly NOT attempting to spread innuendo here. If you please, I'm asking for evidence for the concern that has been raised by others.

 

I have no symptoms of any early wear. If I did, I'd have investigated it myself with an inspection by now. If there's solid enough evidence from the experience of others, I would wish to do an intervention before too much damage has occured.

 

I've simply repeated myself here. Have I been misleading in some way?

"Soft valve stems,plasticene guides"You're nervous about alarming posts"

Whilst you may have some mechanical knowledge,there are plenty of guys on here who might not have as much experience yet and reading this sort of tabloid banner headline could be worrying.

 

I did pay attention to your leading post.I can understand why you asked.It was the phrasing,nothing more.

 

I'm sure that if there were some even small scale problem,it would have been apparent by now.If you're worried and can have the work easily done in a couple of days,then why not just do it and report your findings? It would be more useful than having some poor bugger reading this and thinking" aw f*ck,what is this now?"

[jtucker]

Just to add more fuel to the fire, when I spoke to the folks at Megacycle, they said that one of the reasons they're not eager to produce any more cams for Guzzis is due to problems with soft valves...

[Baldini]

aw f*ck, what is this now...

 

KB

[Guest ratchethack]

Just to add more fuel to the fire, when I spoke to the folks at Megacycle, they said that one of the reasons they're not eager to produce any more cams for Guzzis is due to problems with soft valves...

Thanks, Jason. This is the kinda stuff I'd like to get more detail on. If anyone has any more info on this scenario, including what mfgr/grade of replacement valves have been known to be an exact replacement for stock -- and possibly also have a proven track record in V11's, by all means, let's hear it!

 

TIA

[luhbo]

Just to add more fuel to the fire, when I spoke to the folks at Megacycle, they said that one of the reasons they're not eager to produce any more cams for Guzzis is due to problems with soft valves...

 

Are you sure this makes sense?

 

What I don't understand: what do soft valves have to do with good quality cams and camshafts? Even on OHC engines I couldn't understand this!

 

I can see only one reason to stop the production of aftermarket cams for the V11: there is no more need for them! No more market, if there ever was one. I mean market, not 20 pieces a year or so.

 

And it could be helpfull to be a bit more precise when spreading such things: what is soft or weak? The shaft? The valve-plate? The guides? The seats? And does your bike already suffer from any too soft parts in the engine or is there just rumour that something like this might have happened somewhere?

 

If you open an engine, an air-cooled high performance engine, after 50000 km then you will always find parts showing a certain amount of wear. That's only natural. Where is the problem?

 

The problems arise when someone opens my engine, shows me the worn parts, says that this is normal for a crap bike like mine, sells me his all but cheap aftermaket parts and when I then go home, sit down behind my laptop and write all this what I've just been told right into the next forum. "My dealer has told me that Guzzi is crap and that's why I now had to spend a lot of money. Can you guess how I'm crying?" Crying about what ?!

 

Enjoy your Guzzi. Others do so since years. There's nothing bad with enjoying a Guzzi every now and then. And let them closed. The internals like it dark!

 

Hubert

 

 

Thanks, Jason. This is the kinda stuff I'd like to get more detail on. If anyone has any more info on this scenario, including what mfgr/grade of replacement valves have been known to be an exact replacement for stock -- and possibly also have a proven track record in V11's, by all means, let's hear it!

 

TIA

 

Do you call this "Info"? This "I know someone who has heard from someone who knows the girlfriend that has talked to someone..."?

 

Hubert

[motoguzznix]

Ratchet

 

I am one of the guys who posted about the poor quality of the cylinder head machining and valves. Quoted a post of mine on the subject:

I agree with Al and guzziowr concerning the valve stem hardness.

 

When I dismounted my 2000 V11s heads with 9000 km on the clock last year, the valve stems had considerable wear. I could feel it with the finger nail.

One valve guide had the bore for the valve stem excentric by approx.1 mm, not surprisingly the valve did not seal on that seat. Another valve guide had bronze residues from the machining in the area where the cylindric contour changes to conical. A valve seat showed rattling marks from the machining where it should seal.

I will replace valves and guides soon using carbon coated valves.

The reason for disassembling my (almost) perfect running 9000 km engine and the work done ist documented here: Unpacking the cans

 

I am sure my engine would have lasted 50 - 100 000 km with the cylinder heads in that condition. The only concern with some risk of failure is the excentrically drilled valve guide that brings some side load on the valve stem and a bending force on the valve disk with the possible cracking of the disk. But this occurs only on rare occasions on the big block Guzzis, while very common on the small blocks V35 - V75.

Fixing that sealing problem of the valves reequiered a lot of valve-seat-grinding by hand.

 

If you assemble the engine with new gaskets, pay attention on the thickness of the gaskets: I have seen gaskets from 1,2 to 1,7 mm, being the original ones the thinnest. With thicker gaskets the squeeze area of the combustion chamber gets wider with the risk of increased pinging. Machining the cylinders to get the pistons comletely to the top of the bore at TDC is also a good idea (smaller squish area). Raises the CR as a bonus. Mine were 0,45 mm below the gasket surface. And check valve clearence before reassembling.

 

I like the things to be good but not necessarily perfect as I'm an experienced mechanic and I drive Guzzis since 23 years now. But I wouldn't have disassembled my engine if the engine vibrations would not have been so severe. I balanced the crankshaft and reassembled the engine with all my knowledge and care. Almost everything on the V11 was fine but the head quality was really diappointing for me, as you can read above.

 

I do not recommend everyone to disassemble a good running motorcycle, but when oil consumption and valve train noise begin to increase, a look to the heads is never wrong, and the effort on a Guzzi to fix these things isn't too big....

[Guest Nogbad]

 

I do not recommend everyone to disassemble a good running motorcycle, but when oil consumption and valve train noise begin to increase, a look to the heads is never wrong, and the effort on a Guzzi to fix these things isn't too big....

 

Quite right. Fix the problem when you know you have one. Not some pre-emptive attack on a non-existent rumour.

[Guest ratchethack]

The only concern with some risk of failure is the excentrically drilled valve guide that brings some side load on the valve stem and a bending force on the valve disk with the possible cracking of the disk. But this occurs only on rare occasions on the big block Guzzis, while very common on the small blocks V35 - V75.

Fixing that sealing problem of the valves reequiered a lot of valve-seat-grinding by hand.

 

I do not recommend everyone to disassemble a good running motorcycle, but when oil consumption and valve train noise begin to increase, a look to the heads is never wrong, and the effort on a Guzzi to fix these things isn't too big....

MGNX, thanks for the well-informed and well-written post. Yours was evidently the first reply to my opening post with what I asked for -- actual first-hand experience of having the heads off.

 

In part, it was your prior posts from late last year (and a few others, possibly from different forums) that I recall putting this question in my mind to begin with. Your engine building philosophy appears to be in line with mine, and I appreciate your perspective.

 

When I have the heads off, I will most certainly carefully set and match the squish, and of course check valve clearances in the process. After having some kms now on your engine after setting the squish, what are your thoughts on an ideal squish clearance with the stock pistons for the long haul on the road?

[motoguzznix]

After having some kms now on your engine after setting the squish, what are your thoughts on an ideal squish clearance with the stock pistons for the long haul on the road?

 

Ratchet

 

Unfortunately, at the time of assembling the engine, I could only get some gaskets with 1,7 mm thickness, so I can't tell you the truth. With the right 1.2 mm gaskets the CR will raise from now 9.6 to 10.0 which was my target when I started all that work. I had to complete my bike for a 4day trip to Italy with some friends which was fixed a long time ago, so I didn't want to wait any longer. The guys with the japanbikes shall see that a Guzzi always runs....

So I drove the bike since then for 5500 km with no complaints.

I will rectify this when I dismount the heads next time. At the same time I will drop in new valves of better (carbon coated) quality and guides. The valve seats are of good quality and will only get a very slight rework. So far my intentions.

Due to the fact that I have to build a new house for my family (with a big workshop for me) this and next year, the progress on my Guzzis is minor these days.

 

P.S.: Squish clearence should be in the area of 1 mm according the book "schnelle Motoren seziert und frisiert" written by Helmut Hütten" which is the only source I could find in a Book. A 1.2 mm stock gasket with the pistons decked on the cylinder gasket surface seems the only way to come near that.

[jtucker]

Are you sure this makes sense?

 

What I don't understand: what do soft valves have to do with good quality cams and camshafts? Even on OHC engines I couldn't understand this!

 

I can see only one reason to stop the production of aftermarket cams for the V11: there is no more need for them! No more market, if there ever was one. I mean market, not 20 pieces a year or so.

 

 

For the record, the 2nd (of 2) reason Megacycle gave me was lack of demand. I can understand why they would consider soft valves (or whatever) to be a factor as well. I can only assume that a hot cam could exasperate any underlying problems. If I were them, and I started hearing feedback that engines fitted with my cams were experiencing premature valve failures, I would be inclined to *not* put any more cams out on the market until the problem is sorted out. But that's just me.

 

 

And it could be helpfull to be a bit more precise when spreading such things: what is soft or weak? The shaft? The valve-plate? The guides? The seats? And does your bike already suffer from any too soft parts in the engine or is there just rumour that something like this might have happened somewhere?

 

Unfortuantely, I don't have much more info here. As it was, I was able to locate the cam I wanted, and am having my heads worked anyway, so for me the issue is moot. At the time I had them on the phone, I didn't much care about the details - I just wanted to know if they had the cam I was looking for.

 

 

If you open an engine, an air-cooled high performance engine, after 50000 km then you will always find parts showing a certain amount of wear. That's only natural. Where is the problem?

 

What do you consider normal wear then? I wasn't joking when I said Morgan's valves went pear-shaped. I saw them. I layed my hands on them. They were visibly distorted in quite startling ways.

[Guest ratchethack]

Squish clearence should be in the area of 1 mm according the book "schnelle Motoren seziert und frisiert" written by Helmut Hütten" which is the only source I could find in a Book. A 1.2 mm stock gasket with the pistons decked on the cylinder gasket surface seems the only way to come near that.

All good stuff, MGNX. Thanks again. 1 mm squish squares exactly with the recommendation of a "local", yet world-renowned Guzzi machinist at .040".

[luhbo]

...If I were them, and I started hearing feedback that engines fitted with my cams were experiencing premature valve failures, I would be inclined to *not* put any more cams out on the market until the problem is sorted out. But that's just me.

...

 

Jason,

this sounds quite reasonable so far. On the other hand, shouldn't a well designed cam treat the complete valve train more gently as the OEM one does ? This means soft opening, hard acceleration - - - and in the end a soft seating of the valve? This should cure problems, not enlarge them. When I remember right it was Megacycle that made promises to cure the problems the small-block 4-valve engines had. They tried, found no market and then also stopped their activities.

 

...

What do you consider normal wear then? I wasn't joking when I said Morgan's valves went pear-shaped. I saw them. I layed my hands on them. They were visibly distorted in quite startling ways.

 

That's not normal, right. But you certainly agree that such cannot be the rule for all or all the early v11s sold. To me it sounds as if this was either an extreme example of what Ernst wrote or some other strange thing must have happened. Maybe he or someone else ran the bike into the limiter and then eventualy hit the shift lever. Who knows. Shit happens. Look at the one who got his bike back with a badly burnt wiring harness. There are many possible explanations for this, including: some Italian worker had damaged two wires what then led to this disaster. Maybe. Now, any rules of thumb how to deal with this time bomb? I seriously hope mine is a dud , otherwise the remaining Class-A two disk clutch could make a Scura owner happy again.

 

Hubert

[Guest Nogbad]

Hubert, sleep restfully. All this IS guzzichondria... Remember!