Older Small Bores - One Followed me Home

[kevdog3019]

Dawg here.
Bike comes with third-world valves/too tight springs-- they go BANG. People replace with third-world valves (made in China). Do yourself a service and pay a little more (non-Guzzi content) and get good valves (USA Made Kibblewhites are very good!) and lash caps. This will give your Lario a good start and a prayers chance. There's more to the story, so don't think a good valve train is the holy grail. Make sure you have the right cam. My biggest beef is putting two piece Chinese valves in a bike that's known to pop valve heads.  Again, it's a good start! 2-3 hundred more greenbacks and WILDLY unpopular.

 

[Chuck in Indiana]

Actually, Iceblue's valves are one piece, that's why they need the lash caps, and made in Taiwan. Machining on them is poor, though.
Dawg.. the Kibblewhites need lash caps? That surprises me. Are they one piece? I've not seriously looked at them. When I talked to them, they said they just modified one of their stock Suzuki valves for the Lario, IIRC. My memory is suspect, though.
There is method to my questioning.. I'm planning on "doing" the Monza heads.
TIA

[sign216]

Welcome to the world of smallblocks Roy!

I second that.  Smallblocks forever!

[v65tt]

Small blocks are the best


Love my v7 stone powered TT so much, ultimate small block in my eyes

[kevdog3019]

Actually, Iceblue's valves are one piece, that's why they need the lash caps, and made in Taiwan. Machining on them is poor, though.
Dawg.. the Kibblewhites need lash caps? That surprises me. Are they one piece? I've not seriously looked at them. When I talked to them, they said they just modified one of their stock Suzuki valves for the Lario, IIRC. My memory is suspect, though.
There is method to my questioning.. I'm planning on "doing" the Monza heads.
TIA

My valves do use lash caps according to my parts list. Remember, I'm using bigger valves than the stock set-up so not sure what's available stock. I do know these are quality valves, etc. you pay for them no doubt. It's not something I blink an eye at with these issues. I have never said I'm right, but I will admit to saying "if ever there was a time..."
Give them your spec and see what they come up with. Can't hurt with stretch issues. I've got the performance double springs and ti keepers and only slightly under stock strength springs if memory serves me.

[Kiwi_Roy]

Around 6000 miles. (10 K) Some have made it over 20000, with strict observation of a 7K rpm rev limit. The problem is, power is still going up at that point, and past the 7800 red line. That's where the fun is.   

 

Thanks again Charlie I don't know how I would have got on without your guidance with the Eldorado.
So it's way overdue to drop a valve then.

Seems like I should do something with the valves this winter.
I do know it has dual valve springs according to PO
I will follow the link you posted as time permits.

[Kiwi_Roy]

Dawg here.
Bike comes with third-world valves/too tight springs-- they go BANG. People replace with third-world valves (made in China). Do yourself a service and pay a little more (non-Guzzi content) and get good valves (USA Made Kibblewhites are very good!) and lash caps. This will give your Lario a good start and a prayers chance. There's more to the story, so don't think a good valve train is the holy grail. Make sure you have the right cam. My biggest beef is putting two piece Chinese valves in a bike that's known to pop valve heads.  Again, it's a good start! 2-3 hundred more greenbacks and WILDLY unpopular.

 

Kevdog3019, thanks for telling me what I didn't want to hear, I think.
I will seek some good valves.
What are lash caps, do they fit on the valve stem outboard of the collets?

What about the valve springs do they need upgrading also?

I'm not one to hover around the red line, cam I extent the life by staying under 7k?

I will measure the tappets before I ride it again.

I'm sure the Chinese use top quality Melamine in their valves but I'd rather pay double and do it once.

Thanks
Roy

[Chuck in Indiana]

Kevdog3019, thanks for telling me what I didn't want to hear, I think.
I will seek some good valves.
What are lash caps, do they fit on the valve stem outboard of the collets?

What about the valve springs do they need upgrading also?

I'm not one to hover around the red line, cam I extent the life by staying under 7k?

I will measure the tappets before I ride it again.

Thanks
Roy

Roy, the Lario Rehab thread takes about 4 hours to go through, and will give you a good feel for the Lario.

I'm not one to hover around the red line, cam I extent the life by staying under 7k?

Definitely. It takes a *lot* of fun away from the Lario engine, however. Kevdog has said he does this.
Valves are made in one of two ways. Most valves are two piece, friction welded about an inch or so below the head. This allows the head to be made of heat resistant alloy, and the stem to be made of a wear resistant alloy, a good combination.
Because of the Lario (and other small blocks) tendency to spit the head off the valve, some have experimented with one piece valves. That, at least does away with the join between the two dissimilar metals.
But. That requires using a lash cap. It is a hardened cap that fits over the valve stem to keep the rocker arm from deforming the end of the valve.

What about the valve springs do they need upgrading also?

Yes, but there are two schools of thought on that, too. One is that the double springs are exerting too much spring pressure on the valve, possibly causing the heads to pop off.
The other is the springs are too weak, and not closing the valves rapidly enough at high rpm for heat transfer to the head, and the valves get too hot and drop a head.
 
Got all that?
Ok. Significantly, in my opinion, when Guzzi upgraded the small block valve train, they used a single progressively wound spring. This is what is called the "Nevada" spring, and the modern small blocks use it and it is reliable.
Kevdog's engine was done by Ed Milich.. a racer. His 2 valve small block engines have been tough to beat. Back when I was going to Daytona, he was a regular winner. Kev's has higher compression, bigger valves, and heavier springs. All (except for the heavier valves) is designed to keep the valve on the seat longer because the mods make even more heat. That doesn't matter to a race engine that is only designed to go a few races between overhauls.
Is that the definitive answer to the 4V small block problem?
*I don't know* but my gut feeling is the stock Guzzi valve, which is not third world as Kev alludes to, is pretty good. Not as good as a Kibblewhite, but pretty good. That, combined with the Nevada spring seems to *me* to be the best combination.
Rod Yeomans RIP was a well known small block guy. I'd recommend looking at Greg Bender's site here:
http://www.thisoldtractor.com/moto_guzzi_small_blocks_older_small_block_issues_.html
All this should muddy the waters.. 

[kevdog3019]

Roy, the Lario Rehab thread takes about 4 hours to go through, and will give you a good feel for the Lario.Definitely. It takes a *lot* of fun away from the Lario engine, however. Kevdog has said he does this.
Valves are made in one of two ways. Most valves are two piece, friction welded about an inch or so below the head. This allows the head to be made of heat resistant alloy, and the stem to be made of a wear resistant alloy, a good combination.
Because of the Lario (and other small blocks) tendency to spit the head off the valve, some have experimented with one piece valves. That, at least does away with the join between the two dissimilar metals.
But. That requires using a lash cap. It is a hardened cap that fits over the valve stem to keep the rocker arm from deforming the end of the valve.Yes, but there are two schools of thought on that, too. One is that the double springs are exerting too much spring pressure on the valve, possibly causing the heads to pop off.
The other is the springs are too weak, and not closing the valves rapidly enough at high rpm for heat transfer to the head, and the valves get too hot and drop a head.
 
Got all that?
Ok. Significantly, in my opinion, when Guzzi upgraded the small block valve train, they used a single progressively wound spring. This is what is called the "Nevada" spring, and the modern small blocks use it and it is reliable.
Kevdog's engine was done by Ed Milich.. a racer. His 2 valve small block engines have been tough to beat. Back when I was going to Daytona, he was a regular winner. Kev's has higher compression, bigger valves, and heavier springs. All (except for the heavier valves) is designed to keep the valve on the seat longer because the mods make even more heat. That doesn't matter to a race engine that is only designed to go a few races between overhauls.
Is that the definitive answer to the 4V small block problem?
*I don't know* but my gut feeling is the stock Guzzi valve, which is not third world as Kev alludes to, is pretty good. Not as good as a Kibblewhite, but pretty good. That, combined with the Nevada spring seems to *me* to be the best combination.
Rod Yeomans RIP was a well known small block guy. I'd recommend looking at Greg Bender's site here:
http://www.thisoldtractor.com/moto_guzzi_small_blocks_older_small_block_issues_.html
All this should muddy the waters.. 

Yep... except you forgot to mention the extent of cam wear that also lent itself to destruction of the valves as gaps got closer and closer.  I've got it somewhere, but Ed set it up so that the resting spring rate was less than the stock springs and the compressed rate was near equal.  In other words, no valve float.  The picture is big here and all things added up didn't look pretty.  I've got low end grunt now, so the "happy zone" isn't as big a deal.  The stock Lario is a hoot up top because it's pretty mundane down low.  That gets addicting.  A machine will dictate how you drive it and the wrists got very happy. 
With bigger valves comes greater surface area.  There may be more heat, but dissipation is probably greater as well.  What is the interval in which a race engine driven in a normal (everyday driver manner) has to be torn down and rebuilt?  I dare say a race engine is built pretty heavy duty for its cause, except the extremism is still too much for the long haul.  Without extremism?  I don't think that's a good argument tbh.  Those guys beat the shit out of those things.  Take a normal car and beat it around a track for awhile.  I bet it doesn't last as long as a race engine.

[Matt]

 

...More fun to ride a slow bike fast

I had a V65sp and a Lario, no contest in grin factor. Find a nice lonely highway and run it through the gears not sparing the rod, it's a wonderful package in it's element.

[Chuck in Indiana]

...More fun to ride a slow bike fast

I had a V65sp and a Lario, no contest in grin factor. Find a nice lonely highway and run it through the gears not sparing the rod, it's a wonderful package in it's element.

Absolutely. It really shines when you're caning the tits off it. (Roperism)
Get rid of those tires.