cost of plug thread repairs ball park

P

paulincayman

Hero member
Location
Cayman Islands
I have just stripped the head and can now see my spark plug threads clearly , not a pretty sight..
One seems simply stripped, one looks like it has a helicoil and the third looks like a helicoil over a crack, can't certain but at this point I am now expecting the worst.
The head needs new valves, guides, springs and seats recutting, plus cam shaft bearing blocks.. so I was wonder if anyone could give a ball park , rough as you like estimate for repairing three threads. I see  $ amounts/ hour for shop work but no idea how much or how long this might take or what else might be involved, new seats I suppose, re shape the combustion chambers..
on the plus side the head is still at 94mm thick  and the shims were all in the 2.20 range .  77 3CL
TIA
Paul
 
Repairing stripped plug threads easy, the crack is more difficult & valves/guides/valve seats requires an experienced hand. Red's cam blocks may be necessary if seats recessed. Want flowed heads? More time, more $$. May as well upgrade the cams as well if A11's fitted. Now the slippery slope of bottom end-pistons, etc? Anyone in your area that does this kind of work?
 
Local talent patchy and auto  ..Have 4c cams..need rebore, new pistons..big ends sloppy so add crank rebuild. Original carbs..ancient ignition..butchered loom .haven't got to the clutch and tranny  yet..off slope into bottomless pit.. But I do have a Laverda in the shed!
I'm trying to compare cost of repair vs replacement...
I done all the pondering..looking for an idea of costs.
 
paulincayman said:
I see new  heads available from Europe @1550? ..does anyone know what is included..valve guides ..seats ?
Click to expand...

Really? :o  Who is selling them? Are they NOS or re-manufactured?

There were subtle changes/improvements to the triple heads over the years. Some are better than others.

Cayman Islands is about as far away from specialist Laverda engine builders as it's possible to get (Red, Piet, Keith, etc.). If you want your head refurbished by one of those guys you'd need to send it half way around the world. They probably all have a heap of work so you'll have to wait your turn. If I were in your position, I'd be tempted to take it to a local cylinder head shop. I'd want to find someone who is very skilled in head work but is also prepared to listen to advice from the specialist Laverda engine guys.

My Jota head needed a bit of work a couple of years ago and I took it to a general cylinder head shop near me. The head wasn't flat, so it needed a bit shaved off. I'd had several heads (not Laverda) fettled by them before and trusted the guys not to mess it up. They did a nice job and only took the bare minimum off the face.

 
https://www.laverda-paradies.de/shop-1000-41-en.html

Laverda paradies online catalog ..?? Hope it's correct..
I do take your point about a good local shop if  you can provide all the necessary info and communicate it properly. It does seem that I'm talking a foreign language sometimes.
 
Interesting. I wonder what year they're from. The photo shows the wide gasket face so it's not the early 3C head (with narrow gasket face). So I guess it doesn't have cast iron skulls (not sure about that but others will know more about the various changes to head design).

Photo also appears to show valve guides and seats installed. I presume the heads are NOS, so seats would be as provided by the factory back in the day.

I see that Andy also lists used cylinder heads, so it might be worth asking if he'll take your old head as a trade-in for refurbishment. Better than chucking it in the bin.

 
The heads Andy offers are NOS late 180? triple type, maybe even RGS (can't tell without seeing the top deck).  I fitted quite a few of these "back in the day".

They are rarely a straight plug-n-play fitment.  Valve seats are only rough cut and rarely truely concentric with the guides, the guides were often shagged, straight out of the box.  Luigi must have had quite few bad days.

I ended up at least re-cutting the seats, sometimes renewing guides and seats to get these dinghy anchors set up properly.

Then there is the camshaft locating channel alignment issue... ::)

piet

 
sfcpiet said:
The heads Andy offers are NOS late 180? triple type, maybe even RGS (can't tell without seeing the top deck).  I fitted quite a few of these "back in the day".

They are rarely a straight plug-n-play fitment.  Valve seats are only rough cut and rarely truely concentric with the guides, the guides were often shagged, straight out of the box.  Luigi must have had quite few bad days.

I ended up at least re-cutting the seats, sometimes renewing guides and seats to get these dinghy anchors set up properly.

Then there is the camshaft locating channel alignment issue... ::)

piet
Click to expand...

All I can say is ... I'm so glad I'm a twin man! Sorry you triple-lovers  :-*
 
sfcpiet said:
The heads Andy offers are NOS late 180? triple type, maybe even RGS (can't tell without seeing the top deck).  I fitted quite a few of these "back in the day".

They are rarely a straight plug-n-play fitment.  Valve seats are only rough cut and rarely truely concentric with the guides, the guides were often shagged, straight out of the box.  Luigi must have had quite few bad days.

I ended up at least re-cutting the seats, sometimes renewing guides and seats to get these dinghy anchors set up properly.

Then there is the camshaft locating channel alignment issue... ::)

piet
Click to expand...

A lot of parts rejected by Laverda in the day, somehow made their way onto dealers shelves.
Apparently.

Paul
 
Piranha Brother 2 said:
All I can say is ... I'm so glad I'm a twin man! Sorry you triple-lovers  :-*
Click to expand...

You apparently haven't had a NOS twin head before you... :D  Not much better.

I agree with Paul, it seems loads of bits rejected from actual bike production were retained as spares.

In truth, quality control at the factrory must have been sadly lacking at times.  I have found many machining faults that should never have passed even a very low-level QC.

piet
 
sfcpiet said:
You apparently haven't had a NOS twin head before you... :D  Not much better.

I agree with Paul, it seems loads of bits rejected from actual bike production were retained as spares.

In truth, quality control at the factrory must have been sadly lacking at times.  I have found many machining faults that should never have passed even a very low-level QC.

piet
Click to expand...

Comment was more about triple heads in gen, Piet. Have no doubt twin parts could and were just as prone to Luigi's Tempranello intake on any given day  :o :D

For the most part, as long as an SF head gets the oil it's supposed to, they are pretty solid units. I hope my big-valve conversion on a modified used small-valve head doesn't bring me grief. I recall you saying that once a head had been run for decent number of km the seats in the iron skulls settle. But I've cut that seat area well away to go the big valves - worst case, I have to fit hardened seats.
 
chrisk said:
Paul, have you always lived on Cayman?
If not, were you running away from an ex, Interpol, MI5 or the Mafia, to end up there?
Click to expand...

Nothing so exciting..just a random set of circumstances and a chance encounter at a bbq..
30 years on starting to get cabin fever.. Or rock fever as it's known here.
 
paulincayman said:
Nothing so exciting..just a random set of circumstances and a chance encounter at a bbq..
30 years on starting to get cabin fever.. Or rock fever as it's known here.
Click to expand...

Cabin fever is a bugger: Is it due to the encounterant, or the island?
 
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