Valve clearances

[drikko]

Just wondering why they need to be checked so often? Is it purely preventative ie in general they are usually OK but it's good to check?

Reason I ask is I just checked the K11 clearances and they were all spot on and they haven't been checked in 50k k's and I had the Landcruiser valves checked for the first time in it's life and they were spot on too (all 24 of them!), and it's done 275k k's!!!

So why do they have to be checked every 3000 miles?

 

[laverdakeith]

The quick answer is that Moto Laverda were not very good at cylinder heads. Some are OK some ain't, some are disasterous and loose clearance before your eyes, the RGS ones are the best and are generally very stable, the '77 all aluminium ones are the worst.
An interesting pattern has started to emerge at my workshop, I have had three '80/'81 motors through this year which have been fitted with the '77 heads. Doing my Sherlock Holmes I have deduced that the motors in question probably all suffered dammage early in their lives (while under "warranty") due to broken short valve springs and ended up with soft heads that had been lying under the bench since they were removed from the '77 bike (again, most likely under "warrenty") in order to get them out of the door again. Good old Laverda dealers....
If things go well in the next couple of years I may well look into manufacturing some new heads, fixing up an old one properly is expensive and time consuming and they are only ever as good as the sum of their parts, in the meantime if anyone has a stack of RGS heads cluttering the place up I would quite happily swap them for a stack of cash.


  Keith

 

[Paul LeClair]

The quick answer is that Moto Laverda were not very good at cylinder heads. Some are OK some ain't, some are disasterous and loose clearance before your eyes, the RGS ones are the best and are generally very stable, the '77 all aluminium ones are the worst.
An interesting pattern has started to emerge at my workshop, I have had three '80/'81 motors through this year which have been fitted with the '77 heads. Doing my Sherlock Holmes I have deduced that the motors in question probably all suffered dammage early in their lives (while under "warranty") due to broken short valve springs and ended up with soft heads that had been lying under the bench since they were removed from the '77 bike (again, most likely under "warrenty") in order to get them out of the door again. Good old Laverda dealers....
If things go well in the next couple of years I may well look into manufacturing some new heads, fixing up an old one properly is expensive and time consuming and they are only ever as good as the sum of their parts, in the meantime if anyone has a stack of RGS heads cluttering the place up I would quite happily swap them for a stack of cash.

   Keith

the 77 all aluminum triple heads are the very worst, you say.......    and here just recently the 79's were being vilified.

Presumably the very bad soft 77 heads are fitted to the revered and increasingly sought after 77 Jota? Then the crappy 80 and 81 triple heads with the bad springs etc. Looks to me like the 79 1200 Anniversary being crticized elsewhere here is dead reliable in comparison

Paul LeClair

 

[wdietz186]

Drikko, The short answer is that the materials used for the valves and seats are much much harder and heat resistant than what was available economically back in the 70's. Add to that the casting techniques,alloys, and most importantly,water cooling.

 

[laverdakeith]

The quick answer is that Moto Laverda were not very good at cylinder heads. Some are OK some ain't, some are disasterous and loose clearance before your eyes, the RGS ones are the best and are generally very stable, the '77 all aluminium ones are the worst.
An interesting pattern has started to emerge at my workshop, I have had three '80/'81 motors through this year which have been fitted with the '77 heads. Doing my Sherlock Holmes I have deduced that the motors in question probably all suffered dammage early in their lives (while under "warranty") due to broken short valve springs and ended up with soft heads that had been lying under the bench since they were removed from the '77 bike (again, most likely under "warrenty") in order to get them out of the door again. Good old Laverda dealers....
If things go well in the next couple of years I may well look into manufacturing some new heads, fixing up an old one properly is expensive and time consuming and they are only ever as good as the sum of their parts, in the meantime if anyone has a stack of RGS heads cluttering the place up I would quite happily swap them for a stack of cash.

   Keith

the 77 all aluminum triple heads are the very worst, you say.......    and here just recently the 79's were being vilified.

Presumably the very bad soft 77 heads are fitted to the revered and increasingly sought after 77 Jota? Then the crappy 80 and 81 triple heads with the bad springs etc. Looks to me like the 79 1200 Anniversary being crticized elsewhere here is dead reliable in comparison

Paul LeClair

  Hi Paul,

      The '79 heads are not so bad the factory had gone back to iron skulls by then, the big problem with the '79 bikes is the centre main bearings. The 80/81 head is actualy not bad once the springs are changed for the earlier/later type, biggest issue with the 80/81's is the oversize exhaust valves.


    Keith

 

[3patC]

Keith do you have any idea which engine number range had the all aluminium heads? The 77 Jarama I had didn't seem to have any problems but I dont know which head type it was fitted with. I had the service history with it and in 44000 miles it hadn't been shimmed very often and it ran and sounded sweet.

 

[Ventodue]

The '79 heads are not so bad the factory had gone back to iron skulls by then, the big problem with the '79 bikes is the centre main bearings. The 80/81 head is actualy not bad once the springs are changed for the earlier/later type, biggest issue with the 80/81's is the oversize exhaust valves.

Blimey, and there was me thinking only Zan? bikes were a pile of poo ... :-*   

Ciao

Craig

 

[Paul LeClair]

 Hi Paul,

     The '79 heads are not so bad the factory had gone back to iron skulls by then, the big problem with the '79 bikes is the centre main bearings. The 80/81 head is actualy not bad once the springs are changed for the earlier/later type, biggest issue with the 80/81's is the oversize exhaust valves.


   Keith
[/quote]

Hi Keith

so my 79 1200 Mirage, which was from the "bad main crank bearing" batch, doing 60,000 miles + after the crank bearings were replaced but on the original iron skull head would seem to be well within normal for a Laverda triple..... All I have done to the head is replace the valves guides once and have the seats/valves recut once, both about 15,000 miles ago, and the bike is running better than ever without any obvious head problems. The valve clearances  have remained steady after they stabilized after the valve job, I continue to check the clearances regulalrly but they haven't changed significantly for years now. I change oil about every 1,000 - 1,500 kms typically, and I change the cam chain out every couple of years as preventative maintenance, the primary chain less frequently. The 79 1200 has been essentially bulletproof throughout its service life to date once the bad crank bearing was dealt with. I wouldn't hesitate to ride the 1200 coast to coast across North America and I lend it out periodically to people without any worries abount mechanical issues whatsoever.

Paul LeClair

 

[mauricejota7604]

Doesn't this just prove that any given Laverda in a model range may and could quite possibly be different in certain components used in the manufacture and doesn't this make our bikes so unique
M.

 

[morison]

Keith do you have any idea which engine number range had the all aluminium heads? The 77 Jarama I had didn't seem to have any problems but I dont know which head type it was fitted with. I had the service history with it and in 44000 miles it hadn't been shimmed very often and it ran and sounded sweet.

My engine 55** falls into the 77 range. The valve clearances haven't changed much in the time I've owned it so I wonder if it's had a replacement head or that it actually has an earlier head because it's an export model. Made in 1976 homologated in Australia in 1977? How do we find this sort of stuff out.

 

[jlo]

It would be better to speak about serial numbers instead of years, my 3CL is a 77 model and its all aluminium cylinder head is ok, valve clearance stable. I know some other 1977 models that have no problem too, all of them have the all aluminium heads.
The first triple having the all aluminium head was #3887, I suspect that the problems began later, near the end of 1978. 1977 heads are exactly the same as 1976s, they do crack but rarely have valve recession it seems. The iron skulls fitted to the late 79/1980 models were real crap, iron too soft, no need to mention the batch with short valve springs...

 

[morison]

Thanks JLO