Doubts tighttening cylinder head nuts and about valve clearance

  • Thread starter Thread starter Erivaj
  • Start date Start date
Well, I have a new chain from you Andy, and Keith has the Head...and the NEW cam blocks, so unless the cams have had it , there should not be a problem ....in theory. Good tip to put pressure on the sprocket though.
Reggie..thought you sold you bike..what do you have now?
Nick7
 
Did.  Then got this- The Rescue Dawg  :D

misc3244BANDW-1.jpg


Reggie
 
Ta.  It's a very nice bike to ride, although inevitably I'm on the same path as with the 180; the forks, shocks, wheels, brakes, carbs and cylinder head all need seeing to as funds allow, but even as it stands (slightly shagged out) it goes pretty well and it's a handsome beast for sure.

Reggie
 
Hi,

This evening I take clearances again, and I take too the shims measures:

Inlet Left: 0.10 and 2.38 shim ... I need 2.48 and I have 2.52
    Center: 0.05 and 2.33 shim ... I need 2.48
      Right: 0.10 and 2.29 shim ... Ineed 2.39 and I have 2.38

Exhaust Left: 0.10 and 2.57 shim ... I need 2.67
        Center: 0.20 and 2.52 shim ... I need 2.57 and I have it.
          Right: 0.25 and 2.57 ... It is OK

According to Laverda manual, I can find 2.45 or 2.52 for 2.48, 2.38 or 2.45 for 2.39, and 2.60 or 2.80 for 2.67.

What shims I have to order? Are ther another measures?

 
Erivaj said:
Hi,

This evening I take clearances again, and I take too the shims measures:

Inlet Left: 0.10 and 2.38 shim ... I need 2.48 and I have 2.52
     Center: 0.05 and 2.33 shim ... I need 2.48
      Right: 0.10 and 2.29 shim ... Ineed 2.39 and I have 2.38

Exhaust Left: 0.10 and 2.57 shim ... I need 2.67
         Center: 0.20 and 2.52 shim ... I need 2.57 and I have it.
           Right: 0.25 and 2.57 ... It is OK

According to Laverda manual, I can find 2.45 or 2.52 for 2.48, 2.38 or 2.45 for 2.39, and 2.60 or 2.80 for 2.67.

What shims I have to order? Are ther another measures?
Click to expand...

You need thinner shims on the valves, rather than thicker ones you've indicated, to increase the valve clearances. Do the math the other way..exhaust left..measures .10 and you want .20/.25 and it has 2.57, you need a 2.45, which should give you .22
 
As per above, you need to use a thinner shim to increase your clearance.
You want 0.25 - 0.27 on the exhausts
And 0.20 - 0.22 on the inlets
So for example inlet left you have 0.10 and 2.38, you need 2.26 - 2.28 or so.  I always aim for clearances a little wide (0.22 / 0.27) to allow for some wear.

Your shim sizes are large, this is a good sign BUT with an unknown bike it is a good idea to check the tips of the valves have not been shortened.  With the bucket and shim removed, you need to measure the distance from valve tip to the collet retainers.  This should be about 0.5mm greater than the depth of the counterbore on the back of the shim.  From memory the standard sizes are 4.0mm to the collets and 3.5mm depth of counterbore in shim, but I or someone will confirm this.
When a head is worn, a cheap-fix is remove the valves, grind some material from the tip, then use modified shims with less "depth" to retain the clearance to the collets.  This CAN be sort-of OK as a short-term solution IF it is not overdone, and that suitable shims are always used.  The danger is when a standard shim is installed and it rests on the collets, which can cause the valve to come out (bad).  A shim that is very "shallow" on the back is a warning sign
Anyhow, always worth a look on a bike you don't know the history of.  Hopefully you have a nice head there in good condition and all you need is some new shims and off you go.  By the way the sizes stated in the manual are not gospel, many sizes in between have been produced these days.

Cheers
Steve B
 
Hi Erivaj

I have attached a little spreadsheet with your clearance and shim sizes entered (the file is compressed into a zip folder because this forum won't accept Excel files). The yellow highlighted cells show the shim sizes you need.

There's not much opportunity to rearrange shims, although you could take the shim from the right inlet and put it in the left inlet. You may want to rub it down 0.01mm on an oil stone if you're really fussy.

Grinding them on an oilstone is a possibility for the others, but you'd have a lot of metal to remove. So it's probably easier to get 4 new shims. I have a bunch of shims and would be happy to do a free exchange if I have the sizes you need (will have a look at my shim stock when I get home). I'm in Australia and I'm guessing you're in Europe. So it would be a week to 10 days before you get them. There's probably someone closer that will do an exchange for you. Keith or Piet maybe? Don't ask them to do it for nothing though - they have to earn a living.

Cheers,
Cam
 

Attachments

Rusty Spokes said:
You need thinner shims on the valves, rather than thicker ones you've indicated, to increase the valve clearances. Do the math the other way..exhaust left..measures .10 and you want .20/.25 and it has 2.57, you need a 2.45, which should give you .22
Click to expand...

breganzane said:
As per above, you need to use a thinner shim to increase your clearance.
You want 0.25 - 0.27 on the exhausts
And 0.20 - 0.22 on the inlets
So for example inlet left you have 0.10 and 2.38, you need 2.26 - 2.28 or so.  I always aim for clearances a little wide (0.22 / 0.27) to allow for some wear.
Click to expand...

Sinttulo.jpg



??? ??? ???

Sorry friends, you are absolutely right  >:( ... I increase the measures instead decrease them  :-X



breganzane said:
Your shim sizes are large, this is a good sign BUT with an unknown bike it is a good idea to check the tips of the valves have not been shortened.  With the bucket and shim removed, you need to measure the distance from valve tip to the collet retainers.  This should be about 0.5mm greater than the depth of the counterbore on the back of the shim.  From memory the standard sizes are 4.0mm to the collets and 3.5mm depth of counterbore in shim, but I or someone will confirm this.
When a head is worn, a cheap-fix is remove the valves, grind some material from the tip, then use modified shims with less "depth" to retain the clearance to the collets.  This CAN be sort-of OK as a short-term solution IF it is not overdone, and that suitable shims are always used.  The danger is when a standard shim is installed and it rests on the collets, which can cause the valve to come out (bad).  A shim that is very "shallow" on the back is a warning sign
Anyhow, always worth a look on a bike you don't know the history of.  Hopefully you have a nice head there in good condition and all you need is some new shims and off you go.  By the way the sizes stated in the manual are not gospel, many sizes in between have been produced these days.
Click to expand...

Well, I am the third owner of the bike, and the bike shows 42.200km  ::) ... I am not sure about if the size of the shims I need are according to the 42.000km shown.

On the other hand, I am trying to understand the checking you are proposing me. I will take a look to the drawings.

Dellortoman said:
Grinding them on an oilstone is a possibility for the others, but you'd have a lot of metal to remove. So it's probably easier to get 4 new shims. I have a bunch of shims and would be happy to do a free exchange if I have the sizes you need (will have a look at my shim stock when I get home). I'm in Australia and I'm guessing you're in Europe. So it would be a week to 10 days before you get them. There's probably someone closer that will do an exchange for you. Keith or Piet maybe? Don't ask them to do it for nothing though - they have to earn a living.
Click to expand...

It looks like some shims have been decreased like you said, because the back side is slightly scratched, and yes, you are right about my position. I am in Europe, in the south of Spain. ;)


Thanks again to everybody. It is easier in this way.
 
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