Author Topic: LAVERDA Zane camshaft/timing chain  (Read 1468 times)

Offline Dellortoman

  • Hero Member
  • *****
  • Posts: 13404
  • My wolf mate 6/5/1996 - 3/1/2011
Re: LAVERDA Zane camshaft/timing chain
« Reply #30 on: September 24, 2020, 01:13 »
Pitch and width that is no longer used   No idea what moved the designers to use it. ::)

Thanks Piet.
Yes, that does defy logic. You'd think a common chain size would be an obvious choice.
Just out of curiosity, do you recall the pitch and width of the Zane chain?
Location: Tasmania, Approx 4253S 14723E

Offline Piranha Brother 2

  • Hero Member
  • *****
  • Posts: 3462
  • It was once a 1973 750 SF1
Re: LAVERDA Zane camshaft/timing chain
« Reply #31 on: September 24, 2020, 01:28 »
Thanks Piet.
Yes, that does defy logic. You'd think a common chain size would be an obvious choice.
Just out of curiosity, do you recall the pitch and width of the Zane chain?

FFS. It's simply absurd that a 'modern' (ie post war!) manufacturer would use some weirdo chain size for a part that is destined for regular replacement. Another reason to NOT own a ZANE?! Or fitting a different motor entirely to a fabulous rolling chassis.

I'd probably be adding a new centre piece to the list of 'mods' to go with big-ends ... or is the centre cam sprocket section part of a complete crank web??
What ... leave it standard??!!

Online Vince

  • Hero Member
  • *****
  • Posts: 9363
Re: LAVERDA Zane camshaft/timing chain
« Reply #32 on: September 24, 2020, 02:43 »
I am bloody happy this hasnt occurred more often with Laverda bits and pieces. Couple of examples over the years, Hondas 23-inch front wheel, the 16-inch front wheels that you couldn't get tyres for a very long time. Fashionable bind alleys manufacturers have totalled down and buggared the owners when supplies eventually dry up.

Offline Dellortoman

  • Hero Member
  • *****
  • Posts: 13404
  • My wolf mate 6/5/1996 - 3/1/2011
Re: LAVERDA Zane camshaft/timing chain
« Reply #33 on: September 24, 2020, 03:47 »
I'd probably be adding a new centre piece to the list of 'mods' to go with big-ends ... or is the centre cam sprocket section part of a complete crank web??

Not sure about the 750 twins, but on the triples the cam chain sprocket is part of the crank, so I presume the 750's are made the same way.

Even so, it probably isn't beyond the realms of possibility to machine the sprocket off the crank centre, press a different one on and fix it in position somehow (keyed or welded).
The new chain/sprocket may have a slightly different pitch from the original, so the sprocket diameters might be slightly different. You'd need to make sure there's room for the new chain in the cam chain tunnel.
Location: Tasmania, Approx 4253S 14723E

Offline sfcpiet

  • Administrator
  • Hero Member
  • *****
  • Posts: 8490
  • NRW, Germany
Re: LAVERDA Zane camshaft/timing chain
« Reply #34 on: September 24, 2020, 18:53 »
Not sure about the 750 twins, but on the triples the cam chain sprocket is part of the crank, so I presume the 750's are made the same way.

Even so, it probably isn't beyond the realms of possibility to machine the sprocket off the crank centre, press a different one on and fix it in position somehow (keyed or welded).
The new chain/sprocket may have a slightly different pitch from the original, so the sprocket diameters might be slightly different. You'd need to make sure there's room for the new chain in the cam chain tunnel.

We're talking 500/600/650/668/750 here, Cam.  All have integral sprockets.  Pressing or welding on another is definitely an option.

5/16" x 7/32".  Reckon it was chosen to reduce cam sprocket diametre/engine height and head width(length?).  Tooth count is the same as all other Lavs, 15/30 iIrc.  Might get away with 14/28, using a triple type 06B-1 chain.  At least the chain tunnel is wide enough!

piet
« Last Edit: September 24, 2020, 18:56 by sfcpiet »
180s feel quick, 120s are...      If it ain't broke, fix it till it is.

"A motorcycle is a bicycle with a pandemonium attachment and is designed for the especial use of mechanical geniuses, daredevils and lunatics"  Georg Fitch 1916

Offline Dellortoman

  • Hero Member
  • *****
  • Posts: 13404
  • My wolf mate 6/5/1996 - 3/1/2011
Re: LAVERDA Zane camshaft/timing chain
« Reply #35 on: September 25, 2020, 02:17 »
By saying it's do-able, you could be making work for yourself as the world's supply of 5/16" x 7/32" chain is exhausted. You might have to set up a production line pressing sprockets onto Zane cranks.  :D
Location: Tasmania, Approx 4253S 14723E

Offline Rider668

  • Jr. Member
  • **
  • Posts: 86
Re: LAVERDA Zane camshaft/timing chain
« Reply #36 on: September 25, 2020, 08:47 »
As Piet notes, this is not a Zane specific issue.  All the eight valve twins are affected. Perhaps the title of the thread could be changed?
Then all the Monty, Alpino and Atlas owners can join in worrying.

Offline sfcpiet

  • Administrator
  • Hero Member
  • *****
  • Posts: 8490
  • NRW, Germany
Re: LAVERDA Zane camshaft/timing chain
« Reply #37 on: September 25, 2020, 09:09 »
By saying it's do-able, you could be making work for yourself as the world's supply of 5/16" x 7/32" chain is exhausted. You might have to set up a production line pressing sprockets onto Zane cranks.  :D

Sure... I need that like I need a pimple on my arse. ;D

piet
180s feel quick, 120s are...      If it ain't broke, fix it till it is.

"A motorcycle is a bicycle with a pandemonium attachment and is designed for the especial use of mechanical geniuses, daredevils and lunatics"  Georg Fitch 1916

Offline Piranha Brother 2

  • Hero Member
  • *****
  • Posts: 3462
  • It was once a 1973 750 SF1
Re: LAVERDA Zane camshaft/timing chain
« Reply #38 on: September 25, 2020, 09:51 »
Not sure about the 750 twins, but on the triples the cam chain sprocket is part of the crank, so I presume the 750's are made the same way.


750 (Breg) twins have removable centre pieces that have the cam sprocket teeth machined into them. Not a cheap job to make new SFC style press fit centres but probably only 3 or 4 cam chain's worth!!
What ... leave it standard??!!

Offline Andy

  • Full Member
  • ***
  • Posts: 219
Re: LAVERDA Zane camshaft/timing chain
« Reply #39 on: September 26, 2020, 00:19 »
Sure... I need that like I need a pimple on my arse. ;D

piet

You could always sub the work out.... whats the freight cost to Tassie...?
'84 RGS and loving it
(might have to sell the old honda...)

Offline Dellortoman

  • Hero Member
  • *****
  • Posts: 13404
  • My wolf mate 6/5/1996 - 3/1/2011
Re: LAVERDA Zane camshaft/timing chain
« Reply #40 on: September 26, 2020, 02:22 »
Not a cheap job to make new SFC style press fit centres but probably only 3 or 4 cam chain's worth!!

You wouldn't need to make a whole new centre. Just machine the sprocket part off the centre shaft and press a new sprocket ring on. Maybe a couple of dabs of weld to make sure it doesn't move and you're done. Only an hour's work  :D
Location: Tasmania, Approx 4253S 14723E

Offline Piranha Brother 2

  • Hero Member
  • *****
  • Posts: 3462
  • It was once a 1973 750 SF1
Re: LAVERDA Zane camshaft/timing chain
« Reply #41 on: September 26, 2020, 03:28 »
If it's anything like an SF centre, the sprocket is smaller than the OD of the inner main bearing journals. The sprocket profile is actually machined into the side part of the bearing journal so the bearing presses up against the 'half-teeth' left after machining from the side. They can break off too - the experienced old mechanic at the shop I worked at in Perth convinced me my inner mains were worn and helped me make up pressing plates, then became confused and big mobs of tons onto the wrong part of the centre. A few half-teeth cracked off halfway across the Nullarbor - luckily Lee and I were travelling together so I had a ride home! Took months before a truck coming through Yalata Roadhouse was willing to collect it. Thought it was gone forever - it wasn't fun leaving it there with instructions to put it on the first available truck! No bent valves ... just needed a new crank splined centre - ahem .... thanks Rob!!  ;D :-* :o
What ... leave it standard??!!

Offline Dellortoman

  • Hero Member
  • *****
  • Posts: 13404
  • My wolf mate 6/5/1996 - 3/1/2011
Re: LAVERDA Zane camshaft/timing chain
« Reply #42 on: September 26, 2020, 04:30 »
Fair enough, you know better than me. I've never looked at a 750 crankshaft. I just figured it was do-able because of what Piet said.
Location: Tasmania, Approx 4253S 14723E

Offline sfcpiet

  • Administrator
  • Hero Member
  • *****
  • Posts: 8490
  • NRW, Germany
Re: LAVERDA Zane camshaft/timing chain
« Reply #43 on: September 26, 2020, 13:32 »
Quite feasable on the 4V cranks, I'll throw a couple of ideas and dimensions around...

piet
180s feel quick, 120s are...      If it ain't broke, fix it till it is.

"A motorcycle is a bicycle with a pandemonium attachment and is designed for the especial use of mechanical geniuses, daredevils and lunatics"  Georg Fitch 1916