The Gearbox Bit

  • Thread starter Thread starter Bearsaregood
  • Start date Start date
B

Bearsaregood

Guest
I bravely opened another box this afternoon, one of many that hopefully contain all of the bits that will make up my 750 SF2. Primary shaft and lay shaft lay there, dirty and unloved, but seemingly complete and all present. Then I remembered something that the previous owner had mumbled while we were trying to load the bits and pieces in the midst of a deluge of biblical proportions. The dogs on the lay shaft were a bit raggy, so he had a mate machine them square. Looking at the result, he got them square, but took a lot off in doing so. Having never worked with undercut dogs, can I get an opinion on the end result. Should these work, or should I junk same and buy new ones?

Chris
 

Attachments

  • IMG00303-20141006-1703.jpg
    IMG00303-20141006-1703.jpg
    146.2 KB · Views: 53
  • IMG00302-20141006-1700.jpg
    IMG00302-20141006-1700.jpg
    132.5 KB · Views: 58
Pictures are worth a 1000 words, but not as much as measuring and checking the fit of the dogs. :D

Laverda gears are generally very strong, but not knowing how much material has been removed, I'd suggest you do not use these gears in a box intended for racing or similar.  Will probably be fine for general road use.

NOS standard gears are available, mainshaft 5th. might pose a problem.

Check condition and fit of all the bushes and check axial float of the layshaft (if fitted with roller bearings at both ends), as well as the fit of the selector forks when gears are engaged.

piet
 
When a bronze bush in my SF2 gearbox dissolved, Piero Laverda was very surprised, saying that the factory had huge stocks of gearbox parts since they never broke.

Piet: racing I undersatnd but whats similar?  :o

Paul
 
Paul Marx said:
When a bronze bush in my SF2 gearbox dissolved, Piero Laverda was very surprised, saying that the factory had huge stocks of gearbox parts since they never broke.

Piet: racing I undersatnd but whats similar?  :o

Paul
Click to expand...

Track days, serious abuse of the highway code on public roads, etc, etc... :D

Wear in the bushes causes further damage to the teeth of the gear, up to the point that the teeth clash rather than mesh smoothly.  That's the moment they tend to break up.  The bushes rarely dissolve completely, but I have found them loose in the gears as well.

piet
 
Piet, I'll try to get some comparative measurements today. New bearings, bushes, seals etc. are a given. Does "similar" have anything to do with radical lean angles and fast moving scenery?

Chris
 
I might have been in that same traffic jam on a borrowed SFC1000 (ex Norway), and it too boiled its oil, and never ran as well again, until stripped and renovated.
CLEM
 
Amicale autumn rally 2000 I think Clem.
Massive parisian demo and a fire at the national library that afternoon.
The triples got very hot under the collar.
3rd gear on the SF2 let go two years later. Bothersome as I was on mountain roads when it went.
Paul
 
Bearsaregood said:
Piet, I'll try to get some comparative measurements today. New bearings, bushes, seals etc. are a given. Does "similar" have anything to do with radical lean angles and fast moving scenery?

Chris
Click to expand...

Guess it all depends on how hard and fast you tension the throttle cable... :D

I know people that are ridiculously fast but are very sympathetic to the mechanicals, others are less than half as quick, but manage to bust just about everything they lay their fingers on!  :o

Gearbox dimensions/clearances are shown in the early twin and triple owner/maintenance manuals.

piet
 
You must log in or register to reply here.
Back
Top