Engine mounts for 180 and 120's and case difference.

[padlock]

What ho chums,
                     
    I know that most 120's were rubber mounted but are the mounts in the case's the same as the 180's and did the cases change in terms of dimensions and mounting holes for engine bolts? I guess an easier way of putting it would be, could you theoretically put a 120 engine in a frame designed for a 180 and it be bolted in directly without rubber mounts?

        FFF

 

[sfcpiet]

What ho chums,
                     
    I know that most 120's were rubber mounted but are the mounts in the case's the same as the 180's and did the cases change in terms of dimensions and mounting holes for engine bolts? I guess an easier way of putting it would be, could you theoretically put a 120 engine in a frame designed for a 180 and it be bolted in directly without rubber mounts?

        FFF

Yes, just a question of drilling and tapping a couple of holes.  The bosses are there, just no holes in them.  The rear mounts can be used as is, just the 4 lowers/fronts need to be adapted.

The pictured bike has RGS cases in an old 180 frame, note RH brake and no cross-over gear linkage.  Actually done it a couple of times in the past.

piet

 

[padlock]

Smahing, Thanks for that info. If i could be so bold as to press a bit more, Why Rgs cases and 180 top end? Or is it a whole rgs bottom end? Pip Pip.

  FFF

 

[Grant]

Better gearbox?
Preferred left foot shift?
Preferred 180 engine characteristics?

 

[2622]

If i could be so bold as to press a bit more, Why Rgs cases and 180 top end? Or is it a whole rgs bottom end? Pip Pip.
FFF

I have three guesses

Because he could ? 

Needed a set of cases and had a spare set of RGS floating around ?

In case someone ever asked if it could be done and he would already have the pics to prove it ?

 

[sfcpiet]

I have three guesses

Because he could ? 

Needed a set of cases and had a spare set of RGS floating around ?

In case someone ever asked if it could be done and he would already have the pics to prove it ?

1.  Because I could.

2. Had a spare RGS engine under the workbench. 

3. Was intended for a hobby racer series with 1980 cut-off date.  120s were introduced 1982, so I figured I'd just re-phase the crank and fit a set of 180 C7s I also had in my stash.  Various things prevented participation, most of all the sudden ban of cast wheels in the series.  Sorry, ain't going racing on wire spokes, my self-preservation instinct is quite pronounced.

Is actually a complete RGS engine with re-phased crank and cams, head re-worked to Corsa/SFC specs.  36mm Dellortos, again because flatslides were banned and I couldn't afford a set of CR35 Mikkies.  Quite happy to take advantage of the stronger crank and gearbox as well!  LH change played no role, personally, I couldn't care less where the gear lever is, as long as the gearchange is sweet.

piet