Difference between long stroke and R65 cases

[Andy-Gadget]

Hi all, I'm new here, great site.

Thought I would share some information I found the other day about the differences between R65 cases, and every other boxer.

If this is generally known, I apologize.

A mate, Adrian, has just bought an '84 R65, and wanted to know what, if any, differences there were between the normal long stroke boxer and the R65, and as I have a dead LS motor lying around, I did some research.

The R65 case is specific to the R65 (and probably the R45, but I don't know anybody who has one, so it doesn't matter), and can't be used for any thing else.
The cam is specific as well.

The differences are in the cam follower tunnel angles, and from this the push rod tube termination and cam timing.

R65 case in front, R80 case behind, note angles of tubes in follower tunnels.


R65 case on the left, R80 case on the right, note angle and position of push rod tube termination.


Cam lobe phasing, R65 inlet.


R80 inlet.


Bottom line, you can play mix and match to your hearts content with the long stroke bikes, you have very little wiggle room with the R65.

[Justin B.]

Interesting information.  I don't ever remember it being discussed here but if you think about it it's kinda obvious - at least about the pushrod angles and stuff...

[drewboid]

OK - how about moving further back?
Old flywheel vs. clutch carrier?
What years transmissions are interchangable?
Will those with exposed ribs interchange with smooth?
Final drives?
I know the LS rear brakes differ from the standard.

Inquiring minds want to know!

[Andy-Gadget]

OK - how about moving further back?
Old flywheel vs. clutch carrier?
What years transmissions are interchangable?
Will those with exposed ribs interchange with smooth?
Final drives?
I know the LS rear brakes differ from the standard.

Inquiring minds want to know!

I have never looked into the fitting of a later clutch / fly wheel to an early motor, as it would require the replacement of the gearbox input shaft as well, but can look into it this weekend when I get home again.

The later clutch is much more progressive than the "light switch" early item, but the extra mass of the early fly wheel is an advantage at times.

BTW, I killed the original motor on my LS due to the timing being a tooth out advanced, done by the PO, NOT me  
It made the bike rev like a two stroke, woo hoo, but spending all this time up near the red line ultimately killed it, loud knock at idle, but I didn't twig to what the problem was until I helped a mate fix an R100RS that was timed a tooth out retarded.
I did know that the bike ran differently to how I remember them running when they were new, but not why.
It was changing the timing chain on the RS that made the penny drop, went home and fixed it right then, but the damage was done.
Still don't know exactly what I have damaged, I need some more measurement gear, internal micrometers as my "telescopic hammers" aren't accurate enough, but I know the crank is OK, so that is a relief.

I know that all low cam boxer, > '70, final drives are interchangeable.

The waisted swinging arm, the one without the cush drive, will fit in the later frames, but the fat swinging arm, the one with the cush drive in it, will hit the brake switch bracket on the early frames.

I had an R100 motor in the LS frame at one point, never rode it, but wanted to see if it was possible to do, if everything lined up, which it does.

[Andy-Gadget]

R100 motor in LS.


Early final drive on late swinging arm.


LS donates its R100 motor to make an R80RT an R100RT.


LS gets plain Jane R65 motor transplant.


My fix for the horrible grey twin output coil problem.


Guzzi's and Boxers go well together.