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Small block gearbox questions (V50III/V65)

D

dbarale

Just got it firing!
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I’m working on a V50III that came to me in boxes and ziplocks. One issue is that the rear gearbox cover suffered from the common driveshaft failure. The bike came with a V65 gearbox, of which I am only reusing the cover and some hardware.

There is a small bearing size difference between the two that I addressed today. My problem is that I did not realize that there apparently was two style of bearing retaining plates for the mainshaft, one that includes a plastic splash cover:

IMG_6328.webp

Of course I pressed the new bearings using the other (plain) retaining plate… Does anyone know the actual function of the splash guard? I cannot really see what it does?

Second question, I have a mystery leftover part. I can’t figure out where it comes from. Any ideas? It was with the gearbox internals. It’s steel, and about 2mm thick:

IMG_6329.webp

Thanks!
 
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I've replaced thrust washers in my gearbox, but can't identify bits (due to mist of time & old age)....First thing is if it is in the gearbox or from the clutch shaft that goes through the gearbox/clutch plate and is in a diagram here parts 23/22 (see below).
clutch bits.webp
If it's not from the clutch shaft, it probably is from inside gerabox (except for washer 59 !) & I think you 'just' need to compare what is there with the parts diagram & look for the missing washer/spacer . Guessing you have the parts diag & list for V50 3 below to do this ? BTW I think the splash guard helps stop oil entrainment out the breather.
v50 3 gb.webp
 
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Paul Brice said:
I've replaced thrust washers in my gearbox, but can't identify bits (due to mist of time & old age)....First thing is if it is in the gearbox or from the clutch shaft that goes through the gearbox/clutch plate and is in a diagram here parts 23/22 (see below).
View attachment 38962
If it's not from the clutch shaft, it probably is from inside gerabox (except for washer 59 !) & I think you 'just' need to compare what is there with the parts diagram & look for the missing washer/spacer . Guessing you have the parts diag & list for V50 3 below to do this ? BTW I think the splash guard helps stop oil entrainment out the breather.
View attachment 38961
Click to expand...

Thanks, the splash guard mitigating oil leakage makes sense.
I did download the manual and parts diagram from Greg Bender’s website and I still cannot figure it out. I am doing a “dry” reassembly today and hoping to find out more.
 
Assuming you didn't strip out each gearshaft, there aren't many bits to lose....the washers on the gearshafts are mainly 'special' ones with inside nibs to hold the splines OR they are wavy springy ones, so again easy to spot (the one you show hasn't got internal nibs)......I'm guessing the missing bit is just an end of shaft washer. BTW for full rebuild (if you changed the end case, the shift drum eccentric will have come out & into new one), make sure the eccentric is in the middle so you have max adjustment each way from the 'external nut' that adjusts shift drum tension position...
 
Dry assembly revealed….. absolutely nothing.
It’s shifting “smoothly” through all gears.

Just kidding, it’s a Guzzi, it’s clunking laboriously through all gears. But it’s shifting, the clutch rod seems to be doing its thing. And nothing is binding. That’s with the eccentric in the middle. I’m sure there will be more adjustment needed when the bike is assembled.

As a bonus, I am only missing the clutch lever return spring.
The new seals will be here tomorrow, we’ll see.
 
I don't recall any spacer like that for the clutch push rod.
Could it be item 40? Does it locate the spring?
 
Since we're on the subject of the gearbox, are there any instructions on how to properly index the shift drum when reassembling?
I cannot find anything in the manual and it appears it could go a couple of different ways?
 
If by 'index' you mean the way the shifter forks & shaft fit when assembling, then beyond parts manual & trial & error (& taking it to an expert !); probably best to try working of photos like these.....I didn't take the shift shaft apart, so didn't have any problems like that.

gb pic4.webpgbox pic3.webpGbox pic2.webpgbox pic.webp
 
Paul Brice said:
BTW, when assembling don't forget new O ring in shift shaft opening.
View attachment 38977
There is also a you tube link for how to set up the spring on the shift mechanism - just look for Moto Guzzi Shift return spring alignment in youtube
Click to expand...

Thank you! All buttoned up with new seals all around. The only one that I forgot to replace was the small seal around the clutch pushrod. Oh well… Now I am just waiting on the rear engine main seal and I can start reassembling everything.
 
dbarale said:
Thank you! All buttoned up with new seals all around. The only one that I forgot to replace was the small seal around the clutch pushrod. Oh well… Now I am just waiting on the rear engine main seal and I can start reassembling everything.
Click to expand...
That one is easy to change and can be done easily before you put the bike together. I use a dental pick to remove the old o-ring, then use the handle of the pick to push the new one into place.
 
john zibell said:
That one is easy to change and can be done easily before you put the bike together. I use a dental pick to remove the old o-ring, then use the handle of the pick to push the new on into place.
Click to expand...
It’s off, area has been cleaned (ish) and now it’s just a waiting game. A dental pick would have not been enough for this one though, it required the small hole/wood screw trick and I had to pry it off with a framing hammer (don’t judge me).
 
Adamigo said:
photos.app.goo.gl

New item by Adam Pawlikowski

photos.app.goo.gl photos.app.goo.gl
Click to expand...
Thank you.

It’s back together and in the frame. I had to make the shifter linkage from something else as it was missing. For the clutch return spring I used one from the clutch of a…. washing machine. No kidding. Oh well, it shifts easily through all five gears and the clutch works. Of course that’s just turning the rear wheel by hand and actual riding might be different.

IMG_6333.png

Thanks again for all the help. Next is carbs and exhaust so I can hear it run for more than three seconds.

After that, it will be brakes. I’m not looking forward to that:

IMG_6334.webp
 
You made great progress. Looks very clean now.
Did you put oil in the gearbox yet?
If the V65 is filled to spec (1L iirc) some oil will burp out of the vent.
You can reduce to 900mL or implement a mod with a long hose.
 
Pescatore said:
You made great progress. Looks very clean now.
Did you put oil in the gearbox yet?
If the V65 is filled to spec (1L iirc) some oil will burp out of the vent.
You can reduce to 900mL or implement a mod with a long hose.
Click to expand...
Yes. I put a quart in but didn’t let it drip all the way. So I’m probably just around 925-ish.
I don’t expect long highway runs on that bike, so I may be OK?
I have been driving a ‘67 Land Rover for the past 35 years, so oil leaks don’t really bother me much.
 
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