Author Topic: V65 SP 1984 gearbox rebuild problem  (Read 172 times)

Offline Skiwi39

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V65 SP 1984 gearbox rebuild problem
« on: June 15, 2025, 06:56:22 PM »
Gear selection issue after gearbox rebuild.

My gearbox had a few issues, not least of which was that it was quite noisy on the overrun, so I decided to pull it apart and check its condition, and at the very least replace the bearings in the hope that it would quieten the beast down.

Long story short, there was surface rust on most of the gears and the selector mechanism (20999520) was really rusty probably due to water getting in there at some stage. It was replaced along with all bearings and replaceable items. Reassembly was easy enough and based on the number of pictures I took, I'm pretty certain I put it back together as I found it.

When I took it out for its maiden ride, I couldn't get from 1st to second in one, single action. I would literally have to make a distinct, second movement to move it to the next gear which often felt like 3rd. Despite playing with the linkage (shortening and lengthening it) and rotating the eccentric bolt on the back of the gearbox many, many times in either direction I cannot get past this problem! it's massively frustrating.

I'm wondering if this can in fact be "adjusted out" via the eccentric bolt as a lot of people have suggested or if I have somehow managed to get the selector forks "out of sync"? The selector mechanism I purchased was advertised as having come off a V65 and was certainly identical in looks and dimensions. One odd thing though was that the clamp that attaches to the splined output shaft now sits at a different position to the way it did with the original one. I put that down to the splines being clocked slightly when the part was manufactured.

If anyone can help shed some light on this problem or has any input at all, it would be appreciated!

Many thanks!
« Last Edit: June 15, 2025, 07:00:30 PM by Skiwi39 »

Offline Antietam Classic Cycle

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Re: V65 SP 1984 gearbox rebuild problem
« Reply #1 on: June 16, 2025, 08:43:24 AM »
I have very little experience with the small-block transmission, so can't offer any suggestions. I don't know if you've seen them or not, but there are factory technical training videos about it at the bottom of this page:
https://www.thisoldtractor.com/moto_guzzi_technical_training_videos_eng.html
Charlie

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Re: V65 SP 1984 gearbox rebuild problem
« Reply #2 on: June 16, 2025, 07:31:22 PM »
Know of a new old v65 trans complete  if you want  i could have a look see if it is obtainable uni

Offline Chuck in Indiana

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Re: V65 SP 1984 gearbox rebuild problem
« Reply #3 on: June 17, 2025, 06:36:27 AM »
The problem is you'll get it repaired and then find that 5th gear is noisy from the factory recommending lowering the oil level to keep it from puking out of the mushroom beather. This starves 5th gear, and has been corrected on later models, or there is a fix for that if it isn't too late. I have a baby Beaver transmission in the AeroLario.
Chuck in (Elwood) Indiana/sometimes SoCal
 
87 AeroLario
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Offline Pescatore

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Re: V65 SP 1984 gearbox rebuild problem
« Reply #4 on: June 17, 2025, 07:22:04 AM »
I had to take mine apart a second time because some gears wouldn't engage and was getting neutral in between gears.
I spent hours on the bench with the box open, selecting every gear and watching it engage.
I then closed it, spun it with a flexible drill extension and tweaked the screw some more until I was happy.
https://wildguzzi.com/forum/index.php?topic=102352.msg1816842#msg1816842

Your situation might be different.
2008 Norge red
1991 V65GT
1980 CM400T
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