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General Category => General Discussion => Topic started by: Mr5568 on June 25, 2020, 09:25:35 PM

Title: Eccentric preselector adjuster screw
Post by: Mr5568 on June 25, 2020, 09:25:35 PM
What is the eccentric adjustment screw on the back of my V50 Monza gear box for? The reason I'm asking is I've just finished putting my '82 Monza together after 18 years in boxes. It needed a transmission overhaul, which I performed myself. It shifts up just fine, but to go back down through the gears requires a lot fussing around pulling the foot lever up a bit before I can find the next gear down. I'm exploring all of the possible simple solutions before dismantling my transmission (again). Could an improper setting of the eccentric adjuster be part (all) of the problem? Thanks in advance for any help or suggestions.
Title: Re: Eccentric preselector adjuster screw
Post by: Kiwi_Roy on June 25, 2020, 10:39:11 PM
Thats what the eccentric is for, to centre the pawls for Up/Down shift.
Dont ask me how to adjust it.
Title: Re: Eccentric preselector adjuster screw
Post by: Chuck in Indiana on June 26, 2020, 06:25:27 AM
I *think* it is your problem. Before I disassembled it, though, I'd try changing it a bit one way, see if it makes a difference, maybe the other way, etc.
Disclaimer: I've not done this.. :smiley:
Title: Re: Eccentric preselector adjuster screw
Post by: wirespokes on June 26, 2020, 09:38:49 AM
I just read about that adjuster in Guzziology last week. Dave said to loosen the jam nut and turn the bolt one flat. He didn't know which direction would affect up, or down. But he said it will affect the distance the shifter moves on an upshift or down. You can reduce the distance required on an upshift (or downshift) by adjusting that bolt.

He also said to not adjust it move that six flats - I guess that would be one turn of the bolt. I'm guessing if it increases the distance on way, it will, at the same time, decrease it the other.
Title: Re: Eccentric preselector adjuster screw
Post by: Muzz on June 26, 2020, 06:03:31 PM
When I had my Breva box apart I marked it so that when the mark pointed towards the front of the box that was in the right place.

Must say it was a trap for the unwary though.
Title: Re: Eccentric preselector adjuster screw
Post by: Kiwi_Roy on June 26, 2020, 10:58:45 PM
I know its a loop but this excellent booklet from John Noble mentions the Pawl Adjustment several times.

Towards the end of the text it talks about adjusting it.
http://www.thisoldtractor.com/guzzitech.dk/pdf/gearbox-rebuilding-john-noble.pdf