Richard1964
Registered user
Can anyone help? I'm trying to understand the difference between a paralever and monolever gearbox. I have a 1991 R80GS with a dodgy box and have a decent box from a 1987 mono R80RT. Can I swap them?
Gearbox: Mono vs Para
- Thread starter Richard1964
- Start date
Yes you can. The main difference is the output seal but the mono gearbox will work with the standard seal. if you are using the Mono box in a paralever at the top of the output seal there is a small V that needs to be plugged with silicone sealer or another type of goo. This is a vent for the oil filled mono driveshafts. The paralever obviously doesn't have oil in the driveshaft and vents through the front swinging arm pivots. If you don't plug the v you will get oil from the gearbox in the driveshaft.
There are a couple of other differences (a sealed bearing etc) but nothing that stops you swapping yours over.
There are a couple of other differences (a sealed bearing etc) but nothing that stops you swapping yours over.
Richard,
Welcome to the Forum.
Your 'dodgy' gearbox can be repaired (Rob Farmer is the 'Guru'
) but others also refurb them - including me 
.I'd be happy to rebuild the 1991 box 'at cost' or, if you want to get rid of it I'll buy it from you (subject to the usual provisions). Its handy having a rebuilt box on the shelf in case someone has an urgent need for a repair.
I don't run a business - its just a hobby in my retirement
.Bob.
Richard,
Welcome to the Forum.
Your 'dodgy' gearbox can be repaired (Rob Farmer is the 'Guru'
Thanks for the compliment Bob but I'm not a Guru. Just have experience like yourself and some of the other guys with rebuilding standard boxes.
Richard1964
Registered user
Voyager and Rob - many many thanks. That was my first post and it's fantastic to have access to 10,000 years of collective GS experience at the click of a mouse (I'm not implying that it's just you 2 with that length of experience!) 
electric_monk
Registered user
(I'm not implying that it's just you 2 with that length of experience!)
But you're not far off the mark
Welcome Richard
This is a top site full of top blokes
There is the odd plonker but they are in the "other" sections
This is a top site full of top blokes
There is the odd plonker but they are in the "other" sections
(RIP) Tibs
Registered user
So, does the same apply to the earlier gearboxes? I always wondered if my 79 R80/7 box could mate up to my R100R, if the need should ever arise.
Tibs
Tibs
No. ..
(RIP) Tibs
Registered user
The input shaft on the earlier machines is longer to suit the earlier clutch.
The early input shaft is the one on the right. One of the guys on here had a mishmash of a gearbox that had the early input shaft working in his airhead G/s clutch so it may actually work
Padmei
Registered user
My 91 r80GS box recently started whining so I swapped it with a spare 81 R65 box I had lying around.
The only difference I found was the gear lever had to be swapped over between them as the 65 had a lever with a hole rather than a knob.
It was interesting to note that both boxes have the same definite 'clunk' into first & firm action needed between 1st & 2nd. 3-4-5 are smooth as silk.
The only difference I found was the gear lever had to be swapped over between them as the 65 had a lever with a hole rather than a knob.
It was interesting to note that both boxes have the same definite 'clunk' into first & firm action needed between 1st & 2nd. 3-4-5 are smooth as silk.
(RIP) Tibs
Registered user
The input shaft on the earlier machines is longer to suit the earlier clutch.
The early input shaft is the one on the right. One of the guys on here had a mishmash of a gearbox that had the early input shaft working in his airhead G/s clutch so it may actually work
Cheers Rob, that's marginally clearer. I guess if it does go tits up I'll just have to swap the engine and gearbox all together. Or maybe the R front end onto the /7......
Never was any good at decisions, that what's I have a wife for.
Tibs
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