5 speed - Yamaha FS1 - Rotary Valve 1974 (Build to Morten DK) 5G drejeventil (1/2)

FS1 1974 5 speed rebuild as a rotary valve engine.
FS1 5 gearet renoveret og ombygget til drejeventil.
Til Morten ét sted i Jylland, til den kommende sæson 2023 😀

[@erikjohansson9039]

I have been looking for a 5 speed gearbox for a while, do you have any tips on where to source one? looking on ebay every other day but nothing comes up for sale. I have never heard of one here in Sweden.

[@MrClaushk]

Hey Erik. Yeah, its pretty difficult to find them. The are not very common on Ebay, but i happens sometimes you can find one from the UK or Austria. But the problem is they normally wont ship entire engines, and its almost impossible to find an entire gearbox with drum and forks seperat. Most i know here in Denmark have only had the option to buy an entire bike, and spend a day or two driving to Germany/Austria with a trailer to get it. I working on fitting a 5 speed from another Yamaha bike inside the FS1 engine without mods to the cases at the moment, hopefully with success 🤞
But i can ask around, maybe i can help you with a 'normal 5 speed set'

[@erikjohansson9039]

Thanks for answering! could be interesting depending on price ofc! I have been eyeballing some old yz/rd gearboxes and I think most look to different to fit but some looks quite close to the fs1

[@erikjohansson9039]

Do you know if there is any 5 speed kit for sale?

[@MrClaushk]

@@erikjohansson9039 Not on the market sadly, im still working on something. But its not easy.

[@erikjohansson9039]

Ah ok! Do you think it will be possible to fit that other gearbox?

[@MrClaushk]

@@erikjohansson9039 Yeah, the RD is pretty close. The problem is they had roller bearings on opposite side of the main shaft bearings. And the length of the drum is different. But if you are willing to make chances to the engine cases, it makes things easier. But then its in my world not a kit, if it takes a tig welder and drilling the case.. 🙂