139FMB gear issues

DrKassler · 09-13-2024, 05:40 AM

Hi!
We've got a Romet Division 50cc with a 139FMB 4-speed manual.
It has only done about 1500 km's but are showing issues with the gears.

Issue 1:
It's really tricky to get it into neutral.
From 2'nd to neutral you can barely put your foot on the gear selector. If just a bit more force is used it will go into 1st.
From 1st you most of the time end up in 2nd instead of neutral.
--
Issue 2:
At standstill and in neutral it's tricky to get into 1st and sometimes it's impossible until you switch the engine off.
--
Issue 3:
It goes from 1'st or 2'nd into neutral while riding by itself. Not very common but it happens once or twice at each ride.
--

The clutch is adjusted and releases properly and has no slip while driving.
Can anyone give me some advice on what to do?

How hard is it to split the engine and replace the gearbox barrel if it is faulty for example? Is there good videos available for example?
I'm a quite experienced mechanic but new to bike engines.

Thanks in advance!

09-13-2024, 05:40 AM	#1
DrKassler Join Date: Sep 2024 Posts: 6	139FMB gear issues Hi! We've got a Romet Division 50cc with a 139FMB 4-speed manual. It has only done about 1500 km's but are showing issues with the gears. Issue 1: It's really tricky to get it into neutral. From 2'nd to neutral you can barely put your foot on the gear selector. If just a bit more force is used it will go into 1st. From 1st you most of the time end up in 2nd instead of neutral. -- Issue 2: At standstill and in neutral it's tricky to get into 1st and sometimes it's impossible until you switch the engine off. -- Issue 3: It goes from 1'st or 2'nd into neutral while riding by itself. Not very common but it happens once or twice at each ride. -- The clutch is adjusted and releases properly and has no slip while driving. Can anyone give me some advice on what to do? How hard is it to split the engine and replace the gearbox barrel if it is faulty for example? Is there good videos available for example? I'm a quite experienced mechanic but new to bike engines. Thanks in advance!
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