Gearbox Jawa 250 353 - 4-Speed, Prevodovka Jawa 250 353

This Animation is basic principle of old type 4-Speed Motorbike Gearbox.
Gearbox is from old Motorbike Jawa 250 353.
(Year of manufacture approx. 1960 in Czechoslovakia).
Gear ratio:
I. 1 : 3,186
II. 1 : 1,768
III. 1 : 1,266
IV: 1:1
(Prevodovka z motorky Jawa 250 353, základný princíp.)

[@jawa250rider5]

Pekne :-)

[@branabarum]

konečně...

[@polishguy9272]

I heard once that 350 638 VB had 6 gears instead of standard 4. I can't find anything about it. Could it be true?

[@slushymud]

i have a significant drop in power when i shift my jawa 353 into 4 th gear ... can you please advice

[@polishguy9272]

Engine mix is too rich. When you go on 4th rpms go down and are operated by pilot jet (idle to 1/4rpms) and choke needle(1/4 to 3/4rpms). Check out air filter. Go lean on pilot for best response. If after you still having problems then move clip 1 up on needle.

[@slushymud]

@@polishguy9272 thanks For the suggestion. A little too late... sold the bike :( ( I replaced the entire carb .... still had the same problem)

[@sashiprasad2946]

Jawa 250/353 ,I have 1971/68/73. model
Jawa have problem in 2nd and 3rd gears of (sleeping )