This topic contains 3 replies, has 2 voices, and was last updated by  Madcoop 1 month ago.

  • Creator
    Topic
  • #3033

    Madcoop
    Member
    Joined:
    Apr 22, 2019

    Hey guys,

    After 3 long months, I finally have a decent running bike and have been able to take my first few rides out. As the title suggest, I am having problems selecting 5th gear. I am able to select all other gears without a problem, but when I kick it up for 5th gear there is no click and the lever seems to come to a solid stop. Trying this again, but with more authority makes no difference.

    My gut feeling is that it is something simple, however I am not particularly clued in on the clutch and gear selector setup, so I’m looking for suggestions as to how to diagnose the problem correctly.

    Having done a little reading on the subject, I believe that the clutch could be ruled out as I am able to select all other gears with no problems at all. I did read that the pawl spring can cause similar issues, however I believe that this engine has never been apart before I got my hands on it. There are no worrying noises when trying to select 5th and no metal deposits in my oil, so I am also inclined to think that 5th gear is still intact.

    I am not in too much of a hurry to pull the casings off, but will do so if need be. I am looking for suggestions as to how to proceed with this. I do have a spare engine, so there are a few spares knocking around should they be needed, but I would like to take a methodical approach to finding this problem.

    Any suggestions welcome.

    Thanks guys.

  • Author
    Replies
  • #3045

    Madcoop
    Member
    • Topics: 3
    • Replies: 6
    Joined:
    Apr 22, 2019
    @madcoop
    Location:
    Scotland
    Riding:
    GT125R (carby)
    Points: 250

    Quick update, and 5th is definately still there. Need to go out and do some more testing, but without the engine running I am able to shift into all 5 gears. What I did notice is that after changing to 4th I was unable to select 5th exactly as it had been when riding. Then, when I rocked the rear wheel with upwards pressure on the selector, it slipped straight in. Seems strange that it wouldn’t go in when riding, as the motion of the back wheel was what allowed it to slip into 5th with the engine off.

    I don’t know much about the gearbox setup on bikes, but it seems to me that this is just an adjustment issue. Something seems just a hair out, and if it will actually shift into 5th, then this will rule the pawl spring out, right?

    I will have a closer look at the adjustment on the connecting rod and see if this will make any difference, but it seems that something in the gearbox selector assembly is coming to a hard stop between 4th and 5th.

  • #3047

    ♠️ MARCEL
    Administrator
    • Topics: 32
    • Replies: 181
    Joined:
    Apr 22, 2019
    @mf448kxn6
    Location:
    North UK
    Riding:
    GTR
    Points: 2,433

    It may either be your shift forks / praws that select gears.  I would have hoped this was a clutch issue  (most cases) but that shifting behaviour you describe , reminds me of my ex- kwak bikes with true gearbox issues lol.

    Refer to the screenshot pages here, so you see the layout too.

    Be careful undoing the nut that contains the gear cam spring, as i’ve learned some were not able to find neutral again  , they had to rebuild the gearbox again.  But yes a dodgy spring can do that too.

    // Meditation doesn't mean you have to sit still....

  • #3061

    Madcoop
    Member
    • Topics: 3
    • Replies: 6
    Joined:
    Apr 22, 2019
    @madcoop
    Location:
    Scotland
    Riding:
    GT125R (carby)
    Points: 250

    Thanks Marcel. I have now had time to fiddle a little bit more and am pleased to report that 5th is back in the room!

    Simply a case of slacking off then readjusting the clutch cable again. Took her out and immediately found fifth to be problematic at higher rpm….okay down low tho. Pulled over, put a little more on the lever adjuster and bobs your uncle!

    I then went and took my first proper ride on her since picking her up nearly four months ago. We covered nearly 50  miles in all, with a couple of stops just to check her over but really it was a trouble free ride. 🙂

    I have a lot on at the moment, but I’m now happy that the bike is ready to go and do the runs required to read the plugs and make the necessary mixture adjustments we spoke about a while ago. For now though, the settings on the replacement carbs seem pretty good.

You must be logged in to reply to this topic.

Skip to toolbar