Stumble/All Hell/Destruction Noises in 2nd Gear

Maintenance, repair, troubleshooting, etc.
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RDC
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Motorcycles Owned Currently: '94 Seca II (Blue) & '97 Seca II (Red)

Tue Aug 08, 2017 10:15 am

Hi everybody

So I don't come on here much these days, as I mentioned to someone once I only really frequent the forums when I have a problem with my bike.
Well, I'm here aren't I?

Problem: When rolling on to 2nd gear, there is a skipping/mechanical hell sound that sounds like a skipping chain, sounds like the motor is about to eat itself, and the bike hesitates and chokes and doesn't like it. :cry:

This doesn't happen: In any other gear than 2nd, and if I roll on veeerrrry verrrry slowly into 2nd gear. It'll still do it if I'm not careful.

Recently: replaced the chain - this was happening before that - and replaced the plugs - again, this was happening before that, too.

What are my likely problems here? I have been commuting on the bike and skipping 2nd gear completely out of fear. Are my carbs just sync'd like @$$ or is this more likely a mechanical issue (i.e. transmission-related, bad sprocket, bad ????)?

I'll try to get a video of it happening, but I've been busy lately so instead of being able to deal with it, I've pretty much parked the bike.

Thanks y'all

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radare
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Tue Aug 08, 2017 11:01 am

It is possible that you have damaged second gear. I can't recall any instances of gear-train failure with the exception of shift fork wear. What happens if you apply some pressure, either upward or downward on the shift lever when its happening (without shifting to the next gear)?

Also, maybe pull the clutch cover and check out the shift linkage and primary nut. Both are known (very occasionally) to loosen. If your primary nut comes off, it'd make a racket (though likely in all gears including idle). If the shift star or its retainer came loose, it might scrub the clutch basket in 2nd gear as that one applies an left-right force on the shaft). Actually, I think that might be the most-likely scenario. I'd start there.

Second gear might put enough load on the engine that a carburetion issue presents itself however that doesn't sound right to me.

This is what the shift mechanism looks like, behind the clutch. If that screw or the torx fastener came loose, it'd sound like hell.

Image

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RDC
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Joined: Fri Apr 24, 2015 12:05 pm
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Motorcycles Owned Currently: '94 Seca II (Blue) & '97 Seca II (Red)

Fri Jan 05, 2018 12:57 pm

So, an update months and months later.
I tuned the carbs to an acceptable standard and this noise kept up.
Radare, I inspected around the clutch and this little bracket was broken in half. Screw was still there, bracket was mostly missing. I have a photo of the broken piece somewhere.
Image
Digging that bracket out of my donor motor and reinstalling it took me a month's worth of spare time (which I am severely short on since I started a new job in July).
Once this was R&R'd, I got to take the bike for a ride. I got smooth shifting into 2nd and rolling on the throttle, so I figured this little bracket was the culprit. 1.8 miles later "clack" then back to grinding 2nd gear when I roll into it. Figured I must have broken the "new" part and rushed home to pull the cover off again. Bracket was intact - something else is the issue here, but it's weird that replacing the bracket gave me a few miles of proper functionality.
Bike got parked, borrowed a Ninja from a friend for almost a month until he moved.
Now I'm back to driving my car and hating it.
2nd gear still grinds and I have a feeling the gear itself is destroyed. Bump starts could kill a gear, could they not? Bike had to be bump started a few times right before this issue presented itself (Chrome Pro Gel Battery = absolute garbage FYI)

Anyone have any advice on physically inspecting the transmission? I do have a donor motor here & a second XJ that was set to be rebuilt until I ran into some health problems.

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radare
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Fri Jan 05, 2018 1:28 pm

If you remove the entirety of the shifting mechanism, including the shift shaft (that the shift lever attaches to), you should have enough space to shine a light into the gearbox and inspect the gears and shift forks. You can remove the shifting mechanism without disassembling the engine but take photos to ensure it goes back together correctly.

Also, check the torque on that primary nut that hides behind the clutch cover (big nut just above the clutch) while you're at it. Then tend to loosen (though not likely your culprit).

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