Hard to Downshift 3-2-1

[Jan_P]

Star wheel not turning free as it should seems as there is a stop of some kind.
feel free come with . suggestions

 

[nj1639]

Spacing is off between the star wheel and that shifting lever, at least from this angle. Referencing to post #3.

 

[Jan_P]

Spacing is off between the star wheel and that shifting lever, at least from this angle. Referencing to post #3.

Thank You .
Have taken those parts off everything except the star wheel .
The neutral detent spring and bolt is off but not able to get the part 16 out at the moment
No 16 down there Trying to turn on the screw 8
With the 19 / 18 / 17 off at times appeared to shift as it should
others time not.. Need to test some more.

There was no mechanical sounds rattle or so running . Just difficult down shift or impossible

 

[Jan_P]

Worn Shift Fork ?
Would be surprised if gearbox It .can be a bearing somewhere but I replaced these when rebuilding
Can anything be inspected with a bore Scope .?

Have a Plan B with another Motor --Met an old Co Worker He had a connection --- Expert TIG Welder
Plan welding the small Hole after the chain broke.. Welding without disassembling.
Bolt Out and Bolt IN Motor
Need to check some more. Not good But this is how it goes being in the last owner segment.

 

[Jan_P]

After thinking and .. I started to google and AI has a possibility to hack in questions
Not saying it is the answer but it is interesting Amazing really.

4. Internal Shift Fork Jammed (Worst Case)
If the external components under the clutch cover look absolutely perfect, the issue is inside the crankcases.

• The Symptom: A bent shift fork or a worn gear dog slot. If a previous owner forced a downshift at too high an RPM, the shift fork that slides the 2nd/3rd gear cluster can bend. It will hit a "hard wall" because the bent fork is binding in its track and cannot physically slide the gear over.
• The Fix: This requires splitting the engine crankcases to replace the bent shift fork and inspect the shift drum tracks for deep scoring.

Next Steps to Diagnose:
Before splitting any cases, remove that right-side clutch cover.
Once the cover is off, let me know:

• Are all 5 pins on the shift star tight and sitting at the same depth?
• Can you manually rotate the shift drum smoothly using a wrench on the center bolt of the star wheel while rocking the rear wheel?

This will immediately tell you if the blockage is external (easy fix) or internal (requires pulling the engine).

Write in the Question

Because the shift drum is difficult to rotate manually with a wrench, you have isolated the issue inside the crankcase. The "hard wall" you feel is a mechanical jam affecting the drum's rotation or the sliding gears.

1. Identify the Internal Root Causes
Since all five pins are intact on the star wheel, the resistance means the drum or its attached components cannot move.

• Bent Shift Fork: This is the most common cause. If the motorcycle was forced into gear or downshifted hard, a shift fork can bend. A bent fork binds in its groove on the gear cluster or jams inside the track of the shift drum, acting like a wedge that locks the drum in place.
• Worn or Damaged Shift Drum Track: The tracks machined into the shift drum direct the forks. Over time, or due to debris, a track can develop a severe burr, gouge, or crack. The fork guide pin hits this damaged spot and stops entirely.
• Interlocking Gear Dog Jam: The dogs (protrusions) on the sides of the gears slide into slots on neighboring gears. If a dog or slot is badly chipped, mushroomed, or deformed, the gears cannot slide together.
• Neutral Detent Arm Binding: The spring-loaded detent arm on the outside of the drum may be mechanically jammed or its roller bearing could be seized, preventing the star wheel from turning.

I don't slam any gears so I don't think any Shift fork is bent
I inspected the gears when rebuilt don't think the dogs are bad
The Shift drum maybe
The hope is the Neutral Detent part not coming out.

 

[Max Midnight]

Spacing is off between the star wheel and that shifting lever, at least from this angle. Referencing to post #3.

Have you checked and adjusted as suggested?
You seem to be chasing the more obscure problems without ensuring the basics are correct.

 

[Jan_P]

Have you checked and adjusted as suggested?
You seem to be chasing the more obscure problems without ensuring the basics are correct.

Yes Sir and thank you I did that .Turning on the excenter bolt moving it a bit Still not shifting.
The star wheel stopped rotate and the Shark finned part did not spring into position to hook the Pin
Because another pin raised it
I can always put it back a second time and do it again, Later if i have missed something.

As I understand it the drum should rotate via the center screw in the center of the star wheel
With everything off still not shifting ( rotating ) As it should .
But I have been wrong before. And made mistakes before No hurry I will do some more tests
And before doing major strange things put it back on Try again.
Makes sense but I did try that CSF rule Cheapest Simplest First
But i will do it again putting it back .Something can be bent or so.

 

[Max Midnight]

As you have the shift mechanism disconnected it sounds like are you trying to rotate the drum via the screw?
If so then whilst I may be wrong I suspect that you won't be able to put sufficient torque to achieve that.

Once you are satisfied that the adjustment is correct then I would re-assemble everything and go for a ride.
IMO to see if there has been an improvement everything needs to be rotating.

 

[Jan_P]

As you have the shift mechanism disconnected it sounds like are you trying to rotate the drum via the screw?
If so then whilst I may be wrong I suspect that you won't be able to put sufficient torque to achieve that.

Once you are satisfied that the adjustment is correct then I would re-assemble everything and go for a ride.
IMO to see if there has been an improvement everything needs to be rotating.

I was able to rotate it on the screw center on star wheel But not consistently sometimes it hit a hard stop
the type preventing shifting with the pedal.
Online a Needle nose pliers is used to operate the drum.
Rain on the forecast so not sure when it happens
Need to take out the neutral detent plunger part still down there .
seems stuck ..not anything to grab on

That is the center screw and what is installed now ...everything else is out ... the shark finned part is also off

 

[Jan_P]

Better -- pushing the drum inwards with left thumb and turning on the Screw it appears to go better 30 times
not sure if all gears
Putting the shaft and other parts back . For Testing with shift lever

 

[Jan_P]

No engine must out not working