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Makotosun

73 CT3 175 sprocket no free spinning in neutral

  • tsmitty1958
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Replied by tsmitty1958 on topic 73 CT3 175 sprocket no free spinning in neutral

Shift forks are correct as I never removed them from the shaft. Only the #2. So when installed in left half. Gears spin. When in neutral the countershaft spins freely as does the main shaft. I line up the neutral switch and the indent for the ball. I even install the ball and the switch. Papbt questioned the pin for #2 shift fork may be upside down? All the videos I have seen show that I have it correct.
Installed in right side as shown in pics. The gears are locked up, no spin or turning.
Everything is fine until the cases are 1/4 inch apart and then the countershaft moves forward and backwards 1/4 turn only.
I did confirm them being in the right position in my last reply.

Thanks for having patience I have really nowhere else to turn.

imgur.com/a/cQ8XlLA
21 Feb 2026 13:31 #31

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Replied by tsmitty1958 on topic 73 CT3 175 sprocket no free spinning in neutral

One more pic of the shift forks. The single fork goes in the middle of the other 2. Everything seats well when together. I know this, it's going to be something really stupid screwing me up.

imgur.com/a/pgqZpzU
21 Feb 2026 13:42 #32

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Replied by tsmitty1958 on topic 73 CT3 175 sprocket no free spinning in neutral

One more pic of the shift forks. The single fork goes in the middle of the other 2. Everything seats well when together. I know this, it's going to be something really stupid screwing me up. Here's a video also. Back in the left side. Everything working as it should (until I put the right side on maybe)

imgur.com/a/pgqZpzU

imgur.com/a/yumquPI
21 Feb 2026 14:01 #33

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sorry, I guess I'm looking at 39 diff photos.  I may have been looking at your R hand case making things different than expected.  I'm lost too!

goto 28:16, 33:28

 
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1969 Yamaha CT1 175
1974 Yamaha DT125A
1974 Yamaha DT360A with SP96 Exhaust
Next…196x-197x Yamaha something.


Last edit: 21 Feb 2026 16:34 by pabdt.
21 Feb 2026 16:15 #34

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Replied by tsmitty1958 on topic 73 CT3 175 sprocket no free spinning in neutral

Thanks for sharing. I talked to Dale today. He's stumped as well. I  have watched all his videos regarding the CT3. I have rewatched them so many times, I know I'm not missing anything. He's thinking maybe there's a crack in either case but I sure don't see one. I'll take it apart again tomorrow and recheck but I am completely out of ideas. Something has to be binding somehow. Maybe I just need to lube everything up but I don't see how that would make much difference. Like Mark said, these transmissions aren't rocket science. They go in and spin! Until they don't. 
21 Feb 2026 16:32 #35

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Ok, I have another idea...of course I did this on a larger engine with more space, my 360.

I slipped an iphone cable cam ($20) inside to watch things spin. If you are lucky maybe go through the oil drain or somewhere else.

I look forward to what you find.
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1969 Yamaha CT1 175
1974 Yamaha DT125A
1974 Yamaha DT360A with SP96 Exhaust
Next…196x-197x Yamaha something.


21 Feb 2026 16:54 #36

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Replied by tsmitty1958 on topic 73 CT3 175 sprocket no free spinning in neutral

Now that's great idea! Just ordered.
21 Feb 2026 16:59 #37

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Why not leave it in the RIGHT side as that's when it locks up?  

Without being there to see it, all I can do is try to explain how trans works and then you need to inspect carefully.  

As I mentioned before, there are 3 sliding gears that the shift forks move..  They have "dogs" or protrusions on them that lock into holes or other "dogs" on the adjacent gear.  

In the drawing below, the sliding gears are marked up in blue with the dogs as blue dots.  The yellow squares are the adjacent holes/dogs that the sliding gear dogs lock into which puts it in gear.  

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When in neutral, as shown in the drawing, NO dogs are engaging with an adjacent gear.  This is why trans spins freely in neutral.  

When you select 1st gear, the groove in the shift drum moves fork #3 to the right.  This engages the dogs (blue dots) on the sliding gear with the holes (yellow squares) in the free-spinning 1st gear, locking it to the shaft.  All the other sliding gears stay centered in their "neutral" position.

When you select 2nd gear, the #3 shift drum groove moves fork #3 back to the left, disengaging first gear.  At the same time, the #1 shift drum groove moves its sliding gear to the left, locking in 2nd gear.  Note that only ONE set of dogs can be engaged at a time or the trans will lock up.  That's why the shift drum groove #3 disengages 1st gear at the same time shift drum groove #1 engages second gear.

When you select 3rd gear, the shift drum groove #1 slides the sliding gear to the right disengaging 2nd gear and engaging 3rd gear.  (Shift drum grooves #2 and #3 keep those gears in the neutral position)

When you select 4th gear, shift drum groove #1 moves that sliding gear back to the left into its neutral position, disengaging 3rd, while simultaneously shift drum groove #2 slides its gear to the right, locking in the 4th gear dogs.  

Finally the shift to 5th simply has groove #2 moving the sliding gear to the left which disengages 4th and engages 5th.  Grooves #1 and #3 keep their sliding gears centered in their neutral positions.  

Summary is that in neutral, all the sliding gears are held by the forks so that no dogs are engaged.  

As you shift through the gears, the shift drum rotates and the grooves in the drum slide the sliding gears side to side, sequentially engaging and disengaging the dogs for each gear.  

If the shift drum isn't centered properly, or the forks get bent or mixed up, or the gears on the shafts aren't assembled correctly you can have a situation without neutral, or worse, two sets of dogs will engage at the same time locking the trans up.   

Hopefully this will help you see what is going on and why the trans locks in the right case.  If the forks are in the right places and not damaged (usually pretty obvious if a fork got bent), then my guess is something is allowing the shift drum to move off-center or one or both of the shafts are shifted off center in the cases.

The thing that centers the drum is the "horseshoe" clip and shim on the end of the drum under the plastic cap outside the left case.

The clutch shaft is pulled to the right by the inner basket nut.  The ball bearing in the right case keeps the clutch shaft offset where it belongs.  

Similarly, the sprocket shaft is held in place to the left by the sprocket nut.  The shaft is located by that ball bearing.  

If either of those ball bearings are not the correct parts or not installed properly, one of the shafts could be shifted sideways which can engage dogs when they are not supposed to be engaged.  

Hope you figure it out soon!
1963 YG1-T, 1965 MG1-T, Allstate 250, 1970 CT1b, 1971 R5, 1973 AT3MX, 1974 TS400L, 1975 RD350, 1976 DT175C, 1976 Husqvarna 250CR, 1981 DT175G, 1988 DT50, 1990 "Super" DT50, 1991 RT180, 2017 XT250
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21 Feb 2026 17:20 #38

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Typing as a passenger while traveling isn't easy lol. If it's not been said before then try one shaft at a time.  Just slide case home & revolve. Then remove & try other shaft. Then sector drum with selector & mainshaft. Then pull that & same on output shaft with two selectors. Something like that.
Last edit: 21 Feb 2026 20:28 by RT325.
21 Feb 2026 20:25 #39

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At this point, keep in mind just trying to shoot out "ideas". Yeah, I know... everyone has one. 

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imgur.com/a/yumquPI

3rd gear pinion on main axle is engaging in this video at about 0.21 seconds. The new bearing, clutch side. if thinner, ~may affect this clearance. verify bearing thickness? If I'm correct, pushing a loose shaft inward would disengage. 

In the video, you can see the clearance is minimal before locking.
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1969 Yamaha CT1 175
1974 Yamaha DT125A
1974 Yamaha DT360A with SP96 Exhaust
Next…196x-197x Yamaha something.


22 Feb 2026 00:41 #40

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