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Discussion Starter · #1 · (Edited)
My ‘68 CB450 K1 has developed a shifting issue. It shifts into 1st, neutral, and second, but won’t shift into 3rd. The shifter then gets stuck and I have to ride it back in 2nd gear.

I’ll tear apart the right side and see if there’s obvious issues with the shift linkage and gear selector.

My questions are:

If I’ve understood what I’ve read, there should be a washer and circlip that limits the axial play of the shifter shaft. Is that correct?

I’ve also read conflicting opinions about axial play in the shift shaft, whether it’s normal or not. Mine seems to have more play than it did, but I can’t swear to it. Is there an acceptable amount of in/out movement in the shifter?

Could overfilling oil cause a shift fork issue in the crankcase?

Lastly, what should I look for (behind right cover) preventing normal shifting operation? I understand there could be wear, but is there any acceptable play in the linkage or the shifter shaft on the right side? If all looks fine is there a clue to diagnosing shift fork (internal) issues?

Thanks.



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You are correct about the washer and circlip on the shift shaft, on the left side under the front sprocket cover and right on top of the seal you just replaced - so if it isn't there, it should be. If both are there, the end play is minimal (though I can't speak to a measurement). Without it, there could be issues but unless the movement was extreme - and the shifter itself would hit the sprocket cover, so it couldn't move too far - I don't think it would cause too much shifting problems... but the detent mechanisms and the star assembly on the end of the shift drum certainly can if there's excess wear on those parts, like the rollers that are part of the detent (one is larger and resembles a pizza cutter a little). The shafts wear on the rollers and the sloppiness causes shifting problems, and the wear on the pins and star assembly that holds the drum in the proper gear positions can cause issues as well. No, excess oil will never cause any shift fork problems or wear. Get the clutch cover, the clutch assembly and oil pump off that side and take some close-up pictures, then post them so we can see what you're dealing with
 

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Discussion Starter · #3 ·
Great, thanks! I haven’t replaced any seals, but I did have that cover off cuz I’m having a starter clutch slipping issue. Odd that once I got it back together the 2nd ride the shifter went.

I have axial play, not enough to hit the rotor cover though.


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Sorry on the seal reference, I was thinking of a recent post of someone else here. Yeah, tough coincidence but inevitable with these things. I fixed mine the last time it was apart late summer, but it isn't completely right as yet, still slightly misses 2nd and double-clicks to get to third occasionally. They work well when everything is in specs.
 

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I don't think it is possible for the shift spindle to hit the sprocket cover, but if the clip and washer are missing, it can go too far the other way. On the other end is the arm and teeth that turn the shift drum, and if it goes to far that way, it can make shifting hard, or impossible:
shiftspindel.jpg
 

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Discussion Starter · #6 · (Edited)
I’ve finally found time to dig in to this shifting problem and the only obvious to me problem I found is that the circlip that keeps the gear selector rod in place was out of its groove. So, I fixed that and while the covers are off, I’ve spun the shaft and shifted through the gears.

While it will shift through the gears, it will occasionally get stuck and the shaft will spin free (as in neutral) sometimes. For example, moving from 2nd to 3rd the selector wheel will get stuck, not find 3rd, and the shaft will spin free with a little noise and clunk.

Is this normal if there’s no oil in it and/or the rear wheel/engine isn’t turning fast enough?

Thanks.



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Unfortunately, it appears I’m the newest member of the 2 speed 450 club. Although mine is a 1971 CL450K4, the Honda Service Manual is one in the same for both, so problems I have are (I guess) the same as for NewGuy. I’m going to tear into mine as the axial play in the shifter shaft is also about 1/8”, too much IMHO. Any additional guidance as to what to be looking for would be greatly appreciated. I’ll post up pictures when I get it apart for the collective’s ideas as to what is causing the issue preventing shifts into 3rd gear.

Edit: Further reading revealed that shift shaft end play is limited by stopper spindle (washer) # 24621200000 and circlip # 9451012000. Those parts are shown in post #5 by Wintersol. One (probably dumb) is where is this washer and circlip installed? The exploded view in the parts diagram shows behind (inboard) of the shift lever and hopefully not inside the case behind the oil seal. Can anyone here confirm which side of the oil seal these two parts go?
 

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They are outboard of the cases and oil seal, but under the sprocket cover.......
Usually, the circlip (snap-ring) has jumped out of its seating groove due to improper installation or a "stretched"/sprung clip.....
( Correct is sharp side out/rounded side in)
 

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Installed parts noted in post #7, shifts like a champ. It appears that the missing stopper washer and circlip was the culprit. Thanks to all who posted on this thread, problem solved!
 

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Discussion Starter · #11 · (Edited)
I too have resolved my shifting problems by reinstalling the circlip on the shifter shaft.

Unfortunately, my 450 was pretty noisy upon test riding. It’s got fresh Rotella 10w-30 in it. Of course it’s hot out now, maybe a 10w-40 is better, but It sounds like the oil pump may not be servicing the cam, but that’s a guess.

It’s been a while, can I remove either valve cover (intake/exhaust) to inspect for oil being pumped up the the head?

Thanks.


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