Author Topic: Sloppy shifter (Read 3200 times)

eigenvector · « **on:** December 31, 2017, 12:41:41 PM »

Been riding my Nighthawk more and more, slowly I'm getting that thing into reliable running condition.

I have one last item that's dogged me for a long long time - I simply can't figure it out.

The shifter, one of those forward link shifters has far too much slop in it. I have the shift pedal adjusted as far down as I can - but even with that there's a good 3/4 to an 1" of pedal slop between 1st and 2nd. This makes shifting into 2nd almost impossible except by having the shifter preloaded right before releasing the clutch and even then it's a gamble.

Question is - where is that slop coming from and how can I reduce it?

754 · « **Reply #1 on:** December 31, 2017, 01:29:51 PM »

You have to Bush the holes or pivot points. Some by design rattle themselves into wearing things out.
Are they rod end type or clevises?
You can see it and we cant, so you will have to examine it to see where the problem is.

eigenvector · « **Reply #2 on:** December 31, 2017, 01:45:55 PM »

I always assumed the slop was in the shift mechanism itself between the drum and the contact roller - but I hear you say that it's probably in the actual linkage itself.

It's a ball-socket type linkage.

https://www.ebay.com/i/201545530640?chn=ps

Not mine - just a good image of the mechanism.

Is that basically what you're indicating here?

eigenvector · « **Reply #3 on:** December 31, 2017, 02:49:53 PM »

Well, the linkage itself is tight, no slop there - maybe a smidge but not nearly as much as there is internally.

The shifter moves up, with spring force resisting it about 3/4" when in neutral until it actually contacts the internal drum teeth. To me that says the shift stopper (#17 in the picture) just isn't big enough.
https://www.powersedge.com/oemparts/a/hon/506c81c0f870023420a3cbbc/gearshift-drum-gearshift-fork

At any rate, I'm going to try swapping out the shift lever with a longer one, see if that provides better foot position. Need to get a longer bolt first.

754 · « **Reply #4 on:** December 31, 2017, 02:56:16 PM »

Longer one, even more slop..

eigenvector · « **Reply #5 on:** December 31, 2017, 05:23:16 PM »

Yeah I know, but if I can get a better grip on it with my boot it might help.

Guess I can see about finding a shorter shift lever, but that would just make shifting even more uncomfortable.

It's just a bad shift mechanism all around. Overly complicated, jammed in there between the muffler, kickstand, and oil fill spout.

scottly · « **Reply #6 on:** December 31, 2017, 05:30:37 PM »

Please post a pic of your shifter from the side.

eigenvector · « **Reply #7 on:** December 31, 2017, 05:46:08 PM »

scottly · « **Reply #8 on:** December 31, 2017, 06:17:58 PM »

Your angles are all wrong. If you draw imaginary lines through the pivot points, they should make close to 90 degree angles. Is that a punch mark just to the left of 12:00 on the shifter shaft?

eigenvector · « **Reply #9 on:** December 31, 2017, 06:59:53 PM »

That is a punch mark.

I welcome any back of the head smacks indicating my stupidity. I put this bike together from basically scratch when I got it - so I had little to go by and the shop manual is terrible.

scottly · « **Reply #10 on:** December 31, 2017, 07:20:54 PM »

Pull the lever of the shaft (you will have to completely remove the pinch bolt first) and rotate the lever clock-wise until the punch mark aligns with the slit. Was your bike shifting "backwards"? Down to upshift and up to downshift?

eigenvector · « **Reply #11 on:** December 31, 2017, 07:42:22 PM »

If nothing else I noticed the punch marks - there's a punch mark on the shifter arm as well I didn't see. Line them all up and indeed the whole mechanism forms a relatively square shape.

Not that it helps the issue - there's still about 3/4" travel in the shifter from neutral until it hits the shift drum.

But hey - I'm starting on solid ground now - no guesswork about how it's supposed to be oriented.

TwoTired · « **Reply #12 on:** December 31, 2017, 07:46:26 PM »

I have a CB700SC Nighthawk Shop manual.

It shows the shifter arrangement as depicted.

eigenvector · « **Reply #13 on:** December 31, 2017, 08:17:17 PM »

Yeah that's about right. I think that pic is from the 750 because the shifter is different, larger drop, but generally that's consistent with what it looks like now.

Still has too large of a throw.

There's an upgrade kit that at least used to be available for this bike (and all Honda bikes that share this transmission - quite a few actually) that replaces the shift stopper with a larger contact wheel and I think a stiffer return spring

Just for reference, here is a before and after.
Before - neutral
After - contacting shift drum

scottly · « **Reply #14 on:** December 31, 2017, 08:38:12 PM »

The angle between the arm and the rod still looks wrong to me. Try rotating it one or two splines clockwise.

eigenvector · « **Reply #15 on:** December 31, 2017, 09:05:10 PM »

I haven't really thought about it that much, maybe hashing it out tonight with you guys has made me stop and think.

I STILL think it has too large a throw, but squaring up the angles serves a very useful purpose that I haven't considered until you pointed it out. All the motion is now tangent to the shift shaft ~~which rotates it the furthest~~.

Maybe it's the beer.

Terry in Australia · « **Reply #16 on:** January 01, 2018, 12:38:03 AM »

Have you got the correct shift lever on your bike Rob? I just googled your Nighthawk (we didn't get them out here, thank God) and every pic I saw had a much shorter shift lever than the one in your pic?

eigenvector · « **Reply #17 on:** January 01, 2018, 08:58:53 AM »

Wouldn't surprise me if it wasn't, everything else about this bike is wrong.

I'll keep looking around for another shifter.

Edit: Naw, it appears to be the stock shift lever.

eigenvector · « **Reply #18 on:** January 01, 2018, 12:29:01 PM »

So what are my options here?

The shift mechanism is (now) arranged correctly.
The throw is just too long between 1st and 2nd.

What would be a good solution if I wanted to make shifting this beast easier?

Gene · « **Reply #19 on:** January 01, 2018, 03:35:26 PM »

I AM NOT AN EXPERT but had a decent Nighthawk until I wrecked it recently - we put a longer shifter mechanism on it for precisely the reasons you described earlier - but - no way around that jump from 1st to 2nd. I apologize for not having an answer to your question, just saying that apparently it's common - that leap. All the other gears seem(ed) right. P.S. - I really did enjoy the "overdrive" gear

eigenvector · « **Reply #20 on:** January 01, 2018, 05:13:52 PM »

I appreciate you chiming in. Yeah, that gap is just huge.

I have a new shift lever on hand, now I need to get an insert that fits it - stock insert is a little too long for this one.

By the way, did your leak oil like a sieve too?

eigenvector · « **Reply #21 on:** January 02, 2018, 07:04:31 PM »

Well I've done my best on the outside.

Replaced the shift lever with a shorter one - definitely helps with the shift, but it still a huge gamble whether it will decide to shift or not.

At this point I think all the work has to be in the inside. I can chalk this one up as my extended project.

Gene · « **Reply #22 on:** January 03, 2018, 10:02:58 AM »

Quote from: eigenvector on January 01, 2018, 05:13:52 PM

I appreciate you chiming in. Yeah, that gap is just huge.

I have a new shift lever on hand, now I need to get an insert that fits it - stock insert is a little too long for this one.

By the way, did your leak oil like a sieve too?

It has/had zero leaks. Even after the wreck. go fig.

eigenvector · « **Reply #23 on:** January 28, 2018, 12:48:11 PM »

Something that always troubled me about the shifter itself is that the cover had a screw going through the cover but all it seemed to do was plug a hole in the cover itself.

On the opposite side of the cover is a hole in the shifter itself, plus there's another hole in the shift selector.

I'm thinking,
1) Just a coincidence and don't do what you're thinking of doing...
2) That screw broke off and it's supposed to go through all 3 items - and that's why your bike isn't shifting so well.

I can't seem to dig anything up on it and that screw IS supposed to be there per the diagram of the shift cover.

Thing is - if I stuck that screw in there - how's the shifter supposed to move? Isn't it pivoting about the center axis?

jgger · « **Reply #24 on:** January 28, 2018, 02:58:01 PM »

Maybe it's there to check the alignment/timing of the shifter, you know like stuff a rod in there to see if everything lines up?

IDK.

I had a Montesa dirt bike that checked the timing in a similar way. Rotate the flywheel and install a pin in a hole that should have lined up with the pick up coil at a specific measurement BTDC. Just a guess.

eigenvector · « **Reply #25 on:** January 28, 2018, 05:29:28 PM »

Possibly, it would make it easier to assemble everything.

In any event I'll replace the screw - the one that's there is barnacled with rust anyway. It's a 4x8 pan screw - so that's about 5/16" long, certainly longer than the one there now.

eigenvector · « **Reply #26 on:** January 30, 2018, 04:26:16 PM »

Survey says....

Alignment hole.

The screw does not penetrate into the shifter mechanism - it's just there to plug a hole in the cover, so that you can ensure the shifter and shifter selector are properly aligned when the cover is assembled.

eigenvector · « **Reply #27 on:** February 04, 2018, 05:21:21 PM »

Well for what it's worth I think I've finally run down why the shifting on this bike is so sloppy.

The drum shifter - that is the device which physically rotates the shift drum has a very loose fit.

The drum shifter is connected to the shift drum with 2 spring loaded pawls - those pawls are what contact the shift drum and rotate it. See the image - they're parts 10, 11, and 12.

The connection between the pawls and the shift drum is simply very sloppy - even with brand new pawls. The shift drum isn't worn out, the pawls are too thin.

But here's what I think was actually happening for me to have missed all those shifts. If the shifter shaft is pulled out even a very small amount the drum shifter will no longer contact the shift pedal and it simply won't shift. Basically the gears will no longer be in contact and you can pull up on that shifter all you want - the actual drum shifter won't rotate. It's what I think was happening in my case. So my real solution here is to find a way to get that shift shaft as solid in there as it can get - no in and out motion.

Gene · « **Reply #28 on:** February 07, 2018, 10:24:53 AM »

Interesting. So the shaft is actually a little short.

eigenvector · « **Reply #29 on:** February 07, 2018, 04:40:52 PM »

Or you could say the cover is a little too roomy. $:-\$

I think what I'll try - maybe, is putting a washer between the shift shaft and the cage bearing that forms the oil seal. That should push the shift shaft in, or at least remove the in-out slack that it has now.

I was shocked at how little movement was required before the gears fell out of contact. The gear itself is less than 1/4" wide and even then it's not fully contacting the drum shifter.

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Author Topic: Sloppy shifter (Read 3200 times)