Author Topic: CB750 speedo drive- should the body turn? (Read 8540 times)

MCRider · « **on:** January 11, 2011, 04:47:17 PM »

Its been so long since I've had a functional CB750, some of the details of the running gear have escaped me.

The speedo drive: Once its on and the axle run thru it, with the nut of the axle on the opposite side of the speedo drive, and the nut tightened down, should the body of the drive be locked to the axle? Or should it float?

And then the wheel offered to the bottom of the forks, one has to set the drive in position (worm gear horizontal) and then tighten down the fork leg clamps. Once that is done the drive body is locked in space and can't rotate at all, correct?

Thanks.

madmtnmotors · « **Reply #1 on:** January 11, 2011, 05:07:27 PM »

I think the cable holds the speedo drive in position. Not a lot of force there and I don't recall any other mechanism to hold it. It's free floating.

dave500 · « **Reply #2 on:** January 11, 2011, 05:16:04 PM »

it locks up when the axle nut is tighened.

tango911 · « **Reply #3 on:** January 11, 2011, 05:32:23 PM »

i noticed on my k2 750 that it floats as well unless i tighten the axle nut, but when i tighten the nut the wheel doesnt spin quite as freely.

MCRider · « **Reply #4 on:** January 11, 2011, 05:59:10 PM »

Quote from: tango911 on January 11, 2011, 05:32:23 PM

i noticed on my k2 750 that it floats as well unless i tighten the axle nut, but when i tighten the nut the wheel doesnt spin quite as freely.

Well we have mixed opinions on the floating. I would say that the axle nut must be tightened to its torque spec, 33-40 ft lbs and if that binds the wheel bearings, something else is wrong.

Open for more comments.

The way mine is now, the axle nut is tightened to spec, the speedo drive housing is essentially part of (what i call) the spacer stack, locked in place. The wheel turns freely. The axle and spacer stack is locked in the lower leg clamps.

ekpent · « **Reply #5 on:** January 11, 2011, 06:14:56 PM »

On the ones I have worked on once the front end is tightened down it does not free float. Thats why you want the speedo cable area lined up correctly first.

shizzomynizzo · « **Reply #6 on:** January 11, 2011, 06:21:18 PM »

Quote from: ekpent on January 11, 2011, 06:14:56 PM

On the ones I have worked on once the front end is tightened down it does not free float. Thats why you want the speedo cable area lined up correctly first.

I have a 550 and when I had the wheels powdered, the guy assembled them wrong. he forgot to put the spacer that the axle runs through (sits behind the wheel bearings) back in. My speedo drive would not "float" when it was like this. When I assembled it correctly, it works just fine/ It should have some tension, but not be locked.

Wouldn't it hit the forks if it were locked?

MCRider · « **Reply #7 on:** January 11, 2011, 06:39:26 PM »

Quote from: shizzomynizzo on January 11, 2011, 06:21:18 PM

Quote from: ekpent on January 11, 2011, 06:14:56 PM
On the ones I have worked on once the front end is tightened down it does not free float. Thats why you want the speedo cable area lined up correctly first.

I have a 550 and when I had the wheels powdered, the guy assembled them wrong. he forgot to put the spacer that the axle runs through (sits behind the wheel bearings) back in. My speedo drive would not "float" when it was like this. When I assembled it correctly, it works just fine/ It should have some tension, but not be locked.

Wouldn't it hit the forks if it were locked?

No it is locked to the axle, which doesn't turn. As long as it is positioned properly before tightening the fork leg clamps, all is well ... (it seems). If it floated, it could conceivably turn and hit the forks, the cable would keep this from happening, but is that right?

I don't like the difference of opinion. May have to get HondaMan involved. Anyone with a CB750 go out to your bike and see if your speedo drive is locked in place?

Bodi · « **Reply #8 on:** January 11, 2011, 06:44:34 PM »

Pretty sure the housing is part of the spacer and bearing stack that the axle nut clamps together. It turns with the axle but not with the wheel. You set the angle to suit the speedo cable before you tighten the fork clamps on the axle.
If your bearings stiffen up when you tighten the axle nut they should self-align to be free after a few miles. The axle nut must be tight. Sometimes the hub bore that the "floating" bearing floats in is too tight and the bearing can't align itself. It will wear out before its time then. The retained bearing can be full press-in tight in its bore - doesn't need to be but it can be - however the opposite bearing should be a snug but not tight fit, still able to slide in its bore with a bit of gentle persuasion.

MCRider · « **Reply #9 on:** January 11, 2011, 06:49:19 PM »

Quote from: Bodi on January 11, 2011, 06:44:34 PM

Pretty sure the housing is part of the spacer and bearing stack that the axle nut clamps together. It turns with the axle but not with the wheel. You set the angle to suit the speedo cable before you tighten the fork clamps on the axle.
If your bearings stiffen up when you tighten the axle nut they should self-align to be free after a few miles. The axle nut must be tight. Sometimes the hub bore that the "floating" bearing floats in is too tight and the bearing can't align itself. It will wear out before its time then. The retained bearing can be full press-in tight in its bore - doesn't need to be but it can be - however the opposite bearing should be a snug but not tight fit, still able to slide in its bore with a bit of gentle persuasion.

great! That's 100% what i think, on all issues, but i was getting some contradicting indications. I respect your input. Still open for other comments.

Nikkisixx · « **Reply #10 on:** January 11, 2011, 06:58:01 PM »

Yeah man, you got it. The axel is stationary in the fork legs and the speedo drive should be too. The spedo drive should be locked to the axel when tightened.

HondaMan · « **Reply #11 on:** January 11, 2011, 08:41:33 PM »

Quote from: MCRider on January 11, 2011, 05:59:10 PM

Quote from: tango911 on January 11, 2011, 05:32:23 PM
i noticed on my k2 750 that it floats as well unless i tighten the axle nut, but when i tighten the nut the wheel doesnt spin quite as freely.

Well we have mixed opinions on the floating. I would say that the axle nut must be tightened to its torque spec, 33-40 ft lbs and if that binds the wheel bearings, something else is wrong.

Open for more comments.

The way mine is now, the axle nut is tightened to spec, the speedo drive housing is essentially part of (what i call) the spacer stack, locked in place. The wheel turns freely. The axle and spacer stack is locked in the lower leg clamps.

You have it correct, here, MC: it is part of the stackup of axle parts. The sheer torque friction of the axle bolt holds it as part of the axle. Just make sure of two things: the tangs must engage the notches in the drive plate to prevent worm gear bind, and the spacer inside the wheel hub should mate with the spacing of those wheel bearings, so it does not side-load them. If the bearings are properly set for depth, tightening the axle will not bind the wheel rotation.

ev0lve · « **Reply #12 on:** January 11, 2011, 08:57:41 PM »

You answered this question for me back in 2009. Thanks BTW!

http://forums.sohc4.net/index.php?topic=38242.msg528088#msg528088

Quote from: MCRider on April 18, 2009, 01:27:16 PM

The speedo drive housing should rotateonly if off the bike... till its locked in with the axle tightend down.

You won't need to remove the wheel to re-orient the drive body, (BTW I've done that often) but you may have to lift the forks up a tad, rotate it till the housing where the cable enters is horizontaL, then lower back down and tighten up the caps again. Once properly oriented neither the housing nor the drive tab will rotate. Only with the wheel turning will the cable drive tab turn. Don't force it.

MCRider · « **Reply #13 on:** January 11, 2011, 09:00:04 PM »

Got it, thanks!

And about the tang/notches: I've got a drive plate where someone didn't line them up, and in addition to the 2 factory notches there are 2 "non-factory" notches created by the PO cranking down on the axle nut. Don't know if he ran it that way or not. Sheesh!

having just learned about wheel bearing spacing myself, I can't help but think there are many out there where the "B" bearing is in too tight.

MCRider · « **Reply #14 on:** January 11, 2011, 09:01:11 PM »

Iggy: Sometimes with time and age, one begins to doubt one's self. Sometimes. Your welcome.

madmtnmotors · « **Reply #15 on:** January 12, 2011, 04:25:36 AM »

Okay, It's been a while since I've had my front wheel/axle assembly apart so I would have to retract my previous recollection and agree that the speedo drive would/should follow the axle. Orient the speedo drive/axle prior to tigthening the axle to the forks makes sense. Hopefully I haven't contributed to too much confusion... I hear it's contagious!

MCRider · « **Reply #16 on:** January 12, 2011, 05:07:07 AM »

Quote from: madmtnmotors on January 12, 2011, 04:25:36 AM

Okay, It's been a while since I've had my front wheel/axle assembly apart so I would have to retract my previous recollection and agree that the speedo drive would/should follow the axle. Orient the speedo drive/axle prior to tigthening the axle to the forks makes sense. Hopefully I haven't contributed to too much confusion... I hear it's contagious!

Thanks for the clear up. I think we've got it.

754 · « **Reply #17 on:** January 12, 2011, 10:18:13 AM »

The drive is actually an axle spacer as noted.
If you look at it, you will see it has a cast in steel insert, if it was not load bearing, they would not need the steel insert.

shizzomynizzo · « **Reply #18 on:** January 12, 2011, 03:43:30 PM »

sorry for adding to the confusion. I misunderstood what you were saying.

I thought you were saying that it was spinning with the wheel. I was thinking locked to the wheel not axle...that's why i was asking if it would hit the fork tube

glad you got it figured out

jdenz · « **Reply #19 on:** April 22, 2015, 09:06:28 PM »

Hi,

I am having the same issue! I just put the front wheel back on after changing the tire and when I torque the axle the speedo will turn outside the forks but once i put the wheel on ,the speedo is locked and the wheel won't spin freely. It moves an inch forward and aft but not a full rotation. I didn't want to force things. what should I do? is it normal?

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Author Topic: CB750 speedo drive- should the body turn? (Read 8540 times)