Topic: Won't roll backwards in neutral?

[dingus]

So I recently have run into an issue that I've never encountered before on my 77 cb750 f2. A little background, I've owned and been riding the bike for 4 years now (slowly repairing/upgrading mechanicals as I can) and the engine runs great. Ok, it smokes a tad and this winter I'm planning on tearing into the engine to replace rings, valves/seats, etc, but for the most part it starts right up and runs wonderful for a bone stock 40yr old machine.

Yesterday after riding for a few hours, when parking my bike in my driveway it would not roll backwards while in neutral (or with the clutch pulled for that matter). It rolls forwards with no resistance just fine--just not backwards. The transmission shifts just great when i'm riding--I've never had an issue with the clutch, finding neutral is a breeze, and it never slips out of gear on hard acceleration.

Any ideas on what could be going on? The chain is alligned correctly, and from visual inspection the primary gear appears to be rotating in-plane without any play or wobble. I initially thought one of the brakes could be grabbing, but then why would it roll forward just fine? Sometimes if I'm persistent I can get it to roll backwards a bit but I can feel resistance in the form of grinding (feels like metal on metal from my hands).

Anyways, I'm baffled and I can't find anything similar when I search the forums. Could it be a clutch issue? Any help or ideas would be greatly appreciated, thanks!

[Remcod]

What about the rear wheel bearing? Can you rotate fine on the main stand?

[dingus]

What about the rear wheel bearing? Can you rotate fine on the main stand?

Not yet. To be honest I just got back from the gym and now I'm gonna need my roommate's help to get 'er onto the center stand, haha. I will update then. Is it possible though that the rear wheel bearing would catch only in the reverse direction? I can push the bike forward while in neutral without resistance.

Thanks again

[Remcod]

Could be yes, wear and locked balls in the bearing. Just listen where the sound comes from.

[martin99]

Chain might be aligned, but is it adjusted properly and are the sprockets in good shape? A loose chain may try to 'ride over' a sprocket, even more so if the teeth are worn and hooked over.

Three bearings in the rear BTW, but my money is on the chain and sprockets.

[Don R]

 a loose brake part may bind one direction but not the other, check the brakes too.

[brewsky]

Chain might be aligned, but is it adjusted properly and are the sprockets in good shape? A loose chain may try to 'ride over' a sprocket, even more so if the teeth are worn and hooked over.

Three bearings in the rear BTW, but my money is on the chain and sprockets.

+1
I 've seen sprockets hooked so bad from wear they catch and lock the chain in reverse.

[ekpent]

 Parking brake on ??     I bought a Kawasaki 750 from a guy last year very cheap that he thought had a tranny issue or bad rear wheel bearing because it slipped and skipped etc. He had even already bought bearings. Got down and looked and noticed the rear sprocket literally had no teeth left. Eye roll while loading into trailer.

[flybox1]

To be honest I just got back from the gym and now I'm gonna need my roommate's help to get 'er onto the center stand, haha.

Oh yeah....thats funny 

[Don R]

 Getting onto the center stand is more about the step down than the lift up, if it's lowered a little put the back tire on a 1x4 or 2x4 board then go on the stand.
 Did you find anything yet?

[dingus]

Hey dudes, sorry about the delay--work and #$%*, you know. anyways, figured it out....Chain/sprocket were still good (they only have ~2K on them)...Turns out one of the 10x32 bolts  fastening the front brake caliper to the fork walked its way out 

Easy fix, but I'm glad I noticed it in my driveway and not while trying to stop.

[Don R]

 Good find yeow!

[scottly]

These bikes are metric, and don't use 10-32 bolts. Hopefully the proper 6mm bolts are holding your caliper on, instead of someone improperly replacing them with 10-32.

[ekpent]

A friend and forum member here had that problem with a caliper bolt and luckily just took out some front spokes while riding. Surprised it was only noticeable for you just when the bike was rolled backwards and not forward. Wonder why ??

[evanphi]

These bikes are metric, and don't use 10-32 bolts. Hopefully the proper 6mm bolts are holding your caliper on, instead of someone improperly replacing them with 10-32.

M10x32mm Special fine threaded bolt.

[martin99]

Well, that's why I shouldn't gamble I guess. A bolt is a damn sight cheaper than a new chain and sprockets! Glad to see you found the problem

[70CB750]

You may need to helicoil the thread first.

[754]

10-32 locking bolts..