Topic: Crunchy noise and feeling while accelerating

[Schnell]

I'm noticing a crounchy noise and feeling while slowly accelerating in first and second. Mainly lower rpms, but it may be that higher rpms mak this. It is noticable when the motor is hot, not when cold or after not running for a while and cooled down. At first I thought it was the drive chain and misaligned rear wheel. I made an adjustment but its still there.

It could be valve lash/knock, but it doesn't seem to be there in higher gears.

It could be the cam chain. It could be the primary chain.

It could be a worn drive sprocket.

It could be simple like a drive chain that needs more lube.

But it is a crunchy feeling and noise. Any ideas?

[mrbreeze]

How does the wheel turn up on the center stand? If it were a chain problem you should be able to tell while watching and listening while it spins. It's what first came to my mind when you described it. Hope it's nothing serious. Your trip has been so fantastic up to this point. Keep the rest of us informed.

[Retro Rocket]

How does the wheel turn up on the center stand? If it were a chain problem you should be able to tell while watching and listening while it spins. It's what first came to my mind when you described it. Hope it's nothing serious. Your trip has been so fantastic up to this point. Keep the rest of us informed.

+1, the crunchy sound makes me think chain and sprockets as well, is the chain well lubed.? too tight..?

[lrutt]

I'd say crappy chain and sprockets. How many miles on the bike? You might think they look good but don't be fooled. There are numerous articles out there on how to check it by just pulling the chain away from the rear sprocket etc. Also trying to discern if you have cupping on the drive side of the sprocket teeth. Remember, the front sprocket wears a lot faster than the rear so really need to check that one as well.

[Markcb750]

Could also be pre-detonation if there is carbon build up in the combustion chamber it can cause the fuel to ignite prior to the spark making an odd noise that you just cant hear when the wind masks it in higher gears.

The "when hot" indication leads me to this as the carbon can retain sufficient heat to cause the pre-detonation once the motor heats up.

The chain failure should be very evident when you spin the rear tire to clean & lube the chain.

[TwoTired]

My 78 Cb550 had those symptoms.  The cause was bad rear axle bearings.

[madmtnmotors]

My 78 Cb550 had those symptoms.  The cause was bad rear axle bearings.

+1

My first thoughts were (in order of likelihood):

>Chain/sprockets
>Wheel bearings (front and/or rear)
>Output shaft bearing

Where you at now?

[Schnell]

Northern California, heading into eureka, 30 miles to go.

I'm thinking front sprocket. Chain is new, rear sprocket looks good. I've never looked at the front sprocket, and there are 45000 miles on it.

[Schnell]

With the bike on the center stand, the rear wheel bearing feels fine.

When I get into eureka ill buy an impact wrench and remove that cover. Gear shift lever has to come off first, any other hints?

[TwoTired]

With the bike on the center stand, the rear wheel bearing feels fine.

Yeah my 78 did, too. The remaining bearing balls distributed around fine when no load was on it.  Under power, they squished over to the non-loaded side.  Very odd handling under power as the axle shifted forward, allowed more chain slack and sprocket "grind".  Took a while to figure it out.  Just saying.  I don't know you really have this particular problem.

Do you have 'tight' or 'loose' sections of chain?

[Schnell]

I pulled into eureka and got a front sprocket on order to be delivered overnight!

The chain is new, about 7K miles on it. The front sprocket has 45K on it.
I'm going to replace it and see what happens.

[Schnell]

Damn! It's not the sprocket!

Two tired may be right about the bearing.

[nccb]

it looks a little worn, but those bearings shouldn't be hard to get replaced if you are around any shop right?  Just take the tire off and take it to your nearest dealer/motorcycle mechanic to cut some labor down. . .

[Schnell]

You're right, it shouldn't be a problem, if they have bearings that fit.

Ignorance is expensive. I didn't know how to take off the cover to check the sprocket before I ordered one.

Now I know. Too soon old; too late schmart.

[Jerry Rxman Griffin aka MuthaF'er]

Good luck with the issue.

Tell my sister hello if you see her  If you should need some local assistance I can get you in touch with her. She'll be around until Monday then we meet up in Atlanta.

[Schnell]

Thank you Jerry! You were right about the coast north of Fort Bragg being spectacular. The mountain section heading to 101 was a blast.

Just a bit south of Eureka is a small town with a wifi cafe 101, so I stopped in.
Quite a friendly bunch.

[Jerry Rxman Griffin aka MuthaF'er]

I see you already met my sister!      Obviously kidding......

I really liked the last stretch of 1 before 101 in the trees. That is a blast. Takes a bit to get the rythym of the up and down, side to side but once you do it's great. Not much traffic but lots of trees and lots of miles of those twisties. I actually liked that better than the Tail of the Dragon discounting of course the Dragon accident.

What you missed in Colorado can easily be found in Eureka 

[scottly]

With the bike on the center stand, try grabbing the wheel at 12 and 6, and see if you feel any play. Repeat this after rotating the wheel a few degrees each time, until the wheel has made a full revolution. If all feels well there, be aware that the sprocket carrier has it's own bearings, which may be affected even more than wheel bearings under acceleration.

[Schnell]

With the bike on the center stand, try grabbing the wheel at 12 and 6, and see if you feel any play. Repeat this after rotating the wheel a few degrees each time, until the wheel has made a full revolution. If all feels well there, be aware that the sprocket carrier has it's own bearings, which may be affected even more than wheel bearings under acceleration.

Yikes! That sounds expensive.

[scottly]

Shouldn't be any more expensive than axle bearings?

[Schnell]

So case needn't be split for that?  Good to know. I guess you just check for play on the front sprocket without the chain around it?

[scottly]

I was referring to the rear sprocket carrier; it floats on it's own bearing(s) and drives the rear hub through a rubber "cush" drive.

[scottly]

Pics may help..

[Schnell]

Okay, thanks!

[madmtnmotors]

Yeah, I kind of lumped the sprocket carrier bearing in with the wheel bearings, but the sprocket hub bearing can fail yet the wheel bearings would be unaffected. Grasp the rear sprocket and check for any side to side play.