Engine knocking

[maury]

'83
Starts easy and idles well. 43,000 miles. Complete overhaul minus clutch, carb rebuilds with synchronization at 38,000.
When cold and idling there is a moderately loud knocking (can seem to feel it when seated). At operating temperature and in neutral knocking subsides at idle but if idle is increased only a small amount (1,500?) and held, the knocking continues. When rev quickly and holding rpms higher there is no knocking.
Thoughts?

[Sagebrush]

Primary chain slap comes to mind.

[Shadowjack]

Don't know about the 1100s, but I had a 1200 where the vibration damper on the alternator rotor shaft was seized, and it knocked like crazy around idle, but went completely away at higher rpm. So bad that the PO sold it to me with an extra engine he meant to swap in. I got another damper assembly from Ebay for $20 and replaced it. Although this doesn't quite sound like your problem.

[CYBORG]

When idling, cold,try pulling in the clutch and see if goes away.

[Rat]

A rod knock usually isn’t very subtle …

Gord

[robin1731]

I had one several years ago that had a slight knock. It ended up being caused by a fuel valve being left open and float valve not sealing. let fuel into one cylinder. Bent the rod. Bike still ran but knocked slightly. At TDC the piston wasn't down very much compared to the matching one. But enough to see it.

[maury]

Thanks for the ideas..........
I'm thinking it fits most closely to "vibration damper on the alternator rotor shaft". My plan is to listen more closely for the source of the knocking. I did say "moderately loud" but honestly it's fairly loud and clearly can be heard. Do I have to pull engine for checking/changing the dampers? Anyone know a video/written source (I've looked quickly)?
Keep the info coming!!

[dontwantapickle]

"vibration damper on the alternator rotor shaft"

What is that?

[maury]

"vibration damper on the alternator rotor shaft"

What is that?

I'm not completely sure myself but appears to be rubber pieces that dampen engine vibrations on the alternator shaft.

[cfairweather]

When the engine was rebuilt, was the primary chain replaced? If not, it might be the issue. Also, the bolt that is used to manually turn over the engine may be loose. If someone turned this bolt counterclockwise, it might be loose. To tighten it, get another person to sit on the bike while in gear and then tighten it. I don't think this is the problem, but I would check it to eliminate this as a possible cause. I have seen engines make a lot of noise when the bolt is not tight.

[Shadowjack]

Thiis where the damper is on an 1100. It's a rubber cush drive like in a chain-drive rear wheel and keeps the alternator rotor from shaking so hard under engine speed changes.
https://www.partzilla.com/catalog/honda ... ator-shaft

It's not the same as the damper in a 1200, which is a ball-spring-and-ramp design. There was ink in the magazines about the new design when the 1200s came out.
https://www.partzilla.com/catalog/honda ... ator-shaft

Comparing the two, I doubt the 1100 damper would be making a noise, but if the two parts separated by the rubber got bound together somehow, it might. Hard to see how that would happen. This is an engine-out job even to look at it.