Topic: Long time no post!

[SClay115]

Been a while since I've milled around here, but ran into a bit of an issue and thought I'd see what the experts have to say. I was always able to get knowledgeable answers here, so why not give it another go?

Bike in question is a CB350 twin, and while riding home the other day, I noted a terrible noise in the top end. At first, I thought to myself, "Great, sounds like the cam decided to have a snack out of the rocker box." Runs fine, just absolutely horrible sounding.

So after a bit of diagnosing, and some parts removal. It has been pinpointed to the advance mechanism that sits behind the points plate. What? Yes, for whatever reason, the advance mechanism is making a horrible, horrible noise. Think of basically a constant rattle/grating sound.

So what's going on here? The advance setup, once removed, isn't cracked, in pieces, nothing. It almost sounds like it is colliding with something as the camshaft is rotating, but the rotation path looks free and clear.

The weights themselves seem a bit lose on the plate, but not enough to warrant the racket that was being made. But, it could be, doesn't seem like there is anything else that could be making the noise.

Anybody ever run into anything like this? I'd like to try and figure out the issue before I go and throw another mechanism on it, but if it comes to it, I will. 

Steve

[scunny]

no solution here, but a bump doesn't hurt

[faux fiddy]

no solution here, but a bump doesn't hurt

Me no-know either, but some of those  inconsequential loose things you describe might make more of a racket above 5k RPM.

[SClay115]

no solution here, but a bump doesn't hurt

Me no-know either, but some of those  inconsequential loose things you describe might make more of a racket above 5k RPM.

Ah yes, while true, this happens as soon as I kick the motor over. It's really got me stumped. It truly sounds like the advance plate is running into something during it's rotation, but visibly, there is nothing in it's path, and no visible aftermath(worn metal bits).

I have even wedge the weights with cardboard, to see if they were simply loose, but it did nothing for the noise itself. I will end up digging into it further in the next coming week. It really has to be simple, I'm just not seeing the solution.

Steve

[strynboen]

is there some springs to hold sentifugal regulator together..if they falls of it get loose and rattels..im not in this twins engines..but cd-50 have an sentifugal regulator that way..

[madmtnmotors]

Been a while since I've milled around here

Welcome back! Not meaning to hijack your thread but we missed you for the relay:

http://forums.sohc4.net/index.php?board=125.0

Stay tuned so you can participate next year! Maybe we'll work on putting together a regional ride before then...?

Keep us posted on your progress with the diagnosis.

[SClay115]

is there some springs to hold sentifugal regulator together..if they falls of it get loose and rattels..im not in this twins engines..but cd-50 have an sentifugal regulator that way..

The springs are actually in good shape. But there is some side to side rattle of the weights. I just don't have another regulator to compare it to. With the regulator in my hand, I can spin it, shake it, anything, and it doesn't make the same sound. So I'm not sure how it can be doing it on the bike. That is why I am thinking it is some sort of interference issue, just not sure what!

And thanks for the welcome! I actually did read about the rally, I just had too much stuff going on in my life to even try to add something else. But next year for sure! And I need to update my location, I am not in Orlando anymore, I have relocated to Southwest Florida as of a few months ago.

Steve