Topic: ENGINE HOSED(???)

[scottly]

Can you post a new video?

[Stev-o]

Could it be that you are just used to really smooth running, quiet modern engines?

My 550 is quite noisy on idle when warmed up.  But it always starts right up, runs great and is just as quick as my buddy's 550.

[longshanks]

Could it be that you are just used to really smooth running, quiet modern engines?

My 550 is quite noisy on idle when warmed up.  But it always starts right up, runs great and is just as quick as my buddy's 550.

I don't think so. I've heard other 750's running and they don't sound like mine, could someone with a Mac exhaust post a video closeup of their 750 engine running just like the video I posted on page 2? I'll try and post a new vid soon after all the changes that I've made. I should mention that its still hard to keep running on a cold start(I always have to adjust the idle screw up, start it with the choke for a few seconds, then turn it off. I know this is common with 750's though.)

[longshanks]

So I scoured YouTube a bit and I found a video of a 76 that makes a similar noise from 1:54-2:00 like a "chunka chunka" noise that sounds like its eating gravel for breakfast.

1976 CB750

[Jerry Rxman Griffin aka MuthaF'er]

Sorry but I don't want to read through all this again. I didn't see dude pull in his clutch so we can't tell #$%* really from that video IMO. Sounds like he has an old bike that is not unlike many of ours and which needs some tune up work by someone that knows what he's doing. If that doesn't help all the noises then it could be time for some tear down and serious $$ or just ride the sonna#$%* as is and put in ear plugs. That's what we do with these old bikes. Do you trust this "mechanic" and why?!!

Have we eliminated the standard clutch rattle from your bike??!! VERY first thing.

Then 3 definite things I'd do. Make damn sure the cam chain is PROPERLY adjusted. Make damn sure the carbs are PROPERLY synched. Then and only then drop the oil pan and PROPERLY check the primary chains wear as well as the condition of the tensioner.

It's not doing a bit of good here unless you do these things! Do NOT worry about the bits of metal until after this.

[longshanks]

Sorry but I don't want to read through all this again. I didn't see dude pull in his clutch so we can't tell #$%* really from that video IMO. Sounds like he has an old bike that is not unlike many of ours and which needs some tune up work by someone that knows what he's doing. If that doesn't help all the noises then it could be time for some tear down and serious $$ or just ride the sonna#$%* as is and put in ear plugs. That's what we do with these old bikes. Do you trust this "mechanic" and why?!!

Have we eliminated the standard clutch rattle from your bike??!! VERY first thing.

Then 3 definite things I'd do. Make damn sure the cam chain is PROPERLY adjusted. Make damn sure the carbs are PROPERLY synched. Then and only then drop the oil pan and PROPERLY check the primary chains wear as well as the condition of the tensioner.

It's not doing a bit of good here unless you do these things! Do NOT worry about the bits of metal until after this.

Cam chain is properly adjusted. I did it statically myself twice in a row by the book. Carbs are synched. I will drop the pan and inspect so what am I looking for? abrasions on the primary chain? is there a tensioner on the primary or are you referring to the cam chain tensioner because I have pulled the cam chain tensioner and have cleaned it up and lubed it and everything works and moves freely.

[Jerry Rxman Griffin aka MuthaF'er]

You really need access to a Honda Shop Manual. There are downloads on this site. It will tell you how to do all this including checking for stretch in primary chains which is probably what you're needing to determine. You can see the primary chain tensioner in there too. Perhaps it's all eaten up and not doing a good job. Perhaps the primary chains are stretched and still whipping around in there. Perhaps the primary tensioner spring has broken.

I know the "book" may say NOT to push in the plunger on the cam chain tensioner just let the spring do it's thing. Try pushing in the plunger during adjustment and tighten the lock bolt while doing this. See what happens. Perhaps the plunger is not being pushed in properly by a weak spring or the plunger has burrs on it from tightening the lock bolt.

[longshanks]

Cool. I have the shop manual so I will look into checking for things that are out of spec but I was just asking if people could tell me from personal experience what to look for.

[longshanks]

UPDATE:
I pulled the carbs again since number 1 was still fouling bad and decided to do a compression check. It's all over I'm afraid.
No. 1 -- 110psi
No. 2 -- 70psi
No. 3 -- 120psi
No. 4 -- 90psi

Motor was cold and had the carbs and all the plugs out with the electric start cranking on a fresh battery. Also kicked it over to make sure. Weird since the compression seemed okay a couple weeks ago. The only thing that changed was a valve adjustment and riding it around a bit. I set the valves at .002 and .003 for the intake and exhaust and only a couple valves were off.

[scottly]

Weird since the compression seemed okay a couple weeks ago. The only thing that changed was a valve adjustment

This may be a clue???

[longshanks]

Weird since the compression seemed okay a couple weeks ago. The only thing that changed was a valve adjustment

This may be a clue???

Think I hammered the valves huh?
I'll drop some oil in the cylinders and see if compression bumps up.