Cb750 cam chain noise

Blacklisted_kolasa

Blacklisted_kolasa

If your not using a hammer you're not doing it
I recently bought a 1979 cb750k with about 13,xxx miles. I rejetted and synced the carbs, I've been hearing a loud ticking coming from the front of the motor. Seems to get faster when I rev the bike. I know it's not the clutch basket cause when clutch is pulled in it still makes the noise.

So I'm only guess is that it's the cam chain. I was hoping someone else would have some more advice for me. I plan on doing a cam chain adjustment soon to see if that fixes the problem.
 
Whats the poll about?

When was the last valve adjustment, could be sloppy rocker or a stuck valve. Timing chains are noisy by nature, unless its a new noise getting louder the CB is a noisy motor up front and music out back. Do the chain adjustment and if no known service on valve adjustment, I would do/get that done also.
 
Did the cam chain adjustment, noise went away almost completely.

Now on to the next issue, I have oil spraying out of the exhaust. Check the plugs and cylinders 1,3 were completely black and oil coated! Does this mean my values need to be adjusted or should I dig further Into the rings as well.

Also if the timing was off, could this cause oil to be getting into the exhaust?
 
That's a bigger can of worms, 3 main things come to mind... ring(s), valve seal(s)/guides and sucking oil, make sure the return is flowing good. Sounds like your in for some motor work to get things sorted out. Maybe pull the compression numbers to see where you are in that respect.
 
Blacklisted_kolasa said:
How do I check the return oil???
Click to expand...

It flows into the oil tank on the back side you can open it while its running and see if its flowing good, how long have you had it? has it sat long, and you are running it for the first time in a while?
 
I don't have an external oil tank. I've had it about 2 months. The guy I bought it from had it running last summer but rough the carbs were all outta whack. So when I got it home I tuned it and started stripping it down. So it hasn't ran into about 2 weeks.
 
oh so you have a DOHC 750 then... try checking the breather vent tube to make sure its not plugged up.

Hers a link to a full set of pdf manual links here on the site
http://www.dotheton.com/forum/index.php?topic=44399.msg484864#msg484864
 
Yes yes I do. Breather tube vent is free and clear. I removed the cam shaft cover and found all valve ports are in ponds of oil. I know there's suppose to be a little up there but didn't think that much.

Plan on checking valve clearance tomorrow.

Also I have 4 clymer manuels on this bike.
 
Can you verify it's oil and not just a sooty-watery substance caused by condensation on a cold engine?
 
Wouldn't hurt to drain the oil and fill to spec also to rule out over fill. getting the compression numbers will be next, a gauge from advance or O-Reilly or something on loan can be had for free in most cases with a deposit.

Digital manuals are nice to have so you can print the pages you need and toss em if they get dirty, I use the spec pages on a clip board sometimes and blowups of transmissions in landscape is nice.

And yeah, if you live in a humid area this certainly is soot season, good ole mama nature may just be power washing your valves haha!
 
It's definetly oil, not watery at all. Could to lite of weight oil cause this problem? Never had this problem before. I'm running a simple conventional 5-30 I believe.

Will be picking up a compression guage as well. What do you think would be a good way t drain all the oil in top end.

I'll update you guys with photos in a bit. Also what I find after doing a compression and valve check.

Any other suggestion before I dig into this any further?
 
With greasy oil fouled plugs, are you sure it is actually running on all four cylinders? This could be part of the problem. Have you put new plugs in and do the carbs need cleaning???
 
You will have to pull the oil that is pooling on top with a syringe or something while you have the cover off.

Goldy makes a good point, i just assumed you had checked to see if you are firing on all 4, not just spark but a noticeable increase/decrease in rpm when a plug wire is pulled.
 
Yes it's running on all 4 checked temp of headers on each cylinder, all new NGk iridium plugs.

Even if it wasn't running on all four cylinders, that wouldn't cause an excessive amount of oil loss through the exhaust pipe.

Just picked up compression gauge gonna do that now, and check valve clearance.
 
Blacklisted_kolasa said:
Yes it's running on all 4 checked temp of headers on each cylinder, all new NGk iridium plugs.

Even if it wasn't running on all four cylinders, that wouldn't cause an excessive amount of oil loss through the exhaust pipe.

Just picked up compression gauge gonna do that now, and check valve clearance.
Click to expand...

Not likely you ate rings on all four at once either. Seems like its pumping or sucking it in.
 
Update: compression test cylinders 1,3,4 at 70 cyclinder 2 is at 60. I did this with the valve cover off. I noticed cylinders 2,4 bring a lot of oil to the top intake side??? Not to sure about that.

Going to start valve clearence check now.
 
Your compression test is way off. Bike wouldn't run at those readings.

Did you do the test with the throttle wide open and no choke?

Importantly, it's pretty consistent so with luck your compression is fine across the board. Where is the oil coming from on the intake side? Not sure what you mean by the cylinders bringing the oil.
 
Oil coming from the cam Yellow) is good, coming from the valve guides/seals (red) is not good, The compression is in the dirt on all bores and so low I'm thinking something not right with the readings, are you spinning it with choke open? what carb work did you do, just clean no jetting?
 

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