Topic: I found the source of the mysterious ticking, and retrieved the nut

[Floshenbarnical]

It’s a tick/ rattle that matches RPM. It’s coming from the right sound of my top end. I’m sure it’s valve related, but having adjusted my valve clearances the other day I cannot for the life of me get the buggers off today. I must have over tightened them and then the motor got hot and now it wants to keep them. This is a room-temp motor.

How can I get them off? All my wrenches are just rounding the hex. I’ve only tried two so far, and don’t want to ruin the rest. The first two aren’t ruined but they will be if I keep wrenching.

I’ve applied some penetrating lubricant, would an ice pack contract the metal to where it wants to let go?

[Floshenbarnical]

Well, for gods sake. Going fishing I guess

[dave500]

find a cheap 17mm six sided socket and grind the ramps off it like the one on the left,itll work the little covers better.

[Floshenbarnical]

V good idea mate. Honestly, I’m heartbroken. I’m paranoid I’ll never find the thing with a telescoping magnet

[Jerry Rxman Griffin aka MuthaF'er]

Look down the oil return holes

[Floshenbarnical]

Look down the oil return holes

Can you describe where they are? Also can I take the valve cover completely off with the engine in place or just lift it up and move it slightly

[robvangulik]

Only the latter, but enough to find what you're looking for, it's been done before!

[Floshenbarnical]

Only the latter, but enough to find what you're looking for, it's been done before!

Yeah I read that thread. Where are the oil return holes mate. Here?

[Floshenbarnical]

Nuts nowhere to be seen. I should mention it fell off the intake rocker for cylinder three. It’s not around the rocker and it hasn’t moved to any of the other rockers. I cannot see any oil return holes by the intakes for cylinders three or four. I can see return holes for the exhaust side though. Is it possible that I fell inside the atrium where the cam chain lives? If so, can I get it out of there? Is it possible it moved somewhere else, and is sitting in the oil pan, or the transmission? I found a stainless washer in the oil pan the first time I opened it, it’s from the Allen bolt kit the PO used to strip all the holes on my carburetor.

Will I ruin my engine if I leave it wherever the hell it ran away to and replace it?

[PeWe]

Try with a magnet if you have a slim one on a flexible arm. Nut might be close to cover around spring.
Or fasten a magnet on a thin screwdriver near handle secured with tape. (Or steel wire)
The screwdriver might attach  it.

I lost one nut once, it landed inside a cavity near spring so I could see it. Another cylinder.

[Floshenbarnical]

So is it possible or  not possible that it fell into the cam chain atrium? It has to be located around the spring it fell off? I don’t know how much clearance there is under the valve cover when closed, could it have flown off and bounced around and disappeared? I don’t see any pieces anywhere. It’s too large for the oil return holes.

Will it destroy my motor if I leave it in there until winter and simply replace it?

[PeWe]

If you can't find the nut. Pull engine and open valve cover.
If you have frame kit, easy to remove valve cover without pulling engine.

If bike is not a 100% stock or planned to be. Install a frame kit.
Frank's weldless is really good. Both my CB750 have it.

There is a forum member that produce the clamps. Check with "scottly".

[denward17]

So is it possible or  not possible that it fell into the cam chain atrium? It has to be located around the spring it fell off? I don’t know how much clearance there is under the valve cover when closed, could it have flown off and bounced around and disappeared? I don’t see any pieces anywhere. It’s too large for the oil return holes.

Will it destroy my motor if I leave it in there until winter and simply replace it?

Yes it is possible and yes, it can break a cam chain and ruin other parts on the way if you crank or run it.

DO NOT run it until you locate that nut.

[Floshenbarnical]

I rode it home 15 miles after the ticking started. I didn’t know what the noise meant and had no other method of getting home. I crept home at low RPM, didn’t hear any other noise or notice any difference in performance. I’m now terrified I’ve done serious damage, although it seemed totally normal other than a dreadful ticking.

I’m on the edge of selling the bike to be honest. There is like, zero clearance to get any of the flexi magnets for sale around me down in there. I brought a telescopic camera, also can’t get it in there.

Can anyone tell me what routes it could have taken out of the cam chain area? It wasn’t in the oil pan or oil filter. I’m hoping there are places it might have flowed to that I can inspect before I have my mechanic friend pull the motor.

I’m beyond frustrated. I enjoyed it for a grand total of like, two days before this catastrophe.

[RAFster122s]

It is unlikely you have damaged anything yet. Ticking is from that loose adjuster...
Finding the nut takes some time...be thankful it is an aluminum head and block...means your magnetic tool won't be sticking to those parts, merely going after the magnetic bits in the motor.
Vibration and some fluid (oil) can allow the nut to travel.

Better to call a tow truck or friend with a truck or trailer than try to limp a bike home unless you know that doing so won't hurt the bike. Engine rebuilds are too expensive to gamble with in my opinion.

Pulling the cover or unbolting and trying to move it around is difficult on the 750, so if you cannot find it fishing around then pulling the motor is a worthwhile approach. After dropping the oil and oil pan to see if the nut made it's way there yet.
The center runner for the cam chain is one path fraught with danger of the nut finds itself in the cam chain. Getting bounced into the gears could yield an expensive failure point too.

Sorry you are dealing with this...you just join the ranks of many others before you whom have been in your shoes.

David

[bryanj]

Another one saying take it out and find the nut BEFORE turning the motor over

[PeWe]

You will get used to repair and service your bike

Pull engine so you can lift valve cover is a relatively small job with correct tools.

Extra muscle/hand/arm will help too.
Buy your helping friends beers an BBQ at your home when assembled and working again.

You will enjoy your bike even more afterwards. You will weld together as a family

[Nurse Julie]

Was the nut there in the first place🤔🤔🤔. It wouldn't be the first time a nut was left off during repair / maintainance. Don't run the engine until you've either found it or confirmed it wasn't there in the 1st place.

[HondaMan]

Here's some pix of the bottom end where the nut may be, from an open set of cases. Yours will have the crankshaft in place and primary chains headed toward the back, but the little area near my finger(s) points to where the loose nut may be lying now. In the lower picture you can see the oil pan in this engine, which, if yours is removed, is where you'll be looking up from.

[HondaMan]

Here's the view from the top of the engine's studs, looking down toward the crankshaft area. This is the cam chain tunnel zone.

[HondaMan]

If you don't already have one, maybe look to Motion Pro for their excellent tappet adjusting tool, originally designed for this bike in 1972. It will make the nut-tightening job more secure in that cramped space we have to work. The old nut may well have rounded corners from years of adjustments, making it really hard to snug it down properly in that little hole!

[Floshenbarnical]

Was the nut there in the first place🤔🤔🤔. It wouldn't be the first time a nut was left off during repair / maintainance. Don't run the engine until you've either found it or confirmed it wasn't there in the 1st place.

Did a valve adjustment last week, must not have tightened it down enough

[Floshenbarnical]

Ok. I have small holed magnets coming tomorrow. I’ll find a piece of wire and bend it so it can get down into the cam tunnel.

This afternoon I’ll take off the exhaust and oil pan again so I can look in that little spot

[Floshenbarnical]

Here's some pix of the bottom end where the nut may be, from an open set of cases. Yours will have the crankshaft in place and primary chains headed toward the back, but the little area near my finger(s) points to where the loose nut may be lying now. In the lower picture you can see the oil pan in this engine, which, if yours is removed, is where you'll be looking up from.

I have to be honest, mark, I’m a little stumped by these pictures. If the nut is there, how do I get it, it looks like I would have to go around several corners … what’s my insertion point?

[denward17]

^He's pointing to the center of the oil pan, and just front of the oil pan it appears.

If you are lucky, when you drop the pan, it will be looking at you.