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Dropped a bolt on the engine

grepper

Old Bike Nerd
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So my 81 started to sound like a diesel, I suspected something with the valves. I found the b cam chain tensioner broken. While reassembling I dropped one of the cam sprocket bolts into the engine. I can't seem to find it. I've spent hours with a borescope, magnets you name it from both the top end and through the bottom end. I think my step is to pull the engine. Hopefully I can shake it out. Any suggestions?

 
You might be able to used compressed air. But you would definitely need to have the bottom pan off and also the Alternator side cover and get lucky. This also happened to me during reassembly but I had the engine on a bench. I tried the same approaches as you. bore scope, compressed air and magnets. Ultimately I had to bring the motor onto the basement floor that has a man cave carpet and rolled the motor all around. Upside down, left, right, wiggle wiggle wiggle, roll, twist, listen out for the bolt movement and it will eventually ended up in the bottom of the pan. Don't forget to take out your valve shims and buckets as they will fall out if you are working on the heads. Also, leave one bolt in the pan and leave the pan on. The pick up shaft protrudes really low and will create an unwanted pivot point and can also chip or introduce particles in the motor if exposed. Good Luck
 
Do you know what opening you dropped it through? If so, use you borescope to chase all little hang-up areas down that path. Also, if you have it really well drained, connect ~3/8 - 1/2" tube about a yard long to a strong shop vac and try fishing with it. I've recoverd a lot of dropped parts, pens, tools etc. with that type rig.
 
I have tried compressed air. The bolt fell down the cam tunnel. Another thought I have had is to try to flush it out. Maybe get a gallon of kerosene or another kind of solvent and pour it down the cam tunnel and see if I can wash it out.
 
I have tried compressed air. The bolt fell down the cam tunnel. Another thought I have had is to try to flush it out. Maybe get a gallon of kerosene or another kind of solvent and pour it down the cam tunnel and see if I can wash it out.
Compressed air might just blow it back into a corner, or might (if real lucky) swirl it out to where you can get it. Vacuum cleaner will suck it onto (not into) the tube and allow you to extract it attached to the tube.
 
Well... I pulled the engine, flipped it upside down and "tick!", opened the valve cover and it fell out.
Thank you veterans for your sacrifice and the day off work.
 
It's rough but you will likely take extra care from now on when working on the cams. Just don't do it again anytime soon and you'll be ok. It took many shakes and rolls before mine fell down so I knew it was lodged in some creavise that was nearly impossible to fish out. Sometimes elbow grease works the best. Glad you got it out.
 
Wez: Yes for sure. That was a real pain.

BTW, I got the rest of the bike together and she runs like a top.
 
Wez: Yes for sure. That was a real pain.

BTW, I got the rest of the bike together and she runs like a top.

Makes it all worth the effort in the end. Job well done. Removing the engine for a stinking bolt is usually enough for most to abandon a project all together. My oil pump bolts wiggled lose and the oil pump stopped working and blew my head gasket. This was less than 500 miles on fresh restoration. Motor had to come out for head gasket but now shes better than before so I can feel your pain. cheers
 
Wez, that sucks about your blown head gasket. When I built this engine the oil light came on. Turned out that little pin in the oil pump fell out during assembly, luckily I didn't let it run for long. I had built another CB750, and the oil light came on, turned out to be the sensor.
I was happy when I found out it was only the B cam tensioner that broke. I was able to get it out and a replacement back in without taking the engine out. I almost had it all together when that bold fell into the darkness. Giving up did cross my mind, this bike has been my White Whale, and I can get stubborn when it comes to projects. In all my bike projects I have way more money into them than what they are worth.
 
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