Topic: Help sourcing an engine mount/hanger?

[Aceon]

Hey all, I've been rebuilding my engine and when I pulled it out, the bottom rear engine hanger was extremely bent. This caused the threads to get mashed together when I hammered it out, so I can't bend it back.

I've spent probably 3 hours on Ebay trying to find one (ordered a wrong one already) and I just cannot find the right one. My bike is a 1977 CB750K and it seems like the bolt is slightly different than other years.
The bolt is 14 inches long and is an M12 bolt.

Any help is greatly appreciated. Any website suggestion, Ebay listing, etc. would be super helpful. If you have an extra I'll buy it from you!

[carnivorous chicken]

https://www.cmsnl.com/honda-cb750k7-four-1977-usa_model495/partslist/F++26.html

Should find it there.

[Aceon]

https://www.cmsnl.com/honda-cb750k7-four-1977-usa_model495/partslist/F++26.html

Should find it there.

It's unavailable from that site unfortunately.

Though this one looks like it should be the right size:
https://www.ebay.com/itm/295536736244

Does that one look right to you? It's an M12 but it's 10mm longer than stock.

[BenelliSEI]

These are surprising “soft” and easy to repair. Clean the threads with the correct die. Install a nut and set it on a steel bench with that high spot at the end facing up. A few good “taps” with a 5 lbs. hammer will easily true it up.

[Don R]

 It makes you wonder how that would get bent.
 I have an engine with 3 of the 4 rear motor mounts aluminum welded, I still look at it with amazement not only wondering how it ended up that broken but also welded back together and used.

[bryanj]

I know people will shoot me down but i see nothing wrong with using studding bar in that position as its not highly stressed

[PeWe]

https://www.cmsnl.com/honda-cb750k7-four-1977-usa_model495/partslist/F++26.html

Should find it there.

It's unavailable from that site unfortunately.

Though this one looks like it should be the right size:
https://www.ebay.com/itm/295536736244

Does that one look right to you? It's an M12 but it's 10mm longer than stock.

This seller Andy Cepok has complete motor hanger sets of 3 long bolts with nuts and washers.
The long one holding the foot pegs too has same size of nuts as rear wheel sprocket nuts.
This for my bikes.
I have ordered to my bikes. CB750 K2 and K6.

Check for K7/K8 as you have found if you need a set.
New shiny straight ones feels nice on a restored bike.

https://www.ebay.com/itm/294632018773?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=FAFPPfGgRUK&sssrc=4429486&ssuid=XgCEg0CPSya&var=&widget_ver=artemis&media=COPY

[Aceon]

That looks like the same seller I linked above which is good to see. Feels rough dropping $100 for some bolts, so I might give Benelli's suggestion a shot first. Thanks for the help.

[madmtnmotors]

I should have one. Remind me if you don't hear from me over the weekend.

[rotortiller]

In a pinch I have taken drill rod, cut to length then threaded. You could heat treat and temper the ends crudely if you like.

[BenelliSEI]

That looks like the same seller I linked above which is good to see. Feels rough dropping $100 for some bolts, so I might give Benelli's suggestion a shot first. Thanks for the help.

Take a crack at it. I’m always surprised how malleable they are. Clean the threads first and install a nut. It protects the threads and gets the shaft off the bench so it can be shaped back more easily.

[HondaMan]

I had that on the K8 I restored, too. I put the straight part into the frame/mount, left the bent part hanging out, and threaded on a long nut (I got it at Ace Hardware) so I could get a pipe on it, then bent it straight(er) again. This crossbolt is longer in the F2/3 and K7/8 bikes, and weaker. They get bent when their nut is loose a little and it falls over onto the footpeg somehow (mine was knocked over by a car in a garage, landed on the footpeg on a cement block, sat that was for several days). In the end the whole bolt was sort of S-shaped, but it fit into the frame and held the footpegs fine.

[Aceon]

I’m back to report that I was able to get it bent back! It took a little encouragement from the blowtorch, but the bolt is functional. Not the prettiest thing, and definitely not all the way straight - but it fits and that’s good enough for me! Thanks for the help guys.

[HondaMan]

IF you want to make it harder (for less bending in the future) you can heat it up with a welder and then douse it in water or even oil. Some guys who raced the F2 got tired of the bolt bending repeatedly and did this: they got it smokin' hot with the 100 amp welder and doused it in water, then let it cool off in oil (I don't think the latter did any good, but they did). That stopped it from bending so often. That poor bike was frequently laying on it sides...

[calj737]

IF you want to make it harder (for less bending in the future) you can heat it up with a welder and then douse it in water or even oil. Some guys who raced the F2 got tired of the bolt bending repeatedly and did this: they got it smokin' hot with the 100 amp welder and doused it in water, then let it cool off in oil (I don't think the latter did any good, but they did). That stopped it from bending so often. That poor bike was frequently laying on it sides...

You will not achieve increasing the hardness of mild steel bolts by quenching. Absolute rubbish. Heating steel can change its temper. Oil quenching makes steel more brittle, not harder, and far more susceptible to fracturing.

[BenelliSEI]

I’m back to report that I was able to get it bent back! It took a little encouragement from the blowtorch, but the bolt is functional. Not the prettiest thing, and definitely not all the way straight - but it fits and that’s good enough for me! Thanks for the help guys.

Well done. No one can see it, and it works!