Weak Crank Case Bolts?

[bertypower_imp]

Hey guys, 2nd post on here. Here goes. When I buy a used bike I usually go over everything nuts bolts etc. Long story short. Got a great deal on a well maintained, garage kept CB1100, with a healthy amount of aftermarket parts, Two brothers M2, Bar Risers, Maintenance Manual, New tires etc. The owner used synthetic oil. The only flaw in the bike is that he did have a tip-over in the garage and scratched the left side crank case cover. No biggie...

Upon inspection everything seemed fine test drove and bought it. So I put a couple Hundred miles on the bike in the next few days. Noticed some seepage on the right Head-gasket covers (silver round bits) and the right side crankcase cover (smaller one). So I went over them with my ratchet and could tighten the 8mm bolts by hand pretty easily. So I got the torque wrench out and torqued the 8mm bolts to the manuals spec. 22nm /16ft. Lbs. When I went to the left side, I had significant seepage. Not enough to cause a drop to the floor, but enough... I tightened them by hand with my ratchet wrench first. However I could turn almost all bolts without even trying. So snugged em all up. But snapped the lowest bolt without even trying. Managed to get the broken screw out and replaced it with one of the higher most bolts. I had a M6x25 laying round so I used it as a temporary replacement. Ordering the Set of M6x28 tonight.

Today I felt like I should get the bolts to at least 10ftlbs. The 2nd lowermost bolt almost snapped. I managed to get it out and looks like this screw was going to snap at the same place... discarded. Replaced with another higher bolt, Hand/ratchet tightened. Torqued to a low 5ish ft pounds.

Top bolts by the chrome circles. Were tightened by wrench and ratchet only. But just tight. I didn’t crank it down or anything. Seepage seems to have stoped there.

So I’m thinking that the impact from the tip-over weakened those bolts or slightly bent them making them weaker than the rest. Honestly all those bolts seem pretty weak to me both right and left side. So I think I’m going to order all new 8mm bolts for the left side and right side crank case. Are there gaskets for that? Or is it just RTV or whatever?

Lastly, the synthetic seems pretty thin to me. I’ll probably go back to the manuals recommendations. Never had a seepage problem on any of my other Honda’s I’ve owned. (CB500X /CB300R/Rebel300) but I only used the recommended oil at the dealer. Honda oil I guess.

I’m pretty mechanically savvy (by no means a mechanic.) but I will probably take it to a mechanic for the work. I just want to get the bike up and running leak free. Valve Checks are due soon so I’ll just knock it all out.

Any info or recommendations would be awesome. Thanks!

[Lord Popgun]

Looks over torqued to me being streatched out like that.

If you have a service manual, read it. The covers on either side of the engine do not have gaskets. The manual says to use Three Bond 1207B or equivalent.

Section 10 for the left side (alternator cover).

Section 17 for the right side ( Right Crankcase cover)

The books shows where to put the sealant.

Be careful over torquing bolts on this bike. For instance, the top shock bolt will snap very easily if overtorqued even a small amount.

[PowerDubs_imp]

Somebody isn't reading the manual right...

[peterbaron]

^+1^, must follow the torque chart!

[bertypower_imp]

So is it not 16ft pounds? all 8mm bolts?

^+1^, must follow the torque chart!

Isn’t that what’s in the torque chart? 16ft pounds on 8mm bolt
page 1-9?

As I said in my previous post. I’m not the OG owner and there was drop on that side. The only bolts that didn’t torque correctly were the bottom 2 by the left case. I only set the torque wrench to 10ft. Pounds to undershoot it.

[Lord Popgun]

Good question. The procedure says to tighten the bolts securely with no spec shown. So, to the torque chart.

It says: 8mm bolt and NUT-16 ftlbs (the cover has no nut so this isn’t it)

8MM flange bolt and nut—20 ftlbs (again, no nut so not this)

6mm flange bolt (8mm head, small flange)-7 ftlbs. Use this one

[bertypower_imp]

Good question. The procedure says to tighten the bolts securely with no spec shown. So, to the torque chart.

It says: 8mm bolt and NUT-16 ftlbs (the cover has no nut so this isn’t it)

8MM flange bolt and nut—20 ftlbs (again, no nut so not this)

6mm flange bolt (8mm head, small flange)-7 ftlbs. Use this one

Thanks! Appreciate it!

[pekingduck]

6mm flange bolt (8mm head, small flange)-7 ftlbs. is correct as stated above.

The confusion may come from the the 8mm bolt head with a 6mm bolt thread diameter, which is common to almost all side cover bolts on Hondas. Somewhat surprisingly, the 6mm bolts will stretch and snap, rather than strip the threads.

I use 1/4" drive sockets and ratchets on these to help prevent over-torquing, basically just wrist pressure torque. You need to be more careful with 3/8" drive, as it is easy to over-torque.

Most common torque wrenches do not read the lower and upper limits of their range accurately. With 6mm bolts, the torque wrench would measure in inch-pounds, not foot-pounds.

[PowerDubs_imp]

6mm flange bolt (8mm head, small flange)-7 ftlbs. is correct as stated above.

The confusion may come from the the 8mm bolt head with a 6mm bolt thread diameter, which is common to almost all side cover bolts on Hondas. Somewhat surprisingly, the 6mm bolts will stretch and snap, rather than strip the threads.

I use 1/4" drive sockets and ratchets on these to help prevent over-torquing, basically just wrist pressure torque. You need to be more careful with 3/8" drive, as it is easy to over-torque.

Most common torque wrenches do not read the lower and upper limits of their range accurately. With 6mm bolts, the torque wrench would measure in inch-pounds, not foot-pounds.

In this case that saved him a huge problem so all is well.

Use the factory bolts OP= I wouldn't substitute anything.

Not longer, not shorter, nada.

[bertypower_imp]

6mm flange bolt (8mm head, small flange)-7 ftlbs. is correct as stated above.

The confusion may come from the the 8mm bolt head with a 6mm bolt thread diameter, which is common to almost all side cover bolts on Hondas. Somewhat surprisingly, the 6mm bolts will stretch and snap, rather than strip the threads.

I use 1/4" drive sockets and ratchets on these to help prevent over-torquing, basically just wrist pressure torque. You need to be more careful with 3/8" drive, as it is easy to over-torque.

Most common torque wrenches do not read the lower and upper limits of their range accurately. With 6mm bolts, the torque wrench would measure in inch-pounds, not foot-pounds.

In this case that saved him a huge problem so all is well.

Use the factory bolts OP= I wouldn't substitute anything.

Not longer, not shorter, nada.

In this case that saved him a huge problem so all is well.

Use the factory bolts OP= I wouldn't substitute anything.

Not longer, not shorter, nada.
Yup. Most of em checked out with the torque wrench. But some were stubborn so I just tightened with the ratchet by feel. I rechecked the bolts on the side of the fall. Seems that some of them were ever so slightly bent. Ordered a new OEM set of bolts to replace some of the skewed, broken ones and some extras.

Update: Seems the seeping has stoped today. Ran the bike. a few mins, rev’d a little bit. Checked for leaks. I’ll just keep an eye on it. When I do the Valve clearance I’ll have the mechanic change all the bolts and re-seal those covers.

I swear I’ve had more trouble trusting the T-wrenches on Lower torque settings. On higher I guess it works out ok.

Saw a thread on a guy who was installing crash bars and he felt the torque setting was too high and ended up doing it by feel or a lower torque setting.

Thanks so much for the info guys! Appreciate all the help!