Will my engine crack in half?

[NightRider_imp]

Hi guys. If I understood the other forum discussion on this subject, they are referring to the chain that connects the engine final drive cog with a cog on the other end that drives the transmission, that big wide one, breaking and dropping down into the crankcase and then being driven into the case, as a big wad of chain, by the crankshaft, producing a crack or worse in the lower crankcase. But I could have miss-read the conversations on the 750 forums. Sorry if I muddied the thread.
You know, my engine runs so smooth I cannot believe it is flexing and twitching and about to flex the crankshaft as if it were not supported properly by stong main bearings. Perhaps if the shaft were soft enough I guess it could happen under load but I suspect Honda knows how to build an inline 4 and this one is their best to date, I would hope. I am so confident in this that I spent a lot of money on that bet.

[Dakota_imp]

2010 and up chains are not 1969 to 1976 chains. Manufacturers ahve increased the pin, plate and tensile strength tremendously. Doubt anyone has to worry about the chain on their CB 1100 breaking and going thru the cases these days.

I would be inclined to agree with you...and this is apples and oranges... However, if you do a google search, there are significant problems with timing chains in the today's automotive engines (Nissan, Chrysler, Saturn, etc had recalls over defective chains. Ford's ecoboost is probably heading in that direction). Seems that even if tensile strength has been improved, quality has not.

[Speed_imp]

and the twin engines doesn't flex and torsion the cranckshaft? All mechanic elements get elastic deformations continuously. It's matter of design, a twin engine will have its cranckshaft supported with bearing at the ends (1 support at each end and both connection rods pushing in the middle) and the CB has the supports at each end of the cranckshaft and four more intermediate supports for the cranckshaft, so each connection rods pushes the cranckshaft between two supports, so I think it's easier to deal with the flexion in a 4 in line. That's for the flexion, and for the torsion is a matter of the engine torque and the design of the crankshaft (diameter, length, shape, etc). In my opinion this article you read doesn't make much sense, I am not an expert in engine design but... and all the reliable cars that are using a 4 in line?

[LongRanger_imp]

After being stranded on my CB1100 twice with split crankcases, I tried Cormanus' latch-and-gasket repair technique. It works fine. But since I don't have access to used 20W-50 tractor oil, I've found that fresh GN4 (10W-30), mixed with some 80W-90 hypoid oil, does the trick. If it happens again, I'll try adding a little JB Weld to the oil to hold things together longer. I'll keep everyone posted.

[TINK_imp]

... are we REALLY having this conversation!?
The only crankshaft issue that I'm aware of on a Japanese bike is with the old Kawasaki triple 2-strokes.
The cranks on those bikes were a giant PITA to work on and only a select few specialists could do the job correctly.

[Ulvetanna_imp]

In the February issue of Cycle World page 31 in the article MotoGP Refugee it states, "Yet engineers were dissatisfied with the inline-four because it consist of two 180-degree twins set end to end. Each such twin wobbles vigorously about its center, applying a bending moment that flexes and may in time crack the crankcase and cause cylinder base-gasket leakage."

OH Snap! Do I need to carry JB Weld with me? Has anybody ever had their crankcase crack?

What bike and engine are you talking about? I don't subscribe to Cycle World. Is it that hard to be specific? Anyway we have an edict here that states the CB1100 is not a sport bike so you have nothing to fear.

[Matt F._imp]

I just cracked mine in half on purpose so when it happens unexpectedly I'll already be proficient at repairing it.

"It's not IF your inline 4 is going to crack in half, it's WHEN."

I use plumbers putty and painters tape... Works great.

[Ulvetanna_imp]

OP, you are being ridiculed. The number of smart-a**ed replies should be telling you your engine is not gonna crack in half, unless you get hit by a semi. Ride the dang thing. Take selfies (not whilst riding). Post them. Stop worrying.

I have never seen the numbers of worry-wart posts on any other forum as here. What oil? What filter? What RPM? Is my engine going to crack in half? I am just stopping by for the entertainment value now.

[Papa Weeley_imp]

...I would think that the OP's inclusion of a reference to carrying JB Weld along on rides would have made it obvious that this was posted a la tongue-in-cheek...

[the Ferret]

I believe that 's how most everyone took it. That's how I took it anyway, cause everyone knows duct tape will only hold twins together not inline 4's.