Cylinder #2 Not Firing


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pgilliam1
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Re: Cylinder #2 Not Firing

Post by pgilliam1 »

THX, I'll re-torque the exhaust flange nuts in the morning. I hope getting rid of the puffing is that simple.

The only reason I mentioned the bad vibration is because it had never happened before. I hope your diagnosis is normal?

When I first purchased this bike I marveled at it's simplicity compared to my modern bikes. Now I'm thinking I was wrong.

daves79x
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Re: Cylinder #2 Not Firing

Post by daves79x »

These things are notorious hard starters under most circumstances after sitting a while. I know yours just sat overnight, but they often stumble around on a few cylinders until they all catch.

Even the most simple bike won't work right if everything isn't right. Same with the CBX. There's not a lot complicated about it, but getting everything sorted often is. I think it would be a great idea for you to have someone really familiar with the CBX look and listen to your bike. I'm quite sure there are a few things that still need tweaking for all to be well.

Remember the old CBX axiom: 'A CBX was never parked because it ran perfectly well'

Dave

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Re: Cylinder #2 Not Firing

Post by pgilliam1 »

Comforting words on the starting issue, THX. When first started with the choke on full, the bike starts easily. When it's warm it may take a second or two to start, but if I choke it just a bit it starts at the touch of the button - immediately.

In my travels I'll be looking for that CBX guru. At events I attend I'm finding out there are a lot of guys out there that know quite a few things about this bike, but don't have much experience with it.

The only time this bike is likely to be parked for any amount of time is in the winter, where it will be stored inside, with a fresh oil change, on a tender, with Star Tron added to a full tank, and me hoping for a warm day.

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Re: Cylinder #2 Not Firing

Post by EMS »

pgilliam1 wrote: there are a lot of guys out there that know quite a few things about this bike, but don't have much experience with it.

.
This is somewhat of an oxymoron. Somebody who doesn't have much experience with the CBX, does not know "quite a few things". I meet these guys all the time. Self proclaimed "experts". It is amazing what these guys are telling you about your bike, that you owned for 35+ years from new, just because they always wanted one, had one themselves once or their brother used to own one...

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Re: Cylinder #2 Not Firing

Post by pgilliam1 »

^ I was referring to them knowing about bikes history but not much about it's mechanics.

I looked through the manual and couldn't find any reference to the exhaust flange bolt torque value. I found the general torque values on a 10mm flange bolt was 22-29 ft. lbs. All my bolts are tightened to no more than 5 ft. lbs. With my track record on this bike I'd hate to over tighten and strip out a bolt, so if someone can confirm the 22-29 ft. lbs. I'd much appreciate it. TIA!

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Re: Cylinder #2 Not Firing

Post by EMS »

pgilliam1 wrote:^ , so if someone can confirm the 22-29 ft. lbs. I'd much appreciate it. TIA!
Yes!

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Re: Cylinder #2 Not Firing

Post by daves79x »

Yes, but those aren't 10mm studs - they're only 6mm. You'll strip or snap them if you go that high. Again, just snug them up using common sense.

Dave

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Re: Cylinder #2 Not Firing

Post by EMS »

Before you tighten them, make sure they run nicely on the threads. These things have a tendency to accumulate grime and rust and it will be tough to "feel' when they are tight. The generic 6mm torque value is 6-9 ftlb.

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Re: Cylinder #2 Not Firing

Post by pgilliam1 »

I don't know why they have to make things so overly complicated. The nuts were 10mm so I assumed the torque would be for 10mm (my gut told me 22 ft. lbs. seemed too much). How is anyone supposed to know what size the studs are? And not only that, but the torque seems to change when the studs/nuts get hot.

- Off my soapbox now -

I did snug them up by hand and the nuts spin freely (the shop that did the head work probably did the scary work of initially breaking them loose). Didn't help the puffing at all. I'm going to try and record the puffing sound and if I get a decent copy I'll post it. The sound is definitely coming out of the tailpipes. Nothing leaking from around the exhaust flanges.

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Re: Cylinder #2 Not Firing

Post by EMS »

The torque is always given for a "thread size" - stud diameter - not the hex size of the nut or bolt head. Certain size bolts may have different hex sizes in different applications, although it is rare. And the same hex size may be found on different stud diameters. It is the stud or bolt that snaps or thread that strips, not the hex that breaks. That's why engineers specify torque for stud and bolt diameters.

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Re: Cylinder #2 Not Firing

Post by NobleHops »

EMS wrote:The torque is always given for a "thread size" - stud diameter - not the hex size of the nut or bolt head. Certain size bolts may have different hex sizes in different applications, although it is rare. And the same hex size may be found on different stud diameters. It is the stud or bolt that snaps or thread that strips, not the hex that breaks. That's why engineers specify torque for stud and bolt diameters.
Nice one Mike. That all helps me get my mind around the "how and why" a bit better.

N.
Nils Menten
Tucson, Arizona, USA '80 CBX, sort-of restored :-)

pgilliam1
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Re: Cylinder #2 Not Firing

Post by pgilliam1 »

OK, so how does one determine the stud size? Do you have to measure the stud or bolt shaft with a metric caliper? What I think I'm seeing in the manual is nut and bolt head sizes.

Maybe I need to take a Mechanics 101 course or just stick to the old "snug and 1/4 turn" axiom? I think I've stripped enough bolts to know when to stop tightening, but sometimes you need to know a more precise snugness (spark plugs, head bolts, etc.).

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Re: Cylinder #2 Not Firing

Post by EMS »

pgilliam1 wrote:OK, so how does one determine the stud size? Do you have to measure the stud or bolt shaft with a metric caliper? ).
That would be the sure way, if you don't know what they are. Another nice feature of the metric system is, that there are only a few sizes that are being used for the main bolts and studs on a motorcycle. These are 6, 8 and 10mm.
There are smaller and larger ones, but them are only a very few.

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Re: Cylinder #2 Not Firing

Post by pgilliam1 »

Just when I get good at judging nut and bolt head sizes and can almost always choose the right size socket from my kit just by looking at the nut I'm going after, now I will have to study shaft sizes.

I'm learning - THX.

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Re: Cylinder #2 Not Firing

Post by EMS »

pgilliam1 wrote:Just when I get good at judging nut and bolt head sizes and can almost always choose the right size socket from my kit just by looking at the nut I'm going after, now I will have to study shaft sizes.

I'm learning - THX.

We are all learning every day. Once we stop learning, we might as well turn our punch card in.

But you are hallway there. You will find out, that your hex size corresponds with a thread/stud/bolt size.
10mm hex goes with a 6mm bolt, a 8mm bolt usually has a 13mm hex and a 10mm bolt usually has a 17mm hex. Of course, there are exceptions, where an 8mm has a 12mm hex and a 10mm bolt has a 14mm hex.
Not to mention the occasional 11mm hex and let's not forget the 15mm. :laughing-rolling: And one nice thing: The 19mm hex and the 3/4" hex are the same size.

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