Topic: "Help Juntjoo fix his CB650!" thread

[juntjoo]

If you haven't seen any of my other threads, I'm basically restoring an 82 nighthawk 650. Working on several things but right now the main issue is the 1st and 3rd cylinders not firing. They're warm at most.  It was suggested I start a new "Help Juntjoo fix his CB650!" thread so here it is.  Below I cover most of what's been going on...

Before I put my carbs back up (after cleaning/replacing rubber) I got all four to spray into the throats (on the rack) and before I ever touched my valves 1&3 weren't firing. I switched the plugs and wires for each coil pair individually, no difference, so plugs wires and coils good correct?
I also put some electric grease(or expensive vaseline as I call it) on the connections of the coils which interestingly got #1 pretty hot but stopped working strangely.

#1 https://imgur.com/a/Ht1vV

#2 https://imgur.com/a/NlLIT

#3 https://imgur.com/a/opTEQ

and #4 looks just like #2

Something IS going on with 1&3 since when I take out the plug wires for either the engine doesn't run as good then died a couple times, more abruptly with #1 than 3.

Here's a short vid so you can hear the engine if it tells you anything.

1&3 still just warm but does it sound like they're firing at around 2krpms? I have zero experience listening to engines but I thought I noticed something different.

My alternator is working!! I think. Kinda passed the voltage test at the battery raising with engine speed but couldn't test regulator function by going over 14v as it stops at like 13 and engine is around 6.5krpms. I was afraid any higher something would break somewhere in the garage. But my cheapo meter says battery is 11v all the time and battery was brand new before troubleshooting. So maybe stopping at 13v means 14 and meter is off, but at least dial is moving with engine whereas b4 putting in new fuse it wasn't connected

new fuse holder with glow fuse https://imgur.com/a/bp9CA

I'm about to check my valve clearances again despite getting them perfect last time then I'll check out carbs again I guess. Here's some 'proof' I did it right. Evidence I should say.

oh, I suppose I should point out I haven't done anything with the pilot scews except turn them out 2 or something turns by the book and I know there is a step after it's all up. Hmm... might that be causing this problem? moving along...

[juntjoo]

okay, can't do anything with pilot scews till I get my tachometer in my multimeter that's coming in a couple days. But I did experiment with them (1&3) turning them all the way in then out, waited to see if any change in the pipe temps. The book says leaner turning them in, which confuses me because I thought that would close the air passage, if it works that way, making it richer. Well anyway, that's why I turned them both ways, all in then about 3 turns out. No noticeable change.

Might the tiniest discrepancy between the choke plates cause this? I think I did a pretty good bench sync. Made sure all plates exposed that hole just bit. Hmm... maybe I ought to order that carb vac sync tool. Have both that and multimeter in a could days and hopefully get this solved.

[Yamahawk]

After listening to your bike, I heard a tapping at idle that sounded like one valve that isn't adjusted properly, too loose maybe? better than too tight... either that, or it is your cam chain. Have you adjusted the cam chain yet? The engine has to be on #1 cylinder compression stroke, timing has to be past the 1-4T mark by 15 degrees (not much) and then loosen the lock nut and back off the cam chain adjuster bolt, and let the adjuster take up the slack. Then, remember to snug the bolt and the lock nut. It has to be done according to your manual procedure, so try that.
The bike sounds pretty good after 2000 rpm, and it sounds like your idle mixture screws might be out causing that. Try 1 turn or 1 1/2 turns out instead of 2 turns out. That is where my CB750 carbs start, not sure about yours. Anyway, you are making progress. Here is what I would suggest... Do the 3k mile tune up, and do ALL of it, before thinking you have a problem elsewhere. Completing the valve adjustment is one part of that 3k tune up.
Charlie

[Scott S]

 #1 and #3 fire from different coils. Have you confirmed that the coil wires are routed correctly.
 It would probably be a good idea to get new plugs. After they've been fouled a few times, they're just not right.
 New plug caps? Trim back the plug wires a mm or two and install new caps and new plugs. Ground each plug on the head, one at a time, and see if you're getting spark. Especially on #1 and #3, since those are the suspects.

[juntjoo]

#1 and #3 fire from different coils. Have you confirmed that the coil wires are routed correctly.
 It would probably be a good idea to get new plugs. After they've been fouled a few times, they're just not right.
 New plug caps? Trim back the plug wires a mm or two and install new caps and new plugs. Ground each plug on the head, one at a time, and see if you're getting spark. Especially on #1 and #3, since those are the suspects.

well, since I swapped the plugs on each coil pair individually, separately, if I'm saying that right, that tells me the plugs are good no? I also swapped the connections of the wires (of each coil pair individually /separately) one at the plug ends then the coil ends, and 2&4 kept firing, I assume so as engine ran and no change in temp occurred at headers for either experiment which tells me those components work no?

[juntjoo]

#1 and #3 fire from different coils. Have you confirmed that the coil wires are routed correctly.
 It would probably be a good idea to get new plugs. After they've been fouled a few times, they're just not right.
 New plug caps? Trim back the plug wires a mm or two and install new caps and new plugs. Ground each plug on the head, one at a time, and see if you're getting spark. Especially on #1 and #3, since those are the suspects.

good idea. I'll check that out and just do it for piece of mind even if it does not seem related. And I'll put the chain on my list after 3k svc...

[robvangulik]

I'm still not convinced you've got the plug leads in the right order, you keep talking about 1 and 3 , and 2 and 4 as pairs, and that is not right. I looked at your films several times and still cannot see if they are correct.
Make a clear picture of those leads and convince me you got it right, please.

[juntjoo]

I'm still not convinced you've got the plug leads in the right order, you keep talking about 1 and 3 , and 2 and 4 as pairs, and that is not right. I looked at your films several times and still cannot see if they are correct.
Make a clear picture of those leads and convince me you got it right, please.

2&3 on the right, 1&4 on the left. scout's honor

[Scott S]

 The leads or the coils themselves?

 The 1/4 coil wires go to the two outer plugs.  The 2/3 coil wires go to the two inner plugs.

[Yamahawk]

As your bike sounds like it is running correctly, except for some small details, I would have to say your plug wires are on correctly. The one coil feeds the outer two cylinders, 1-4 - the other coil feeds the two inner cylinders 2-3. I believe this is what you said. Now, get that 3k checklist and do everything it says, including adjusting the cam chain. It can be responsible for your timing being out due to it being loose, and the cam not held in the proper position. If you find it still isn't coming off idle properly, it may well be the carburetors have an idle mixture passage not passing fuel in one of them or possibly more than one.
Charlie

[juntjoo]

The leads or the coils themselves?

 The 1/4 coil wires go to the two outer plugs.  The 2/3 coil wires go to the two inner plugs.

coils

[juntjoo]

Just waiting on multimeter/tachometer to do timing and idle adjustment and carb sync tool to do that.

Re-did cam chain tension. No help.

In the meantime will finish brakes, loctite choke plate screws I forgot and other maint. stuff. BTW why might the 1&3 carbs causing this? Remember wetter plugs. Floats too high? Could that cause too much fuel? So I can check those out too.

Have to always charge the battery for a couple minutes after a while but I guess that's cuz Im not riding the bike. If that's the most you gotta worry about the charging system, not a biggie. Tho I might get a lower wattage led headlight or whatever people get. But I digress..

Or could the pilot screws have something to do with it? As previously mentioned I I experimented turning them in then out drastically and noticed no change but suppose they're dirty, less air = more fuel = too much? or not. I'll check those too after taking off carbs...

[Yamahawk]

Just waiting on multimeter/tachometer to do timing and idle adjustment and carb sync tool to do that.

Re-did cam chain tension. No help.

In the meantime will finish brakes, loctite choke plate screws I forgot and other maint. stuff. BTW why might the 1&3 carbs causing this? Remember wetter plugs. Floats too high? Could that cause too much fuel? So I can check those out too.

Have to always charge the battery for a couple minutes after a while but I guess that's cuz Im not riding the bike. If that's the most you gotta worry about the charging system, not a biggie. Tho I might get a lower wattage led headlight or whatever people get. But I digress..

Yes, that could be a reason. I have a feeling it is your carburetors after listening to your video. Many times we think it is ignition related, when it really is a fuel issue. If you had the carbs off and disassembled as far as the choke plates, there is a good chance something isn't adjusted correctly. Float level can cause a rich condition if they are too high.
But, here is a good encouragement... you haven't given up, and you are making progress. My own mechanical abilities came from trial and a lot of error when I was younger. I didn't have anyone who I could ask about the bikes I owned, so I bought a manual, and learned. Now we have forums, and web pages, and all sorts of help that can be called upon when we haven't a clue... and really, that's a good thing.
Charlie

[Scott S]

 Out of synch carbs can make a bike sound terrible.

[juntjoo]

Just waiting on multimeter/tachometer to do timing and idle adjustment and carb sync tool to do that.

Re-did cam chain tension. No help.

In the meantime will finish brakes, loctite choke plate screws I forgot and other maint. stuff. BTW why might the 1&3 carbs causing this? Remember wetter plugs. Floats too high? Could that cause too much fuel? So I can check those out too.

Have to always charge the battery for a couple minutes after a while but I guess that's cuz Im not riding the bike. If that's the most you gotta worry about the charging system, not a biggie. Tho I might get a lower wattage led headlight or whatever people get. But I digress..

Yes, that could be a reason. I have a feeling it is your carburetors after listening to your video. Many times we think it is ignition related, when it really is a fuel issue. If you had the carbs off and disassembled as far as the choke plates, there is a good chance something isn't adjusted correctly. Float level can cause a rich condition if they are too high.
But, here is a good encouragement... you haven't given up, and you are making progress. My own mechanical abilities came from trial and a lot of error when I was younger. I didn't have anyone who I could ask about the bikes I owned, so I bought a manual, and learned. Now we have forums, and web pages, and all sorts of help that can be called upon when we haven't a clue... and really, that's a good thing.
Charlie

heck yeah. 'props' to you learning  before the internet. I did brakes, gaskets and a clutch by the manual in the late 90's and that was tough enough for me. internet is a godsend in this respect.

[juntjoo]

compression 1,2,3 & 4 https://imgur.com/a/MXrkx

in going into the head.

if I don't return within 24 hrs call 911...

[juntjoo]

compression after oil added 1,2,3 & 4 https://imgur.com/a/9uezu

[Scott S]

The leads or the coils themselves?

 The 1/4 coil wires go to the two outer plugs.  The 2/3 coil wires go to the two inner plugs.

coils

 Just to confirm: The 2/3 coil is on the right, but you don't have the two plug wires from that coil going to the two right cylinders, do you?
 And the 1/4 coil is on the left, but you don't have the plug wires going to the two left cylinders, do you?

 The wording in the previous posts is a little confusing.

[juntjoo]

The leads or the coils themselves?

 The 1/4 coil wires go to the two outer plugs.  The 2/3 coil wires go to the two inner plugs.

coils

 Just to confirm: The 2/3 coil is on the right, but you don't have the two plug wires from that coil going to the two right cylinders, do you?
 And the 1/4 coil is on the left, but you don't have the plug wires going to the two left cylinders, do you?

 The wording in the previous posts is a little confusing.

sorry

"The 1/4(LEFT SIDE) coil wires go to the two OUTER plugs.  The 2/3 coil(RIGHT SIDE)  wires go to the two INNER plugs."

anyway, book says if after adding oil and compression "returns to normal, the valves are good but the piston rings are defective". For sure? Wouldn't any pair of piston and rings produce more compression after a dose of sealing sealing oil?

[juntjoo]

Check this out: if 1&3 are wet and cold and producing BETTER compression than 2&3 my inner sherlock says it might be the exhaust valves not staying open long enough causing tighter compression and interfering with combustion no?

well that's where I was going anyway....

[juntjoo]

another listen if ya wanna listen

[juntjoo]

do coils fail altogether or does one cylinder usually fail to fire?

[scotto84]

I'm having a very similar issue, bike sounds the same at ow rpm's as well. Curious to see what it may be. I just posted a thread about it earlier but it hasn't been posted yet

[juntjoo]

great news, my timing is OFF! that could mean an easy fix, *fingers crossed*

but what special tool do I need or special trick is there to get those Philips head screws off the timing plate? And how do you even get sideways leverage on it? I wish there were a wall next to this side of the bike. I tried wd40 and hit the heads of them with a hammer behind a small punch. There's gotta be an easier way.

[juntjoo]

How to get a large seized philips head scew out. https://imgur.com/a/pOOyY