Author Topic: Did I kill it?  (Read 3236 times)

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Offline Cartman98

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Did I kill it?
« on: September 12, 2009, 04:27:59 PM »
I just changed the nasty oil for the first time since I bought it.  It has always started really nice and easy, no choke, just tap the starter button and it fires and idles.  I wasn't sure exactly what I was supposed to do when waiting for the oil to drain down and I read a little about it and someone said kick it over several times and then fire it up.  Well I did that and the oil light was on for the whole time (30 seconds or a bit more) so I got worried then shut it off.  I found advice that said to open the plug above the points cover and put a little oil in there and then kick it over.  I did that and then the oil went down to the appropriate level. 
So what happened?  I fired it up with the oil at the proper level and it didn't want to stay idling.  I took it down the road and it would kill every time I let off the gas.  It is not firing on 3 and 4 at all, the pipes are cold to the touch but 1 and 2 are hot.  Could I have broken something?  What should I look for?  I don't have time to check right now so I figured I'd ask and see what the general consensus was while I am at work.  Thanks for any help!

Offline Laminar

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Re: Did I kill it?
« Reply #1 on: September 12, 2009, 04:40:06 PM »
Do I understand correctly that you actually ran the engine with the oil drained? Not just turned it over by hand/kick-start, but you started up and ran the engine?

If so, you might have messed it up. Do a compression check to make sure you didn't fry any rings and ruin your cylinder walls.

Offline Cartman98

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Re: Did I kill it?
« Reply #2 on: September 12, 2009, 04:45:35 PM »
I kicked it over several times (30?) then fired it up like someone here suggested... Probably a bad idea.  Could running it for such a short time kill the rings?

Offline Ogri

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Re: Did I kill it?
« Reply #3 on: September 12, 2009, 05:08:00 PM »
I'm still not clear on whether you ran the engine for 30 seconds before you put fresh oil in or after. If you can first answer that then everything will be clearer.

Personally, and I hasten to add I'm no engineer, I don't think running the engine for 30 seconds at moderate RPMs with no oil in it will do any major damage. Unless of course the engine had been sitting for a while and all the oil had run off of every bearing surface. Did you warm up the engine before draining the oil? If you did, I think it's highly unlikely any damage was done. Oil is clingy, it will be held between bearing surfaces for a long time.

I think what you read concerning kicking the engine over when changing the oil relates to pumping out the last dregs. You might also be confusing that advice with starting a rebuilt engine for the first time, when you need to pump oil around the engine, fill all the oilways etc. without the presence of heat from combustion.

Lastly, I don't think the running problem you now have is related to the oil issue. Sounds like a fuel problem to me.

Offline bucky katt

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Re: Did I kill it?
« Reply #4 on: September 12, 2009, 05:44:55 PM »
i wonder if the cam siezed and broke right after the sporcket?
Of all God's creatures there is only one that cannot be made the slave of the lash. That one is the cat. If man could be crossed with the cat it would improve man, but it would deteriorate the cat.
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Offline Cartman98

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Re: Did I kill it?
« Reply #5 on: September 13, 2009, 01:03:51 AM »
Ha!  No, I did not run the engine without adding the oil first.  Sorry that wasn't clear.  The engine was pretty much completely drained of oil, and had been sitting for a while without oil because I needed to replace a engine cover seal. 

The thing is, it ran and idled fine the first time I started it, and then the next time I fired it 5 minutes later it didn't run.  It wouldn't seem like a fuel problem to me, but then I'm no mechanic either (obviously!).

Offline mystic_1

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Re: Did I kill it?
« Reply #6 on: September 13, 2009, 09:05:19 AM »
What bike is this?




I'd pop the tappet covers on #4 exhaust and make sure the valves are operating, that'll eliminate the possibility that you snapped your cam shaft.  A coil problem would affect 1+3 or 2+4 as those share coils.  Problems running on 3+4 are often fuel related.  Early 750's had two fuel hoses from the petcock each feeding two carbs, you problem might lie there if you have that model bike or one with a similar fuel system.

At this point I'd suggest running through the whole tune-up process, something will likely turn up.

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Offline Cartman98

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Re: Did I kill it?
« Reply #7 on: September 13, 2009, 08:22:36 PM »
It is a '75 750. 

The only thing I'm having a problem believing is that is is fuel related.  Maybe electric...  How would it go from running great 1 minute and not 20 minutes later?
I'll try check the valves and get back to you guys.

Offline Ogri

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Re: Did I kill it?
« Reply #8 on: September 14, 2009, 12:22:02 AM »
It is a '75 750.  
=  How would it go from running great 1 minute and not 20 minutes later?


Dirt/rust particles in the fuel tank getting into the carbs and blocking the idle circuit or even just blocking fuel flow at the petcock ?

If you've not done so already I'd check the carb float bowls, the amount of fine red dust at the bottom will indicate the probable state of your carb fuel circuits.

If you pull off the fuel hose from the fuel tap and open the tap, does the fuel come out in a healthy stream ? Catch the fuel in a glass jar and inspect it for particles.
« Last Edit: September 14, 2009, 12:30:15 AM by Ogri »

Offline Cartman98

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Re: Did I kill it?
« Reply #9 on: September 14, 2009, 11:48:21 AM »
I just checked it all and the valves move on 3 & 4 so that made me happy.  I checked for spark on 3 and 4 and it seemed pretty weak in comparison to 1 & 2.  I'm just going off the color of the spark using the same spark plug and moving it to different wires.  Is there a better way to check the coil?  Or should I be looking at the points?

Offline Jay Allen

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Re: Did I kill it?
« Reply #10 on: September 14, 2009, 12:52:05 PM »
You may have accidentaly knocked the blue or yellow wires connectors apart for your points. They are sorta right behind your rear brake switch above your swing arm axle

Offline Ogri

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Re: Did I kill it?
« Reply #11 on: September 14, 2009, 01:24:23 PM »
It's a fuel problem. You need to pull the carbs off and clean the idle circuits out with spray carb cleaner. Then fit an inline fuel filter in the fuel hose to the carbs.

It ran and idled fine the first time you started it..then it sucked a bunch of crap from the tank into the carbs and blocked the passages/jets. It didn't block the main fast running jets because the motor was idling; the dirt in the fuel went through the much smaller diameter idle jets and blocked them.

 Did you at any time turn the fuel tap to Reserve by any chance ?
« Last Edit: September 14, 2009, 01:28:13 PM by Ogri »

Offline Laminar

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Re: Did I kill it?
« Reply #12 on: September 15, 2009, 06:45:54 AM »
I'd pop the tappet covers on #4 exhaust and make sure the valves are operating, that'll eliminate the possibility that you snapped your cam shaft.  A coil problem would affect 1+3 or 2+4 as those share coils.

Call me crazy, but all of my Hondas have 1+4 and 2+3 sharing coils.


Offline mystic_1

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Re: Did I kill it?
« Reply #13 on: September 15, 2009, 01:32:19 PM »
No you're not crazy, I'm just a slightly dyslexic dumbass  :D  You're right of course and that's what I meant, the point being that 3+4 don't share a coil.

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Offline Cartman98

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Re: Did I kill it?
« Reply #14 on: September 16, 2009, 05:30:42 PM »
Ok.... If 3 & 4 don't share a coil...then WTH?  I checked the compression, it was about 90 psi on all cylinders.  Maybe I'll check the carbs.

Offline Laminar

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Re: Did I kill it?
« Reply #15 on: September 17, 2009, 05:53:01 AM »
Ok.... If 3 & 4 don't share a coil...then WTH?  I checked the compression, it was about 90 psi on all cylinders.  Maybe I'll check the carbs.

When you cranked it/kicked it over, were you holding the throttle wide open? 90psi just sounds a little low. My '77 750 got 150psi completely cold after not running for a year.

Offline Cartman98

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Re: Did I kill it?
« Reply #16 on: September 26, 2009, 02:59:20 PM »
Okay, now I changed the plugs and it runs on 1 and 4 but not 2 and 3... Cleaned the connection on the 2 and 3 coil and it seems to run a little just by feeling the exhaust.  I'm guessing the points are off.  Now I'll attempt to figure out how to adjust the points.  Am I correct in thinking that one set of points is for 2 and 3 are together?

Offline mystic_1

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Re: Did I kill it?
« Reply #17 on: September 27, 2009, 06:33:54 AM »
That is correct.  Do you have a manual?  If not, go here and download one:

http://forums.sohc4.net/index.php?topic=17788.0

mystic_1
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Offline Cartman98

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Re: Did I kill it?
« Reply #18 on: September 27, 2009, 05:00:36 PM »
Don't ask me what is going on, but I messed with the timing, and now it runs great!.... On 2, 3, and 4.  1 does not run so great.  I must have reset the timing 5 times today, and after I put a new plug in 1 that cylinder seems to be firing somewhat. It has plenty of power down low, but it doesn't like anything over 6k RPM.  It pops and sputters and all that.  I heard there is a pointsless ignition available for these things, are they good?  Easy to set up?  Do they require days of work to set them correctly?

Offline Cartman98

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Re: Did I kill it?
« Reply #19 on: September 27, 2009, 05:03:03 PM »
Yup got the manual download.  Maybe I should invest in a timing light so I can do this like the manual says...
That is correct.  Do you have a manual?  If not, go here and download one:

http://forums.sohc4.net/index.php?topic=17788.0

mystic_1

Offline shizzomynizzo

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Re: Did I kill it?
« Reply #20 on: September 27, 2009, 05:14:25 PM »
yes, you can pick one up for under 20 bucks, at most auto parts places. I got an old craftsman from my dad. They really do work great. once you get it done once or twice, it will come natural!

you'll look back and laugh how easy it was once it's done.
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Offline mystic_1

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Re: Did I kill it?
« Reply #21 on: September 27, 2009, 07:44:33 PM »
Once you become accustomed to points-based ignitions, setting them up and tuning them becomes a very quick proposition.  I think a full tune-up on my bike takes maybe an hour or two at most.

mystic_1
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Offline tomsweb1

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Re: Did I kill it?
« Reply #22 on: September 27, 2009, 07:48:02 PM »
I had a similar issue with my old girl. turned out to be carbs. What colour are your plugs when you take them out? Something tells me they are black and sooty.
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Offline Cartman98

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Re: Did I kill it?
« Reply #23 on: September 29, 2009, 09:08:45 AM »
Yeah, black and sooty, I despise every second of working with carbs, I can never seem to get them running properly.  The guy I bought it from told me that the bike had been sitting for a while and there was garbage in the bowls.  I haven't had them apart yet personally.  I did notice just now that there was something (gas?) on the floor right below the overflow lines. 

Offline mystic_1

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Re: Did I kill it?
« Reply #24 on: September 29, 2009, 09:20:09 AM »
I did notice just now that there was something (gas?) on the floor right below the overflow lines. 

OK, there's yer problem :)

One or more carbs is flooding leading to a super-rich condition.  Probably crap in the float valves.

I see a carb cleaning session in your future.  :)

mystic_1
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