Author Topic: Bike sputtering, oil on fins, oil on plug #3 - Where to start?!  (Read 2853 times)

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Offline jdubb1977

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All right gents, having some problems here that I'm hoping you can help out with.  Bike in question is a 1976 750F. 

History: I've owned it for about 4 1/2 years.  It's pretty much always left me smelling like exhaust after a ride (head gasket?), but has ran reasonably well.  Over the past few months about half the time it'll run well from the start.  The other half it sounds like it's maybe not firing on all cylinders, but after warmed up for 10-15 min it steadies out and runs great.  Carbs thoroughly cleaned recently, good air cleaner, new battery. 

Now: sputtering like crazy, and very little power.  However, as it sputters the power fluctuates up & down while riding.  the #2 & #3 pipes taking a looong time to heat up.  Found oil on plug #3 (all others look good, maybe slightly rich).  There's oil on the fins also.  That's been an ongoing issue, but the weeping has increased. 

Solutions?  Top end rebuild?  I've rebuilt much of the bike, but never pulled the engine...so feel free to talk me through things like I'm a 5yr old! 

Offline flybox1

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Re: Bike sputtering, oil on fins, oil on plug #3 - Where to start?!
« Reply #1 on: March 18, 2014, 01:41:08 PM »
What is your goal?
Get it to run better?
or, get it to run better AND stop leaking oil?

the former take a weekend, or less, and involves completing the 3000 mi tuneup.
the latter, if done properly, involves engine removal for new gaskets.
but along the way to installing new gaskets you might want to do all sorts of other stuff costing lots of money, and hours in the garage, so be prepared. ;D

IIWM, and I knew riding season was just getting started, id do the the maintenance and then stick a bunch of oil-wicking rope between the fins, changing as needed, and enjoy riding season with the plan for a tear down in the fall.
'78 750K (F3 engine) PD42b's, Modified airbox w/K&N  filter, 40/110 jets, 1 needle shim, IMS@ 1 turn out. Kerker + Cone 18" QuietCore

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Offline jdubb1977

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Re: Bike sputtering, oil on fins, oil on plug #3 - Where to start?!
« Reply #2 on: March 18, 2014, 02:56:17 PM »
Thx Flybox.  Ideally I'm going for running well, no oil weeping, and hopefully no more exhaust smelling pants after every ride.  I'm in San Diego, so riding season is pretty much year round.  Any down time is a bummer.   :(  And yes, I'm definitely afraid that I'll get a case of the "Well, since it's torn apart I might as well..." mentality! 

So does a top end rebuild sound like it'll most likely put me back on the street? 

Offline ekpent

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Re: Bike sputtering, oil on fins, oil on plug #3 - Where to start?!
« Reply #3 on: March 18, 2014, 06:39:31 PM »
If its cylinder 2 and 3 not running right it could be a bad set of points or condensers that run those two cylinders or maybe a coil connection or issue. The weepy head gasket won't on it own make it run bad per say.

Offline jdubb1977

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Re: Bike sputtering, oil on fins, oil on plug #3 - Where to start?!
« Reply #4 on: March 18, 2014, 07:12:40 PM »
Yeah, the head gasket is more of a nuisance than anything. Could a points/condenser be an intermittent issue?

Offline grcamna2

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Re: Bike sputtering, oil on fins, oil on plug #3 - Where to start?!
« Reply #5 on: March 18, 2014, 08:09:16 PM »
Yeah, the head gasket is more of a nuisance than anything. Could a points/condenser be an intermittent issue?

I think the electrical/ignition is usually the weakest link as far as intermittent running goes IMO.
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Offline jdubb1977

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Re: Bike sputtering, oil on fins, oil on plug #3 - Where to start?!
« Reply #6 on: March 18, 2014, 09:21:42 PM »
Here's a pic of my 2-3 point.  There is a nice divot right in the middle of both sides of that point.  Ya think that's enough to affect cylinders 2&3 from firing properly?  Also, point 1-2 looked pretty good, w/ just a tiny divot right in the middle.  Like pin-sized.  New points, or should we keep exploring? 

Offline Stoli

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Re: Bike sputtering, oil on fins, oil on plug #3 - Where to start?!
« Reply #7 on: March 19, 2014, 03:33:23 AM »
The oil leak is not necessarily your head gasket. There is a chance it is just one of the cam tower pucks (although your pics indicate it is likely the head gasket). Lots of threads on here about that. In general, if the oil is only on your cylinder fins, then it is likely your head gasket but if the oil is on the 2nd or 3rd fin up from the bottom of the head, then it could be a puck. You still have to pull the engine to replace the pucks but much easier than replacing the head gasket. As others have mentioned, the roughness and oil leak are probably not related.
« Last Edit: March 19, 2014, 03:46:29 AM by Stoli »
My Project Threads:
Project #1 - http://forums.sohc4.net/index.php?topic=117106.0  First bike
Project #2 - http://forums.sohc4.net/index.php?topic=127364.0  Something different
Project #3 - http://forums.sohc4.net/index.php?topic=123831.0  Long and Low

AJK

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Re: Bike sputtering, oil on fins, oil on plug #3 - Where to start?!
« Reply #8 on: March 19, 2014, 03:58:16 AM »
Yeah, Stoli is right, you need to chase it further. I've got a post here about where to look for a leaky puck.
http://forums.sohc4.net/index.php?topic=134800.msg1514858#msg1514858

Offline ekpent

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Re: Bike sputtering, oil on fins, oil on plug #3 - Where to start?!
« Reply #9 on: March 19, 2014, 05:02:08 AM »
I wo
Here's a pic of my 2-3 point.  There is a nice divot right in the middle of both sides of that point.  Ya think that's enough to affect cylinders 2&3 from firing properly?  Also, point 1-2 looked pretty good, w/ just a tiny divot right in the middle.  Like pin-sized.  New points, or should we keep exploring? 
It won't hurt to file and clean them up a little. Try some new plugs in the colder cyclinders also to see if that helps for awhile. I am not a big fan of cleaning old plugs.

Offline grcamna2

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Re: Bike sputtering, oil on fins, oil on plug #3 - Where to start?!
« Reply #10 on: March 19, 2014, 05:49:28 AM »
I know it wouldn't hurt to adjust your valves and readjust your cam chain.
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Markcb750

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Re: Bike sputtering, oil on fins, oil on plug #3 - Where to start?!
« Reply #11 on: March 19, 2014, 05:58:40 AM »
The guys are right sounds like a spring tune up. 

A lot of oil can flow from the Tach connection.  I wrote this up, works like a champ everywhere I have tried it.

http://forums.sohc4.net/index.php?topic=133247.0

The head gasket issue is a PIA, as the guys say be prepaired.

Couple of things I have found on my K6

1  Keep the RPM in the 5K range or below most of the time.  I found that chasing NikkiSixx thru the mountains and down the interstates at 6500 to 7500 rpm increases the oil loss exponentially, as much as a quart every tank during one run from Barber Sports Track to Charlotte. (now I run the 900  ;))

 2. I use brake cleaner to clean up the motor, I use the chlorinated CRC brake cleaner which some are aftraid of it because it will create poison gas if you use it around welding ::).  I find it pretty damn nice, melts off the baked on oil and does not harm anything rubber.

I have tried using a piece of cotton rope stuffed in the fins at the head gasket to act as a tampon, but the lower RPM approach works better IMHO.

My K6 has 32,500 miles on it.

Mark
« Last Edit: March 19, 2014, 06:07:22 AM by Markcb750 »

Offline jdubb1977

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Re: Bike sputtering, oil on fins, oil on plug #3 - Where to start?!
« Reply #12 on: March 19, 2014, 03:13:53 PM »
Sounds like the consensus is that I've got a couple of unrelated issues:  weeping from the fins, and the cylinder 2 & 3 problem.  Hey, one problem at a time would be too easy!  And I agree that not pulling the engine is definitely preferable. 

Any good tips on testing my coils w/o an actual tester?  That's what the manual calls for, but of course my garage toolbox didn't come w/ one.  :) 

AJK: thanks for sending thank link along.  i'm going to give the fins a good scrub down and see if I can trace the oil leak.  it's still pretty minor (weeping, not dripping), so unless it gets worse I might just throw some cotton rope btwn the fins (if that's where the oil's coming from) for the time being.  I'm guessing that wind won't dislodge it?

Ekpent:  good call.  i'll file the points down a bit to get rid of that divot, & try some new spark plugs.  Z1 has a points/condensers kit for $16, so maybe I should just swap for the new ones?

grcamna2:  also a good call.  i've never adjusted my valves or cam chain, but it's time i learned!

markcb750:  oh man, keeping the rpm's below 5k would be tough! my first few motorcycles were modern sportbikes, so going slow and mellow isn't a habit i've ever learned.  :)  i just bought another gallon of simple green for cleaning, along w/ some fine brass wire brushes and a stiff nylon brush.  if those fail, i'll grab some brake cleaner and keep it away from any open flames!

Offline grcamna2

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Re: Bike sputtering, oil on fins, oil on plug #3 - Where to start?!
« Reply #13 on: March 19, 2014, 04:51:39 PM »
jdubb,
Get some Quality points,ND's are better than Diachi's..,by a mile.  ::) When buying points go w/ Japanese O.E. style(Chinese points suck),I wonder if they're still available through Honda ?
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Offline jdubb1977

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Re: Bike sputtering, oil on fins, oil on plug #3 - Where to start?!
« Reply #14 on: March 19, 2014, 08:48:23 PM »
thanks for the advice on the points.  good japanese ones are about double the chinese, but still inexpensive.  i guess my question is, are the divots on my current points enough to cause a problem?  Here's why I'm skeptical....I'm getting spark from all 4 plugs.  doesn't matter if plugs are new or old, they're still sparking.

I did discover something though.  Decided to check inside the plug caps, where they connect to the cables.  1 & 4 were dull.  2 was duller.  and 3 was covered in oil & grime. 

so do I start w/ new cables & caps, and hope that that solves it?  maybe hold off on the points? 

Offline ekpent

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Re: Bike sputtering, oil on fins, oil on plug #3 - Where to start?!
« Reply #15 on: March 20, 2014, 05:28:30 AM »
Most of the time when folks get new projects one of the suggested to do things is to remove the spark plug caps, they just unscrew, and test them to see if the resistors are good or bad. Then clip about 1/4" of wire off the old leads when reinstalling to get into some fresh meat on those wires.  Coil problems are not real common but the fact that both your 2 and 3 may be running cooler could point to something in that loop.
  Here is a starter thread on testing caps, more on the google search  http://forums.sohc4.net/index.php?topic=67096.0
« Last Edit: March 20, 2014, 05:30:26 AM by ekpent »

Markcb750

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Re: Bike sputtering, oil on fins, oil on plug #3 - Where to start?!
« Reply #16 on: March 20, 2014, 06:14:33 AM »

markcb750:  oh man, keeping the rpm's below 5k would be tough! my first few motorcycles were modern sportbikes, so going slow and mellow isn't a habit i've ever learned.  :)  i just bought another gallon of simple green for cleaning, along w/ some fine brass wire brushes and a stiff nylon brush.  if those fail, i'll grab some brake cleaner and keep it away from any open flames!

Which is why I have the 900F..:)

Offline jdubb1977

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Re: Bike sputtering, oil on fins, oil on plug #3 - Where to start?!
« Reply #17 on: March 20, 2014, 02:10:23 PM »
Ekpent:  I'm hoping that the coils are good!  a while back my tach cable sprung a leak, and I replaced the seal.  i'm wondering if some of that oil dripped down onto the #3 plug boot and started to crud things up.  i took your advice and trimmed 1/4" off.  things were still bad, so i trimmed some more until i got to a nice clean spot in the wire.  now it may be a bit too short. :) 

just ordered new boots, some spark plug wire, and the NGK splices.  gonna trim the stock wires up near the coils, splice in some fresh wire & new boots.  hopefully that'll do it!

Offline grcamna2

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Re: Bike sputtering, oil on fins, oil on plug #3 - Where to start?!
« Reply #18 on: March 20, 2014, 02:17:33 PM »
Have any of you ever used the NGK splice kits ? I've heard about them but don't have any experience w/ them.
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Do your BEST...nobody can take that away from you.

Offline jdubb1977

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Re: Bike sputtering, oil on fins, oil on plug #3 - Where to start?!
« Reply #19 on: March 20, 2014, 03:53:16 PM »
I'll take some pics and let you know how they do next week.  Seems like they're pretty simple.  Someone recommended off-setting them a little & keeping them high since they're a little bulky.

Offline mcswny

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Re: Bike sputtering, oil on fins, oil on plug #3 - Where to start?!
« Reply #20 on: March 20, 2014, 04:12:26 PM »

I'll take some pics and let you know how they do next week.  Seems like they're pretty simple.  Someone recommended off-setting them a little & keeping them high since they're a little bulky.

Yeah I'm curious about the split kits, my wires are almost too short.


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Offline jdubb1977

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Re: Bike sputtering, oil on fins, oil on plug #3 - Where to start?!
« Reply #21 on: March 20, 2014, 08:43:16 PM »
Victory!  I cleaned up & clipped the old plug wires & cleaned the old plug caps.  Bike fired right up & ran on all 4 cylinders from the start.  Hopefully it'll hold up until I get the new parts in.  Felt good to have things back in order, so I took a victory lap down to the beach.  ;D  In my excitement I forgot to put the air filter back in, which resulted in a nice flat spot around 5k rpms. 

The real PITA was when I dropped plug #3 down into the engine while trying to get it threaded in.  The stupid plug got stuck in there & it took me the better part of 45min to get it out.  Ugh.  Finally got it out of there after much sweating and dislocating my wrists. 

Offline grcamna2

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Re: Bike sputtering, oil on fins, oil on plug #3 - Where to start?!
« Reply #22 on: March 20, 2014, 10:22:13 PM »
Great news It's nice to have it firing on all cylinders.  :)
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Offline mcswny

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Re: Bike sputtering, oil on fins, oil on plug #3 - Where to start?!
« Reply #23 on: March 21, 2014, 05:34:07 AM »

Victory!  I cleaned up & clipped the old plug wires & cleaned the old plug caps.  Bike fired right up & ran on all 4 cylinders from the start.  Hopefully it'll hold up until I get the new parts in.  Felt good to have things back in order, so I took a victory lap down to the beach.  ;D  In my excitement I forgot to put the air filter back in, which resulted in a nice flat spot around 5k rpms. 

The real PITA was when I dropped plug #3 down into the engine while trying to get it threaded in.  The stupid plug got stuck in there & it took me the better part of 45min to get it out.  Ugh.  Finally got it out of there after much sweating and dislocating my wrists.

Great to hear! Did you have to use the splice kit?


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Offline ekpent

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Re: Bike sputtering, oil on fins, oil on plug #3 - Where to start?!
« Reply #24 on: March 21, 2014, 05:57:07 AM »
Some folks use a piece of rubber tubing over the end of the spark plug to get a little grip on them to get them to start threading in. Kind of like a rubber tube handle  ;)