Topic: Oil pressure light on after highway speeds?

[csendker]

New to CB’s, new to biking.  I’ve been driving it around town; 7 miles to work, 35-45 mph for a couple of months.  Everything seems to be running OK until I took it on the highway for a 60 mile run, at 65 mph.  Besides scaring the crap out of myself, the motor seemed to run hot.  Then the oil light came on when I was at idle.  I had to hold the idle up higher & higher to keep the light off; like 2+K rpm.  I ran it straight home and parked it.  No problems since then, all back to normal.

I’m thinking I’m running rich:  wife says I smell like gas whenever I get off, MPG not good – 28mpg, runs better with air filter off – smoother operation and no popping when slowing down in gear.  35K miles on it, only 1K are mine.  I have no idea what has been done in the past.  It has an aftermarket 4-1 exhaust, looks like original carbs, with no idea if they have been modified.  Standard ignition with new plugs, points & condenser when I got it.  Any thoughts?  Thanks.

[MetalHead550]

Check this out..

http://www.sohc4.us/forums/index.php?topic=1143.0

Yeah you are running rich.  Read the carb FAQ, then do a search(on this site) on Plug Chop, reading plugs, carb adjustment, pilot screw/adjustment.  Any ? after that let us know.  Later!

[csendker]

Thanks, I'll dig into this after I get home.  I had looked into the carb FAQ (that's where I got my 'running rich' idea from), and thought about looking at the plugs, but I need a spark plug wrench that actually fits to pull the plugs, and carbs scare the heck out of me.  It's been a long time since I fooled around with any engines, and I don't want to screw the bike up so it doesn't work.  I thought about trying to score a spare set of carbs and play with them to learn, but I want to make sure they would eventually work and aren't just for fun.  How interchangable are they?

[hymodyne]

your oil pressure light may indicate low pressure issues that relate to the condition of your oil pump assembly. It may also have to do with the type of oil you are running in your engine.  I started with the cheapest of cheap in the engine, only to find out as I transitioned to castrol , then to rotella T that most of my indicator light issues went away.

hym

[MetalHead550]

Yeah I agree, when I first got into MCs I found wrenching on them to be intimidating, but only because it was different.  These bikes are damned simple though and if you are reasonably mechanically inclined you will have no prob. digging into them.  You just gotta do it, and youll surprise yourself with what you can learn and accomplish.   Thats a great idea as far as getting spare carbs to learn with.  Just make sure they are from a 74-76(those are the ones I know for sure) 550K model.  The Fs have different jets.  You could make carbs from a 77+ work but youd need a differnet intake manifold etc.  This link is a good intro to carb theory.  Cool stuff!

 http://hondaex.com/techtips/carb101.htm

[MetalHead550]

I second the Rotella T 15w-40.  dont want to start a war though!  Check this link on plug readings.  They will tell the story of whats happening in your cylinders.  credit twotired.

http://www.dansmc.com/Spark_Plugs/Spark_Plugs_catalog.html

[Einyodeler]

 Have you ever seen gas under the bike when parked thats coming out of the carb drain hoses ? The reason I ask is because a stuck float valve can let gasoline into your oil and that will thin it down enough to cause oil pressure problems.

[TwoTired]

Are we talking about an F model CB550?

Oil light issue. 
Could be the pressure sender failed or gunked up and falsely indicating.
Could be very thin oil.
Could be worn out oil.
Could be oil pump wear.
Could be main and rod bearing clearances to large (worn).
Wouldn't it be nice to know just what the pressures was when the light is on?

Just to scare you.      Low oil pressure can deprive the cylinder walls of lubrication.  The increased friction makes the engine run quite a bit hotter.
Poor spark timing can also make it run hot.

Your fuel mileage is dismal.  Especially for an F model.  Before you attack carburetion, though, do a complete tune up.  Plugs, points, timing, cam chain tension, tappets and air filter.  This should be done every 3000 miles anyway.  I find the UNI foam replacement filter flows a bit freer than stock.  But, if you operate in dusty environments the stock paper type saves wear on the engine cylinder walls.

The carb bodies look the same for all Cb500/550 models prior to 77.  However, internal parts and set up are different, depending on displacement and exhaust type.  550 F Carbs are stamped 069A, 550K carbs are stamped 022A, and 500 carbs are stamped 627B.  There's a chart in FAQ with specifics.

Cheers,

[csendker]

It's a 1975 CB550 K1 I bought in August.  I had it tuned up by a reliable mechanic when I bought it; I wanted someone in the know to OK it as safe before I started.  Plugs, points & paper air filter have about 1,000 miles on them.  Buffalo, NY in the late summer & fall isn't very dusty; great weather actually (I've been considering the foam replacement).  I'm hoping it's something simple other than playing with the carbs.

This only happened once, and only after my one and only long high speed run.  I'm thinking that if it were part of the oil pump system, it would show up at other times.  It runs great on a daily basis, but it ran increasingly bad on the high speed run.  Seemed very hot, ran rougher & rougher, oil light flickering.  Paranoid, I parked it for the rest of the day.  I thought that it just overheated, thinned the oil, dropping the pressure.  Next day, and since it's back to 35-45 mph, and running great.  I've had it up to speed since, but short hops only, not an hour solid down the thruway.

This whole issue kind of went away, forgotten until I started trying to figure out why my milage stunk.  I started reading about carb settings, and came upon the symptoms of a rich setup.  I don't know if anything was changed when the 4-1 exhaust was put on.  Then I remembered this incident and thought it is connected.  I'm thinking another full tune-up is a good thing to start with.  Somnething to ease myself back into mechanics. Carbs however, I am thinking of the spare set idea, as I really, really want to drive this again and assume I'll screw something up the first time out.

I bought this because it was cheap, smaller & agile.  I thought that learning on a heavy, expensive bike wasn't a smart idea.  Damn, now I'm hooked with a growing urge to tinker with it.  Spare carbs are an idea, but I'm currently trying to figure out how to convince the wife that I really need a spare bike.  I'm thinking this site is heavily to blame - you guys are great, and infectious. 

Thanks.

Oh, and where are the carb drain hoses?  I haven't seen any gas anywhere though, just a heavy smell when I get off.

[TwoTired]

 Multi grade oil should behave as thicker oil when it get hot.  It is possible to permanently damage oil by overheating it.  It can lose it's viscosity properties, thinning when it shouldn't.

The Oil light was flickering as higher RPMS?  I don't like that!  Visions of doom dance in my head!

When you get to carb adjustments, temporarily mark your throttle, so you can tell what position it is in, 1/4/ 1/2, etc.  Then you will know what in the carb needs adjustment.  And, learn to read your plug deposits, of course.

I think you should treat the oil issue and the rich running issues as separate problems.

There is a hose at the bottom of each carb bowl, that usually runs down just ahead of the rear tire.  The nipple is part of a stand pipe inside the carb bowl.   If the fuel level is too high and reaches the top of the stand pipe, the overflow drains onto the ground.  That is, if the hoses aren't blocked by insect nests or somesuch.

Cheers,

[KB02]

There is a hose at the bottom of each carb bowl, that usually runs down just ahead of the rear tire.  The nipple is part of a stand pipe inside the carb bowl.   If the fuel level is too high and reaches the top of the stand pipe, the overflow drains onto the ground.  That is, if the hoses aren't blocked by insect nests or somesuch.

Or screws...as I once saw on a buddy's bike. (I told him, "We need to fix that.")   

[csendker]

Thanks, and no I've never seen gas below the bike. 

Clarification: The oil light flickered at LOW rpm's -idle speeds- and only after the high speed run.  I had to hold the throttle open to 2-3K rpm to turn the light out and the bike ran progressively worse.  This condition has not happened before or after, only on the day of the long, fast run.

Sometimes my idle will stick at ~2k at a red light, and I have to either blip it or slip the clutch to get it back down, but never an issue with the oil light.  I'm guessing it could be anything from old, sticky cables to gunked up carbs to anyting inbetween.  I've done very little with this, with no idea what the PO may have done.  The more I read here, and with winter approaching, I'm starting an increasingly long list of tune-up/preventative maintenance things to do.

[dusterdude]

pull your dipstick and smell it,see if you can smell gas,if so you know you`re getting gas into the oil.

[csendker]

Dusterdude: does it matter if it's hot or cold?  And what would this tell me anyway?  Shot rings?

Metalhead: great article.  I have to reread it a couple of times to really digets it.

[dusterdude]

cold would be better especially after it sits overnight.if you smell gas that means gas is getting into the engine probably thru the carbs which means are running rich for one reason or the other.

[csendker]

Great.  I'll check it when I get home tonight.  However, I'm religious about shutting the petcock whenever I stop (that "thumb-key-valve" thing...); will this impact any smell?  Would running rich drop my MPG so dramatically?  Especially when it runs great while puttering around town. 

I thought the oil light was related to poor carb adjustment by running real hot at extended high speeds, thus lowering the viscosity and associated oil pressure; particularly noticable when at idle and the oil pump isn't cranking out pressure (I'm assuming the oil pump is geared to the motor, and it's a centrifugal so the pressure would increase with engine speed).  I'm normally running in 5th gear, about 30-40 mph or so, so that's around 2K rpm.  At highway speeds, 5th turned 3-4K rpm (if I recall correctly); where I usually don't go for long periods. 

I'm wondering if maybe it's the main jet that's off because it seemed to be espically bad at an extended higher throttle setting, which is main jet operation territory if I'm not mistaken.  Assuming the jet needle is an integral component of the main jet, this may be off too, thus screwing up the air-fuel mixture enough to suck gas, but not exhibit poor performance.  Then again, being new to motorcycles, I may not know if I have poor performance or not.  The 4-1 exhaust may have been added with no carb modifications.  Hmmmm.  Information overload.

[csendker]

I ran without the air filter for one tank, it ran smoother and my milage jumped to 36 mpg.  While only one tank, it has been consistently in the upper 20's, never into the 30's.  I have a paper air filter that I thought was fairly clean and new (<1,000 miles), but now I'm not so sure.  I'm going to order a Uni foam filter, as they seem to flow a little better.  Besides, I like cleanable on lieu of replacement.

I went to the local Wally-world to pick up new oil & filter.  I got a couple of Fram filters, but the only Shell Rotella thay have is 5W-40.  Anyone have any issues with the 5W vs. the 15W?  A little thinner may not be a bad thing when it's cold out (this is Buffalo, NY...).

I wanted to change only one thing at a time, to discover each modification's impact.  However, I'm going directly to good oil and a good air filter, as they should both be there anyway.  I'm not sure I'll have an opportunity for another extended high speed run this year, to see if anything has changed for the better.

Assuming I can find a second set of carbs to fool around with, does it really matter which I get as long as it's a clean bolt-on?  I have 022A's now, but with the existing aftermarker exhaust and impending Uni filter, I suspect I will have to rejet anyway (or do they cancel each other out???).  Assuming a rejet is impending, are there any other differences between the 022A's, 069A's and 627B's?

Thanks.

[csendker]

And I forgot...no gas in the oil that I can smell.  I may be able to tell better when I change it.

Also, isn't Shell Rotella T a synthetic oil?  There seems to be an abundance of concern all around the boards about using synthetic oils.

[SteveD CB500F]

There's a carb chart in the FAQs:

http://www.sohc4.us/forums/index.php?topic=5410.msg26534#msg26534

[dusterdude]

i think your basic rottella t is dino oil.the bottle will say synthetic if it is.

[Jonesy]

I ran without the air filter for one tank, it ran smoother and my milage jumped to 36 mpg. While only one tank, it has been consistently in the upper 20's, never into the 30's. I have a paper air filter that I thought was fairly clean and new (<1,000 miles), but now I'm not so sure. I'm going to order a Uni foam filter, as they seem to flow a little better. Besides, I like cleanable on lieu of replacement.

What color is the paper in the filter? Bright white or dark yellow, like a 5-year-old newspaper clipping? I ask because I ran into a similar problem on my wife's CB360. It had the original 30 year-old filters which didn't have much dirt on them, so I thought they were OK. However, It had some carburetion issues so I tried running it a bit with no air filter to see if that was contributing to the trouble. It ran better so I popped for new filters (I was hesitant at $35.00 each!). When I got the new ones, I could tell a noticable difference- The paper was bright white. I learned that over time, old paper air filters can pick up moisture and cause some of the fibers to clump together, blocking airflow. The new filters made a good difference.

Just food for thought...

[csendker]

This is the stuff on the shelf:

Shell Rotella T Synthetic 5W-40

http://www.shell-lubricants.com/products/pdf/RotellaTSynthetic.pdf

[csendker]

The air filter is white, not yellow.  But now that I think of it, it may be the one that was in it when I bought it.  That would mean it's been sitting around for over a year.  A new Uni foam filter will be ordered today.

[csendker]

SteveD:  I have looked at that chart before; however, it's all Greek to me.  I'm assuming that the type PD is physically different than the type 1 ("You could make carbs from a 77+ work but youd need a differnet intake manifold etc.").  The only other differences (627B, 022A & 069A) seem to be associated with the jetting.  And with a non-OEM exhaust and soon-to-be foam filter, I may have to rejet anyway; which would make those differences moot.  Or am I missing something?

[SteveD CB500F]

Given that there are guy's on here who put flat slide carbs on their 750s, you can make anything work (as long as it fits physically)

Way back (see avatar) I had a 4-1 (Piper) and a washable K&N air filter and never changed a jet, even though in theory it should have run very lean.

My room mate, on the other hand, was always chopping mains (he had K&N pod filters but same exhaust).

So yes, as long as they bolt up, go for it...