Running terrible after oil change. What?

[marcopasco39]

My carbs are flappin in the wind haha. And yea i stripped them all apart and used brake cleaner on all passages and blew them out. I turned the idle mixture screws out 2 turns from lightly seated. I was also thinking thqat maybe the thicker 20-50 was dampening some engine noise as well. i guess i will put 20-50 back in it and see if that does anything.

 

[Larry D]

My carbs are flappin in the wind haha. And yea i stripped them all apart and used brake cleaner on all passages and blew them out. I turned the idle mixture screws out 2 turns from lightly seated. I was also thinking thqat maybe the thicker 20-50 was dampening some engine noise as well. i guess i will put 20-50 back in it and see if that does anything.

Brake cleaner is for brakes.........You should do this. Completely disassemble, dip each carb for 24 hrs in a can of Berrymans, reassemble using new o-rings from cycleorings.com.

http://www.thegsresources.com/gs_carbrebuild.htm

The two turns out sound good, I usually go about 2 1/2.

You SHOULD be running very lean with no airbox at all. Be careful with that, bad things can happen.

Before changing the oil, try this. Take some socks or an t-shirt and wrap the carbs to restrict the airflow some and see if it runs a little better. Of course, this isn't a permanent fix. If you're planning to go with pods, re-jetting will be required.

 

[MikeJ]

I am not worried about my carbs right now kdo, I'm going to put filters on them. I'm more concerned about why my motor sounds like it has rocks in the head and my oil light came on when i changed my oil.

Putting aside all the other stuff you wrote originally, and which other GSers have commented on at length, I think the above has a very simple explanation. Your newly acquired liter-class GS with well over 30,000 miles on it may not have been as well cared for in the past as some other GS's which seem to last forever if treated right - its engine may already be in need of teardown and overhaul.

Maybe PO didn't change the oil often enough, or did something else to abuse the engine (drag racing??) and to make it wear out prematurely, which increases the clearances between its moving parts - and then he started using the heavier 20w-50 oil because clearances inside the engine were way looser than they were supposed to be, and the thicker lubricant "filled in" those excessive gaps and let the bike appear to run halfway decently. That's why foax with high-mileage older-model cars used to put STP or other super-thick oil treatment into their oil. (Most newer cars are built to much tighter internal engine tolerances and are designed to use much thinner oil for their lifetime than old cars were.)

When you switched back to 10w-40 the lighter oil opened up those clearances again, meaning possibly - more clattering and noise, less compression, poorer valve operation and timing, or all of the above. That also may explain why your oil light came on - much lower oil pressure, even with the engine running. Partly that's due just to the thinner oil, but maybe your oil pump is worn out too, and it can't pressurize the thinner oil enough to fully open the gap in the idiot-light oil-pressure sensor unit and prevent the light from flickering.

It's also possible that, if you used regular car oil instead of oil intended for wet-clutch motorcycles (or diesel oil such as Rotella-T) the lack of all those wear-preventing and gap-filling additives that old motorcycle engines require may have made the problem even worse than merely the thinner viscosity rating of 10W-40 alone would have caused. Your clutch will slip, and your internal parts will rattle even more, if you used oil intended for a modern, catalyst-equipped car. The oil makers took all that good stuff bikes need _out_ of modern car oil because it gummed up the emissions control catalysts, and that's why newer cars _had_ to be built to tighter internal tolerances and use thinner oil. That's also why diesel oil is still OK to use for old bikes - diesels don't have catalytic converters on them.

Changing back to 20w-50 isn't going to solve your problem, though. It's just going to mask the noise again as its cause continues to get worse, if what I suspect about Previous Owner is true.

 

[Clone]

I have heard that not so reputable folks will put 20/50 or straight 50 in a motor even shoot grease into the oil which eventually disolves to cover up the racket caused by worn bearings. If it make a lot of noise with the recommended oil in it, the engine is most likely been abused like a rented mule.
I can't imagine that a bike would run well, without the carbs, that begs some serious questions.

 

[blowerbike]

folks these are roller bearing engines that could care less about the weight of oil.
these engines don't knock like a car.
i ran 20/50 in all my GS's through the summer months..
what was i hiding?
thats my point.

 

[GSXTommy]

I have run the bike without the air filter on my carbs without any problems but it`s not good to do so. but when you suddenly got ratling/cranking in your engine and your oil lamp start to light up, something tells me that your engine don`t get the oil pressure that it shall have. Poor oil pump or poor oiling in the engine and the parts. it can also be that some part have been seal`d up because of dirt in the oil or too thick oil. I also thinking about the oil pipe on top.

 

[MikeJ]

folks these are roller bearing engines that could care less about the weight of oil.

I'm not disagreeing - while that is true, OP said his engine sounded like it had "rocks in the HEAD." I don't think he was talking about the roller-bearing bottom end, sir. And the roller bearing crank won't have anything to do with how the top end components sound, or how worn out they are.

these engines don't knock like a car.

"Knock" is a whole different thing. Nobody was talking about "knock," pre-combustion due to excessively-low-octane gas or due to carbon deposits in the cylinder. We're talking about camshafts, cam chains, pistons and rings, etc. all rattling around because their tolerances have been loosened up due to excessive wear, perhaps due to some kind of abuse. Or, maybe not. But, such out-of-spec looseness, and resulting noise, can happen.

Frankly, I'm not so sure you're right about "these engines don't knock" either. Try running one on kerosene or diesel fuel or 70 octane gas and see if it "knocks."

i ran 20/50 in all my GS's through the summer months..
what was i hiding?

What were _you_ hiding? Nothing, sir, assuming your GS's are in good shape. Which we have no reason to doubt. But -

What was OP's PO hiding? We _don't_know_. But I offered, as a possibility, that _maybe_ he was hiding something wrong with his top end, masking the noise by using heavier-than-spec oil.

The fact that both you and OP's PO ran 20w-50 has nothing to do with the possibility that the PO of OP's bike was hiding something, even though _you_ plainly were not. The 2 of you ran heavy oil for different reasons, it seems.

thats my point.

But your point is based on assuming that I said _everyone_ who runs heavier-than-spec oil is hiding something. No one ever said that. What I did say, was that _some_ unscrupulous sellers of cars _or_ bikes, _do_ cover up problems with their engine internals by using super-heavy oil, or by larding the oil with heavyweight additives like STP, or by putting oatmeal or sawdust in the transmission (haven't heard reports of anyone doing that last trick since the 1950's, but I offer it just for an example)

Apples and oranges, sir.

 

[tkent02]

by larding the oil with heavyweight additives like STP, or by putting oatmeal or sawdust in the transmission (haven't heard reports of anyone doing that last trick since the 1950's, but I offer it just for an example)

Squished bananas will make a noisy differential run really quiet. For a while.
Probably even work on a GS shafty.

 

[blowerbike]

mikej you went to a lot of trouble for nothing typing all that stuff..IMO
the knocking i'm talking about is bearing shell knock...roller bearings do not do that.
also..
i see it as someone assuming the previous owner was hiding something..
aka the 20-50 oil.
when people call me and ask what weight of oil i ask there location and how they ride..ride hard/ride in traffic and so on.
i recommend 20-50.
i stand by my 20 plus years of working on 90% GS engines and i stand by my opinion(s) as well.
no plssing contest here...
someone mentioned "previous owner may be hiding something"
thats where my comments was pointed.

 

[bmac]

After reading the first post, I would get a manual. It was stated that you replaced the oil and added 3.6 qrts. If you did not change the filter you have to much oil in it. 3 qrts. is added without a filter. Do all the proper maint. items listed by the members and put the proper equipment on it and see where you are at and change that filter. I believe 10w 40 or 20w 50 oil are both fine, as long as the are made for air cooled, wet clutch applications ONLY. bmac

 

[tom203]

Well, I hope marcopasco keeps us updated as we discuss 10-40 vs 20-50 oils. From his original post, I assumed he first "cleaned " carbs, was happy with result ( rode bike ) , and then opted to change oil - at which point, things went downhill. Or did he do both at same time?

 

[FZRCraig]

Both 10W40 and 20W50 will be the same thickness at normal engine operating temperature. It is below and above this temperature that the thickness of the two differ.

Craig

 

[blowerbike]

in the end......
the weight of the oil used did not make his bike run bad or "cloak" any pre-existing problems.
kind-of-a-silly-thread title anyways as it may have happened that way but one had nothing to do with the other.

 

[Guest]

Has he reported back? It would be interesting to know the cause.

 

[marcopasco39]

Sorry I have not replied in quite some time. I fired her back up a couple days ago and it ran better than it did before. Smoother but still with a little too much noise. I believe the lights came on only because it was about to die at idle. I still need to order air filters for the carbs and fire it back up. I will also get an oil filter and replace that. Then we will see what happens. Thanks for posting.

 

[tom203]

Thanks for update - get those filters on and let us know.

 

[marcopasco39]

I know it's been awhile but I finally got her back together. I re-changed the oil, putting 20-50 in. Changed the filter too and put exactly 3.6qts. in. I also got pod filters and i re-jetted the carbs to 130. It has a 4-1 exaust too. It fired right up and runs great! I am still getting some rattle in the head though.. It sounds like the valves and increases with rpms but i'm not too sure. Could it be that the oil drained to the case and it needs to get flowing? I only ran it for about 4-5 minutes. Or could I need a valve adjustment? Maybe the cam chain? Any suggestions would be much appreciated. Other than that noise, it's running very strong with the new intake setup. Thanks guys.

 

[JEEPRUSTY]

I know it's been awhile but I finally got her back together. I re-changed the oil, putting 20-50 in. Changed the filter too and put exactly 3.6qts. in. I also got pod filters and i re-jetted the carbs to 130. It has a 4-1 exaust too. It fired right up and runs great! I am still getting some rattle in the head though.. It sounds like the valves and increases with rpms but i'm not too sure. Could it be that the oil drained to the case and it needs to get flowing? I only ran it for about 4-5 minutes. Or could I need a valve adjustment? Maybe the cam chain? Any suggestions would be much appreciated. Other than that noise, it's running very strong with the new intake setup. Thanks guys.

If this bike is new to you then most certainly adjust the vaves.
its normal routine maintenance like oil but with a longer interval.

i use a light oil and get a modest clatter but 20-40 and its gone.

 

[marcopasco39]

It was the cam chain! I adjusted it while at idle and now it's quiet as a mouse. I'll take it for a couple of rides then I'll do a valve adjustment. Thanks for all the help.

 

[1_v8_merc]

You're SURE you didn't put too much oil or too little oil?

Cause I put too much oil in one time, and it ran kinda choppy and was just acting funny.

Then another time, my oil was critically low, and the bike kept wanting to stall on me and overheat.
(the minute I added more oil, it ran better and stopped stalling and overheating)
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Does your bike's tranny share the same oil as the engine?
If so, make sure you drain the tranny plug too!

Check the peep hole or dipstick and make sure oil level is correct.

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Also, get a damn air filter man!

These bikes WILL run extremely wacky without an air filter sometimes.
I mean you can Idle it without one, but I wouldn't wanna ride it!