Changed the oil - one week later, no idle

[spenczar]

So I got a 81 GS650G a few months ago - my first bike ever. I changed the oil (finally!) about two weeks ago. It ran pretty well the next few days, but then a week later on Friday, I rode to work, and when I left work to come home I had a lot of trouble getting it to start. It's always been a little nasty to start cold - need the choke out all the way and it takes a few tries - but this time it took waaaaaaaay longer than usual. I would probably guess it took 5 minutes straight of hit-the-starter-for-three-seconds, then wait-five-seconds, then repeat. Finally got it to start, but it couldn't idle really - I had to have the choke halfway out and keep the throttle open the whole way home.

The next morning (Saturday now), I had the same problem with outrageously hard starting. It got sunny out, pretty warm - still nothing. I decided something seemed pretty wrong and I didn't want to push it, so I decided not to ride it and have been taking the bus to work since

So, most things I read say this sounds like the intake o-rings are busted. I've bought a set from cycleorings.com and I'm going to clean up the carbs and put in the new o rings this weekend. I think this makes sense. But what gets me is how it totally suddenly changed that Friday night. What could have happened?

One thing I'm worried about is that I think I overfilled the oil a bit when I did that oil change. I noticed a small spot of oil under the bike this morning - a pretty minor leak, but it looks like there's a leak now, and there wasn't one before. When I saw the leak, I decided to move the bike onto the center stand and check the oil level. Yup, way past full, well past the "F" line. I would estimate that I poured in about 3.5qts when I changed the oil two weeks ago, which is a little high. I'm worried that after overfilling oil and riding around, I may have blown the head gasket due to high engine pressure. Could this be the real problem, not the o-rings? How bad is it?


Brief service history:
- Guy I bought it from said "I never changed the oil or worked on it, but I did clean the carbs" rolleyes: I don't completely believe him)
- Replaced the battery two months ago.
- Replaced spark plugs one month ago.
- Dropped the bike a month ago while at a stop sign on a steep hill and the clutch lever snapped, but replaced it.
- Replaced the choke cable about three weeks ago.
- Changed oil two weeks ago (as I mentioned)

 

[Nessism]

Sounds like you have a poorly maintained 31 year old motorcycle. It's very difficult to say what could be wrong when the maintenance is not up to date.

Please check the Newbie Mistakes thread and carb rebuild tutorial linked in my signature. I think the info contained within will prove useful as you work to update the bike.

Good luck

 

[tkent02]

What he said, valve clearances, gummed up carbs, improperly adjusted choke or mixture screws, many other things can lead to hard starting, such as your three seconds on five second off routine. Just hit the button and hold it until it starts. It is much easier on everything that way.

 

[spenczar]

Sounds like you have a poorly maintained 31 year old motorcycle. It's very difficult to say what could be wrong when the maintenance is not up to date.

Please check the Newbie Mistakes thread and carb rebuild tutorial linked in my signature. I think the info contained within will prove useful as you work to update the bike.

Good luck

Thanks a lot. Yeah, I completely agree - it's frustrating to try to work on it without knowing what's wrong, so I'm not riding it until I can work on it enough to get a clean slate. It's just tough because I'm impatient to get riding again - the bus really sucks.

Any thoughts on the overfilling-the-oil stuff? How likely is serious damage there?

 

[spenczar]

Just hit the button and hold it until it starts. It is much easier on everything that way.

Really? This surprises me a lot. I though I had read somewhere that it strains the engine a lot to keep the starter motor running for more than like 5 seconds. Incorrect?

 

[tkent02]

Probably a non functional petcock leaking fuel into the carbs when the engine is shut off, then they overflow into the intake, and down into the crankcase. It could also be a good petcock but it was left on PRI. Now you have too much oil although is is partly fuel, not oil. Oil diluted with gasoline is not all that good for your engine. If you didn't run it much it will be OK, but change the oil before you run it again if it smells like gasoline, fix the petcock, and then do all of the other neglected stuff.

Incorrect, on and off starter usage strains the starter clutch, the starter motor, the battery and everything else to do with starting, and it doesn't start the engine very well either.

 

[SqDancerLynn1]

Never hurts to check the petcock operation.. I would suspect bad gas or just crap in the fuel system & needs to be cleaned

 

[tom203]

3.5 quarts won't overfill, so like others said, check/understand petcock operation.A brand new one can be had for $45. Doesn't sound like PO did much and I'd doubt his carb cleaning talent.
When all is done right, this thing will start up instantly and once warm, will idle perfectly. For your own safety (and sanity), lots of maintenance to catch up on.

 

[Guest]

Check your oil for a gas smell, that is a sign there is a petcock/fuel problems for sure. If it does smell like gas, drain the oil period and take out the filter. Though don't replace the oil and filter until you have corrected the problem. Like the other guys said, you have a 31 year old bike with a questionable maintenance record., time to start checking and fixing stuff.

 

[BassCliff]

Hi Mr. spenczar,

Slightly over-filling the crankcase will not harm the bike at all. Every other problem you are experiencing is strictly coincidental and related to other maintenance that has not been done. The link below will help you get started along the path to a well-maintained GS motorcycle.


BTW, welcome to the forum!

New Members, CLICK HERE!! (You'll see why.)



Thank you for your indulgence,

BassCliff

 

[spenczar]

So, the oil definitely smelled like gas. I changed it and made sure not to overfill this time. Also, I took out the carbs, cleaned them, and replaced all the o-rings. It looked really, really clean to me to start with, and the o-rings that were in there actually all were pretty rubbery still, so I actually think the PO wasn't lying when he said he cleaned the carbs. But I cleaned them anyways and replaced everything just to be sure I know the service record.

Also, while the carbs were off, I took off the cam chain tensioner since there was a bit of a rattle around 2k-2.5k RPMs and a much-more-mechanical friend of mine said it sounded like cam chain tension. Couldn't really figure out anything to adjust on the thing, but I did take it apart and it looked OK, except the gasket which was completely cracked straight down the middle - half the gasket stayed on the bike and half came off with the tensioner. Not good! I'll probably try to track down a new gasket, but my hunch is that this isn't a super-critical gasket to replace before turning on the bike, right?

Now, I put the carbs back in. I wanted to make sure it would turn on and that I hadn't screwed anything up too bad, so I turned the petcock to prime for a little bit (20 seconds, maybe?) to get fuel back in the carbs. Pulled choke all the way out and it started in about 20 seconds. Woo! That's back to the old behavior!

Bad news though: the second cylinder's exhaust pipe was totally cold. I assume this means the second cylinder isn't firing at all. I took out the spark plug for that cylinder, and it was shiny, oily black - oil fouled, I think? All other spark plugs looked pretty happy. Could this be problems with the petcock? Did I make a newb mistake by trying to start the engine without replacing the petcock like everyone said? I just wanted to make sure I did the carbs right.

Second bad news: The cam chain rattle (or whatever the rattle is) got a LOT worse. Now, around 1k RPM its a loud rattle, goes away, then comes back around 2k-2.5k RPM (but faster), then disappears higher up. It's definitely a loud rattle. What could I have messed up while reinstalling the cam chain tensioner? I put it together at the absolute loosest possible since that's what the service manual said, but could I have forgotten something else?

 

[tkent02]

The cam chain tension is adjusted automatically, there is no manual adjustment. Read the service manual again, it shows how to install it correctly. The important step, after the tensioner is torqued in place, is to release the setscrew on the side to release the plunger inside, this is what allows the tensioner to work... Again, it's all in the manual.

Do you have a good spark on the dead cylinder? Does it have compression?

Have you adjusted the valve clearances yet?

Does the new oil smell like gasoline yet? It soon will if the old petcock is still leaking away.

 

[spenczar]

The cam chain tension is adjusted automatically, there is no manual adjustment. Read the service manual again, it shows how to install it correctly. The important step, after the tensioner is torqued in place, is to release the setscrew on the side to release the plunger inside, this is what allows the tensioner to work... Again, it's all in the manual.

Ok, I'm 99% sure I did all this, but I'll check the how tight that screw is again tonight. I didn't ride around or anything, just started the engine and shut it off pretty soon, so I don't think I could have done any very permanent damage. (right?)

Do you have a good spark on the dead cylinder? Does it have compression?

Not sure on both of these. I'll check the spark tonight too. Compression might have to wait a little while until I can get my hands on a compression gauge.

Have you adjusted the valve clearances yet?

No, that was my plan for the next project as soon as I made sure the carbs are clean and intake rings are good - hopefully would want to work on it in the next two weeks.

 

[tkent02]

I didn't ride around or anything, just started the engine and shut it off pretty soon, so I don't think I could have done any very permanent damage. (right?)

If the tensioner isn't right and the chain slips a few teeth you can bend valves in an instant.

Really just do all of the maintenance on Cliff's list, get everything working right and it will run like a Swiss watch. Doing a little at a time is nothing but heartache and pain.

 

[spenczar]

If the tensioner isn't right and the chain slips a few teeth you can bend valves in an instant.

Really just do all of the maintenance on Cliff's list, get everything working right and it will run like a Swiss watch. Doing a little at a time is nothing but heartache and pain.

Yeah, that's definitely the plan. I just work pretty long hours, so the only free time I have to work on the bike is weekends from about noon to 6. But it's a ton of fun to work on the bike, so I don't mind doing it every weekend

One thing that I've run into that makes it hard to "just do" everything on the list is that I don't always know what parts I'll need to replace ahead of time, I don't have a complete set of tools (you need a nail punch to take apart the floats in the carbs, for example - not everyone will have one of those), and I don't have any other transportation than the bike, so I gotta wait for parts and tools to come in the mail to be able to work. So, it's a little slow. If somebody out there made a list of "Here's everything you'll need to do the Basscliff list," I think some newbies like me would really appreciate it... maybe I'll try to put that together when I'm done.

 

[tom203]

It sounds like you might have messed up on camchain tensioner reinstall- (didn't wind it back enough and/or release the lock screw). see this link

http://members.dslextreme.com/users/storagecliff/images/engine_odds-n-ends.html#A06

#2 plug wet?? probably petcock leaking down the vacuum line- this is what likely caused gas in oil problem. Sooner or later, you'll want a new petcock- available for less than $50

Best to be safe and check camshaft to crankshaft timing in case chain skipped- not much room for error, so better to find out.

 

[spenczar]

#2 plug wet?? probably petcock leaking down the vacuum line- this is what likely caused gas in oil problem. Sooner or later, you'll want a new petcock- available for less than $50

Ok, I'll order that ASAP. Where do I go to look for a new petcock that cheap, though? All the ones I'm finding online that are OEM are like $80+

Best to be safe and check camshaft to crankshaft timing in case chain skipped- not much room for error, so better to find out.

Yessir, that sounds bad. How do I check this?

 

[gearhead13]

For a petcock I would have said Z1 ent.
I am not sure of the exact model but check here:
http://www.z1enterprises.com/ListItems.aspx?keywords=petcock
maybe this one:
http://www.z1enterprises.com/ItemDetails.aspx?itemDescription=Petcock+(vacuum)+Suzuki&item=KL18-4358

 

[tom203]

Yes, Z1 has the petcock. My Florida guy is sold out of the $45 ones.

My Clymer's manual is sorta OK regarding cam timing- the B&W pics aren't great. But there are pics floating on this site that make it clearer as to what you're doing. see attached pic (courtesy of SuzukiDon, down under)
Basically, you're looking at camshafts from right side- on exhaust cam, there are numbers 1 and 2 marked on camshaft- you want 2 pointing up and 1 pointing at camcover/head mating surface. At this point crankshaft should be at TDC mark (you know how to check this ,right?). Then you count # of chain pins from mark 2 to mark 3 on intake camshaft (the count includes the pins at 2 and 3) -if things have gone astray, you will know by this.

 

[spenczar]

My Clymer's manual is sorta OK regarding cam timing- the B&W pics aren't great. But there are pics floating on this site that make it clearer as to what you're doing. see attached pic (courtesy of SuzukiDon, down under)
Basically, you're looking at camshafts from right side- on exhaust cam, there are numbers 1 and 2 marked on camshaft- you want 2 pointing up and 1 pointing at camcover/head mating surface. At this point crankshaft should be at TDC mark (you know how to check this ,right?). Then you count # of chain pins from mark 2 to mark 3 on intake camshaft (the count includes the pins at 2 and 3) -if things have gone astray, you will know by this.

Ok, I think I understand. I don't actually know how to check the TDC mark, but I can probably rely on a manual to check that. I've got the Clymer manual too, so I can take a look through there for extra help.