Guess it can't be all that good... where to start?

[O.C.D.]

I am seeking the higher powers on this site as I am quickly learning that I am not that knowledgeable about bikes like I thought.

I have never ran a bike on the street until this GS.  Played in dirt many years ago.  I think I need to be schooled by people that can help.

I have been on many trips since I got the bike a month ago.  I would say over 300 miles total.  High speeds, low speeds, cruising, light to light, etc.  Tonight I went for a ride and made it about 15 miles.  I knew I was getting close to needing fuel but I am measuring my mileage so I was not ready to fuel up.  I was cruising and I felt the hesitation of fuel so I switch on the reserve.  A minute later the bike is literally bogging down and slowing significantly.  I pull over when I can and kill the motor.  I check the carbs, no fuel leaks.  I check the lines and they are good.  So I fire her back up - no issues.  I start off and there is no hesitation.

About 10 miles back home it starts again.  This time I know it is a problem I am not aware of.  I notice at higher rpm it will slowly bog down and then I see the oil light come on.  Within a second the bike dies at 65mph and I coast to the side of the road.  I couldn't downshift past 3rd gear?!  When I am completely stopped I have to finesse the shifter to finally get into first.  I am thinking that if the engine is seized I would have locked up the rear and had a fun high-side on the highway.  Didn't happen.  I look it over and it is at the normal operating temperature and not smoking or anything noticeable.

I then realize a few things.  Lately the bike has been smelling really gasy like it is really rich.  I am on 85 octane for the last tank.  I also think about how stupid I have been and not checked the oil lately.  I do and there is not a drop in there?!  The guy I bought it from said he changed it before I bought it.  Still though, I should have made sure.  I also noticed that I got 168 miles out of the tank of gas.  That is not the best mileage.

I call the wife and she brings me the oil I had for the bike.  I fill the case with the whole quart and wait for it to circulate as I turn it over.  After a little while the engine turns and it runs very poorly.  After a few minutes it revs up and then idles higher than usual.  It calms down and I hop on it to get her home.  Like before, a mile or so away and it bogs down and then completely dies.  I can't get it back into first again.  With the wife behind me I am walking the bike down the hill and then hit the starter.  It fires right up again no issues.

I cruise to a gas station and fill up 3.9 Gallons of 91 to give it some more octane.  Started it up and was off again.  Seemed to be running better with the higher octane so I figure I should get on it.  Seemed very slugish with bad response.

I make it into the garage and the thing smells like a gas bomb but there are no leaks.  The wife says when I got on it she could smell tons of gas while behind me.  I obviously need to do a few things.


Get a damn manual and learn how to take the carbs apart.  Check the oil more frequently.


I searched and think it can be a few things.  For a 17 year old bike I am betting the petcocks are bad.  I am betting the carbs need to be cleaned as the floats are probably sticking.

Where should I look first?  Should I yank the carbs and rebuild them or clean them?  While I am in there, should I check the jetting setup?  What should I be running with a K&N Lunch/V&H Supersport?  I know nothing about the washers or jets etc.  I am a learn as I go kind of guy.


In general I am thinking carbs.  I am getting bad mileage, it is smelling rich, backfiring alot when I coast, and apparently eating oil.  Should the GS eat that much oil in 300 miles?


Don't strike down the noob, lol.  I need insight.  Sorry for the long post but I am betting you all know what to look for.

Thank you.
Jon

[ineedanap]

Where should I look first? 
Should I yank the carbs and rebuild them or clean them? 
While I am in there, should I check the jetting setup? 
What should I be running with a K&N Lunch/V&H Supersport? 
I know nothing about the washers or jets etc. 
I am a learn as I go kind of guy.

1.  Gstwins
2.  Yes, yes
3.  Yes
4.  Ask buddha.  Nobody knows GS500 jetting better than him.  He made a business out of it!   
5.  Nobody was born as a "washers or jets" expert
6.  Cool, me too

Sorry I modified your original post slightly.  It made it easier for me.  I answered 6 questions in a row.  I guess I earned a beer or three.  Time to get started.   

[O.C.D.]

Where should I look first? 
Should I yank the carbs and rebuild them or clean them? 
While I am in there, should I check the jetting setup? 
What should I be running with a K&N Lunch/V&H Supersport? 
I know nothing about the washers or jets etc. 
I am a learn as I go kind of guy.

1.  Gstwins
2.  Yes, yes
3.  Yes
4.  Ask buddha.  Nobody knows GS500 jetting better than him.  He made a business out of it!   
5.  Nobody was born as a "washers or jets" expert
6.  Cool, me too

Sorry I modified your original post slightly.  It made it easier for me.  I answered 6 questions in a row.  I guess I earned a beer or three.  Time to get started.   

Hell, I need a few beers after that first post. 

Is this common from a bad carb setup though?  The bad mileage and everything?

[The Buddha]

K&N and pipe = 40/150/1 washer 3 turns.

Oil light = not carbs, the rest sounds lean, but you're also spewing gas ... AKA classic case of high float, lean jets ... you're nearly overflowing into the airbox, sucking it back in, and drowning in it.

Clean it, jet is etc etc ... carbs baby.

Toss in 25 bucks with your handlebar and you get the jets for it, BTW my formula needs stock needles, with aftermarket needles ... you have to send me the carbs.
Cool.
Buddha.

[O.C.D.]

K&N and pipe = 40/150/1 washer 3 turns.

Oil light = not carbs, the rest sounds lean, but you're also spewing gas ... AKA classic case of high float, lean jets ... you're nearly overflowing into the airbox, sucking it back in, and drowning in it.

Clean it, jet is etc etc ... carbs baby.

Toss in 25 bucks with your handlebar and you get the jets for it, BTW my formula needs stock needles, with aftermarket needles ... you have to send me the carbs.
Cool.
Buddha.

Oil light was obvious but I am still concerned about that one. Do these bikes eat oil that much?

I am going to sound really stupid here but I have never worked on a bike carb,..........ever.  Is there a quick way I can tell you if the needles are stock or modified?  If I get into it is it as easy as I think?  I hear about people going to Home Depot or Lowe's and buying washers etc.  Supposedly the PO had the carbs rejetted for the mods or so he says.  If you can tell me how what to look for I will.  I am thinking of just yanking the carbs tomorrow anyway to learn.

Petcock(s)?

THanks for the help guys, and Buddha, I think I need to just fly you out here and teach me GS lore, lol.

[ineedanap]

Carb work is much easier than most people make it out to be.  It can be intimidating at first, but what isn't.  

It's really easy to tell dynojet from stock.  Dynojet needles have 6 notches in them so you can raise and lower them by changing the clip position.  Stock have 1 notch and you use washers to change the height.  

If you find dynojet needles and are planning on switching back to stock stuff you'll want to pitch the main jet too.  Dynojet uses a different numbering system.  For example 134 DJ = 150 stock style

Also if you find dynojet stuff the PO might have tapped the slide holes and used DJ restrictor plugs.  If you find one hole per slide is plugged and are planning on returning the bike to stock style stuff let me know.  I have an extra set of restrictor plugs that will return it to close to stock size...or you can replace the slides.  

[O.C.D.]

Thanks for the info.  I am tearing it apart after work tonight.

I wouldn't think it need to go back to stock with the mods on it.  I could never inhibit the sounds of the V&H, lol.

I will take it apart and snap some pics tonight.  We shall see?!?!

[ineedanap]

I didn't mean put it back to stock.  I meant convert the carb back to using stock style mikuni jets.   The only reason I threw it out there is because so many people get rid of their dynojet stuff to return to stock style (not stock size) mikuni jets.  Dynojet and mikuni are not interchangable.

Dynojet needle= Dynojet jets
Stock needle = Mikuni jets

Since there is so much good info about jetting the Mikuni stuff, alot of people with the dynojet stuff return their carbs to stock style internals and then rejet from there.  

For example buddha said a good jetting setup for you is 40/150/1 washer/3 turns.  This setup works very well using stock style mikuni jets.  If you happin to have dynojet needles and do this setup you will be too rich in the midrange and the bike won't run correctly.  The dynojet setup would be 40/134dj/3rd clip/3 turns.  

[O.C.D.]

Ahhhhhhhhhhh, got ya now.  I will rally have to learn this stuff well.  When I tear her apart I will show YOU what I have found, lol.

[CliffHanger]

Remember, when checking the oil level make sure the bike is level... i.e. not on the sidestand.

Also, when I purchased my used 98, the valves were way out of spec and the exhaust always smelled of gas, until I adjusted them.
My mileage also sucked.

[The Buddha]

Only thing is ... DJ setup he posted ... not as much of a sure shot.

Example:
Mine runs fine with a slightly higher float level ... but I pay the price @ start up. It needs choke for ~3 seconds, then it is too rich, I have to blip the throttle and get the choke off. But it does well past that, the thing also has a little hovering problem. I idle @1200 when cold, and 2K when hot, I fix that by air screw and it behaves worse on the startup. I set the floats back down, the neelde and/or the mains have to go up ... then I open air screws ... may work, but its close enough now, I am OK, may fiddle in winter if its in my hands till then.

BTW I have 1.5 blocked holes in the slides, and it behaves well on anything related to that. Midrange, opening, WFO ... all of it is beautiful. That could be the ticket, but its as irreversible as they come, no one should do it till they have everythign else perfect, and the bike runs great when opening throttle slow, but misbehave (falls on its face and never recover) ... and they oughta practice slow throttle opening. I hate blocking the things. But I have a few that have been blocked already. So I use one of those.
Cool.
Buddha.

[JB848]

No one answered his eating oil question so I will. In 300 miles you should not be able to notice any significant oil change unless your running it extremely hot the whole 300 miles which is not likely.

Sounds like ring blow by but you have not mentioned anything about loss of power, but then again you just got the bike and probably wouldn't notice. Keep an eye on that oil and fix the other problem first in the mean time.

I don't have anything else to add. What do you think Buddha? Am I on the mark or way off?

[The Buddha]

No one answered his eating oil question so I will. In 300 miles you should not be able to notice any significant oil change unless your running it extremely hot the whole 300 miles which is not likely.

Sounds like ring blow by but you have not mentioned anything about loss of power, but then again you just got the bike and probably wouldn't notice. Keep an eye on that oil and fix the other problem first in the mean time.

I don't have anything else to add. What do you think Buddha? Am I on the mark or way off?

Oh my 89 with 48 K used 300 miles per qt of oil. So yes you can use that much, and it really ran without any problems ...
But yea keep it topped up.
Cool.
Buddha.

[O.C.D.]

The comment about the power - yes I wouldn't know how it should feel.  I have never rode another GS500 before.  When I got it it seemed smooth and powerful though.  The only thing I noticed was constant backfire when off the throttle and coasting.  A few people have said it smells really rich, etc.

I did the sprocket up front and it added a little. 

Last night I was about to tackle the carbs and then I realized a few things.  One it was a little late. Two, I have a completely full gas tank.  And three, I have no idea what I am doing without a manual.  I can get in there and yank it all out but I don't think I can do that with a full tank?!  Can that be done?

I pulled the plugs and they are not "that" bad.  Here is what they look like.

Here is the left plug:


Here is the right:

What do you think, do they look bad?  There was a little gas on them when I pulled them.  I also noticed that there was an even stronger gas smell while I was near the carbs.  Still no leak though.

At this point in the night I decided I would do something easier so I did the advanced ignition mod.  I need to get back out in the garage and hit this.  I will wait and see what I hear about the full gas tank thing. 

Oh, and before I forget, is there only the two bolts that hold the tank on?

[JB848]

Spark plugs look relatively good they are not overly black and have grey tint which is good. That means you are burning all of the fuel getting to the combustion chamber efficiently. As far as the deceleration backfire? That means the carb is overloading(sending too much gas to the chamber needed to keep the normal combustion cycle going) and you plugs, ignition, and valve train are doing there best to consume all the fuel and some is actually combusting on the way out the exhaust. This is definitely a carb setting and I will defer to The Buddha for this expertise.

As far as the gas tank I take min off all of the time no problem. What I do is turn off the gas valve and carefully remove the main and reserve feed line one at a time and plug them with a round piece of plastic. You just have to find the right size. carfully feed the rubber lines through the frame and there you go. Don't forget the vapor line on the right side. That does not need to be plugged.

Unless someone has a better method that is how I do it. Don't worry about marking the hoses..it is obvious which one goes back where by their length! 

[O.C.D.]

Ok, so I have some insight I might need confirmed.  Again, this is my first bike.

I buttoned up the ignition advance and fired her up - runs awesome.  So I get ready to tear into the carbs.  I call my buddy and he asks me what is gong on.  It is then that I realize that I have been running the bike on PRI ever since I have owned it.  This is because of the MSF class telling me that "all" bikes have an up and down petcock.  I assumed PRI meant primary but from what I have learned it is prime.  So I think that I have been forcing too much fuel into the carbs the whole time. 

I set the valve to "on" and fired her up again and the damn thing runs better.  I warmed it up and took the choke off after a minute.  Low and behold it idles at 1200 finally.  A more gently idle too.  Sounds better than it has.

Chalk it up to learning I guess.  My manual should be here by Tuesday, lol.

I am not saying this resolved the issue but I think running on PRI was dumping too much fuel at all times.  I will have to run her tomorrow and see.  My life never works out where the issue can be that simple but we shall see.  If not, I am still gonna tear the carbs down and learn.  If I can work on a Jeep I can work on a bike, lol.

Jon

[sankyo]

It sounds unrelated to your problem, but I would also recommend just sticking with 87 octane gas.

Remember that the higher the octane rating, the harder it is to ignite the fuel. If you had premature detonation, or engine "knock", then you might want to try a higher octane, but otherwise you are not doing it any favors by "treating it" to a tank of the "good stuff"

from wikipedia: http://en.wikipedia.org/wiki/Octane_rating
High-performance engines typically have higher compression ratios and are therefore more prone to detonation, so they require higher octane fuel. A lower-performance engine will not generally perform better with high-octane fuel, since the compression ratio is fixed by the engine design.

[O.C.D.]

Well, now I am more confused?!

Bike has been riding great since the last incident in the first post.  Put another 120 miles on the odometer.  On my way home last night, bam, same thing - bogs down and then dies.  I check the fuel and there is still half a tank. I pull over and let it sit then start it up and it goes fine.  Near my house it bogs down and dies again.

Would the petcock be causing this?  What should I look for in the carbs?  Like last time when I got it home the thing wreaked of gas. 


I would really appreciate the insight, thanks. 
Jon

GS

[bill14224]

Ride it with the petcock on prime (PRI) to bypass the petcock's vacuum-operated valve.  If the problem goes away, the valve is not opening enough.  If it precipitates a lake of gas, your float needles are sticking open.  From your description it sounds like it could be both.  You're throwing so much at us at once my brain has become overloaded!

[O.C.D.]

I know, I am like that when I get concerned; I hope the answers are out there so I throw em all.

When this started I did ride with the PRI on all the time.  So I switched to ON to try and rectify it.  Was good for a couple of weeks and then it happened again.


I have read all over the wiki but I guess I am lame. Is there an easy way to check for a sticking needle?

Thanks!
Jon