Normal Highway Behavior?

[geekonabike]

Hi folks,

I just got a chance to take my newly beloved '98 on the interstate today.  It seemed it had a lot more power five months ago when I took it home on said freeway, and since then I've replaced the D&D's with stock and had a mech do all the adjustments.  Anyhow, I'm relatively new to this kind of bike.  It was 100F today, and after a couple miles riding to the ramp, I got on, and tried to accelerate to 70mph from about 55-60mph in gear 5, with an Oklahoma headwind and little luck doing that in gear 5.  I found gear 4 could do it, quickly bringing me up to about 82 on the speedo (which is what, 74 really?).  I could then keep it that speed with gear 5, speed apparently dipping in gear 6, and then I had to get off to turn around.   The way back had a tailwind and gear 6 was probably fine for maintaining speed then, though it seemed clear that gear 4 would still be needed to pass anyone.

Anyhow, is that how this bike is supposed to be ridden?  That is, gear 4 to get up to the HW speed, gear 5 to keep it, and 6 as a true overdrive?

Sorry, I'll be ordering an owner's manual soon I hope.  'Til then I'll have a couple more stupid questions.

--Mike D.

[Rema1000]

I've never had a problem accelerating in 6th on the freeway, up to 75mph (which is about as fast as I care to ride).  I have not experienced the Oklahoma wind, but we have wind farms here, so we must have some    .   Sounds like there may be some misadjustment.  Keep at it, and if it's still like that, talk to the mechanic about it.  Did he take it for a test ride at speed, or just adjust it by eyeball?

[geekonabike]

Thanks for the reply.  Good info.

I don't know if/how it was test ridden.  I should make it a policy that he tries it on the highway.  Hmmm.....I'm suddenly struck by the thought that If he doesn't trust it enough to be on it there himself, maybe he needs to do more work on it before turning it over to me.  

I was going to post this separately but maybe it's related:

The bike's choke is taking some getting used to.  I can get the bike to idle at about 1200rpm, and then I let it warm like that about five minutes before I go.  It seems to like different choke settings at idel than at, say, 4-5000 rpm.  I may be imagining this, but it seems to like it more open for the higher RPM's.  Where it likes it for the mid-upper range it wants to stall at the stops.  Does that sound normal either?  Originally I thought about putting the idle where it would be at 1200rpm with open after a 5-minute warm-up, but....
When I came off the highway after putting about 8 HW miles on it, the idle wanted to be 3000 rpm and steady.  Throttling or putting it in gear and then out didn't change this.

Any more ideas appreciated.  Even if it is just to take it back for another look-see.

--Mike D.

[cernunos]

Once the bike is warmed up it shouldn't want any choke at all. And yes, during warm-up most motors don't need as much choke at higher RPM than at idle. You may still have some kind of carb problem. BTW the choke on the baby G is really an enrichener device and not a true choke in the sense that the venturi isn't restricted on the Le Enfant 500 during choke application. Also, you said it was 100 F during your acceleration run...at that temperature and especially if there was high humidity, that you were able to get the toddler 500 up to 75-80 sounds respectable. I guess too it depends on what you weigh with gear on. Still, you might check for any carb problems as a guess. I love my baby 500 and think this forum is pretty neat also.

C.......

[Rema1000]

I'm a little confused when you say that you warm-up the bike at 1200 RPM.  Is that all you get with choke full on?  If your idle is set right (set to 1200RPM when the bike is fully warmed-up), then when you first start thte engine cold, with choke full on, the engine should be idling and warming-up at 3500-4000RPM (and if you back off the choke at this point, with the engine not warmed-up, it will probably kill).  So most people warm-up the bike at 3000-4000RPM, not 1200RPM.

Or do you mean that you apply full choke, and still only get 1200RPM.  If adding full choke when starting a cold engine does not raise the RPM by at-least  2000, then it's possible that your choke is always partially on, and the idle has been adjusted downwards to compensate (perhapas the choke cable is stuck).  That would make it warm-up OK, but would make it seem sluggish once warm (and once fully warm, the engine would probably kill when you pull the clutch lever at stop signs).

You should be able to shut the choke off completely after about 1 to 5 minutes of warmup at 3000-4000 RPM, and the bike should not kill.  Idle should drop down to about where you set it when warm (1200, or maybe a bit lower), and it may not run smoothly, but it shouldn't kill.

[geekonabike]

Thanks again for the reply!

In fact, all I can get for warm-up is about 1200rpm, which I thought was OK since I read somewhere that is the desired idle speed, but I guess what I read did not specifically address warm-up.  Without choke the bike will die cold.  Interesting.  So I guess something is going on there.  Maybe it just needs a higher idle adjust?  I'll check into the choke, and some obvious things like air filter, etc., and if necessary bring it on back to the fellow.  Oh, and go find an owner's manual!

I very much appreciate your input.

Best regards,
Mike D.

PS:  I forgot to mention that when I purchased the bike back around April got me about 35mpg on the highway brining it back.  THAT sounds like a bad choke.  Hmmmm.....

PPS:  Do you think that the bike then wanting to do 3000rpm idle after getting off the highway yesterday, presumably fully warmed, is consistent with that too?  I'm 50/50 on that myself.  Maybe I'm looking at a choke AND idle adjust problem.

[geekonabike]

Once the bike is warmed up it shouldn't want any choke at all. And yes, during warm-up most motors don't need as much choke at higher RPM than at idle. You may still have some kind of carb problem. BTW the choke on the baby G is really an enrichener device and not a true choke in the sense that the venturi isn't restricted on the Le Enfant 500 during choke application. Also, you said it was 100 F during your acceleration run...at that temperature and especially if there was high humidity, that you were able to get the toddler 500 up to 75-80 sounds respectable. I guess too it depends on what you weigh with gear on. Still, you might check for any carb problems as a guess. I love my baby 500 and think this forum is pretty neat also.

C.......

More good info!

In fact when idling in this weather it runs fastest at about 2/3 choke.  Maybe that is significant.  More stuff I guess I should have mentioned in my original post.

I don't think the humidity was high.  It was pretty typical Oklahoma summer heat.  The bike did seem peppier when I bought it in April (w/D&D exhaust back then too) in weather that was maybe upper 50's.  (It sat in the shop most of the time in between, to get some work done for sure but mostly because I went overseas to visit family.)  I weigh probably 220lbs suited up.

Thanks to both repliers.  There does seem to be some difference of opinion on what the bike is capable of at those speeds.  Interesting.

Best regards,
Mike D.

[MarkusN]

On idle and choke:

An originally jetted GS will die without choke cold. Idle should be adjusted to about 1200 RPM when warm. To keep her running before warming up use choke. Most need almost full choke to start, then gradually less while warming up, none after about 3 to 5 minutes riding.

[mjm]

You said that it idled at 3000 after an 8 mile ride.  After an 8 mile ride is when you should be adjusting the idle to about 1200 rpm - you adjust idle on a bike that is fully warmed.

Based on your description -

1. The choke may also be partly sticking open
2. The amount of power you seem to have on the highway is way too low.  The bike should have no trouble accelerating from 50 to 100 in sixth gear (OK-stiff headwind and uphill that may be harder).  Now it is true that these bikes are faster (sometimes) in 5th than 6th - but you were not going hose kinds of speeds.  If your bike was re-jetted for the aftermarket exhaust , you could be jetted too rich.  What color are your plugs?  Black or dark brown I bet.  
3. Check the throttle cable(s) as well - make sure that the throttle fully opens the butterfly

[geekonabike]

You said that it idled at 3000 after an 8 mile ride.  After an 8 mile ride is when you should be adjusting the idle to about 1200 rpm - you adjust idle on a bike that is fully warmed.

Based on your description -

1. The choke may also be partly sticking open
2. The amount of power you seem to have on the highway is way too low.  The bike should have no trouble accelerating from 50 to 100 in sixth gear (OK-stiff headwind and uphill that may be harder).  Now it is true that these bikes are faster (sometimes) in 5th than 6th - but you were not going hose kinds of speeds.  If your bike was re-jetted for the aftermarket exhaust , you could be jetted too rich.  What color are your plugs?  Black or dark brown I bet.  
3. Check the throttle cable(s) as well - make sure that the throttle fully opens the butterfly

Thanks.  I very much appreciate that information.

The plugs are new (like about 40 miles on them) and are in fact kind of black.  Both look the same.  I didn't check them right off the highway, but let it sit for a couple hours (finishing up at work) before riding it about 1.5 miles home, so I don't know if that makes a difference as far as diagnosing from the look of the plugs.  I have child watching issues that keep me from doing another highway run for a while.

With the tank off (first time for me) it seems the choke and throttle are moving their full ranges from the outside of the carbs, but I can't see what's happening inside the carbs.  The air filter looks a bit dirty both inside and out but I could exhale through it without any noticable resistance.  (I know, one shouldn't put one's mouth up to it.  At least I knew not to inhale  There is a hose out of the top of the left carb that looks like its routing could get in the way of the throttle, and maybe that is what was happening, but it would be a coincidence that it happened in gears 5 and 6 and not in gear 4.   Still I'm looking to how I can get that hose out of the way just to eliminate that possibility.

I'm thinking I may send Srinath the carb to check it out and maybe rejet, since he's seen so many of them relative to the local guy.  Well, GS500's anyhow.  Maybe not the cheapest way to troubleshoot, but one likes to know which components are known to be in spec.  Maybe better to check things like compression first, to see if it's all moot, but I don't have the tools.

When I took off the tank it seemed awfully light and splashy considering I only have 36 miles on it since I filled it.  I had lousy mileage when I rode it home in April (like about 35mpg), so this is all sounding consistent with what you are saying.  I'd have to actually fill it to have useful information.

Anyhow, thanks again.  I'll keep the thread going whenever there is news, and any more feedback is greatly appreciated.

--Mike D.

[mp183]

Even if the choke is out of whack.  When you are doing 60 mph or more it should not matter.  Unless someone messed with the carbs once you are up to speed the sucker should move.  If the valves are out of whack you loose power but it should not be as much as you are loosing.