Engine stalling

[jjwalker98]

If I change to premium gas should I drain the tank first then put "new" gas in?  Or would mixing not necessarily change performance?

[3imo]

no need to drain, it will mix just fine.

only thing though is that you won't know if it makes a difference if you have a mix. until you refill.

if you have more high octane than low octane, you should notice a difference if thats your problem.

be advised, that some people swear up an down that low octane is ok.  I dunno about them.
  in my experience low octane fuel causes serious performance issues with both my bikes.

try it and let us know if your symptoms disappear. 

[jjwalker98]

OK I got a can of carb cleaner.  I understand I have to move the tank or remove it to get at the carbs.  Once there do I just spray the suff in and let it sit?  Are there any parts (plastic, rubber o rings) that I should avoid spraying?  Thanks

[Alphamazing]

OK I got a can of carb cleaner.  I understand I have to move the tank or remove it to get at the carbs.  Once there do I just spray the suff in and let it sit?  Are there any parts (plastic, rubber o rings) that I should avoid spraying?  Thanks

Take your carbs out. Remove all rubber and plastic pieces. Spray carb cleaner through every hole and on every surface. Spray carb cleaner through each jet. Let it soak if you want to. Replace all removed pieces, place back on bike, enjoy.

Carb cleaner can deteriorate rubber and make it useless. I don't want to take the risk with plastic either, but I'm anal like that.

[jjwalker98]

Thanks, I'll try it and let you know the outcome.

[jjwalker98]

All right I put in the highest octane available (91 or 92), put on PRI and she started right up with minimal choke required.  Went up the street a couple of minutes and turned the choke off.  Still purring like a kitten.  Took a drive about 10 miles through some twisties (not to crazy) and all was well.  It didn't stall once.  When I came back home and turned her off I realized I had been running on PRI the whole time .  Is this going to foul out my plugs?  I haven't gotten around to cleaning the carbs out yet.  I thought I would try one thing at a time first.  Also, I noticed that when idling even after some time riding it looks like it's around 900rpm is that normal or should it be higher? Thanks

[TragicImage]

mine idles from between 900-1200


And I've been known to ride around on PRI a time or two...




I'm doing Boquet Canyon tomorrow

[Kerry]

I realized I had been running on PRI the whole time .  Is this going to foul out my plugs?

No.  In the PRI position the fuel is simply making its way from the fuel tank to the carburetor float bowls via the REServe hose rather than the ON hose, and it is being pulled through the hose by gravity rather than vacuum pressure.  Once in the float bowls, the fuel is sucked into the mixture chamber the same way regardless.

I noticed that when idling even after some time riding it looks like it's around 900rpm is that normal or should it be higher? Thanks

For pre-'01 bikes, Suzuki says that the idle should be set at 1200.  I prefer to have it closer to 1300, but 1200 is fine.  Do you know how to use the idle adjust screw to set it?

[jjwalker98]

I haven't touched it and I'm not exactly sure the way to go about adjusting.  Any help would be greatly appreciated. I thought the Clymer's manual said the adjustment srew was not supposed to touched unless the carbs were being rebuilt or cleaned.
I think that's what it said.  But I wouldn't mind bringing it up to where it should be 1200 rpm.

[Kerry]

The screw that Clymer says not to mess with is labeled "Mixture Screw" in the photo below (which shows the float bowls removed).  Each carburetor has one.



The "Idle Adjust Knob" is what you turn to adjust the idle up / down to 1200.  It pokes downward between the carburetors.  Turning it "righty-tighty" will increase the idle RPMs.  "Lefty-loosey" will bring them down.

Here's how it looks "in situ" on a pre-'01 model:

[jjwalker98]

So, should I let the bike idle or drive around abit before making the adjustment?  I assume I want the choke all the way off (forward) correct?  When I do turn it I want the bike running to make sure I "see" the reading as I turn it, correct?  Thanks for the pics, makes it very helpful and easier to understand what I am doing

[TragicImage]

Choke off, and ride around for 10-15 minutes.


BE CAREFUL!

The engine will be super hot.


Make the adjustment while the engine is running.

[jjwalker98]

Ok it seems like when  I am driving let's say 50 and the RPM's begin to lower, say dropping below 5000, I pull in the clutch to downshift and the engine cuts out.  There is plenty of fuel in the tank, and it only happens when the petcock is in the ON position.   If I do this in PRIme position everything is fine.  Since vacuum pressure is used in the ON position to deliver fuel and PRIme position is using gravity does it seem likely that there is a vacuum problem?  It still doesn't start back up if in ON position only PRIme.  Maybe my shifting wrong but the engine shouldn't die like this should it?  Thanks

[jjwalker98]

I just looked at the petcock and there is a clamp missing on the ON line at the petcock.  I don't see a leak, but could enough gas escape causing my problems???

[Kerry]

The whole problem may turn out to be too little fuel in the tank.  The tip-off for me was when you said

"I am driving let's say 50 and

the RPM's begin to lower."   ()[/list]

To me that sounds like you're either experiencing the all-too-common "fuel starvation" problem, or you need to switch to REServe.  The fact that the bike won't start again in the ON position kinda eliminates the "fuel starvation" possibility, because that tends to fix itself after the bike sits for a minute.

You said "There is plenty of fuel in the tank".  But since you are, by your own admission, a "complete newbie", let me say that looking at the fuel level in the tank can be deceiving.  If you get anywhere near the 1-gallon-left point (still seems to be "plenty of fuel" when you look in the tank), the bike could start bogging down because you need to switch to REServe.

-----------------------------------------------------------------------------------

On the other hand, if all of this is happening with a FULL tank ... let's try an experiment using the REServe setting.

I mentioned before that both the ON and REServe settings work by vacuum pressure, and that the PRIme setting works by gravity.  I think I also mentioned that the PRI setting draws fuel through the REServe hose.

So, here's what we know so far:

Petcock setting |	Hose |	Fuel draw method |	Bike idles OK?
ON	O	Vacuum	NO
PRIme	R	Gravity	YES
REServe	R	Vacuum	??

[/list]

If you repeat your ride with the petcock turned to RES, that will eliminate the ON hose from the equation while still testing the vacuum method of fuel delivery.  If the bike dies, we can concentrate on vacuum problems.  If it runs fine, we can concentrate on the ON hose.

[jjwalker98]

So I went for a 30 min ride today with the petcock on RES.  It seems like the same problem exists with it in the ON position.  Do I know concentrate on a vacuum leak somewhere?  Thanks

[jjwalker98]

Seems like it could also be the petcock valve itself.  It seems like there have been many who've had a problem running on  ON or RES.  What do you think?

[TragicImage]

lots and lots of people have had a problem with the Petcock.

[Kerry]

So I went for a 30 min ride today with the petcock on RES.  It seems like the same problem exists with it in the ON position.  Do I know concentrate on a vacuum leak somewhere?

Yep, that's the next step.

Q: What does it mean to say that the ON and RES settings are "governed by vacuum pressure"?
A: When the fuel switch is set to ON or RES, fuel is not allowed to flow through the switch unless an internal diaphragm is actuated.


Q: How is the diaphragm actuated?
A: By vacuum pressure generated when the engine is running.


Q: How is the vacuum pressure applied?
A: Via a hose that runs from the right side of the right carb (on '01 and '02 models, at least) to the back of the fuel switch.
[/list]

[Just saw your follow-up post, jjwalker98.  Hang on ... we'll get there!]

So, the next thing to check is everything related to that vacuum hose and its connections:

* Any splits, cracks, etc in the hose?

* Is the hose kinked or pinched in any way?

* Is the hose connected tightly on both ends?

IF your bike passes all of these tests, THEN we look at the petcock itself.

[jjwalker98]

The hoses have that black netting on them.  Do I have to take it off to check the hoses?  Do I only need to check the vacuum hose?  Thanks