1985 GS450 starting issues

[dennco2]

1985 GS450 starting issues

"Is 115 within compression limits and enough to fire atomized gas?"

plenty, BUT there has to be enough atomized gas in there.. You didn't explain your carb cleaning technique

I separated the 2 carbs from the support brackets and removed the bowl covers and all (I thought) jets and adjustment screws and needle jet and jet needle and sliders. Then I submerged the carbs one at a time into Berryman's carb dip. Didn't dip the sliders with the rubber diaphrams. I only dipped the first carb a couple hours ... as it looked clean on the outside. The other carb I dipped overnight.

Turns out I missed removing the choke plungers ... the Pilot air jets and the Pilot mixture screws and those parts didn't get the benefit of the dip solution. Later, I pulled those assemblies apart and squirted spray carb clean in there and used a can of compressed air to blow out those areas. No, I am not sure all those passageways are completely clean and clear. I was kinda learning as I went along.

I did soak all the jets and and small holes and passageways and inspected. Pretty confident about those parts. Put it all back together and no fuel leaks when new fuel was supplied through NEW Petcock and fuel lines.

But I agree, it seems fuel may NOT reaching the right carb! The floats were both set the same at .910" ... inverted measurement from the bowl gasket area (without the gasket) .... to the rounded part of the float bottom. Previously were at .800" or so. The 85 carbs seemed to have slightly different specs and the floats were made out of some kind of black plastic instead of soldered metal.

I guess I could open the drain plug to see if there is any standing fuel in the bowl? If there isn't it seems the likely suspect is the pilot air jet passageway? I seem to remember holding that up to the light and seeing a clear hole, but that was 2 months ago now.

I'm open to removing the carbs and doing another cleaning and thorough inspection, if needed. I'm hoping there is a easier solution to get the right side piston to fire. I will check the spark again with the removed plug.

[tom203]

Can you post a pic of your carb, so we can determine if you have removed the cap over the idle/air mixture screw (to get at the screw itself) ? Earlier 450 carbs had a different setup apparently.
Your bowls could be full but fuel mixture might not make it up the idle circuit passages to carb throat. See pic to note how mixture squirts out over throttle plate area

After you did your cleaning and put everything back together, did you bench sync the carbs to make sure both throttle plates were equally just about closed when resting on idle stop screw?

[dennco2]

Yes, I checked the 2 throttle plates and they close and open together ... and look synchronized with no extra play.

The mixture screw cap was already removed. After a brief cleaning, I screwed it back in and opened both screws out 2.5 turns. I will go back and check those settings. I took a lot of before and after cleaning shots of the carbs. I will post a pic ... if I can figure out how to on this site.

Also, I found a great teaching resource on youtube for GS carb operation.

https://www.youtube.com/watch?v=wyspAHrMbb8

[tom203]

"After a brief cleaning,"

These tiny passages don't always respond to "brief" cleaning- that's why folks on here talk about the 24 hour dip. Some folks have to do it twice! Stuff could be jammed up somewhere on path back to fuel bowl. Or Look for an ultrasonic guy near you who has experience with carbs. Without a clean pilot circuit, these things run poorly.

did you get the o-ring kit from cycleorings.com ? 30 year old o-rings are past their sell date. I don't know if the 80-82 kit is the same as the 85 version, but inquire (he's a member on here)- good info on his site

http://www.cycleorings.com/450.html

[Steve]

Also, I found a great teaching resource on youtube for GS carb operation.

https://www.youtube.com/watch?v=wyspAHrMbb8

Interesting? Yes.

Accurate? NO.

Please don't take that video as an accurate depiction of how your carbs work. In principle, it's not too bad, but ports are in the wrong places, the slide does not operate the way the video shows, many other details are just ... wrong.

.

[dennco2]

I started this thread I think back in November. I put this GS450 project aside for the winter and now getting back on it.

I pulled the starter button apart and filed the contact points. Put it back together with coil spring. It now activates the starter relay! Now I have a new problem that baffles me. I think the engine started to fire on the left cylinder but when I let off the starter button ... I heard the starter motor continue to rev and wouldn't release. The engine would not run faster than at idle, just like back in November and only on one cylinder. I desperately was trying to stop the engine/starter motor and turned off the ignition switch, kill switch ... then put it in 1st gear and it would not stop till it ran the battery down or motor got hot, I guess.

So can someone tell me what happened there? Apparently, the starter clutch did not release as it should and the ignition switch should have shut off power to the starter motor? I just pulled the stator cover off to look inside and also the starter motor cover. Don't see anything obviously wrong in there. The starter gears are supposed to turn one way freely, right? It did turn but not freely. Since the motor does not turn the engine over with much power, I suspect it need rebuilding. Have not pulled it out as yet to inspect.

I don't have the tools Suzuki recommends to pull things apart. I do have a Suzuki manual and will try to solve these problems if possible after your good suggestions. Otherwise, does someone in this group know a qualified group member in the Seattle area who can help out for $$?

Also, I will need a cover gasket now ... any recommendations?

[dennco2]

"After a brief cleaning,"

These tiny passages don't always respond to "brief" cleaning- that's why folks on here talk about the 24 hour dip. Some folks have to do it twice! Stuff could be jammed up somewhere on path back to fuel bowl. Or Look for an ultrasonic guy near you who has experience with carbs. Without a clean pilot circuit, these things run poorly.

did you get the o-ring kit from cycleorings.com ? 30 year old o-rings are past their sell date. I don't know if the 80-82 kit is the same as the 85 version, but inquire (he's a member on here)- good info on his site

http://www.cycleorings.com/450.html

Hi tom203, I attempted 3 times to send you a PM but never got a confirmation it was sent ... or show up as "sent items". Looking forward for good advice here to proceed intelligently.starter clutch.jpg

[tom203]

I got those 3 messages when I logged ithis AM.

It's possible that the starter solenoid has failed internally and is locking "on" - neither key or kill switch would then be able to cut power then. If you still have the stator cover off, just remove the immediate gears and test solenoid. The small wire on solenoid is the trigger wire - when starter button is pushed, this wire gets 12 volt positive,which triggers solenoid "on". But when button is released, solenoid should disengage and starter motor stops spinning . An internal short in solenoid might let it stay engaged. You can always disconnect a battery cable to kill power to solenoid.
You need to fix this issue before you return to carb issues!

Edit: since you fiddled with right hand switch, you might have misconnected it somehow. Both the key switch and run switch should have killed ignition system, though the solenoid might have failed as described above and let starter motor still run.

[dennco2]

The picture I posted shows the smaller gears that slide in and out on that hollow shaft. The gears slide without any resistance and stay wherever I leave them. Is there supposed to be a spring action there to snap it in or out when start button is released? Is that the "start solenoid" you speak of ... or the large solenoid (relay) on the left side of frame connected directly to the battery?

My knowledge is very limited in these area. Is the starter clutch mounted behind rotor? I attempted to turn that part by hand and could not turn it either way! Supposed to turn one way freely? Not this one!

[tom203]

That hollow shaft that holds the intermediate gears will slide out towards you to let you remove those gears; beware, there is likely a thin washer/spacer on other side of the hollow shaft,so try to catch it!
Once those intermediate gears are out, you should be able to spin that big gear in one direction only - this gear drives the starter clutch that spins the rotor. Does this happen?

[dennco2]

Yes, I pulled out the intermediate gears and hollow shaft but did not see any thin washer. I then tried to turn the large gear both ways and it turned freely in the clockwise direction. Locked up on counterclockwise. Seems all is good there?

[tom203]

Starter clutch seems good... while the intermediate gears are out, grab the shaft on the starter motor, it should turn easily and not bind up. Hopefully it will.
Now you have to figure out why/if the solenoid locked up and why the key switch and kill switch did not kill power to solenoid to disengage it. Leave the intermediate gears out- no sense killing the starter motor till you fix this issue. You can always pull off a battery cable to kill power.

[dennco2]

I just tested the starter solenoid twice and all was well when I pushed the starter button and then released ... the starter motor ran fine and stopped immediately. Still perplexed on how the intermediate gears can align or miss align to the large gear as it slides in and out? I will pull the intermediate gears back out to check the starter motor for ease of rotation.

This 450 has not ran for about 3 years, so some gremlins to be expected. Was hoping to get lucky in that area. I will go thru and clean up as many electrical connections as I can to get my system voltage up as high as possible. Then tackle the carb issue again.

Update: Okay I am learning more each day. I saw the housing design of the stator cover and how it supports the outside hollow shaft of the intermediate starter gears. Also, the starter motor has a lot of drag when attempting to rotate by hand .... seems sluggish. And when I fed power to the motor thru the starter button ... it didn't spin up near like I would expect. So I attempted to pull the starter motor, but couldn't clear the cam chain tensioner. So now I am reading up on how to pull it and retension later. Should I also pull the carbs now to create more working space? The carbs also will need more dipping in solvent before attempting to engine operation. I will need to see if fuel is in the right fuel bowl AND why fuel is not allowed to suck into the engine.

[John Park]

Yes, I pulled out the intermediate gears and hollow shaft but did not see any thin washer. I then tried to turn the large gear both ways and it turned freely in the clockwise direction. Locked up on counterclockwise. Seems all is good there?

It seems as though the washer was deleted on the 450 but was there on the old style 400 [?] and some other motors. Given that there is no end thrust with these gears it was irrelevant. Putting one in could result in binding - maybe.

[tom203]

The sluggishness of starter motor might mean that it got damaged with the locked on episode. It should turn freely by hand with no sense of binding. They can be rebuilt (new brushes, bearings,etc.) or you can find them on ebay. The 450 shares the starter motor with the gs300 and the shafty 650's. Get it out and check p/n

"Okay I am learning more each day. " yep!


Edit: check this thread for pic

http://www.thegsresources.com/_forum/showthread.php?247914-Starting-problem&p=2410186#post2410186