85 GPZ900 not idling....

[cutchemist42]

So basically here is a list of everything done in the past month since this bike was not starting last fall...I should also mention that my dad had air filter pods, aftermarket exhaust, and rejetted the bike.

• Cleaned out tank with POR15 since fuel tank was rusty. Gas came out carb drain screws bronzey looking. After cleaning, inside of tank looked great and gas drained out looking like normal gas.
• Replaced spark plugs

Now I have a few feelings about the carbs and was actually thinking of buying a new whole unit off a local parts bike. The guy said every other part off this parts bike has worked great when ripped onto his working GPZ900. I know the brake cylinders I bought worked!

• All pilot screws were at factory suggested amount of turns. Also, there is gas sitting in all 4 of them since I checked to see if gas drained out.
• Carbs all seem well seated into the intake boots; cannot push them in any further as they are right up against the carbs. Would it matter about the angle the carbs are sitting at? They are angled upward and was wondering if they sit more parallel to the ground.
• I have my doubts about one of the vacuum slides; the rubber looked wavy and was not exactly sitting in the groove. Now I don't remember getting carb cleaner on it but am afraid it happened.

Now I'm basically assuming there is no gas getting to the engine based on how it sounds. Here's a video and a few pictures of how the carbs are sitting....

eaf35154.mp4 video by sneedham6 - Photobucket

Thanks for the help and suggestions!!!

 

[ABerns]

You mention in the subject that it won't idle, but it sounds like it won't run at all, correct? Even when applying choke (enricher) or throttle?

Starting from the basics (air, fuel, spark), have you checked for spark? Have you tried putting the factory air elements back (if you still have them)? Depending on how much you have done with the carbs, it wouldn't hurt to synchronize them, either.

 

[cutchemist42]

Originally Posted By: ABerns
You mention in the subject that it won't idle, but it sounds like it won't run at all, correct? Even when applying choke (enricher) or throttle?

Starting from the basics (air, fuel, spark), have you checked for spark? Have you tried putting the factory air elements back (if you still have them)? Depending on how much you have done with the carbs, it wouldn't hurt to synchronize them, either.


Correct, out of maybe 5 attempts I only heard ignition-like sounds twice. I will check both compression and spark this weekend to check. How fat of a spark should there be across the spark plug gap?

 

[cutchemist42]

I should also mention I changed the spark plugs with the American suugested ones and not the Canadian ones. Would that have such a serious effect you think?

Anyhow, I'll do a rundown on each spark plug and give compression readings later! I did try choke and no choke but did not try putting throttle into any of my starting attempts.

 

[BigCahuna]

If your gas came out goldish and smelled like old gas, I'm betting your carbs need to be removed and cleaned. That old gas turns to varnish and will plug up the small holes in the jets. If no gas is flowing thru the jet, putting a cleaner in the gas won't do anything. It shouldn't be hard to remove the rack and clean them out. This way you can tell if the slides a free and the floats aren't stuck..,,

 

[cutchemist42]

So I don't know what happened overnight but after more attempts tonight it starts! It starts now with the choke being used in what is 25 degree Celsius weather. Starts easily too and can idle. However, it is smoking pretty bad....Now this is my dad's bike and based on his familiarity with it, he said the following:

-Definitely running rich, even with the choke on. (Don't know how he can tell but I can't)

-He feels like it's missing on one cylinder; I will thus check the spark plug and compression tomorrow. I'm not familiar enough with the bike so did not notice that seemed out of place.

Will post a video tomorrow of it.

 

[Robenstein]

If its missing its easy to tell. One header pipe wont get hot since its not firing.

 

[cutchemist42]

Originally Posted By: Robenstein
If its missing its easy to tell. One header pipe wont get hot since its not firing.


Well yeah, that was easy, cylinder 3 was the culprit. I guess the obvious checks are spark across the spark plug gap and compression? Or maybe that one carb is simply dirtier then the other.

 

[Robenstein]

Could be that the idle circuit is plugged. Rev it up and see if the pipe gets hot. My suzuki ran on 2 of 4 at an idle, but picked em up at higher revs. The carbs were full of junk when I pulled em.

 

[Robenstein]

Also there should be raw fuel going into that cylinder if its spark or compression, so you should be able to rule out the carb if its got fuel in there. Should be on the plug or ya can probably smell the raw gas in there. If the plug sparks and its dry, probably a carb I would say.

 

[cutchemist42]

Well confirmed a few things:

-Spark on that third cylinder spark plug. Looks the same as the other 3 cylinders when I tried their corresponding ignition coils

=Did notice any wetness on that 3rd cylinder spark plug when I pulled it after running it again. Could not notice a strong gas smell, very very faint trace

Guess that means I'm checking out that carb when I got time next!

Also did a compression on the cylinders and bad results I think.....(psi). The test was done about 25 minutes after starting the bike for 3 minutes.

CY1=90
CY2=150
CY3=110
CY4=90

The manual says it should be 141 +/- 31 psi. The bike is running 10W40, would running 10W50 make an improvement really?

This bike was garaged for 7 years at my dad's place before I got it from him...

 

[cutchemist42]

UGH!! i just realized I did not once open the throttle wide open when doing the compression test! I should probably disregard all those results until I redo it tomorrow!

 

[cutchemist42]

Just posting what the results now that I held the throttle open haha...

CY1-150
CY2-150
CY3-155
CY4-160

These definitely look better!

Will not be able to check that cylinder 3 carb this weekend because of homework but next week I'll see what I can find!

 

[ABerns]

Excellent, compression seems fine. Keep us posted.