Cranking but not running...?!

[4uproductions]

First off, I am new to this forum as well as to FZRs. I feel as though i am fairly competent with mechanical stuff, but am just needing some extra guidance on this problem. So, thanks in advance!!!

I have a 1992 FZR 600 that is completely stock as far as i know. It has 8000 miles on it. I recently bought it from a guy who was the only owner and had it sitting around for the last year or so. When I purchased it, it started right up every time, no questions asked. Only thing was that it would only run with the choke on. Test drive went well and second gear and evrything else felt good, so after I bought it I decided to get it back up to par.

I cleaned the carbs which included all the jets and everything. When doing so I noticed that 3 of 4 diaphrams were pinched looking so I replaced all 4 of them. I also noticed that the air/fuel mixture screws (the ones that you have to drill out the plug to get to) were all stripped. So i replaced all of those and turned them 2 1/2 turns out. Everything else looked good after a good cleaning.

I flushed the coolant out and replaced it with engine ice, replaced the spark plugs with autolites, put new gas in it, and replaced the air filter. And am planning to do an oil change when I can get it running again.

**SO the problem is that it wants to ONLY crank and not actually fire up and run. Lights come on bright, cranking sounds strong, I can hear the fuel pump engage, tested battery and it is at 100% charge, tested the spark on ALL 4 spark plugs and they are ALL good, petcock is ON and fuel is atleast getting to where the nozzle is on the carbs ( I took the hose off and fuel came out).

So now I am out of ideas!! Sorry for the short story, just trying to be thorough.

[DonTZ125]

Welcome to the madness!

Do you have the 'choke' / starter lever on the left side pulled down?

[4uproductions]

I turned it up to cold start it on the first try with the throttle open, then closed the choke and tried starting it again. I did this each time.

[DonTZ125]

Choke on, throttle fully closed.

[4uproductions]

Just tried that. Cranked, huffed a couple times... but nothing

[4uproductions]

Just checked fuel filter and it is not clogged either. Also made sure that the fuel pump is working. Any suggestions?

[4uproductions]

I must say that I am a little surprised at the lack of response in this forum. Did I not post inthe right section or something??

[DonTZ125]

Did you clean your carbs before or after you cleaned out the tank? Pull the plugs - are they wet? When you reassembled the carbs, did you swap the starter and main jets? They are the same pattern, just very different sizes, and easy to mistake.

[willandrip]

I must say that I am a little surprised at the lack of response in this forum. Did I not post inthe right section or something??

You posted with correct terminology and a good description of the fault and your efforts to resolve it in the right section, you already sound knowledgeable !
This probably prevented all the spurious immediate replies .
Lots of members on here may be very busy at the moment and unable to find time to read and reply to questions.
I do agree though; I thought replies would be more forthcoming.


I immediately thought; application of starting fluid when cranking when I first read your post.
Are the plugs getting wet ?
These carbs have hard to access drillings internally; may take a few goes (sonic baths) to get them immaculate.
Full choke, no throttle to start, if the plugs have fouled; the old trick of cleaning and then heating on a gas stove
and refitting when still hot does help recalcitrant starters.
When originally procured and it only ran with choke, varnish was probably already affecting carb internals,
some may have been dislodged by your cleaning and now blocking a circuit.

[goosefartfan]

Timeline:

1. bike starts, runs.
2. rebuild carb.
3. bike won't start or run.

Frustrating, but seems like you got to back to square one and make sure everything is put back together properly. Putting wrong jet in wrong place sounds like a good place to start.

I would have suggested hard starting = bad valve clearance, but if the mileage is true, prob not that.

Another thing, use Google advanced search to search for terms restricted to this site. I'm sure your problem has been addressed here before.

Best of luck!

[4uproductions]

thanks for the replies!

After cleaning the carbs the first time, I put new plugs in. After recently spraying some carb cleaner into the airbox she fired up again. But wont stay running. I have to give it full throttle to get it running and then it stays around 1000rpms. When i let off the throttle it immediately dies.

I checked the plugs afterwards and found that they were black and wet. That along with the white smoke coming from the exhaust made me believe that it is ruinning rich. I tried adjusting the mixture screws to 2 turns out instead of 2 1/2 or 3 but then it wouldn't run at all.. Also tried 3-4 turns out as well.

So i decided to go back through the carbs again:

**immaculately cleaned EVERYTHING
**Did my best to measure float hieght and ensure they were all around 22mm
**Did my best to sync carbs with a piece of wire. Starting with #3 and going from there until they were all as close to the same as I could get them.
**Realized that my battery was dead due to all the attempts, so I got it back up to 100%
**Turned mixture screws to 2 1/2 out
**Put in brand new spark plugs again. This time using the oem NGK ones.

So it is still only being able to run at 1000rpms with full throttle but i noticed that (when looking over head at the bike) carb #1 had slightly less suction from the top and almost no gas on the slide, whereas carbs 2-4 had a significant amount of gas on the slides and really sucked your hand down.

[4uproductions]

Hopefully this isn't a valve seal problem......?

[willandrip]

Hopefully this isn't a valve seal problem......?

I doubt it.
Carbs have internal blockages somewhere.
Did you take note of Don's comment re. jet transposition.

I believe from the description its either not getting enough fuel to start/run ( only ran initially with choke on and now starts with carb cleaner)
or has insufficient vacuum to lift and vapourise fuel.( leaks/pinched or holed diaphrams/ cracked inlet rubbers)

White smoke ?
More likely condensation from cold exhaust.
Black smoke indicates richness.
Carb sync. method would be more than adequate for initial starting.

Carburation is the number one cause of poor running on both these and the 400 variant.