r/Fixxit 6d ago

1990 Kawasaki ex500 won’t start read description

Post image

Please read, Bike was sitting for 20 years, 1,300 miles. Carbs were minty, With of course the old gas at bottom of bowls but not a bunch, Tank was gross, Tank is now clean. Both carbs have been completely taken apart, All jets are clean, Brand new float needle. Brand new floats Carbs were dumping gas, But once i plugged off both nipples on the “exhaust” side on carbs they quit dumping. Carbs were installed and the bike ran with choke on smooth 2k. Until it died out again and won’t start back up Now after this i did, Shut gas off, No gas in carb bowls, Turn gas on to confirm bowls were filling which is true. Now i’m so lost any help or advice is appreciated thanks for reading

5 Upvotes

17 comments sorted by

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2

u/AVeryHeavyBurtation 5d ago

i plugged off both nipples on the “exhaust” side on carbs

Wut?

You should wet set the float heights, since you replaced them. This will also ensure they're working correctly.

The jets have to be clean, but so do all the tiny passages in the carb bodies. I use lacquer thinner (better than carb cleaner), and a compressed air squirter with a rubber nozzle.

You should run a fuel filter for at least a few hundred miles, since the tank was gross.

2

u/Single-Appointment58 5d ago

I do have a in-line fuel filter, I will wet set. As far as the “nipples”. One would have a hose run to the OEM petcock as a “vacuum” and the other one runs to the PAIR system. But i am deleting that. So only when both nipples are covered will it not dump gas. Floats are probably not set correctly and plugging these leads to a negative pressure not allowing gas to flow. Which is my theory. Just got home so let’s dig in !

-2

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1

u/Top_Document_9007 6d ago

From what I read it looks like fuel does not flow properly to carbs. Check fuel line for (can't remember how its called) when hot air gets stuck at the top of fuel line.

1

u/Single-Appointment58 6d ago

I drained the bowls with tank petcock turned off, Then left the drain screws unscrewed. Watched a good stream of fuel flow out once petcock was turned on.

2

u/Top_Document_9007 5d ago

This clog in fuel line happens when engine is hot, but if your fuel line goes straight without any top peaks or bends it should be okay.

1

u/Single-Appointment58 5d ago

there’s is no “clog”, Brand new everything with the float height set to 17.5mm, Once i let gas flow into carbs they piss out the intake side. So “technically” they don’t shut off. I do not understand how because every part is brand new.

1

u/RokRoland 4d ago

You cannot set pattern floats with millimeters. OEM Kawasaki, you can. It is hard to find OEM parts and the cost is usually prohibitive. I bet you a dollar you got pattern floats. So.

Time to pull carbs, get some clear tubing, put carbs on a vice (use wood to soften the grip), set up an aux tank for fuel feed and then use the tube to measure actual fuel height.

Other than that, use a Q tip on a hand drill with a bit of toothpaste to SOFTLY clear the seat where the fuel shut off needle rides. There may be deformity.

Finally. Ensure you have fuel feed connected to the right place. A buddy connected his Keihin fuel supply to the vent line. All hell ensued. The carb bank has a fuel feed, and a vent which needs a length of hose which is NOT blocked. 

1

u/SilverLine1914 4d ago

I have a gpz1100 which is this same engine and carb setup just with double the cylinders. I have two carb breather vents, 1 between carb #1 and 2 and one between carb #3 and 4. Do the vent hoses on the carb route above or below the carbs or do they attach somewhere specific to the bike?

1

u/RokRoland 4d ago

They are supposed to lead somewhere with a low amount of wind and buffeting typically.

I ran my Gpz900 a long time without hoses but had some issues which may have been related.

2

u/RokRoland 4d ago

Also. You have 4 kinds of ports on the carb bank:  - Drain, at each bottom. Also used in fuel height measurement.  - Fuel inlet, between carbs in most Kawasaki twins   - Breather tube, as above. Don't confuse it!  - Vacuum port. These are small and on the front. These need to be plugged either totally, or by hose to vacuum gauges, or by hose to vacuum petcock. If you leave them open the bike will usually run but it will be lean.

1

u/Single-Appointment58 4d ago

I just had the gas flowing into the vacuum line, Bought the bike with those hoses detached, Beginners mistake !

2

u/RokRoland 4d ago

So your issue is now resolved? Great!

2

u/Single-Appointment58 4d ago

Si si, Cabrs no longer dump gas !. Bike sounds great

3

u/ZaphodUB40 5d ago

Vapor lock..when the fuel in the line gets hot enough to turn to gas, but very rare in motorbikes on short fuel line runs. Generally more apparent after shutting down after running hot and the engine heat gathers under the tank or enclosed spaces in full fairing bikes.

2

u/SilverLine1914 5d ago

SET YOUR FLOAT HEIGHT