Can't get bike to start

matt234 · August 25th, 2023, 07:51 AM

I bought an '89 250, non-runner, for a few hundred dollars, that would turn over. I pulled off the carbs, took them apart, gave them a good clean and put them back together. I did an oil change and replaced the oil filter, and got some new spark plugs. But it won't start. The petrol tank is rusted, so any time I'm trying to start the bike I'm using a direct line from a container to the carbs, with the petrol just being gravity fed to the carbs, and I disconnect it so there's no petrol going to the carby when the bike's just sitting. It has spark, and fires if I spray engine starter into the carb. I've got the airbox off. I have the mixture screws unwound 3 turns, and it did start and idle, with choke and without any engine starter, for about 8 seconds. But that's all I've been able to get out of it, and it hasn't done that since. It just turns over. The carbs don't seem to be leaking at all and I'm not too sure where to go from here. I'm convinced it's carby related because it has spark and seems to have compression. The jets, floats, float valves and diaphragms seem alright so I'm not too sure. Any advice would be much appreciated.

Triple Jim · August 25th, 2023, 11:03 AM

Hi Matt, welcome!

These carburetors are notoriously difficult to get completely clean. The problem you're having is very common with bikes that have been sitting for a long time. Here's some information about cleaning the carbs:

https://n4mwd.blogspot.com/2013/10/s...-passages.html

DannoXYZ · August 25th, 2023, 12:24 PM

You'll need further complete disassembly of carbs down to every last nut, bolt and individual component for scrubbing with brushes and poking out with matching-gauge soft copper wires. Bike ran perfectly fine when leaving showroom floor. It will again when carbs are restored to factory-fresh clean with all factory settings.

Spray carb-cleaners no longer work due to removal of chlorinated compounds. Scrub with PEA-based fuel-system cleaners:
- Red Line SI-1
- Techron Concentrate Plus
- 3M Max Strength Fuel System Cleaner #08814
- Royal Purple Max Atomizer 18000
- Gumout All-in-One (may be off list soon due to reducing amounts of PEA)

Scrub-brushes from Amazon: https://www.amazon.com/dp/B01N6QEINN

Scrub secret hidden passages in carb-body with PEA-based fuel-system cleaner.
N4MWD's blog: Secret Ninja 250 Carburetor Passages

Completely disassemble emulsion-tube and pilot jet. Poke out all lateral bleed holes with soft copper wire. Dried petrol turns to plastic and cannot be dissolved again. Must be mechanically scrubbed away. Also poke out all bleed-holes in carb-venturi towards float-bowl. Especially the mixture-screw hole.

Ultrasonic soak everything, micro soda-blast. Replace all rubbers: fuel-rail O-rings, float-valves, flow-bowl seals, pilot-screw O-rings. Set float-height with wet-test. Sync-carbs

That's a lot of work and requires lots of experience and equipment. Unless you want to practice and destroy hundreds of carbs to learn this kind of work, I recommend sending petcock & carbs off to ducatiman (gordon) for complete restoration work.

https://customcarbservices.com
Expert work, reasonable costs and fast turnaround! Bike will run like brand-new off showroom floor!!!

BTW - can search "ducatiman clean carbs" on this forum for procedure & photos of what's involved in thorough carb restoration back to factory-fresh OEM clean.

August 25th, 2023, 07:51 AM	#1
matt234 ninjette.org newbie Name: Matt Location: Melbourne Join Date: Aug 2023 Motorcycle(s): 1989 GPX 250 Posts: 1	Can't get bike to start I bought an '89 250, non-runner, for a few hundred dollars, that would turn over. I pulled off the carbs, took them apart, gave them a good clean and put them back together. I did an oil change and replaced the oil filter, and got some new spark plugs. But it won't start. The petrol tank is rusted, so any time I'm trying to start the bike I'm using a direct line from a container to the carbs, with the petrol just being gravity fed to the carbs, and I disconnect it so there's no petrol going to the carby when the bike's just sitting. It has spark, and fires if I spray engine starter into the carb. I've got the airbox off. I have the mixture screws unwound 3 turns, and it did start and idle, with choke and without any engine starter, for about 8 seconds. But that's all I've been able to get out of it, and it hasn't done that since. It just turns over. The carbs don't seem to be leaking at all and I'm not too sure where to go from here. I'm convinced it's carby related because it has spark and seems to have compression. The jets, floats, float valves and diaphragms seem alright so I'm not too sure. Any advice would be much appreciated.

August 25th, 2023, 11:03 AM	#2
Triple Jim Guy Who Enjoys Riding Name: Jim Location: North Carolina Join Date: Jul 2016 Motorcycle(s): Ninja 250 Posts: A lot. MOTM - Oct '18, Aug '17, Aug '16	Hi Matt, welcome! These carburetors are notoriously difficult to get completely clean. The problem you're having is very common with bikes that have been sitting for a long time. Here's some information about cleaning the carbs: https://n4mwd.blogspot.com/2013/10/s...-passages.html
	1 out of 1 members found this post helpful.

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August 25th, 2023, 12:24 PM	#3
DannoXYZ ninjette.org certified postwhore Name: AKA JacRyann Location: Mesa, AZ Join Date: Dec 2011 Motorcycle(s): CB125T CBR250R-MC19 CBR250RR-MC22 NSR350R-MC21 VF500F CBR600RR SFV650 VFR750F R1M ST1300PA Valkyrie-F6C Posts: A lot. MOTY - 2018, MOTM - Nov '17	You'll need further complete disassembly of carbs down to every last nut, bolt and individual component for scrubbing with brushes and poking out with matching-gauge soft copper wires. Bike ran perfectly fine when leaving showroom floor. It will again when carbs are restored to factory-fresh clean with all factory settings. Spray carb-cleaners no longer work due to removal of chlorinated compounds. Scrub with PEA-based fuel-system cleaners: - Red Line SI-1 - Techron Concentrate Plus - 3M Max Strength Fuel System Cleaner #08814 - Royal Purple Max Atomizer 18000 - Gumout All-in-One (may be off list soon due to reducing amounts of PEA) Scrub-brushes from Amazon: https://www.amazon.com/dp/B01N6QEINN Scrub secret hidden passages in carb-body with PEA-based fuel-system cleaner. N4MWD's blog: Secret Ninja 250 Carburetor Passages Completely disassemble emulsion-tube and pilot jet. Poke out all lateral bleed holes with soft copper wire. Dried petrol turns to plastic and cannot be dissolved again. Must be mechanically scrubbed away. Also poke out all bleed-holes in carb-venturi towards float-bowl. Especially the mixture-screw hole. Ultrasonic soak everything, micro soda-blast. Replace all rubbers: fuel-rail O-rings, float-valves, flow-bowl seals, pilot-screw O-rings. Set float-height with wet-test. Sync-carbs That's a lot of work and requires lots of experience and equipment. Unless you want to practice and destroy hundreds of carbs to learn this kind of work, I recommend sending petcock & carbs off to ducatiman (gordon) for complete restoration work. https://customcarbservices.com Expert work, reasonable costs and fast turnaround! Bike will run like brand-new off showroom floor!!! BTW - can search "ducatiman clean carbs" on this forum for procedure & photos of what's involved in thorough carb restoration back to factory-fresh OEM clean.