Starting issues after long rest period

[Howley]

Hi, remember me?

My bike, a 94 m900, has been sitting for years with no additives in the fuel. I've been working on getting it running.

I pulled the carbs, cleaned the jets, checked oil and belts.
Old fuel was drained and replaced. After a while of turning over it finally caught and started, and was running OK for a little before dying again.

I suspect it's a fuel issue.

- If I pull the hose after the petcock, I get some fuel but it's not flowing out super consistently. If detach the filter from under the tank and move it around a bit I get more. I did drain about 4l of old fuel this way, and it seems like it was flowing better then.
- The hose at the tank will fill a 600ml bottle in about 30 seconds, but is very sensitive to the hose position.
- I can blow air through the fuel filter.
- I can't get to the fuel pump (external square type) without taking off the air box so I'm hoping for some other leads, but I suspect I'll need to pull the fuel feed from the carbs and crank it to see if I've got fuel there.

The confusing thing is that it started, although I suspect it's from fuel slowly making its way there, or the fuel I manually blew through the pump.

Can anyone offer any suggestions?

Cheers,

Luke

[Frank C]

The OE fuel pump is a simple diaphragm type.  I can see the diaphragm drying out and cracking after a few years.  The failure mode is usually the transfer of fuel from the tank to the crankcase.  Fun stuff.  Inexpensive rebuild kits are available.  Can also go with an electric fuel pump with the correct flow rate and pressure (Airtex has a few options)

Also, do you still have the original vacuum petcock?  That was one of the first things that failed on my 97 monster.  Went with a manual shut off.

[koko64]

Should have a manual tap on that year (most countries). Definately consider rebuilding the pump and expect to change the filter again. You might go through a few filters in a short time as crap dislodges, so it would pay to clean out that tank. A thorough clean of the carbs is essential and if things stay dirty upstream you may have to clean them again. Gel and wax like material in aging fuel can seal up the filter medium. Check the mini strainer type filter in the carb inlet barb (I remove it). The lining of old fuel hoses can also dislodge.

Give that poor old girl a birthday.