XJ550 won't start after sitting for a couple days

I've read, and I've read, believe me I've read a lot the other posts about non-start issues. But nothing I've applied has really helped me.

Status quo:
=========
-bike will start and run fine if ridden daily
-when it is running, engine runs smoothly and predictably; no problems

-if bike sits for more that 2 or 3 days without riding, it will not start

-start button will crank and crank, and engine will turn but i'll hear no combustion

&nbsp&nbsp&nbsp-actually, after sitting for a few days, the first second of cranking will produce that combustion noise(residual fuel in cylinders?)

&nbsp&nbsp&nbsp-after sitting, the only way to get it going is to bump start it. But it takes a a lot of tries to work, it's not instant, however after getting it to start this way and letting it warm up, it will run and start reliably(if ridden daily)

-spark is good

-cleaned the carbs(I hope I was thorough enough)

I feel like this is a fuel issue, I'm wondering if anyone can draw parallels to my situation.

Thanks

 

Have you tried switching the petrooster to prime for 30 seconds or so before attempting to start it. The bowls on the carbs may not have enough fuel in them to deliver the proper amount to start it.

 

You can leave the fuel tap on prime to start. Then switch over to run once the engine in running.

How about a list of what you have already tried?

Start out with a fully charged, and load tested battery. These bikes draw a low of power through the starter, and a weak battery may not have enough power to fire off the coils after sitting for a couple days.

With a starter that will turn the engine over. It may be possible that the starter has enough carbon dust build up in it to cause the starter to pull to much power while trying to start. Cleaning, and servicing the starter, and replacing the brushes if necessary will help considerably.

One other point to check would be the generator brushes. It may be putting out enough power to keep the bike running, but not fully charging the battery. Once again. Carbon dust build up may be limitimg the amount of power that the generator is putting out.

That covers the 3 critical points of the electrical system part to starting the engine.

With the bike running good on a daily basis, and firing off with the bump start. Only acting up when left sitting. I would tend to think the fuel system is working properly.

Ghost

 

MIGHost says good.
i can add following thing: when you start after a couple days, when it not starting - after cranking via starter, turn out one spark plug, and see that - it is a dry, or wet?
what is spark plug central isolator color?
when you cranking, it be a smell of gasoline ( petrol) around?
also try look at oil level in engine - it is not higher than when you parking after drive? it possible some petrol leaking to cylinders and oil in carter, who in result make too rich mixture, maybe...

 

At risk of being a smart-A$$; do you use the choke?

How old are spark plugs?

 

I'm voting battery. Start there.

 

if starter cranking with good revs, not like as dying fish, then there is not reason to voting for battery, i think.

 

There is on XJ's....

The starter will still spin over just fine on some bad batteries (like one with a dead cell, for example) but not leave enough power to fire the ignition at the same time.

 

As above, yes there is. It is VERY COMMON for a battery to have enough "juice" to spin the motor quite vigorously, but then have nothing left over to fire the ignition. It's happened to me personally, twice, and it was a marginal battery both times.

 

Fitz beat me to it....sounds like the battery to me too.

 

Thanks for the the quick response guys.

In response:
- I usually set the petcock to prime after its been sitting

- Spark plugs were replaced only a couple months ago, in an attempt to solve this same problem

- yes I use the choke, and it works fine to warm up the engine when it does start, but is no help when it won't

Thanks MiGhost for the comprehensive list. I'll start with the battery, and so on. Will post my results in a few days(went for a ride today, gotta let the bike sit)

 

What voltage have you got on the battery after rest as a start?

 

Above advice on the electrical system is absolutely true - but might not address your actual question. The question isn't just 'why is it hard to start', it is "why is it easy to start after one day but very hard to start after 3 days?" A battery on it's way out will do that, but in my experience a) it should bump start easily even with a so-so battery, and b) once it starts to go, the problem gets progressively worse very quickly and soon it won't even start the next day.
So what could be happening between day 1 and day 3 to make such a difference? We all experience that to some degree (at least I do) but your situation seems worse.

1. Battery discharging, either because everyone above is right and the battery is weak, or else there is a small drain somewhere in the system. Put a trickle charger on the battery next time you are going to park it for 3 days. Or, hook up jumper cables before you start cranking. If it starts up just like day 1, your problem is one of those 2 things. If not, you need to look elsewhere.

2. Moisture somewhere in the electrics. Is the bike parked somewhere dry? Is it covered with dew every morning? Does the weather affect how hard it is to start?

3. Moisture in the fuel. If there is moisture in the fuel it will settle to the bottom of the float bowls. Crack open the float drains, then put the PC on prime to fill them up. Then try to start (do this before you start cranking).

4. Oil issues. Oil drains down into the sump over time, and the film in the cylinders and elsewhere gets thinner the longer the bike sits, which means more friction when you try to turn it over, which means more work for the starter and less energy for the coils. Better quality oils retain the film better. You aren't using cheap Walmart oil are you? Overfilling the oil also increase the internal friction when starting.

I fully agree with all the suggestions to keep your electrical system (starter, alternator, coils, plug caps and wires, etc) in tip top shape as your best defence against hard starting in general. But there may be something else going on here as well.

 

"Oil issues. Oil drains down into the sump over time, and the film in the cylinders and elsewhere gets thinner the longer the bike sits, which means more friction when you try to turn it over, which means more work for the starter and less energy for the coils. Better quality oils retain the film better."

mmmmmm well in my humble, the sluggishness is caused by reduced chemical reaction in the battery because of lower temp and greater oil viscosity due to temp again. Ergo - Greater work for the starter and less power for the ignition system. Changing his oil won't help him get around that cold reality I'm afraid....

Thunder Thighs - try a car battery and get rid of that ridiculous beak :lol:

 

After one day, the bike is as cold as it is going to get. It doesn't get colder 3 days later unless the weather changes. So that doesn't explain why it is easy to start after one day but very difficult after 3.

 

Well as you know the battery loses charge incrementally each day...on a dodgy battery, two or three days that could be the deal buster...

 

That is true, and that's why I suggested using a trickle charger or jumper cables to test for that possibility...

 

Check your charging system voltage. Make sure you are getting a good healthy charge voltage back into the battery.

I had hard start problems on my 550 too. I think the best thing I did for it was cleaned and re-greased my starter. At 9500 miles on the 30 year old bike the grease was solidified and the commutator was crudded up with brush dust and oxidation. After cleaning, lubricating, and throwing in a few gaskets it works great and cranks much better than before. With that, the bike fires up almost effortlessly. I just fired it up last weekend after sitting all winter long. It started almost immediately. It was never like that before. I think the cleaning probably removed a lot of resistance that was built up between the brushes and the commutator, so it uses less amperage to do what it needs to, leaving more energy available for ignition. Thats my theory at least.

 

I used to get exactly the same starting issues with my maxim X untill i discovered a starting technique that now works for me every time.... on start up apply full choke, crank the engine with the throttle FULLY CLOSED and the engine will catch, then apply minimum throttle / adjust choke to keep engine going . Applying throttle whilst cranking the engine always prevents my engine from starting when cold - ok to use throttle on warm engine.

 

TJ!!! Dude! Where you been?

Oh, sorry.

It's the battery, we're just waiting for OP to discover that.

MEANWHILE:

STANDARD starting procedure for the aircooled XJs (and it sounds like the pumpers too) is:

Full "choke" and DO NOT TOUCH the throttle. (All you'd be doing is opening the butterflies which does NOT help.)

Once the motor fires, it will start to "race." Use the choke to turn it down and hold about 2K rpm. Meanwhile, put on your helmet, your ...turn the motor down, it's getting toward 3K... gloves, find your ... turn the motor down, it's running up again... sunglasses, and saddle up.

Ok, so now it's holding 2K or so and has been running for a couple of minutes. NOW you can go ahead and "blip" it. Readjust choke so it doesn't die, but by now it should be time to drop it in gear and ride away. Pull the choke all the way off within a few blocks as it warms fully.

This is a routine I've been through about oh, maybe five or six hundred times, with two (properly tuned) XJs.