Bike wont start - possibilities??

Zipppy

CB250 lying up for a few months.
It was always difficult to start (turning over but not firing for ages) but now it wont start at all.
Turns over and over (until battery weakens..)
Battery charged
New plugs fitted
Checked air filter and seems ok

Next?? I reckon its fuel related...always flooded easily...my options???

paddy147

Dodgey starter relay/solenoid or fuel pump perhaps???

spiggotpaddy

Clean the carb and fresh petrol would be the place to start.

jameshayes

it could be really badly flooded... its up to you if you want to try this because it will harm your battery... hook it up to a running car with jump leads... fully hold open the throttle and press the starter for 5 seconds, keeping your finger on the starter, let go of the throttle and then when you hear the bike kick in, open it up again for a few seconds to clear the lines...

CJhaughey

jameshayes wrote: »

it could be really badly flooded... its up to you if you want to try this because it will harm your battery.

And blow a lot of sensitive bike electrics.
Bikes aren't made to handle the kind of amperages that a car puts out.
OP
Your problem is likely to be old fuel and possibly blocked carbs.
The old fuel in the tank should be drained and recycled into a car petrol tank.
Drain the old petrol from the carbs using the little drain screw in the side of the float bowl.
Refill the fuel tank with fresh fuel and refit.
The new petrol should help with starting, if it still doesn't start then you will have to pull the carbs and clean them.
I assume you have checked for spark etc?

sethasaurus

CJhaughey wrote: »

And blow a lot of sensitive bike electrics.
Bikes aren't made to handle the kind of amperages that a car puts out.
OP
Your problem is likely to be old fuel and possibly blocked carbs.
The old fuel in the tank should be drained and recycled into a car petrol tank.
Drain the old petrol from the carbs using the little drain screw in the side of the float bowl.
Refill the fuel tank with fresh fuel and refit.
The new petrol should help with starting, if it still doesn't start then you will have to pull the carbs and clean them.
I assume you have checked for spark etc?

When you say 'amperage', you really mean 'current', and this is not an issue. Actually, the reason you would jump from a car is to provide more current, as the bike battery will tend to drain faster if you are cranking the starter for an extended time.

Definitely a fuel or spark problem though.

paddy147

So can you jump a bike off a car battery??

And is it safe to do it??

CJhaughey

sethasaurus wrote: »

When you say 'amperage', you really mean 'current', and this is not an issue. Actually, the reason you would jump from a car is to provide more current, as the bike battery will tend to drain faster if you are cranking the starter for an extended time.

Definitely a fuel or spark problem though.

Amperage is a measure of current
Bikes by their nature produce small amounts of current, Most bike batteries charge optimally at 1A for long life.
Otherwise why do people use specific motorcycle battery chargers instead of just using car battery chargers?
You hook a bike up to a running car producing 14v or so and probably 20+ amps what do you think is going to happen to the bike electrical system given that its only designed to handle the current the bikes system makes?
The other problem is that most people will keep their thumb on the start button for as long as the engine refuses to fire.
This is bad news for the starter which gets very hot from all the current.
I would use a car battery from a non-running car but not from a running car the potential for harm is too great.
If you do use a car battery 10 seconds is all I would crank for at a time and then let it cool.
I'll leave it there. If people want to try starting from a running car then its their own look out.

The Nutty M

CJhaughey wrote: »

Amperage is a measure of current
Bikes by their nature produce small amounts of current, Most bike batteries charge optimally at 1A for long life.
Otherwise why do people use specific motorcycle battery chargers instead of just using car battery chargers?
You hook a bike up to a running car producing 14v or so and probably 20+ amps what do you think is going to happen to the bike electrical system given that its only designed to handle the current the bikes system makes?
The other problem is that most people will keep their thumb on the start button for as long as the engine refuses to fire.
This is bad news for the starter which gets very hot from all the current.
I would use a car battery from a non-running car but not from a running car the potential for harm is too great.
If you do use a car battery 10 seconds is all I would crank for at a time and then let it cool.
I'll leave it there. If people want to try starting from a running car then its their own look out.

The bit in bold is where you are getting confused.You're not trying to start a truck.

Skill Magill

What I've done in that situation was to take the air filter off and spray easy start into the hole while jumping it off a running car.
You have to find a sweet spot on the throttle where the engine begins to shudder a bit, keep the throttle open at that point and your finger on the starter. I had this with a cb1, nightmare to start if left for any amount of time.

Hotblack Desiato

An idling car isn't going to produce 20 amps FFS. It'll barely be charging its own battery. It'll never go above the voltage the bike alternator can produce, either. Just don't rev the crap out of the car with no lights, etc. load on it, and there can be no possible harm.

What can do harm is car battery chargers which can overheat and damage a bike battery by charging it too quickly, but that takes hours.

sethasaurus

CJhaughey wrote: »

Amperage is a measure of current
Bikes by their nature produce small amounts of current, Most bike batteries charge optimally at 1A for long life.
Otherwise why do people use specific motorcycle battery chargers instead of just using car battery chargers?
You hook a bike up to a running car producing 14v or so and probably 20+ amps what do you think is going to happen to the bike electrical system given that its only designed to handle the current the bikes system makes?

Actually, current is a measure of amperage, if you're going to get it right.

You're not trying to charge the battery.

The current is simply not the issue if you are jumping battery to battery. No more currrent than normal is going to flow in the bike's electrics anyway, particularly because a revving bike will also put out up to (approx) 14V (very similar to a car regulator). If the car is not revving, then it won't be giving you much more than 12V anyway.

In any case, current depends on the load, and the load on the car battery will draw exactly the same (given the same voltage) as the current drawn from the bike battery.

CCA for a bike battery is up to 200A. Just because a car battery is able to provide up to around 4 times that much, it doesn't mean it is going to.

(Just for a common-sense argument, a bike battery with rated CCA of (e.g.) 180A is not going to harm a bike any more than a similar battery with a rated CCA of 200A.

The battery produces a voltage, the load draws the current.
car battery: I = V/R = 12V/<"starter resistance">
bike battery: I = V/R = 12V<"starter resistance">
No surprises there.

Additionally, batteries are excellent self-regulators and the current draw, if one happens to be at a low voltage reduces as the voltage comes up to normal spec.

The only issues I ever heard of were:
People connecting the jumpers wrong.
Some cars with electronic engine management, when jumped from another one with noisy DC output, being damaged by the spikes on the line.

If you really want to argue, let's begin another topic entitled 'Actual physics vs backyard auto-electrics'. Then again... it would just turn into the 'special olympics'..

sethasaurus

To be more helpful to the OP:
take a plug out and hold it against the engine body while cranking the bike (keep the plug lead connected). If you get a spark, you're halfway there. Check the the other plug as well.

Really does sound like fuel problem though..

paddy147

ninja900 wrote: »

An idling car isn't going to produce 20 amps FFS. It'll barely be charging its own battery. It'll never go above the voltage the bike alternator can produce, either. Just don't rev the crap out of the car with no lights, etc. load on it, and there can be no possible harm.

What can do harm is car battery chargers which can overheat and damage a bike battery by charging it too quickly, but that takes hours.

This is fantastic for bike batteries.

Also brings diesel car/jeep batteries back from the dead too.:D

Hotblack Desiato

Paddy, it would really help if your post #2 had given any evidence at all of having read post #1. It didn't. I fail to see the relevance of this post either, perhaps you can enlighten us.

CJhaughey

The Nutty M wrote: »

The bit in bold is where you are getting confused.You're not trying to start a truck.

I'm not confused, read post #4

Wonda-Boy

I am confused about what the original post was about with all the chest puffing....:rolleyes:

paddy147

ninja900 wrote: »

Paddy, it would really help if your post #2 had given any evidence at all of having read post #1. It didn't. I fail to see the relevance of this post either, perhaps you can enlighten us.

ninja900 wrote: »

What can do harm is car battery chargers which can overheat and damage a bike battery by charging it too quickly, but that takes hours.

I simply posted a pic of a battery charger that maintains and charges up bike batteries safely and will also bring back to life a dead diesel car/jeep battery.

Now go get yourself a nice hot cuppa tea,a bowl of wheatabix and enjoy the rest of your day......if you can.

Regards.

jameshayes

paddy147

jameshayes wrote: »

^^^^^^^^^^^^^^^^^^^^^^
I agree.

Looks like some people want to take issue with other people for no reason at all.

So Im bowing out now.



Enjoy your day and be safe out there.:)

Allready saw 1 crash this morning involving a motorbike and a car outside Ikea.:eek::(


Best Regards.

Wonda-Boy

Seen it all now.....:rolleyes:

Please Kill Me

paddy147 wrote: »

So can you jump a bike off a car battery??

And is it safe to do it??

I've done it a couple of times, but the advice I was given was to only jump off a car battery when the car is not running!

KamiKazi

Please Kill Me wrote: »

I've done it a couple of times, but the advice I was given was to only jump off a car battery when the car is not running!

Got it in one.

Now will all the wannabe physicists please f*ck off and leave people to actually help the OP?

bladespin

Is there a strong smell of petrol from the bike? If not then it's unlikely it's flooded.

I've jumped bikes off cars running and not dozens of times without damaging either, I doubt a CB would be overly sensitive but I suppose there is a small risk.

As it's a Honda and been lying up (I've had a few of these) then it's more than a possibility the jets in the carb are gunked up, a good clean is time consuming but worthwhile.

Zipppy

Thanks all..sorry for delay in reply but I took exit 17 and ended up over on the electronics forum somewhere

Will try draining fuel firstly..

If that fails its off with the carb and see what happens

CJhaughey

Zipppy wrote: »

Thanks all..sorry for delay in reply but I took exit 17 and ended up over on the electronics forum somewhere

Will try draining fuel firstly..

If that fails its off with the carb and see what happens

Ultrasonic cleaners work very well for cleaning carbs, if you can get them cleaned in one it makes a big difference.