1987 VFR400R not starting help

[Maffoo]

Ok i have a mates vfr here ....

what it does do - goes really well once it starts

what it doesnt do - start on cold mornings (say below 2-3c) or start if left for a few days

ive reset the gap on the plugs & shimied up the choke linkages, as both were badly worn, no luck....

i will be removing the plugs & replacing them with new ones later in the week but i thought id throw it out there to see if there is something im missing. I dont know how to check the ignitor without actually replacing it but i figure the fact that when its going it hauls ass counts that out as a cause....

any known issues with these bikes? i dont know the engine designation but it is a v4 configuration if that helps....

tia
maffoo

[Ragingrob]

What does it do exactly when it tries to start? Turn over but just not fire?

It could be something really simple as in how it likes to be started... If mine's cold or been left for a while, it starts first time everytime with full choke no throttle, anything else and it wont wanna start!

[Dargor]

You've found the choke right.

[Maffoo]

yeah it just turns over with no fire at all

& yes ive found the choke.... & sorted out the slop in the linkages

[lostinflyz]

yea the viffers can be pretty grumpy about starting up. as stated its gotta be all choke no throttle. and a nice grunty battery.

[Maffoo]

ok ill take the all choke no throttle thing on board

& let you know what happens with new plugs

[Maffoo]

ok !!! i got it started ... & it will run without the choke

however i have another problem .....

the battery that was in it was pretty dead.... it is a new(ish) battery & has been trickle-charged a couplke of times in the last 6 weeks 3due to the starting issue
I attached another battery to it to start it, but as soon as i dis-connect the jumper battery, it runs like ass at idle & wont rev at all... it bogs down & dies

now, i would have thought that as soon as it was running, the charging system should take over & provide enough charge to run it but this obviously isnt happening

i dont have a multi-meter to check the charge rate, but ihbts never had a battery issue before now....
how many times can you charge a dead battery before it dies?
is there a certain amount of time an engine has to charge the battery before it can run on its own?

any ideas would be appreciated
tia
maffoo

[MSTRS:Me]

A dead battery is just that...dead. A battery that keeps running down is highly suspect. As should be the charging system. I can put you on to an auto sparky (also a biker) and he will no doubt come round and check it all.

[Maffoo]

I gave alan a ring & he said to trickle-charge it again... apparently the charging system on most bikes isnt very efficient
so the battery really needs to be fully charged to start off with

cheers for that number mstrs ... ill add that to my phone

[MSTRS:Me]

Fully charged? Yep - more or less. But if the battery is old and suspect, that's never going to be possible.
You could check that all cells have enough water in...that's often a problem when batteries 'go bad'. And then charge for 12+ hours.
The other thing about batteries that have a low state of charge...the charging circuit does not operate to potential when a battery is low, so that battery will never get charged whilst the engine is running. Or is that cars?

[Maffoo]

yah the water is good... the battery should be ok, its not that old, been flat once before ... only went flat while trying to start it (see original problem)

a car will run with a dead battery as long as the charging system is working properly... which is why i thought the bike would to

[Mishy]

yah the water is good... the battery should be ok, its not that old, been flat once before ... only went flat while trying to start it (see original problem)

a car will run with a dead battery as long as the charging system is working properly... which is why i thought the bike would to

Running lead acid batteries flat can be kinda bad for them. If you have a flat battery, then trying to start your bike, or just charging them at more than a rate of 10% of it's capacity can lead to what's called "plate hardening" What happens is that your battery will only take a surface charge, and will loose that fairly quickly, rather than holding a good charge. Bike charge systems are kinda crap at dealing with poorly charged batteries, which is why battery minders are a great idea. trickle charging for a long period of time is perfect (10% of the capacity of the battery) but keep an eye on it, sometimes the damage is already done, and they go flat again in short time.

[Maffoo]

well i trickle-charged the battery & it seems to be r unning fine now

only time will tell if that continues to be the case

thank you everybody for your assistance

[MSTRS:Me]

Now that it seems to start/run ok, get Alan to check the various voltages as I suggested yesterday. That way, you will have a better idea as to what is going on.

[quickbuck]

Charging a bikes battery from near flat using the bikes charging system overheats the regulator/ rectifier.
This stuffs it, and then gives said bike a bad rep for having a crappy reg/rect.

I hear it all the time... apparently CBR's are one of the worst! Just so happens there are more CBR's on the road than anything!
Therefore the total number of CBR reg/rect's that fail is higher.
VFR's aren't much better according to the experts!

Good to hear it starts fine now, just hope it keeps charging itself.