gettin low-voltage ABS workin' method

[Tsiklonaut]

Just found a simple over-the-corner method getting ABS working when you have a normal battery (in terms BMW ABS system needs excellent battery, normal or anything below it isn't enough - i did various tests with my multimeter, and confirmed the ABS needs 12,3 volts to start up - normal battery immediatly gets down to 11,9 if you turn the ignition on, and slowly rises to 12,2-12,4, but takes alot of time, and if you shoot starter after that then the bike must start in first turn of starter, otherwise the voltage almost immediately will fall to 10,5 volts and say goodbye to ABS-start, it'll take decades for battery to get 12,3V up again, so you're in dead-circle

Thus, after lot of ABS-won't-start-up after starting engine problems i found the cure to be simple if you don't want to buy high end battery:

start your bike, ABS says "not workin", you say "shut up" and drive away, get about speed 60km/h or more, put 5-th gear, engage clutch, turn off ignition and then back on and release the cluch - the ABS starts now normally on the fly - two lights flash together, but while engine running you have to stop the bike to finally start the ABS coz the sensors need zero to 5kph movement, fly off and it WORKS! The physics behind it is simple - you start the bike w/o the starter you know - the voltage is sufficent for ABS

Be careful tough, if newby on this - don't practice it on traffic areas etc - the rear wheel may block if your speed isn't sufficent or the ground is slippy or don't have the "feel" for clutch - take some practice first

This method is extremely effective on very cold days when it's almost impossible to start up ABS even if your engine is hot and battery has charged alot while driving, you still can't start it up - so here's the alternative.

Cheers, Margus

 

[pikeydave]

There is an easier way you might want to experiment with.

Get rolling in 5th, clutch in coasting, ign.key off, on, ABS arms (clonk clonk!) start engine on starter (a bit of clutch assist if you like wouldn't rec. bump starting with the 11:1 comp. ratio) carry on safe in the knowledge that when granny turns right into Specsavers car park you won't leave any skidmarks on the tarmac. Maybe somewhere else but not the tarmac.
(guess who I saw in Specsavers? Fcuking everyone!)

 

[Muddy]

I've always found that giving it loads of revs when setting off in 1st sorts it. Same principle, less hassle...worth a try?

 

[(RIP) Kaister]

loads of revs when setting off in 1st sorts it.



Hmmm - cold frosty morning - thick oil - lots of revs ????

cold partial seizure anyone ??

you'd never know though until you strip it and find score marks on the pistons.

They heat up much faster than the barrels and expand onto a cold cylinder wall - causing scuffing.

 

[Muddy]

Ok then, just enough revs so the ABS doesn't think the batttrey's low on charge.

 

[Tsiklonaut]

Don't rev cold engine!!! It'll dye very soon then, just like high revving inline or V-sportsbikes. BM's not for made that.

Altought the principe is that there's no real battery charging below 3K rpm, but even revving it more than 3K rpms on short terms will overheat yout engine - my sumps glow like a setting red Sun if i synced my carbs yesterday revving it a bit harder. It's aircooled engine and needs some moving if engine not idle.

So - no, don't rev it, especially when it's cold.

At least i see only two anternatives getting ABS workin w/o doing harm to engine - the method i described above, OR, if you start your bike every time from your home garage, then you may remove the seat or the plastic piece where the 12V socket is under there are starter-motor cables that come directly from battery - it's a bit more comfty to get the cables from there than pushing them under the tank. So put your Optimate or any other battery charger to battery's inputs and start the bike normally - then the external battery charger gives some additional voltage on start and ABS goes online - i tryed it, my USSR charger has special "Start" option, dunno if Optimate or other have it, but my ABS turned on every test i did. For more comfort you may extend some cables from the battery to some comfty place you can put the charger on w/o removing the seat or the plastic piece.

But since i don't drive away only from home, then my alternative is the first method . If the wheather goes hot, and the ABS don't strat too, then i got to look for a new (high-end , but expensive ) battery.

Cheers, Margus

 

[richie]

Easier still, park on a hill, turn on ignition and roll away. Once the ABS cuts in start engine with button....

 

[Tsiklonaut]

Easier still, park on a hill, turn on ignition and roll away. Once the ABS cuts in start engine with button....

Youp, if there is a hill.

 

[Muddy]

I'll try to be a little clearer with my suggestion. I don't mean reving the engine at a standstill or reving the bike down the road for a few miles.

What I actually mean is just give it some extra revs just at the point of releasing the clutch as you're setting off.

 

[Tsiklonaut]

Noupe, no help. I runned engine hot from 2-5bars on RID with above 3,5Krpms hoping that the battery gets some charge, stopped, and tryed to start up with hot engine - same thing - no ABS. So the igition off&on while riding & stoping method looks the right one for me now

Cheers, Margus

I'll try to be a little clearer with my suggestion. I don't mean reving the engine at a standstill or reving the bike down the road for a few miles.

What I actually mean is just give it some extra revs just at the point of releasing the clutch as you're setting off.