My new 1250 rallye BROKEDOWN

Not confused at all - with port injection, 50-60 psi is not going to be blocked by gases in the inlet port which will be at or near atmospheric pressure, or less once the inlet valve opens and the engine starts sucking in air via the air inlet, filter and inlet port. Talk of vapours blocking entry of fuel, if as you say originated from the dealer, just sounds like the usual customer service BS when they can't be bothered investigating a fault.

Like others, my experience has always been that engines start more readily when warm. Any effects of a weak battery would be more apparent in cold starting. If that was not the case for the OP, then I still think a temperature related fault is the most likely answer.

Certainly the batt has fully cured 2 x 1250’s that I know of personally. The vapour lock in fuel lines is a known entity and it happens more than you might imagine in bikes. Try starting a hot 4 stroke Mx bike compared to cold, they are a bitch. You generally overcome it on road bikes because you can crank past it. Less so if your batt isn’t up to it.
 
So what size is the OE battery that's causing the problem and what size is the one that provides the fix. Asking for a friend ;)
 
So what size is the OE battery that's causing the problem and what size is the one that provides the fix. Asking for a friend ;)

I’m not 100% but I think the dealer said they went from a 170cca batt to a 200cca. He intimated that the 170cca batt didn’t even meet the 170cca it was specced at.

Certainly on my mates bike he could visually see the batt voltage fall away via his nav 6 when it had starting problems. Jump it and away it went every time.
 
The battery may be the issue, there has been a run of car batteries displaying similar symptoms, defying the most sophisticated tester results,
checking voltage before cranking the engine ignition on ,should reveal battery volt significantly low causing comms errors and warnings as well,
The optimate is possibly keeping the battery volts up with no load, once its done some work its not recovering,
cranking from cold start 4 0r 5 times it may show its lack of reserve capacity,
 
I text my friend to ask if he could remember the new/old batt specs. He couldn’t but said his original batt was a lithium version and the one they replaced it with is agm. He said the agm batt sits about 4 or 5 volts higher than the lithium did at idle. ( that might be normal I don’t know) The lithium would drop below 12 volts within 1 or 2 turns of the engine when he had hot start problems.
 
I text my friend to ask if he could remember the new/old batt specs. He couldn’t but said his original batt was a lithium version and the one they replaced it with is agm. He said the agm batt sits about 4 or 5 volts higher than the lithium did at idle. ( that might be normal I don’t know) The lithium would drop below 12 volts within 1 or 2 turns of the engine when he had hot start problems.

As I have no hot start problems a question would be why would some need a bigger battery and some do not , this would point perhaps to other issues as mine has never not started hot /cold , at any point , UK or abroad . I have a habit to turn my engine off in hot places as it gets really hot , but never has it struggles to start , the opposite in fact , touch starter and its running no different to cold starting.
 
As I have no hot start problems a question would be why would some need a bigger battery and some do not , this would point perhaps to other issues as mine has never not started hot /cold , at any point , UK or abroad . I have a habit to turn my engine off in hot places as it gets really hot , but never has it struggles to start , the opposite in fact , touch starter and its running no different to cold starting.

Might be down to variation in battery quality but as with all issues, for every 1 with a problem, 10 don’t, much like the rear brake thread etc. Out of interest is your battery lithium or agm ? Bmw seem to have suppllied a mixture on the 1250
 
Booked in at AJ's on the 27th May, soonest they could fit me in :blast
 
The fix is a higher cca battery. It manifests itself on a hot engine because a hot engine is full of combustion and fuel vapours. They act as a block to fuel flow etc, meaning the engine needs a good, fast spin up to purge it.

I think this is not correct.
 
Might be down to variation in battery quality but as with all issues, for every 1 with a problem, 10 don’t, much like the rear brake thread etc. Out of interest is your battery lithium or agm ? Bmw seem to have suppllied a mixture on the 1250
Not sure . It’s a 2018 November bike . I will try to check and let you know .
 
I’m not 100% but I think the dealer said they went from a 170cca batt to a 200cca. He intimated that the 170cca batt didn’t even meet the 170cca it was specced at.

Certainly on my mates bike he could visually see the batt voltage fall away via his nav 6 when it had starting problems. Jump it and away it went every time.

Thanks :beerjug:
 
Just in case anyone is interested had a new battery fitted this morning at AJ's along with another guy on his RT.I think its been mentioned before on here but there was a bad/faulty batch fitted to new bikes last year, anyhow fingers crossed that will be the last of the problems :thumb2

Looks like you were right Spoonz !
 
Just in case anyone is interested had a new battery fitted this morning at AJ's along with another guy on his RT.I think its been mentioned before on here but there was a bad/faulty batch fitted to new bikes last year, anyhow fingers crossed that will be the last of the problems :thumb2

Looks like you were right Spoonz !

I had to get lucky eventually. Do you know if your old one was lithium ?
 
I have the same problem, new agm battery doesn't solve the problem. They have tested lots of stuff on advice from BMW, tomorrow they will put on a new starterengine and relay, I hope it solve the problem but honestly very sceptic. I had lots of BMW before and, they never had this problems (1200GSA LC). I have to rolling start it sometimes and I really can't trust the bike at all. Very dissapointed and my last BMW for sure.
 
I have the same problem, new agm battery doesn't solve the problem. They have tested lots of stuff on advice from BMW, tomorrow they will put on a new starterengine and relay, I hope it solve the problem but honestly very sceptic. I had lots of BMW before and, they never had this problems (1200GSA LC). I have to rolling start it sometimes and I really can't trust the bike at all. Very dissapointed and my last BMW for sure.

Is it only on hot starts or cold starts also ? If it’s both that’s a different issue ( a few have had a sticking pressure relief valve )
 
Happens on both cold and warm, most warm though.

The batt issue manifests itself on hot starts only generally. Ask them if they have checked for a sticking pressure relief valve. It may not be obvious as it sticks intermittently. If the cylinder stops on a compression stroke on the sticking side the starter can’t overcome the pressure. Hence why it’s random and not temp dependant as it has to be on the right stroke on the problem cylinder at the same time as the valve chooses to stick.
 


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