hi all,, am in need of your help. I've recently just bought a 748 1997 model, I took it out on a ride out on Sunday and 30 minute down the road it started to back fire, so I pulled over turned the key off pressed the start button fired up. But as soon as I tried to rev it it would instantly cut out,,,, pressed the button again the same happened. I then left it for 30 minutes fired it back up and it revved so I immediately turned round went home only thing is 10 minutes further happened again. has this happened to any one am needing some help please.
many solutions possible but you need to go straight for the regulator and particularly the wires connecting this with the alternator (2 or 3 yellow wires and a plug) running across the engine just as a matter of precaution as symptoms you describe can point to this and it is a safety issue.
Charge your battery and see if it runs ok with a charged battery. Use a meter to check your battery is holding 12V, ignition off. With the motor running the meter should read 13-14v. If it doesn't your regulator is probably dead.
hi all thank you for your replys,, don't ask me why but when ive looked 2 wires have been cut which I presume is the positive and negative and have been cut and put directly on to the battery terminals. is this a mod that's been done ?????
yes it is - it's a mod often recommended by aftermarket Regulator manufacturers but sometimes means that a fuse is now omitted - can you see if an inline fuse has been fitted? I also strongly urge you to check the condition of the yellow wires (as said previously) and the inline plug for signs of overheating and melting. The plug lives behind the battery box. It seems the search facility doesn't get used much on this Forum not necessarily due to the user but the latter wires and plug are slightly under par for the job in hand and with heat and inevitable corrosion in the UK, can lead to heightened resistance, overheating, melting, short circuiting and and even fire in worst case scenario.
don't forget rochie (sorry to be a doomunger here) that this was only a first suggestion because fault-finding has to start somewhere. Sounds like the Reg/alternator are doing their job but the wires still need 'crossing off the list' safety-wise as if they show signs of previous damage they could still be responsible for your symptoms. Once you've checked they are ok it's on to the next possibility (and i'm sure much help will follow).
Might be worth checking the tank breathers. Doesn't sound electrical tbh as it started up on the button. There's a single pipe connected to base of the fuel pump where it then branches off onto a T-piece. The usual problem is the internal pipes blocking up or the single pipe gets trapped.
there is 2 yellow wires coming out of RR going in to the engine on l/h side there a white wire from RR going in to the wiring loom and a green wire going to the negative and a red going to positive,,,,
yes - just check all the junctions made but particularly the 2 yellows as some Regulators use ordinary bullet connectors which are even more prone to possible resistance in the future than the original inline plugs! Just a note on above reply - sometimes if original wires have only partially melted all will be fine on start up but will start to play up when engine heat and the original resistance adds it's own heat again.
Do you know when fuel filter was changed last and is it a metal filter(plastic ones are no good for injection models)? Another thing to check with a fullish tank of fuel with the cap off is if there's any bubbles coming from the pipes inside the tank when the pump primes when you turn ignition on. You may have a leak there or knocked a pipe off when filling up. (I have done this on my 907).
as above, mine wasnt running right, had a plastic fuel filter fitted, and loads of crap in the tank, so fitted the metal mahle one, and been loads better, fuel pumps are known to play up too
Does it have the standard plastic fuel line connectors in the base of the tank, or have they been swapped for the chrome versions? I ask because I had a similar issue with my 916 where the replacement connectors had Buna (not-fuel compatible) 'O' rings internally and they had swelled causing an intermittent fuel supply blockage, left me stranded at the roadside but when I removed/refitted the tank it worked again - until it broke down again on the test ride. :frown: Easy enough to fix but took some finding, but it seems that almost all the suppliers of these connectors don't supply them with the correct Viton 'O' rings.
hi all well Chris as you said about bullet connections you where right so ive removed them and chased wire bak and soldered back together. started her up gets to about 80 degrees and same happens ticks over then cuts out
sorry to hear rochie. Hard to know where to go next particularly as you have no history of symptoms having just bought it. Both above suggestions worth checking for a start. I think I would also begin checking all ignition related connectors - there is a knurled barrel connector on the right hand side just behind radiator which you twist just a few degrees to remove, have a look for any black or green corrosion on pins to get an idea of how much damp the bike has been exposed to. If the symptoms appear consistently at the same time running/temperature then might be able to home in on heat related items failing obviously.
