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Discussion in 'Yamaha 250cc In-Line 4's' started by Tigger996, Jun 25, 2018.
is the battery being charged when the engine is running ?
Don't know. The problems listed above do get progressively worse during a weekends sprinting.
So with the voltage around 12v it should have a minimum of 12.6v after sitting for an hour. Idling it should be putting out about 13.8v, then at 4000rpm + it should be around 14.4v
I will check it as soon as the temp in my bike shed drops to a sensible level. We are in a heat wave in the UK and a flat roofed shed acts as an oven.
Voltage remains constant at about 12.7V with or without the engine running. Do they suffer with regulator/rectifier problems (hopefully yes as it is cheap to replace).
I would first start by checking all the plugs between the stator and regulator for melting and corrosion, then check the stator is good before buying a new regulator
Yeah any older bike can have problem's with the regulator/rectifier.
If your reading's off the stator are good, and no problem's between the plug/socket's near the fuel pump and regulator maybe check the diode's in your reg/rect
You can either put a new reg/rect in or find a good low km's reg/rect off another bike and modify you wiring to suit, i used an R6 rec/rect on mine.
I will check. Reg/Rec only about £12 (21.26 AUD)
For a cheap china one maybe, the genuine Shindengen SH578A reg/rect would be around $150 AU
Battery charging is OK, the reason that it seemed faulty was that the regulator earth was on a panel bolt and I removed the panel to get at the regulator and didn't notice that I was testing without an earth ... D'oh. I will now move on to the coils
Bike still has the problem 50% of the time. When it is being a pain the rightmost exhaust is cold so I will test the coil and the float chamber.
Many people have suggested "**** in the carb" the problem is that you have to have a good sense of balance and you cannot trust the sidestand, so at my advanced age I am not going to try it.
If there's still problems since the shop rebuilt it, I'd be going back and getting them to investigate.
Before doing that I would suggest checking the slide needles for wear
I think the problem is a heat (coils?) or a intermittent blockage. Most likely the coil/lead/cap as the plug was wet when I checked it. Would any make of dual coil work as I can get new ones rather than an old genuine one?
You need to match the coil resistance against the spec in the manual.
Chasing parts numbers
Coil is the same part as fitted to Yamaha TD850
Plug caps same as Yamaha Thundercat
Might be cheaper doing a coil on plug conversion to it,
my 4x used COP coil's cost me $75, and the wiring for them is pretty easy to make up
Coil On Plug conversion
If u need caps , this is what I put on mine
Which is these guys
^ Those cap's are only 5K Ohm, standard FZR cap's are 10K Ohm so it would be pulling a lot more amp's through the coil's
Ive had them on there for years ... Im sure I researched that before replacing them ... where did u get your info from?
So I dug into the archives to find this on a very old post (couldnt find it actually on any spec sheets)
FZR 250 specs
Coil primary 2.8ohm +/- 15%
Secondary 15Kohm +/- 20%
Spark plug resistor 10Kohm
Pickup coil 230ohm +/- 20%
But 99% of the caps available are 5k ... why is that ?
And what will it do having the different caps on there? ... damage the coils over time ... ?