Looks to be the regulator not regulating.
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750 Big Bore Battery
- Thread starter funky
- Start date
What you are saying is that you don't have a working reg rec. Could be either the unit or how you have it wired. The alternator is just going full blast full time. You will need to pick a reg rec and wire it to the alternator per it's instructions.
There are lots of info regarding charging and reg/rec. Search in the tech section. A little light reading before bedtime, all will be revealed. May take a few nights but you will be the wiser for it.View attachment 135790 View attachment 135791 View attachment 135792 View attachment 135793 View attachment 135794 View attachment 135795 Ok new battery fittied and the bike started on the starter motor, crancked over lovely.... multi meter attached I rev the engine and the meter read 13 volt and as i throttle the bike it keeps rising up to about 21 volts
it has to be the reg/rec.
I have checked the wires and both connetctors at the multi blocks the 3 pin left side which has two wires from the reg/rec but three from the loom show a slight signs of heat on the outer casing of the multi block .
I am so confused bloody electrics mess with my head dam my ignorance
All the best funky
funky
XS650 Junkie
I have had a little read and have got little knowlrdge about these now there is no wrong wires they are plug and play my confusion is in testing the Reg/Rec thats so confusing ....This is what i have worked out so far.... diodes pass current one way and not the other so as far as i am aware is that the stator give current at A/C into the Reg/Rec then it converts the current to D/C it limits the voltage to 14.5V as to not over charger the battery and electrical system ... so if the battery is over charging to the point it swells in the battery try it has to be the Reg/Rec there is no other reason as the Regulator part of the Reg/Rec is clearly not doing that as SUperjet stated afew posts ago , I have ordered a new Reg/Rec from Germany so will see if this does the trick ..... Thanks for all the responses will let you know how i get on .
All the best Funky
All the best Funky
funky
XS650 Junkie
To all you who read this thread and are looking for a good battery .... I got a Motobat MBTX14AU 210 CCA and it crancks the 750 big bore fineI beleive its made in the good old USA Jacksonville FL
http://www.motobatt.com/MBTX14AU
http://www.motobatt.com/MBTX14AU
funky
XS650 Junkie
Well all it was the Reg /Rec all working fine fitted a volt meter to the batter so i can monitor when working on the bike
Thanks for all your help
All the best Funky
Thanks for all your help
All the best Funky
Glad you have it working now!
This is not to pick on you, it's a truism in electrical and other troubleshooting....
The most popular statement made just before spending money that doesn't fix the problem is "It HAS to be X "
Chasing overcharging; loose connections, faulty grounds, bad connector blocks, are often the culprit. Even if component "X" seemed to fix the problem, it could STILL be a bad connection somewhere, now temporarily working after connecting, moving, reconnecting during parts replacement! Great that you have a voltmeter now. I see you have a charging port also. I like to wire a voltmeter onto an SAE connector with several feet of wire so I can plug it into the charging port and place it where I can watch voltage while operating anytime there's a charging issue, and now and then just because. I will be looking over the electrics on resto cuz I have seen some unusual voltage variation while riding but no other issues SO FAR!
funky
XS650 Junkie
Thanks gggGary I mean that as i hold your wisdom and knowledge on these bikes i the highest regard.
I think that the issues with the over charging was that when i mounted the old Reg/Rec to the bottom of the battery tray unbeknown to me there was a pertuding mount or lug on the botom of the battery try that i did not see, which when i tightened the Reg/Rec down using the two slots either side of the cooling fins caused the Reg/Rec to bend and the Lug or pertrusion pushed into the nylon matirial on the underbelly of the Reg/Rec and this may have caused the malfuntion of the old unit.
When i removed it i saw the indentation in the nylon or plastic thats when i looked under the battery try and saw the lug.
I used stainless shims/spacers on the bolts holding the new Reg/Rec to create clearance and this also improves cooling around the component.
All the best Funky
I think that the issues with the over charging was that when i mounted the old Reg/Rec to the bottom of the battery tray unbeknown to me there was a pertuding mount or lug on the botom of the battery try that i did not see, which when i tightened the Reg/Rec down using the two slots either side of the cooling fins caused the Reg/Rec to bend and the Lug or pertrusion pushed into the nylon matirial on the underbelly of the Reg/Rec and this may have caused the malfuntion of the old unit.
When i removed it i saw the indentation in the nylon or plastic thats when i looked under the battery try and saw the lug.
I used stainless shims/spacers on the bolts holding the new Reg/Rec to create clearance and this also improves cooling around the component.
All the best Funky
Gary, I have a few questions about 750's. I talked to Hugh at Hugh's Handbuilt's, and said a stock cam would be plenty. I'm curious, on your XS650 big bore, what modifications other than the CC increase have you made, and what recommendations would you make to get the most bang for the buck BTW, it's an '81.
The 750 in Madness has a lot of internal "upgrades" but it was built decades ago, long before I bought it. I have a completed big bore motor with no other mods but it's still sitting on a stand not in a bike. Sorry to be of no help.
One thing I will say is to be cautious of how much you mod. A motor that has been breathed on for big HP numbers often ends up being little fun in normal street use with the horse power found only at high RPM where it just isn't used that often. I kind of tuned modded to trade off the High RPM bias on madness for more grunt lower and enjoy it more now. Smaller carbs, more restrictive exhaust, the biggest changes maybe retarded the timing a bit.
One thing I will say is to be cautious of how much you mod. A motor that has been breathed on for big HP numbers often ends up being little fun in normal street use with the horse power found only at high RPM where it just isn't used that often. I kind of tuned modded to trade off the High RPM bias on madness for more grunt lower and enjoy it more now. Smaller carbs, more restrictive exhaust, the biggest changes maybe retarded the timing a bit.
That's what I want low RPM torque. I've had high RPM stuff in the past (Kawasaki 750 triple) and an early Mazda RX-7, and it's not fun trying to keep something within that narrow of a power band. I'm going to have to do some research on cams, as I want something that will make good power down low. BTW, what carbs are on madness? What's your opinion on flat slides?
She had VM38's when I got 'r now VM34's nothing fancy but they work fine. I REALLY need to grab that set of pumpers the Grizzly bear sent me and install 'em
I agree with Hugh, nothing wrong with a stock cam 'specally a later one. Exhaust header length and a muffler can that can generate a clean back pulse help with low RPM grunt. If you go with large diameter headers for the look, inserts are needed.
I agree with Hugh, nothing wrong with a stock cam 'specally a later one. Exhaust header length and a muffler can that can generate a clean back pulse help with low RPM grunt. If you go with large diameter headers for the look, inserts are needed.I'm probably going to go small on the exhaust. When you say pumpers, are we talking flatslides? If so, who is a good source?She had VM38's when I got 'r now VM34's nothing fancy but they work fine. I REALLY need to grab that set of pumpers the Grizzly bear sent me and install 'em
Picking a carburetor size depends more on how you are going to use the bike. Around town some highway use go small. Better throttle response. Spirited 2 lane riding if you have the roads next size up. If you have the roads, abilities and desire use the biggest thing you can bolt on. Smaller is easier to tune and ride.
If you are going to drag race you would probable want a big carburetor. If going to ride on the road it pick something smaller. Yes the cam and pipes make a big difference, it starts at the carb and ends at the exhaust. They have to work together to achieve the result you are going for. The porting of the head is important, cam is also very important. No 1 item makes it work. It all has to work together to achieve the result you want.
My XS2 motor work for me. The stock cam, carbs, head and exhaust make the right amount of power that suits my riding style. (slow)
If you are going to drag race you would probable want a big carburetor. If going to ride on the road it pick something smaller. Yes the cam and pipes make a big difference, it starts at the carb and ends at the exhaust. They have to work together to achieve the result you are going for. The porting of the head is important, cam is also very important. No 1 item makes it work. It all has to work together to achieve the result you want.
My XS2 motor work for me. The stock cam, carbs, head and exhaust make the right amount of power that suits my riding style. (slow)
