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jaz21uk

Joined:

Jan 13

Posts: 9

jaz21uk says:

cb700sc issues

Hi all in need of help basically I cleaned the carbs out on my bike put them back on and the engine would crank very slowly not enough to turn over then eventually the solenoid burnt out so purchesed a new solenoid and battery for good measure and got no power at all checked the solenoid and I have power going to the solenoid but not coming out of it I've used 3 different solenoids and I have changed the enitre wiring harness any ideas


Cheers in advance
Jason

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  • Posted 2 years ago (23 June 2013 20:55)

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kcmc

Joined:

Jan 08

Posts: 7513

kcmc says:

Honda CB 700SC Nighthawk

Hi Jaz21uk

This bike was an American only market bike produced between 1984-86,so you must have an import if you're in the UK as your avatar suggests?so your doing well to locate parts like a wiring harness?.Anyway your imformation is a bit on the sketchy side,like why did you strip the carbs?was this because of a starting problem(has the bike ever run and been ridden by yourself?)fitting three different solenoids with no difference would suggest to me it isn't the solenoid causing the problem(providing all the solenoids were of good condition?).Think this could be a project going wrong due to lack of knowledge and understanding?with your poor information which could well be putting me on a wild goose chase i would suggest investigating the starter motor(as the thing must be at least 28 years old)the handlebar switchgear(start button)any safety switches etc.Good Luck

KCMC:tongue:

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jaz21uk

Joined:

Jan 13

Posts: 9

jaz21uk says:

info

Hi sorry for the lack of infomation when I wrote this. Yes this an American import the reason why I stripped the carbs as the previous owner pet sealed the tank and forgot to take the fuel line off so the carbs were rather gunked

 up so cleaned them put
 prior to this she did start and run of not poorly. After I put the carbs back on I had power tp the
 bike but the bike was cranking very slowly so I
 thought this could be a fuse issue and batter
 terminal wire issue so I replaced the fuses and
 the wires and the engine would not crank at al
l the lights would still dim when I hit the starter
 button. I replaced the solenoid due to I opened
 the previous one up and all the contacts were
 burnt  so I brought an after market one. After I
 changed the solenoid I had no power to The front end of the bike just to state the solenoid is after market now if o run a wire directly to the solenoid I get power if I try using the connector from the harness  I get nothing
Cheers
Jason

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hairybob

Joined:

Jan 09

Posts: 485

hairybob says:

you need a manual

or at least a wiring diagram and a meter.

Charge your battery.
Post some pictures so we can see what you mean.

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jaz21uk

Joined:

Jan 13

Posts: 9

jaz21uk says:

update

right just an update i have by bypassed the 4 pin connector on the solenoid and i can finally get power to the bike but i have still got nothing to the starter motor, do you reckon this could be a bad earth?? the lights dim when i hit the starter

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kcmc

Joined:

Jan 08

Posts: 7513

kcmc says:

Honda CB 700SC Nighthawk 1984-86

Hi again

Try taking the spark plugs out,see if it cranks,if not take the starter motor out and see if this is working,check the bearings and pick up brushes.if it has a starter clutch or intermediate starter gears check they are in good serviceable order.Good Luck

KCMC:tongue: 

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jaz21uk

Joined:

Jan 13

Posts: 9

jaz21uk says:

update

when the bike wouldnt start we assumed bad battery so we just bump starting and the negine was cranking just ouldnt turn over, took the starter motor out opened her up, was full of oil  and brushes were non existant :D good thing i got a rebuild kit, could this be the problem also for power gettign round the bike as its a one terminal starter

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kcmc

Joined:

Jan 08

Posts: 7513

kcmc says:

Honda CB 700SC Nighthawk 1984-86

Hi again

Well it sounds like you have found the problem,as one of the things i suggested the starter motor.All starter motors only have one main heavy duty positive terminal as they pick up their neutral from being earthed to the engine when bolted in, and the engine and frame are earthed directly from the negative terminal from the battery.The reason the starter motor is full of oil is because the oil seal on the starter motor drive shaft has worn out allowing crankcase pressure to blow oil vapor past and condense inside the starter motor itself.Once this happens the oil being a conductive will breach the positive of the starter motor to the earth of the engine effectively shorting the whole system out(this is probably the reason the starter relays keep burning out,would have thought though the main 30 amp fuse would keep on blowing first before this occurred?) .Good Luck

KCMC:tongue: 

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jaz21uk

Joined:

Jan 13

Posts: 9

jaz21uk says:

update

well under closer inspection seems to be completly cooked dont think theres a part of it which isnt burnt, my friend decided to test the starter a while back from my booster box with a live cable do you think that will cook it, and luckily enough i have found out the starter from an old fz600 will fit my bike perfectly :D

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kcmc

Joined:

Jan 08

Posts: 7513

kcmc says:

Honda CB 700SC Nighthawk 1984-86

Hi again

Hope your right with the FZ6 start motor,i've looked them up(both 1985 models if thats what you mean?) and must say they do look very similar but not the same by a long way,but you maybe able to build one good one out of the two? Good Luck with that i hope you're successful,must say i would like to know,so keep us up to date:winkie:again good luck

KCMC:tongue:

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jaz21uk

Joined:

Jan 13

Posts: 9

jaz21uk says:

update

still waiting on the starter motor :P the one thing i have noticed is that my starter motor has to turn ccw and a fzs turn cw, although the fzs is mounted on the left and mine will be mounted on the right if that makes any difference, ive heard there are some ways of reversing the polairty  like crossing the connections on the brushes also heard bout  flipping hte case 180 degrees any tips?

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