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Recondisoned startng motor HELP NEEDED


BIKERDAD
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Hi all 1srt thread new year for me ..


Ok . I have a cb750 P reg . Iv been having some problems starting the bike .if i leave it say a week when i try to start it the starting motor sticks so i have to tap it with a hammer or back screwdriver just a tap then it starts . So I bought a new brush for it opened the starter( top section . The main part the starting motor still on /in the bike ) it was cloged with oil I spotted the rubber ring around the starter cap was snaped. ( I guess oil off the engine ...got a wee leak ...has been dripping on to the starter and in to the top section where the brushes are ) so cleaned all the oil off put the new brushe in and it won't start . There is no noise at all or dipping of the dash lights when pushing the starter button .(It's a brand new battery on top up) so there's power there . I pulled the whole starter out the bike. And cleaned all inside the top part ( NOT STRIPPED THE WHOLE MOTOR DOWN ) just cleaned where the round copper touches the brushes as that was all covered in oil . Sanded it with brass wire brush cleaned it all put it all back together back in to the bike and still nothing ..


Back to the round copper part that the brushes touch to make it spin how easy should that be to turn .. as I had to grip it very hard (with my hand not in a vice or grips ) and really strain to turn it .. how easy is This part to turn could my starter be almost seased up that's why it wont turn .


Does any one know who no can send the starter to to be striped down and recondisoned... as I think it is that is faulty unless any you guys know different . Thanks ..

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I'm not sure If I'm doing it right I used a multi meater thing (It was my dad's he gave it to me and didn't show me how to use it lol) so I put the red one to the screw on the starter and the black one to the frame and pushed the start button (wife did ) and the numbers went to just under 13 v on it is that right if not plz tell lol .


Also I used a spare battery with jump leads black to the frame ( bare metal ) then the red jump lead to the screw on the starter nothing happened ..no spark or noise.

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I'm not sure If I'm doing it right I used a multi meater thing (It was my dad's he gave it to me and didn't show me how to use it lol) so I put the red one to the screw on the starter and the black one to the frame and pushed the start button (wife did ) and the numbers went to just under 13 v on it is that right if not plz tell lol .


Also I used a spare battery with jump leads black to the frame ( bare metal ) then the red jump lead to the screw on the starter nothing happened ..no spark or noise.

 

Does this help ? https://www.mrcycles.com/startermotors

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I'd next check for continuity between the starter motor coil and ground. Sounds like it's open to me.


(Set meter to beepy mode and it should beep across the coil to ground) :thumb:

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Thanks ill have a go at stripping it . Also i checked with Honda how much a new one was £965.00+vat .. a grand for a starting motor on 25year old bike .. I just need to find a kit for this . Honda don't do one none on eBay any help plz ..

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:cheers: thanks fastBob looking in to it now . Got to get a circlip pliers for years of been saying that but I need a set now so of to shops Monday. Then see icing.can find a starting motor kit.. if asked the guys on the link you posted waiting for a reply so thanks FB .. if any one else on here might know where to get a kit plz let me know . Or any more info on the problem plz let me know

As still no life on the bike .. from what iv tried it sounds like the starter . The ound copper thing at the front of the starter is what I think is the problem as i think it's worn too thin .. I hope this part is in the kit ..

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.Measure the diameter of the commutator and compare your measurement to the service limit specified for your bike. If the commutator is worn past the service limit, replace the armature.



This part ... as the one on mine looks very worn ..


God this site Is fantastic .. :3some:

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.Measure the diameter of the commutator and compare your measurement to the service limit specified for your bike. If the commutator is worn past the service limit, replace the armature.



This part ... as the one on mine looks very worn ..


God this site Is fantastic .. :3some:

The commutator won't be in the kit but I'd be surprised if its worn away . It's the carbon brushes that are designed to wear away . Here you go , everything you need here . https://www.wemoto.com/bikes/honda/cb_750_f2t_f2v_f2w_f2x_cb_seven_fifty/96-99/picture/starter_motor_repair_kit

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Hi FB . Yes i found that iv sent.them a question as mine is fn2 just.checking.if it.fit . .it's just the lines on the part look very thin like a worn tyre less tread but if you say they don't ware then I guess your right as I really don't know . . Soon as they get back to me I'll buy the kit . And let you know how its goes or it lol . Thanks

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Hi FB . Yes i found that iv sent.them a question as mine is fn2 just.checking.if it.fit . .it's just the lines on the part look very thin like a worn tyre less tread but if you say they don't ware then I guess your right as I really don't know . . Soon as they get back to me I'll buy the kit . And let you know how its goes or it lol . Thanks

 

Can you provide some good close up pics of this part ?

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Starter brush plate......https://www.davidsilverspares.co.uk/CB750F2S-SEVEN-FIFTY-RETRO-1995/part_85428/


TBH the starter shouldn't be that hard to turn by hand.......could be that the oil has gummed the bearings up on the starter......try soaking the bearings with a thin oil and see how that goes......If you can't free them up you may need to replace them..... :wink:

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Ok guys look like bad news. :notworking: :notworking: ok due to the fab info from fast Bob I tested the starter going round the copper part checking the continuity (god knows what that is ) lol . And it showed 00.06 on the reading on all the coppers slots . Then the next pat is touching the copper part then the steel rod in the middle ..............nothing . It says .!! If no reading then the (bugger can't remember what it was called again) the big bit that runs right thro the starter . Needs to be replaced . I'll post it now ..

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.Using a digital multimeter set to measure resistance (Ω X 1), touch one meter lead to any one commutator strip and touch the other meter lead to all of the other commutator strips one by one. Polarity of the meter leads does not matter. There should be continuity for all of the readings, if any readings show no continuity there is an open circuit and the armature must be replaced


Done this pic 15




Next, touch one meter lead to the steel shaft of the armature and touch the other meter lead to each commutator strip. Polarity of the meter leads doesn’t matter. There should be no continuity. Continuity between the shaft and the commutator strip indicates a short in the windings, and the armature must be replaced


Pic 16 ..

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I got the armature to turn which was not as stiff as yesterday so I put it all back togeather then put neutral (black cable )to the body of the starter

Then the red cable to the bolt that sticks out the starter as this is a way to test the starter nothing happened . Just sparks off the bolt the motor didn't turn at all .


So I need a new armature part were the feck do you get them from ...

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So, with one side of the meter on the copper segments and the other side to the steel shaft running through the middle shows high resistance?......If that's what you're reading, then that's OK. You shouldn't get a low reading between the copper segments and the steel shaft, as that would indicate that the insulation had broken down......so, if I'm reading what you're saying right, it's measuring ok.

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The armature should turn pretty freely, with a very slight resistance caused by the brushes rubbing on the commutator.........The sparking you mention means that current is flowing.......sounds like the bearings on the armature are too stiff.

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Don't forget that a fully assembled motor would be very hard to turn by hand because of the sun planet reduction gear and the fact that there's nothing to grab hold of except a small splined shaft . Regarding the armature , I think that means the entire guts of the motor so I'd be straight on eBay looking for another motor if it turns out to be knackered.

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When you put the red wire to the bolt , are you sure that all the insulating washers are in the right order so that the brushes are completely isolated from the outer casing ?

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