1974 cb450 no spark?

stunterdude

stunterdude

New Member
started working on my cb450 i got out of a barn here in tx and theres no spark...points look good, and eveythings hooked up....could it be the coils? condensors??its been sitting for a good minute rolly 15 years,thanks alot
 
bettery is new, everything comes on when i tun the key, bike turns over and gets gas just no spark? dont have a voltmeter....im guessing its the condensors? would my local honda shop have them? i know they used them on quite a few of other bikes they made....
 
When you get no spark, first thing I would check would be the switch on the handlebars.

make sure you getting a solid connection there - and you will need a voltmeter.

And from there, you will need to check everything from the switch to the the plug wires - it could be a number of problems.

Keep us posted as you go, and we can be of better assistance.

p.s. where are you located in Texas? I am in SW Arlington...
 
vtwin650 said:
When you get no spark, first thing I would check would be the switch on the handlebars.

make sure you getting a solid connection there - and you will need a voltmeter.

And from there, you will need to check everything from the switch to the the plug wires - it could be a number of problems.

Keep us posted as you go, and we can be of better assistance.

p.s. where are you located in Texas? I am in SW Arlington...
Click to expand...
ya i was just trying to get a quik answer i knew id have to buy a volt meter, i actually live in austin now but he bikes at my garage in houston(we dont have garages at my apts here) but ill be in houston tom so ill def have time to trouble shoot, thanks!!!
 
On my barn find builds in the past, I have found all kind of crazy reasons the electrical systems would not work first go around, from handlebar switches, to wires missing from wiring harness' all together. It never fails that the reason is something you would never easily find. I have learned to start with the easy fixes and work towards the more difficult.

Good Luck and congrats on the "Barn find"
 
hi,
good plugs? points corroded/dirty? run a pts file through them and then some contact cleaner and a match or cardboard to remove any debris-make sure you do not leave any residue or material behind once cleaned , then make sure you have voltage at the coil...i doubt if both condensors or coils went bad..do you have the points cover off? ck the leads are not grounded at the points or hitting the cover as this is common on several honda's with that type cover.. you can actually unhook the leads at the condensor, hook meter up to lead going to points and ck continuity to ground, points open -it should show open,closed cont to grd...if you have no (v) power ck a wiring diagram for your year and see where the issue is..
let us know what you find...
joe@ vcycle
 
joea said:
hi,
good plugs? points corroded/dirty? run a pts file through them and then some contact cleaner and a match or cardboard to remove any debris-make sure you do not leave any residue or material behind once cleaned , then make sure you have voltage at the coil...i doubt if both condensors or coils went bad..do you have the points cover off? ck the leads are not grounded at the points or hitting the cover as this is common on several honda's with that type cover.. you can actually unhook the leads at the condensor, hook meter up to lead going to points and ck continuity to ground, points open -it should show open,closed cont to grd...if you have no (v) power ck a wiring diagram for your year and see where the issue is..
let us know what you find...
joe@ vcycle
Click to expand...

thanks for the info!! points are good, cleaned them to. need to check to see if i get anything at the coil, prolly do this tom night when i get back in houston and update this thread, thanks alot guys
 
I've done the relay mod on my 450 and never looked back... What a difference in the spark.

Both plugs are not firing? If so check the switch... Or battery... Both coil can be bad but less chances than battery or switch connectors...
Let me know... I had the same problem than you.

Sent from my HTC Panache using Tapatalk
 
well i messed around with tha bike a little today and still nothing....everything looks decent just dirty, i found the ignition switch was completly shot i dont even know how it worked when i turned the key on, it had bare wires exposed and chewed up(was melted to were it plugged in the main harness) so i took it off and just jumped the contacts it plugged into to get the power on...could that be the problem?? something to do with the ign. switch??ill try to get some pix up asap,thanks

oh and i also noticed there are some empty connectors by the coil?am i missing something??

IMG_0514.jpg

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yes that distributes power...follow the previous instructions, power at coils?
 
just checked with this pos test light i found and im not getting shit at the coils.....theres about 4 wires coming out the main harness that go towards the coil and one lights up that goes to some kinda of relay or something but none of the other wires are getting any power? pulled apart the switch on the handlebars and it looks good
IMG_0519.jpg
 
cleaned all contacts and connections good, now there is power at the coils?? this things driving me crazy i know its something simple
 
on old machines that have sat for a while you may have multiple electrical problems due to corroded contacts, connectors etc.. glad to hear you figured it out...
joe
 
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