Topic: 1976 750f no spark ?

[fatkid]

he guys i just wanted to run this by you this bike has not ran since 1980. i put a jump box on it and tried the starter button. nothing and the head light went out when i let off the button the light never did come back on. I put oil down the cylinders and left the plugs out so i could turn it over by hand and see if i could get spark. if you were setting on the bike the right cylinder first was tested . it had spark then test the other three nothing so i went back to the first one . it now has no spark at all . were do i start and what do i check.

[steam-powered man]

my current project/heap also had no spark, not registered since 2005.  i fully charged the battery, cleaned/gapped the points, had v at the points and at the coils.  tested the coils - yikes, all dead.  2 busted wires plus 2 faulty caps = nada.

i'd check these things first.
-- charge the battery overnight
-- clean both ends of the battery connections
-- clean the wiring connections to the points
-- clean/gap the points
-- check v at the points
-- check v at the coils
-- test the coils, with caps
-- new plugs

[fatkid]

hey thanks for the info i cleaned the points and man oh man I just blew out 31 years if cobb webs. now the only other thing i am working on is no electic start

[BeSeeingYou]

Don't think we have talked about this yet but the original starter button is a common age related  failure point on this bike.  The headlight is also fed through the starter button thus no headlight.  The button is not available but a complete right side control is for about $100.  Hondaman has mentioned another option of using a relay and fitting an aftermarket switch into the housing and others have also made their own set ups.  That's the options you have.  Just do a search and you will find plenty of info on this if you want to see the alternatives to a new stock switch.  I would not bother with used parts here as they are at the failure point too.

[fatkid]

well thanks guys any way to test the starter switch

[BeSeeingYou]

The switch sits in a plastic housing inside the right hand control.  The plastic housing cracks and the internals of the switch fall apart.  I was able to take out the two screws that hold the control together and you can get it open enough to see the starter switch. 

[fatkid]

srust got all that done but here is my next thought when i hit the start button the lights on the indicater dash  dim just a little . that means it has to be making a circut right so is there anything else to  check. could the starter be stuck or bad maybe silinoid

[BeSeeingYou]

You can also check the wiring.  The wires go into the junction box on the frame above the headers.  The black with red feeds the headlight and should have power when the switch is not pushed or you could just go to the headlight fuse and check for power there it's the same thing. The yellow with red goes to the starter relay(solenoid) and should have power when the button is pushed.  Peeking in to see if the housing is cracked is easier but if that looks okay then test the wiring.

You could test the starter by jumping the positive wire from the battery and starter terminals on the solenoid with a large gauge wire of a screwdriver.  If the starter button is okay and the starter spins while jumped then suspect the solenoid.   I still suspect the starter switch as it's always the usual suspect.

[fatkid]

well did some looking this am the yellow and red wire has power all the way back to the solenoid . jump it and it turned the starter over so i am saying the solenoid is bad ? correct. but back to the light it still does not come on so i would say the switch is bad on the light side . ?

[BeSeeingYou]

It's very possible that the switch could fail like that.  Give the solenoid a sharp rap with the handle of a screw driver as a last resort.  So no power at the headlight fuse?  Check the fuse close up and see that the contacts in the holder are clean.  Sounds like the switch and the solenoid may be bad.

[fatkid]

the wires down in the wire box tested like this yellow red power when button pushed. no power on black and red at all but one time and it was weak . i flipped wires and plugged back in now when i hit the button the light comes on. as for the solenoid i will work on that . headed to pick up a nother 76f today has all my missing parts but no title

[Willy_754c]

Hey Fatkid,
I had the same issue with the switch.  I did a quick work-around (although ugly and not very correct) to get it running so I could work on other stuff. (Top photo)
Just got my new starter/kill switch in the other day.  I got it from BikeBandit.com for about $110 shipped.  It came much quicker than I expected.  I figured OEM meant long wait, but it came in 4 days. 

[fatkid]

thanks willy for the info. its funny how they all had the same problem . but for me i got a parts bike that has a switch that works perfect. but just in case i will keep bikebandets in mind . how is the 754c coming ?

[Willy_754c]

Not worth a crap......I got in points, condensors, and caps.  I just put them on, and tried to gap the points and time it.  Couldn't get it.  Running bad.  I still have problems with cold cylinders.  I think it's the connection between the caps and wires......I have cut some off to try to expose good wire, but still not getting a good connection.  Got fed up with it for the night.  Plus my rusty tank is bumming me out. 

[fatkid]

well guys its all good in my hood . this am i took the parts bike solenoid of and put it on my bike hooked the jump box up and bam we now have electric start. and as a bonus i now have my head light back. i got to thinking the other day maybe that switch has to connections in there one to start and one to shut the light off. so i sprayed some contact cleaner in there then sparay some electric slide into it couple days later and i got contact. thanks for all the help guys. now my next problem she runs but only with the choke on i will need some carb work i guess any thoughts