84 750 interceptor electrical problem please help ive tried everything

Hey guys still no luck with my bike, (84 Honda 750 interceptor) I recently changed the 2 cdi packs, battery, starter solenoid brand new, changed the starter 2xs and the voltage reg/rect 2 times, I cleaned all connections on the harness with contact cleaner and a wire brush. heres the problem the bike starts up fine when cold and continues to run great until I turn it off, it seems after it's hot if I turn it off it wont start, (seems like the starter is struggling when its hot) , it seems to be an ignition prob or electrical short, cause when the bike is hot it wont start and starter shows resistance, but if I disconnect the ignition wires (cannon plug with 5 wires) from the solenoid the starter then turns like a champ but obviously the bike wont start because the ignition isn’t engaged, if I plug the ignition wires back into the solenoid then the starter struggles again. There is one relay that im not sure what it does (the whole relay is covered with a rubber boot its to the left side of the voltage rect.) does anyone know if that relay has anything to do with the ignition or starting system? I couldn’t find anything about it in the Clymer manual either. like I said the bike runs great, I can start it cold fine , but if I have to restart it before it fully cools down it wont start? once its cool again will start no problem and run till i turn it off, The only thing I can think this problem might be from is last year the starter button stopped working so I was jumping the solenoid to start it all the time, but I got tired of taking the side plastic off every time, so I decided to wire a manual switch from the battery to the solenoid it did the same thing as jumping it, worked fine for months until one day the bike was running hot, and the wires for my switch melted on the manifold and got red hot like a toaster oven, the bike still ran after this, but always had trouble starting that’s why I changed 80 percent of the electrical components, does anyone know any components in the ignition line that comes from the solenoid that I might have fried when this happened that would cause the problem I have been having? please someone help, I have been trying to get this going for months now, thank you for your time< you guys have all been a great help!

Razor

 

hi....
the same happened to me with my vfr 750 (87) : good start, engine runs well, but after 20 min......uhhhhhh, no more life...waiting for a while it cools....and then it goes...
FUEL PUMP : an old pump as it becomes warm (20 min....) blocks itself and there 's no more gas to the carbs. It cools and begins to run again (the pump, I mean..)
Lamps !

 

I'm a student motorcycle mechanic, so im learning now...But! I think your problem is not already with electronic... So the problem is with the valvegap, or the caburettor titre.(i think!!!)

 

nope its not the fuel pump the bike will run forever till i turn it off, its after its hot wont start

 

that doesnt make much sense the bike runs fine till i turn it off, then when hot wont start till the bike sits for 30 mins, its def eletrical

 

I've had this happen with several of my VF's and it's always been the carbs. The fix is to fully rebuild the carbs and then get them adjusted properly (sync and mixture, mostly the idle mixture).

 

Did you replace the starter with used starters? Like I said before, I've seen this before and it's always been the starter. I know you think I'm crazy, but the kit is only about $30.00 and is easy to put in. Just be sure to sand the armature (where the brushes touch) until you get nice shiny copper. There are a number of reasons why the starter turns easier while there is no spark. You might have a carb leaking gas into the engine while it is off and hot causing it to flood, but the starter rebuild is easier and cheaper to do before a carb rebuild. Try bump starting it while hot and won't start. If it starts, BAD STARTER!!!! If it won't bump start, I'd check the carbs.

 

i would agree with u on the carb issue, but why when i go to start it when hot, does the starter seem like its not turning hard, as soon as i diconnect the ignition plug that goes to the solnoid and jump the starter it turnd free, so there has to be a short, and i cleaned the carbs on this bike last year. i had a starter switch rigged up last year and the whole idea went bad when the bike got real hot and melted the wires i ran to the switch, so thats why i think its eletrical, but ive changed almost everything, what else can be giving me a direct short once the bike warms up? the only thing i havent changed yet is the stator , coils and harness, all else has been changed

 

ARE YOU DEAF???? BAD STARTER!!! The engine is harder to turn when it gets a spark to the plugs!!!!! Remember, the spark fires just BEFORE the piston hits the top of it's stroke. Also, you are removing the electrical load of the ignition system, leaving more "juice" for the starter to play with. There does NOT have to be a short!!! If you had a short, it would be sparking and melting wires all over the place. PLEASE Give the starter kit a chance before spending hundreds on things you don't need. If you were close, I'd come rebuild it for you, but I have no idea how far away you are. At least, pull the starter apart and clean everything up. Like I said, the kit is only about $30.00. Be sure to get BOTH parts, a brush set AND the holder. My Sabre (same engine) has done this twice over the last 25 years and my '83 VF750F just did it. A starter job, and it's fixed. Good luck and keep us posted.

 

I tend to agree with eddie, assuming it's not a charging system problem. I've seen lots and lots of starters act this very way...fine when bike cold...turn real slow when hot.

I disagree with JamieD...but I have too much respect for his other posts not to consider what he says. If it was simply hardstarting I could lean that way...but I don't know what in the carbs would make the engine turn over THAT differently from hot to cold...unless the engine was hydraulic locking from dumping gas into the combustion chamber.

You could eliminate the rest of elecricals (outside the starter) as being a problem by doing a voltage drop test. Turn your meter to VDC...put one probe on the positive battery terminal and another on the starter positive lead at the starter, then turn the engine over and watch the meter. If you see near 0VDC...the problem is likely the starter. If you see much more than .2 VDC, or especially more than .5VDC, then some other elecrical component or connection is consuming too much of your battery for your starter to operate properly and you need to look elsewhere.

Rebuilding the starter with brushes may not be the answer either. If the armature is shorting to the starter case or the armature shaft when hot, you'll need to address that...usually by replacing the whole starter motor. I've seen that happen quite often also.

 

thanks for the help

No im not Deaf, i will try either rebuilding the starter if i can find a kit (do u have a link), or ill just buy a brand new one, i still have a hard time believing the starter i had on my bike and the 2 others i purchased from ebay off bikes that had low miles that looked clean and in good condition all have bad brushes on them, but i guess its worth a shot, i cant think of anything else, and i will do some volt meter tests, and i will let u all know how things turn out, i wont just disappear, i appreciate all of your ideas and all your help
thanks and anyone else with any imput please feel free

Razor Tongue

 

So today i recieved a used wiring harness in the mail, changed it out quickly before work, and it seems to have solved the problem, let it run for a half hour and then started up again like a champ, again i thank u all for your imput, and all your help, much respect to u all, and no im not deaf stupid or crazy, i just didnt think i would have 3 bad starters and i was right, thanks for the idea though, could have went without the sarcasm

Razor Tongue
MySpace.com - NASSAU CHAINSAW DisGracElanD Demolitions Committee - Brooklyn, New York - Grime / Hardcore / Concrete - www.myspace.com/nassauchainsaw

 

I hope your problem is fixed. I was afraid you'd end up spending hundreds on stuff you didn't need. I've seen 3 bad used starters in a row. I'd even say that almost ALL 25 year old starters are either bad, or on their way out. I've owned 1st gen Honda V-4s for over 20 years, and it seems they all need the starter rebuilt every 20-25 years.

 

i feel ya, thanks again for your help, and im sure sometime soon i will be rebuilding that starter, where do i get the kit, do u have a link?

 

Your local Honda dealer should have it. Take your old set to match it up, just to be sure they sell you the right one. You can look it up at Motorcycle Parts|ATV Parts|Honda|Kawasaki|Suzuki|Yamaha|Dealer|Tires|Repair Manuals|Wholesale Discount Prices They have a complete parts breakdown. Make sure to get both parts, the brushes and the holder.