78 cb750K won't fire up. (1 coil fires other doesn't)

[mitchberry]

Hey guys,

There's going to be a lot of questions here.. i really hope that you guys don't mind taking the time to answer most of them.

Not sure how many people are familiar with me at this point, so i'll tell my story again. I am new to cb750's but not new to bikes, fabrication, or working on motors n electrical etc...

so, i just got this 78 cb750K from a dude for 200 bucks and he IS a novice.. basically, he had no idea what the hell he was doing. he had wires all mis-matched in the bucket, was missing a bunch of things, put parts from various years on this bike, and i have no idea what year they were off of so cant buy stuff to fix them etc etc etc..

It's really a clusterfrack...  

 ok, so, i do have a few questions.  

1. Am i safe in assuming that if the oil light is lit on the dashboard, that the bike will not start?

2. If the bike is running down the road and the oil light comes on, will it kill 1 coil / 2 pistons to stall the motor out softly as opposed to completely cutting the power completely and killing it while riding?

basically, i have power to one coil (the yellow wire one)  where as i do not have power to my blue coil.

yes.. i've done all of the obvious stuff..  

A. tested the blue and the yellow wire for juice with a volt meter at various parts of the revolution to make sure the points were either opened or closed.  

B. swapped the blue and yellow wire around to see if the blue wire coil fired with the yellow wire, since the yellow one is the one that has juice.  (it did by the way)...

C. ran a brand new wire in place of the old blue one in anticipation of there being a short somewhere in it..
(it still didn't get power to the coils)

D. printed about 5 wiring diagrams and color coded them / completely re-wired the bike as if starting from scratch.  

E. made sure that all 4 plugs were grounded firmly to something before doing my test... in fact 2 are in the engine still and the other two are firmly "mounted" to a place they will ground.

still no luck getting that damned coil to fire..

the only common denominator that i can find is that the oil light is on now whereas it wasn't before i re-wired it.   not to say i screwed something up, but on the contrary, i don't think it was plugged in correctly before whereas now it is.

before i did this, you didn't have to hold the clutch in to start the bike.. now you do... (took me a while to figure out why the hell it wouldn't engage the starter... i thought i blew the solenoid somehow.

i've done other stuff too, just cant think of it right now..

SO..... given all that i said, is there anything -else- that would cause only 1 coil (2 plugs) to fire and not the others?

another question....


there is a little "thing" that i am completely unable to find on ANY parts diagram that i've looked at including the clymer manual. i have no idea what it is, how it works, or what it does..

 it is mounted under the battery box and has some 1/4" to 1/2" hoses coming off of it.. i think 2 or 3...

is it for an oil cooler that's missing????

Does this bike NEED/REQUIRE an oil cooler? if so, i sure as hell don't have one with the bike.

does it go to the airbox that didn't come with the bike?

is it an oil pump?  

 i really don't know..

i'm NOT trying to advertise another forum here, however, i DID post the pics of this gizmo to another forum and didn't get much of a response out of it aside from "take it apart" and "are you sure it's supposed to do that?"


http://www.motorcycleforum.com/showthread.php?t=103752


Is that part something that will disallow it to run if the tubes aren't plugged into something?

There IS oil in the bike by the way, so there shouldn't be a reason for the oil light to be on that i know of..

 is it for oil LEVEL, or oil PRESSURE?  

 if it's for pressure, then why do i not have pressure?

I guess you're supposed to fill the bag with oil and not the crank case right? I do have 3 vintage bikes..  this included... the other's are 69 suzuki 2 strokes... my other bike is an 06 busa...  so, i'm really not sure what the oil bag does on the bike either...

Basically, i got no crash course on this bike, and the LITTLE things i don't know about it are all things that could be keeping this bike from starting!


well sorry for the long post.. i do hope to hear some answers though..   it's very appreciated!

[mitchberry]

I know it's a long post, but i really cant believe no one has attempted to answer any of these questions in 13.5 hours.

:(  


That's kinda frustrating!

[LukeM]

In the US, it's a holiday weekend. People are celebrating what may be the last long weekend for a while.  I'm sure it'll pick up. :-)

I personally was waiting for someone to answer.  I think you've troubleshooted/troubleshot the coil thing pretty well.  All I could suggest is replacing the bad coil with a known good one, and seeing what happens.  My guess would be the igniter thingie inside the left engine cover, or perhaps the igniter amp under the seat.

As far as I know, the oil light only comes on if the stop lamp fails, or the oil pressure sensor fails (or you've lost all oil pressure).  Based on the schematics I've seen, there isn't anything that will tell the engine to go on one pair of cylinders if oil pressure goes away.  Running with no oil, especially with these tight tolerance engines, is usually trouble fairly quickly.

If I think of something else, I'll follow up.  Perhaps someone else will chime in.
Luke M

[LukeM]

If your bike is like mine, that gizmo is a crankcase rebreather/capture system.  It pulls crankcase fumes from the case, and routes them into the air cleaner assembly.  The reservoir under your battery box is to capture the condensed stuff that won't go into the engine.  Every once in a while, you are recommended to open up the drain, let all the wet stuff drain out, and then plug it back in again.  I can't believe leaving that open would bother the engine all that much.

Luke M

[LukeM]

If you had an oil cooler, it would be on the bottom front of the engine, where the oil filter is.  Check this post for a closeup of what that looks like.  That's the only provision I know of for adding an oil filter.

Luke M

[mitchberry]

Cool man thanks for the input.. as for the coils I know for sure they both
work.. the problem is the point on the upper left not getting power to trip the
condenser to spark the coil and plug... not sure why.. even ran a completely new
wire. The weird thing is that I can't for the life of me figure out where the heck
the electricity comes from....  the wire goes from the point to the coil...
nothing is power in... maybe the power switch somehow? I have no idea what gives the blue wire electricity....  i do know though that the black wire is supposed to complete a circuit with the black and white wire through use of the off on off switch, though it wasn't so i ended up having to bridge it with a piece of wire... i then took the wire out, put a piece of solder on the bottom of the place where the two wires were soldered to the switch (which didn't seem to work)...  

maybe having to jerry rig the bad off on off switch is what's causing all of this?????  damn.. maybe i should just... replace ALL of the wiring, coils, switches, and whatever other electrical crap i can find on this bike...  looks like i will end up doing so before diagnosing this problem....
 
I think if I knew how the blue and yellow wires actually GOT their power, I could find my problem.....

As for the oil light, I had the tail light unplugged.. I did plug it in but the
oil light is still on.. worth a shot anyhow.. with that said the rear brake
doesn't trigger the brake light.. either THAT switch is bad too, or wired incorrectly (still).. or
maybe that filament is burned in the bulb..  

Maybe if I fix that the light will go off... or maybe I have a faulty oil
switch...

Are you sure the oil switch won't keep it from running? Where is the sensor
physically on the sohc motors? i'd like to try to bypass it temporarily to see if that helps anything.  of course i don't want to run it much until i know for sure that i'm not actually minus oil pressure..


I dunno... maybe I just need new points or something.. I don't know if the kid
tried to adjust them. All of this effort and maybe its just not connecting when the cam spins past it.
 
Though there's still no juice to the point itself so idk.. actually there is, but it's like half a volt. Either way I found tonsssssss of stuff that I had to fix and am still finding things like the
fact he had the shop put a -used- radial tire on the front wheel backwards...

fortunately ill be buying new ones, but that's a SERIOUSLY UNSAFE no no...

[Re-run]

I will answer as much as I can in your order.
1: Your oil light will always be on if the engine is not running and the key is on. It should go out within a couple of seconds after starting.

2: The oil light will not effect anything coil related, unless wires are somehow crossed somewhere. Normally totally independent.
When you swapped the wires, did the other coil stop working? The yellow wire had juice but not the blue wire? Is that right? If you disconnect the oil light, what happened?

So if you connect the yellow wire to either coil, that coil fires but not either coil when connected to the blue wire?

I just want to make sure I have it all.

[mitchberry]

hey thanks!  

yeah, basically, the yellow wire will fire either coil that it is plugged into, and the blue wire is 99% dead... it shows a faint voltage...  like.. less than 1v most of the time but not a complete 0v..

i guess it would help if i posted a wiring diagram here but, i have no idea where the wires get their juice from...

they literally only go from the points to the coils... and the condensers plug in opposite of where the points do on the same side, and nothing else goes into the condensers..  it really makes absolutely no sense... at least on my suzuki's there are multiple wires on the condensers, and one is power in, and the other is power out to the points, coils and all that stuff....  

There are only 2 wires on the coils... a black/white one and then either the blue or yellow depending upon the coil... the black and white one is grounded to my knowledge..

this isn't the exact diagram i've been working with, BUT... it is the same in the places that matter...

as far as what happens when i unplug the oil light, basically, it just goes off.. nothing more or less..

 where i do have a problem though is that i have to connect the black/white wire with the black wire in the headlight bucket or none of the 4 coils spark..

 said wires are going to the off on off switch on the right grip... so i assume it's bad.. since then, i pt a bead of solder in it, but that didn't seem to work...  



seriously though.. if you look at this,

 you could literally unplug the black and white wire, and pull the coils and points completely out of the loop there... the only thing i can think of is that the black and white wire gives the coils power.. but it IS as far as i know, a dead / grounded wire.........

 maybe not?"???   i could be going about this all wrong... the black wire may not be negative... but why wouldn't a black wire be negative -logically-  ?  

hmm.. actually, i don't see this grounding anywhere at all upon further inspection.. the green wire seems to be negative where the black seems to be power... and the black n white pulls power from the black wire through the on off on switch and then feeds to the coils which go to the points and condensers..


 please correct me if i'm wrong at this point...


----------


 ok so if that IS the case, and the black wire is +  

then, in theory, if i just ran a new wire in place of the blue wire, this sucker should fire right up right?


-----------nope --------

 i did that the other day with absolutely no luck.... still dead....  


i dunno.. i think it's coming along now but i'd still like more advice...  

i'm going to try switching where the black wires plug into the black and white wires instead of changing the yellow and blue wires, and see if that gives the blue wire power.


 if it does, then i'll just replace part of the b/w wire and i think i'll have power to all 4 cylinders finally and can fire this beast up...

i'll keep you guys posted....

[mitchberry]

basically, here's what i got....  most current info..

the black and white wire provides power from the wiring harness... it then goes through the coil into either a blue or a yellow wire, and the blue or yellow wire, (blue is left coil, yellow is right coil)  go directly to the points from the coils..

the same bolt that holds the blue or yellow wires on holds a green wire which is attached to a condenser..   those wires make what you said happen...

the black and white wire has a dual female connector  which the two black and white wires from the coil plug into... 2 into 1 connector.. the 1.. goes back to the harness.. (then ultimately, to the off on off switch which severs or creates a connection to a black wire, which is a POSITIVE wire that also connects other components etc..

the black and black/white wire do not connect at the switch... whatever position the off on off switch is on, no power goes to the black and white wire, therefore the switch is bad...  i have placed a wire in the headlight bucket prematurely bridging the black and black/white wires together to provide power to the coil, to hotwire the bike.... (in order to totally hotwire the bike and omit the ignition switch, i would need to cross a few other connections, but that's not my goal....)

once i connected the black and b/w wire, the b/w wire gets power, which goes to the 2:1 connector, and into the coils... so....

LEFT coil gets 12V going into it... actually something like 9 when the running lights are on.
RIGHT coil gets the same 9v to it..... therefore, it has power to spark....

when i hit the button, the yellow wire coil sparks the plugs... the blue wire coil does not....

logic would tell me that the wire that the blue wire coil is bad....

so, i plug the known good wire (yellow) into the presumably bad coil, and......... the plugs spark.....
i plug the yellow back to the yellow, and THOSE plugs spark...

That leads me to believe now that the coil is good...   because it is now sparking...    therefore, the problem must be beyond the coil....

therefore, the blue wire, condenser, or point is bad..

 If i run a completely separate wire from the blue coil, to the blue point, still no spark.... that leaves either the point or the condenser...

When i test the ohms of the condensers, both of them go to zero on the reading....  if i swap condensers and put the known good one on the coil that won't fire, i still get no spark....

so maybe the point is bad?  i crank the motor by hand to visually check the gap to see that it is firmly pressing it's grounding point when the revolution requires it to....  however when the bike is cranking over, there is no spark in the point, whereas on the working one there is......

furthermore, when i disconnect the yellow wire at any time from a coil (either left or right), it makes a zapping sound and you can visually see a blue arc between the male and female connections... the blue wire does not do this in either coil...

So... maybe the spark plug i'm testing is bad? so, i change the known good spark plug with one which i use to test the non firing coil....  hit the start button,  the possibly bad one fires and the left coil does not fire..

 maybe it's the boot that holds the plug.....     / so, i plug the plug into it and test the far left cylinder to find no spark...

The ONLY thing i haven't done at this point is to replace the points place for a new one, but there is no guarantee it will work... granted it should probably be done anyway, it's still a pricy investment for a "maybe" ...

additional thoughts??????????

[LukeM]

Well documented and logical troubleshooting process.  My compliments. That would be the next step.  Point sets aren't that expensive, and not knowing what happened to this bike before, it's not a bad idea.  Remember there's a little coating on the points to prevent corrosion.  Make sure you take that off with a points file or emery cloth, and remember to clean them very well before putting them on the bike.

Search around on this forum or SOHC4.net for the procedure to install and set points for a SOHC bike. The DOHC models don't use mechanical points, though. If your 750 is like my son's 550F, one of the point sets has a little pin to lock it into the plate.  Please make sure your point set fits flush to that plate.

Lastly, don't get too frustrated with these old machines.  Once you get it running, it'll all be worth it.  Trust me.  I'm waiting for that same feeling once I get the Avenger up and running.

Luke M

[Re-run]

I have to say I am lucky to not have had an issue like that. It could very well be the point that is bad but maybe before you replace the point, the wire going TO the "bad" point could be jumpered. Maybe there is no power getting to the point.

[mitchberry]

post 1 :

"C. ran a brand new wire in place of the old blue one in anticipation of there being a short somewhere in it..
(it still didn't get power to the coils) "


post 4:

"then, in theory, if i just ran a new wire in place of the blue wire, this sucker should fire right up right?
-----------nope --------
 i did that the other day with absolutely no luck.... still dead....  "
 
 
 post 5:
 
 " If i run a completely separate wire from the blue coil, to the blue point, still no spark.... that leaves either the point or the condenser... "
 
 
 Re-run, what do you mean by "jumper" the point?  .. sorry, i didn't mean to sound like a smart ass by copying and pasting these things, i was just wondering if you meant something other than this. -also, i know i typed a LOTTTT in here, and it's easy to miss things reading through it, so i wanted to reitterate it in case this isn't what you meant.
 
 i decided to take a day off from working on this and put new points on my T125 so i can get it running reliably in order to sell it (for money for my 750 project).
 
 check it out!
 
 
 my T125


 
 
 my T500 (has been painted black since then)


 
 my hayabusa


 
 
 and, i dont have any pics on the computer yet of my cb750 (which is what you guys would be most interested in seeing probably.. lololol.
 
 -------
 
 
 luke.... thanks for the compliments.
 
 i think i mentioned elsewhere that i am a patient man...  given the fact i built both of my other vintage bikes ground up, i know that stupid little things can cause a lot of grief..  in fact, i really wouldn't doubt if it's something so simple and minor that i will have to fight from being angry with myself for having not found it immediately... "OH the kick stand has to be up!" or some crap...  
 
 It doesn't help that i really don't know anything about the small details of the cb such as those... it could be any number of things... "OH the tires are too low" anything... (i'm positive it doesn't BUT) it could be something as stupid as there being a low tire pressure sensor or something that causes it not to start....  obviously this bike doesn't have that..  but... aside from common sense, i wouldn't know that.. some new bikes have things like that...  i don't know the little things that this bike DOES have similar to that... and i won't know until it runs...  
 
 on my hayabusa, you pull the clutch before you start it, and then if you put it in gear while the kick stand is down, it kills the motor... kinda embarassing actually if there are people around when you do it.  
 
  and despite it has 170 horsepower, it's actually pretty easy to stall it in a launch if you're not prepared for it... say a light turns green and you're not paying attention, so you floor it.. 80% of the time i stall it and piss the people behind me off... also embarrasing..  
 
  the absolute MOST embarassing thing on that bike is pulling onto the sidewalk at a grocery store, putting the stand down, and realizing it didn't go all the way down  / the bike rolls forward and it starts to fall over and it takes every ounce of strength you have to keep it from hitting the ground, and you're HOPING your foot doesn't slip on the pavement... the whole time in your head you're saying " NONONONNONONONONONONONo NOOOO NOOOOOOOOO" and there's at least one hit girl giggling, and some little kid " HE DUN ALMOST DROPPED HIS MOTORCYCLE!!!" ...
 
   i'm a pretty strong guy, but the center of gravity and height on that bike makes it VERY hard to keep from crashing to the ground if it gets off balance...  it's a 500 pound bike as are the cb750's... but, i would have no problem keeping the cb up if it teetered. there are more places to grab it...  
 
   well... way off subject... but... i'm not so sure there's much else that can be said about my cb problem right now....  
   
    i got the points plate on order... condensers, points, plate... should be getting it soon, and i'll update at that point... though, please continue to comment if you have thoughts or ideas... or.... comments.. lol  i'm still open to ideas and will be messing with this thing all weekend...

[Re-run]

Well you have power going to the points via wire of course. Then you have the wire going from the point to the coil(blue/yellow wires) If you have no sparking at the point, there may be no power getting to it. So of course nothing to go through the blue wire. It has been awhile since I used points but I thought there were wires going to the points, then to the coils. I switched to the dynas.

[mitchberry]

on the plus side, RANDOMLY, i started getting power to both coils, and spark in all 4 spark plugs.. but it still wouldn't fire up.   the coil in question had a much darker spark than the good one..

at this point, i think i need to change the plugs and keep going with it. the problem i'm having now is that i have probably 4 minutes or less crank time before the battery goes dead, and, i'm not heavy enough (178 on average) to kick the kick starter hard enough to make a bit of difference towards starting the motor...  

Usually, i laugh because when people try to start my other bikes, they have no idea how to make the kick start work properly to start the bike...

so, i have to mention i'm all too familiar with kick starts and what it takes to make one fire a motor, but i'm simply not heavy enough.   when i first went to look at the bike, i couldn't even budge the kick starter... the dude i bought it from was probably about 400 pounds... he stepped on it and moved it but ran out of breath after about 2 kicks and or broke the left foot peg loose of it's hold because he hadn't tightened it down like it was supposed to be.  (didn't harm anything, just.. flipped it upside down and almost racked himself when the foot peg gave way... )  

anyway, i have about 4 minutes of time, then 6 hours of charging on the trickle charger i have.. then 4 minutes.. then 6 hours of charging then 4 minutes.. etc etc....  so basically, whatever i do, i have to make sure i'm doing it well in those 4 minutes...

not sure why any of that matters to this post..

as for the points, and dyna coils and all of that, i'm not sure if they make dynas for the SOHC motors.. i sell parts for a living and was looking at them through our distributors, but wasn't able to find one at the time for an SOHC motor.  maybe i missed it..

I did put an aftermarket ignition system on my T500 though, but it was an optical system..  it was from newtronics or something like that, and i waited 8 MONTHS for them to come back into production.

Come to find out, the only difference from one to the other was the plate that the points mount to.. they were supposed to be specifically made points plates that held the optical sensor where they needed to go in place of the points.

well.. after 8 months of waiting and several hundred dollars to buy this thing, and shipping them from australia, i opened the package to find that they had basically cut a piece of sheet aluminum with tin snips, drilled and tap/die'd a few screw holes, and took a hand file to it where it needed markers..

I COULD HAVE DONE THAT MYSELF!!!!!!!!! IN FACT I COULD HAVE DONE A BETTER JOB OF IT!!!  the ******* things DIDN'T EVEN FIT!   nowhere close in fact....

but i figured, it doesn't matter.... i have tools, they did most of the work, i can finish it..

so i did.... i made the points plates fit, but still had trouble with the tiny bolts being too long, and i had to use spacers, which of course made the roatating assembly not fit through the optical sensors, so i had to fashion a spacer for the cam out of a washer and what not...

 it took me about 10 hours of work over a few days to make the stupid things fit...

basically, i could have easily bought the system 8 months before that, and used my STOCK points plates which i know fit, drilled, tapped and died the screw holes, and it would have worked flawlessly - had i known that this is the quality of crap they would give me...

so... i got everything mounted, the bike ran great, better than it had for a long time, but, i couldn't make it go faster than about 30mph.. it has something to do with the electronics part they gave me...  no matter what i did, it wouldn't work...  finally, at some point while adjusting the timing with the motor running, my screwdriver slipped, it caught the rotating plate, which flung it into one of the optical sensors, destroying the mounting ears and more or less rendering it completely USELESS after all of that work...

i was however able to fix it with bubble gum duct tape and bailing wire, but it still wouldn't run past 30mph..

i got pissed off, stripped all that crap off of there and bought brand new points and condensers from sudco, which of course didn't arrive......... so i had to call them back and have them ship me another set which did arrive... i was hoping that the other would eventually arrive so i could put them on my 125 but they haven't to date...

i put the points on there, tuned it up, adjusted it, and put about 250 miles on it over the course of about 3 nights with one of my friends who was the lucky bastard that got to ride my busa and leave me in the dust everywhere we went...  then of course for some reason the bike crapped out on my about 10 miles from home leaving us on the side of the road at about 2 in the morning.. fortunately it fired up and i was able to ride home at about 45mph and it ran just fine...   so we decided to park it, drain the crank case thinking it was flooded, and either go back out, or continue adjusting...  it turns out it wasn't flooded, so we didn't know what the deal was...

At a loss, we decided to prep and paint that bike...  we stripped the tail section and the tank, but it was too heavy to mess with after the first coat of gas, so we drained the gas out of it to find that the lining inside the fiberglass tank (by neuxstone on ebay) was dissolving, flaking, floating, and getting into my bike..  i checked the fuel filters and they were completely gummed up with crap.. (i use inline filters instead of in tank.) of course that crap went into my carbs and caused it to crap out on me and not run right...  

so, i emailed that dude about it asking what to do, and he said he would make me a new one until i showed him a pic.... once he saw the pic he accused me of putting "sea foam" in the tank which would cause that to happen, and since i did that he would repair it rather than making me a new one...  

honestly, i have HEARD of sea foam, but i have no idea what it does, or what it is...  and i have never -once- put anything at all in that tank aside from pump gas... no race gas, no high octane gas, no additives, no lead additive, nothing.... -nothing-  but he doesn't believe me....

Basically i'm out a $400 gas tank now. i did send it back to him.. we'll see if he builds me a new one, or if he tries to "repair" that tank..  i don't trust that a repair would be any better than what i sent him..  

i went ahead and bought a mid 70's style cb750 gas tank for that bike, and as we speak, i'm going through the Kreem process on my suzuki's original gas tank since i dont trust fiberglass tanks anymore...

i need to get the gas tank situation figured out and finalized though so i can figure out what to do about my tail sections..  

My friend says he will buy my glass tank for his 76 gt550, so i'm not at an entire loss.

Either way, now i have 4 non working bikes in my garage including my friend's triumph.  his bike is torn apart into about 500 pieces taking up space in my garage because he doesn't like to finish what he starts.. now he "doesn't feel like coming to get it today... "


so, my 500 doesn't run because of the gas tank, the 750, who knows.....  my 125 runs now that i put points on it, but smokes like crazy and has weird electrical issues that i have yet to figure out.. theres a ground somewhere and i cant find it... everything is brand new on the bike as far as wiring.. i don't know..

Thankfully my busa runs or i'd be out a vehicle.  i guess that's the good thing about newer bikes... they still run without having to mess with them every other day..

as for the 750 though, i still don't have much to say about it and won't until i get that point plate and plugs for it...

If it runs though, all i need is a chain and i can ride it around the block and such...

as eccentric as this may sound, i love it when ALL of my bikes run at the same time... i am test riding them all the time making adjustments, or riding them to keep the fluids from congealing, or, the batteries charged, or whatever...

 often times there are people sitting in their front lawns, and i'll ride by with a bike, then ride by with another bike, then another bike, and it always trips them out...  

with that said i'm probably going to sell the 125 and the 500.. which is why i'm trying to get it all figured out... if i do, then i'll have money to make my 750 like i want it....  

similar to carpy's koppa cafe...

only better....  no shortcuts on this bike... my others were meant to be rat racers. I'm gonna pull out all the stops on this 750 and give the fish a run for his money.... (if only because he told me the 78 doesn't make a good cafe racer).. well.... i'm not going to supercharge mine though..

[Re-run]

You know, it is funny. I have never had a major issue with my bike. It runs as reliably as any bike I have seen.
I mean, I had a battery issue cause I didnt tighten the cable all the way. A signal light bolt vibrated out and a flat tire! I must be lucky.
Tomorrow, I will try to look under my points cover and see what things look like. Since I put on my Dyna-S, I 3 years ago, I havent taken the sucker off.

http://www.z1enterprises.com/detail.aspx?ID=437
In the US and one of the lowest prices I have seen. I got mine from there.

[mitchberry]

hey bud.. thanks for the link!   I think i modestly mentioned that i sell parts for a living elsewhere on this forum, which actually work out to my advantage.. i was able to use that manufacturer's part number and cross reference it against our site, and found the vendor's part number

217512  

We have it listed for $2 more on our site than the link you sent me, but... fortunately, i get stuff at cost... so that's pretty awesome... i just may get one of these...

 of course i would probably jump right on it if i didn't just buy a brand new points plate. I suppose i could always ebay it for profit considering i got that at cost too.  

ON ANOTHER NOTE:

i don't have any idea what changed....   none what-so-ever

I don't have a gas tank on it right now because the kid i bought it from conveniently broke the nipple on the petcock (two potentially dirty words in a row) that you plug the hose onto, so... the petcock is pretty much unusable. i have been conveniently using the gas tank as fuel storage though since of all the things i have, i have not 1 gas can in my garage.  

anyhow, i plugged in a hose to the carb and taped a funnel to the end, and poured some gas into it until the bowls were filled, sprayed some carb cleaner / degreaser into the carbs directly, put the choke on and hit the button....

after a second or two of cranking, a 3.5 foot long column of fire shot out of the end of the header (4 into one without a muffler on it) and i stopped hitting it...  

 i put more gas in it and hit the button again and the bastard FIRED RIGHT UP!!!!  ran for a second and died...  put more gas in it and kept enough gas handy to keep filling it as needed (which was constantly.. that thing drinks gas like it's going out of style)...

 anyway, it kept dying, which i assume was because the carbs need hella adjusting, synching, idle adjustment and everything else....   but, i think if i had a tank on it and could keep up with it's appetite for gas, i could make this thing run....

anyway, like i said about that battery, i got to do this about 6 times before it went dead.. so now i'm waiting for it to charge again for a few hours or over night considering it's 1am as i write this...

pretty exciting though...  

 oddly enough, this thing sounds like more of a riding lawnmower than my vintage 2 stroke 500... and it revs like one too...  that's probably because of the lack of a muffler.  my busa sounds literally like a pissed off VW beetle without the mufflers off of it...  


anyway, FOR NOW the thing runs... i'll keep it at that until i get my 75 model gas tank on tuesday and can Kreem it, put a filter on it and run some plumbing...

 i DO have a question about the carbs but i'll post a new thread about that...  pretty simple question though...

[mitchberry]

oh yeah... re-run..   as far as never having a problem with your bike....  

That's cool..  i have heard nothing but good things about these bikes... and.. well.. honda in general is NOTORIOUS for making a VERY mechanically sound motor... those stupid little scooters from the 60's n 70's claimed literally to be bulletproof... and... they pretty much were.. i saw a clip where they dropped one off a 5 story building just to test out how indestructible they were..   and.. it fired right up..   albeit, they couldn't ride away with it because the wheels were destroyed..  

anyway, honda is a super reliable machine in general.. and these cb750's are no exception for damned sure.. that's why there are soooooooo many of them around...  and there are soooooo many parts to choose from..

 whereas my 69 suzuki T500, i only know of 3 in my entire city ... only mine and 1 other run and are street legal...   not saying they aren't dependable, but.... nowhere NEAR as dependable as the cb's have been..

 with that said, someone at some point was going to restore this bike, and they tore it into pieces and stuck them in a box for god knows how long...  then the guy GAVE it to this kid who started to put it back together but realized he had no idea what he was doing, and eventually sold it to me for $200 bucks...  since then i went completely over the wiring...

 now that it (somewhat) runs,  i'm going to fine tune it and tear it BACK down to pieces and clean, powdercoat, chrome, polish etc all the crap on it that i can afford to do as i can afford it...   put it all back together and get it street legal..

the fortunate part is that since i have a vintage bike already that is titled, registered, inspected and street legal,  i can pretty much swap my license plate between them..   my 2 suzuki's are both 69 models, and no one knows the damned difference...  i probably wont have honda badging on my 750.. .so, really, no one will know even a cop...  not that i ever get pulled over on my bikes...   then again, i will get everything taken care of with the bike once it runs reliably and get it titled and registered so i can sell it eventually..

once i finish this project, i'll sell and start another... i enjoy making them as much as i enjoy riding them.

[LukeM]

Well, there you are.  Suck, Squeeze, Bang, Blow.  Glad to see you got it going.  Keep us updated.
Luke M

[mitchberry]

Sounds like the average frat party on a Saturday night! Glad to see i'm doing something right..