Topic: Electronic Ignition

[thenewbie]

Soooo im having issues with my ignition, only one cylinder has spark (#3). Im planning on replacing the plug wires and caps. Is there a kit i can get to switch over to electronic ignition to possibly solve my problem and prevent future headaches?

[CB750F2]

I would fix the problem with your current ignition system before deciding to install an electronic system. If after fixing your current system and you still want to go electronic I suggest that you have a good look at Hondaman's system. It represents excellent value for money, Mark provides good support and you can easily revert back to the points system if in the unlikely event the electronic system fails. It is important that you fix what you have first because the fault you have may affect the electronic system as well. Pat

[Bailgang]

+1 to what cb750f2 said. Definitely figure out what the problem is with what you have first THEN decide about an electronic conversion later. Jumping the gun right away with an electronic ign isn't going to be some sort of cure all.

[Scott S]

 Even if you go with an electronic ignition, you still need good coils, wires, caps and plugs. Start there first and see what happens.

[70CB750]

I installed Pamco with coils from vintagecb750 and I am very happy with the setup.

My cables were shot and I wanted to have cables I can replace as needed, not that molded together Honda solution.  Probably the best spent $250 on the whole project.  Also I dealt with points in my previous life - 2 stroke, 250 CZ - and I did not feel like messing with them ever again. 

Got the ultimate Ignition kit: http://www.vintagecb750.com/products/5/electrical

[Duanob]

The consensus is fix your current problems first. As far as which EI to buy everyone has a different opinion on that. And they are just opinions.

Have you replaced the plugs? Have you looked at the plugs? Do they have gas on them? Or are they dry?

Then try new caps, snip the ends of the plug wires back until you get good core wire. Then try it again.

Do you have a multimeter? You will need that to check for other problems.

[Bankerdanny]

EI won't give you spark if your coils and/or wires are bad. It also won't give you spark if there is a hidden break in the power supply to the points.

Replacing the points with EI when you have no spark is like replacing a hand bilge pump for electric in a sinking boat. If you don't fix the leak, the kind of pump doesn't matter.

[thenewbie]

Ok I snipped the ends of the plug wires and i managed to get a spark to all the cylinders. Now im thinking its a problem with the carburetors. When I first brought the bike home and turned the gas petcock on, gas immediately started running out of the overflow tubes. It had been sitting in a unheated storage garage for 3 months and the bike was still pretty cold (does cold weather cause floats to stick?). I let it sit for awhile in my shop and that seemed to fix the problem. I tried to start the bike for awhile after I fixed the plugs and after a minute or two of fiddling with the choke and the throttle I heard a subtle pop. I stopped what I was doing and looked down to see a bunch of gas on the ground from one of the overflow tubes. The guy I bought it from said the carbs had been acid dipped about 2 years ago. Should I pull the carbs off and start cleaning? Or is there somthing else I should do first.

[Bankerdanny]

Newbie, first, add the year and model bike to your signature so everybody knows what you have. It can make a difference in the answers to some questions.

It would sound like the carbs are next. They are a bit of a pain to get on and off, but with practice and proper technique you can do it pretty easily. Heat is your friend here. The carb boots are now 40+ years old. Use a hair drier to warm the rubber so that it is more flexible. When reinstalling I use heat and a light smear of grease on the inside of the boot.

With the carbs off remove the bowls (carefully so as not to tear the rubber o-ring that seals the bowl) and floats and clean everything with carb cleaner. You can test to see if that cleared up the problem without putting the carbs back on. Just attach the fuel hose and hold the carbs in your hand while you turn on the tap. If you don't get a leak then reinstall and take it from there.

[lone*X]

If your carb to air box boots are still intact use extreme caution in removing the carbs as the boots are hard to come by.  After you have them off they can be reconditioned and softened with a mixture of wintergreen and xylene.  It's a good fix for old rubber.

[Bootlegger56]

I would fix the problem with your current ignition system before deciding to install an electronic system. If after fixing your current system and you still want to go electronic I suggest that you have a good look at Hondaman's system. It represents excellent value for money, Mark provides good support and you can easily revert back to the points system if in the unlikely event the electronic system fails. It is important that you fix what you have first because the fault you have may affect the electronic system as well. Pat

I got two of them thar Hondaman Ignitions.......You will love it......but like all the rest of em say.....get the rough edges off of the bike first so you can see what you have.  The carb dis-assembly isn't difficult on most of these old bikes....just takes time and diligence along with some parts.....It seems to me that these bikes dont "sit" well with our current fuel.  It dosnt take long for it to deteriorate and cause corrosion to the components....ie leaking float needles.  There is a wealth of knowledge on rebuilding the carbs and even some members who specialize in rebuilding them regardless of what model of bike you have.

[thenewbie]

Well, today at 1:30 I started to surgically remove the carbs from the bike. Lets just say if i was performing surgery on a live human being, he or she would have been as dead as the Beatles. I cleaned em up and they were pretty nasty. One of the bowls had somthing that looked like what you would imagine the Hulks piss would look like in it. Thankfully I didnt break anything (that im aware of). I got the bike back to the point to where I would be ready to start it at around 11:00 (no im not kidding). I attempted to start it for a couple minutes and it turned over but nothing happened. So I pulled a spark plug out and it was flooded so I just left it and called it a day. Suggestions?

[HondaMan]

Well, today at 1:30 I started to surgically remove the carbs from the bike. Lets just say if i was performing surgery on a live human being, he or she would have been as dead as the Beatles. I cleaned em up and they were pretty nasty. One of the bowls had somthing that looked like what you would imagine the Hulks piss would look like in it. Thankfully I didnt break anything (that im aware of). I got the bike back to the point to where I would be ready to start it at around 11:00 (no im not kidding). I attempted to start it for a couple minutes and it turned over but nothing happened. So I pulled a spark plug out and it was flooded so I just left it and called it a day. Suggestions?

Ummm...if the Hulk piss was green, it was some of the "gas preservative" leftovers from letting it evaporate out of the bowls. If that happened, getting the carbs clean by 11 PM would have been a wondrous feat: it would have taken me the rest of the whole weekend! That stuff turns into a caked powder that blocks the emulsifier tube holes, pilot jets and their emulsidier holes, the bowl bleed air holes, and the fuel valves themselves. It takes a LONG time to clean carbs that have let that preservative dry inside: it's a nasty thing to do to carbs with ethanol.

[darmahman]

Find someone that can ultrasonically clean them. It will save much time and wear on you. Then rebuild.

[70CB750]

Like your optician:)

[BobbyR]

Well, today at 1:30 I started to surgically remove the carbs from the bike. Lets just say if i was performing surgery on a live human being, he or she would have been as dead as the Beatles. I cleaned em up and they were pretty nasty. One of the bowls had somthing that looked like what you would imagine the Hulks piss would look like in it. Thankfully I didnt break anything (that im aware of). I got the bike back to the point to where I would be ready to start it at around 11:00 (no im not kidding). I attempted to start it for a couple minutes and it turned over but nothing happened. So I pulled a spark plug out and it was flooded so I just left it and called it a day. Suggestions?

There is no shortcut when it come to carbs. Hondaman and most of us who have been where you are know this for a fact. I had mine off four times and I finally realized everything I read was correct. Simple Green eats up the varnish very well. It is not a miricle, you will need to clean every passage with a thin strand of copper wire from a light cord, you can use a high E string from a Guitar, but you have to be careful no to enlarge any hole with the harder metal. When you rod out the passages you blow the debris out with spray carb cleaner. Your floats need to be proerly set. I know it sucks, but you will enjoy the results later.

[70CB750]

It is advisible to wear gogles when spraying jets with carb cleaner. I don't know how many times I had that stuff hit my eye

[thenewbie]

So I should clean them again?

[TwoTired]

What was/is the problem definition?

[Bootlegger56]

Don't end up making my mistake.....I cleaned/rebuilt the carbs in May when I got the bike...did a "get it running" service....ie oil/filter, points, plugs, valves ect.... in order to see what I had engine wise before I took the bike apart for a thorough going over and some mods.  When I pulled the carbs during dis-assembly I didn't drain the bowls.  They sat on the assembly parts table from June till October.  When I went to re-install them they were full of Hulk Piss too!  Had to tear them back down and go through them again.  Its amazing how fast our new wonder gas goes bad!!!  Whats the saying...."stupid is as stupid does!"

[thenewbie]

I cant get it to start, wont even attempt to fire like it did before I cleaned the carbs. I did notice that when I would feather the throttle when starting it, it would slow the starter down a little. Does that indicate a problem or is it just the battery starting to die from trying to start it so many times?

[scottly]

What do your spark-plugs look like?

[Grnrngr]

If you didn't actually inspect those emusion tubes to make sure they're clear, then yes, pull them again, and give them a serious work out. It's easier the second time around, but it won't work if those tubes are plugged. I lucked out with my Honda, the carbs were sweet, but my Yamaha was gunked. Took me three trys to get them right, but it runs great now. If the bike was sitting for a while, I'd start at one end, and work your way to the other, taking every electrical connection apart cleaning the contacts, and putting them back together, so you'll know that won't be an issue when you test the electrics. Then inspect all the rubber fuel lines and replace them if they don't look good, that stuffs cheap. That's the kind of intimate stuff that builds the bond between you and her. I wouldn't even try starting it again until after all that. The starter might sound a little different with the throttle open as opposed to closed, shouldn't really drag, but it probably wouldn't hurt to put the battery on the charger while you're doing all the other stuff. And the Beatles are only half dead...I mean..only half the Beatles are dead..

[Bankerdanny]

Multiple on-off's are not unusual while you are sorting a bike that sat for a while. Mine had been sitting for 24 years when I bought it (with 24 year old gas in the tank). I had the carbs off 4 times in all before I got everything to work right.

[HondaMan]

Multiple on-off's are not unusual while you are sorting a bike that sat for a while. Mine had been sitting for 24 years when I bought it (with 24 year old gas in the tank). I had the carbs off 4 times in all before I got everything to work right.

Now, THAT sounds normal!

[thenewbie]

Well I got the bike to run today (bought the pamco ignition to save from headaches). It runs ok. I couldnt get it to idle but it may have been because it wasnt warmed up? Anway the header from cylinder #1 wasnt as hot as the other 3 so after I shut it off I pulled the plug and it was damp. So if I sync the carbs would that clear it up?

[TwoTired]

Anway the header from cylinder #1 wasnt as hot as the other 3 so after I shut it off I pulled the plug and it was damp. So if I sync the carbs would that clear it up?

Unlikely.

Swap plugs and see if the problem follows.  Other wise, it's probably a carb issue.

[thenewbie]

If I do end up needing to replace a plug should I replace all 4 or just the one? Because supposedly the plugs were replaced only about a year ago or so.

[TwoTired]

Anything man made can fail.  And, there is no time guarantee.  A year ago is a long time under some conditions.  The bike ran well 30 years ago, now it doesn't.  Other bikes run well that are older.

A carb providing too rich a mixture can make an otherwise good spark plug fail due to excessive carbon deposits.
We don't have a good description of the spark plug deposits other than "damp".

However, "damp" indicates the cylinder not firing, which can be a bad plug, a fouled plug, or connection issues.
That is why I outlined a minimal diagnostic process.

Stop trying to jump ahead, and do the work and investigation to determine true cause.  Or, just keep throwing money and parts at the problem along with "hope".

Your choice.

[thenewbie]

ouch

[dave500]

how old are the plug caps?if you have a multi meter you can test them.

[70CB750]

TT is right. Now you can drill your problems down by swapping parts around and finding the real issue. You almost there, keep going

[BobbyR]

TT is right. I think you have a carb throwing a rich mixture and fouling a plug. Ignition usually fails in pairs with the waste spark system. If I had a bad connection on #1 then 4 would misfire also. Look at your float levels and yes I would buy new plugs at Autozone they are fairly cheap. 

[LesterPiglet]

Hee hee, whinging about points. Try owning a Kawa triple. 

[bwaller]

Hee hee, whinging about points. Try owning a Kawa triple. 

Or a Trident or Rocket 3. 

[HondaMan]

Hee hee, whinging about points. Try owning a Kawa triple. 

Did you know I make a Hondaman ignition for those, now?

[LesterPiglet]

I did Mark but the triples are long gone. 

[thenewbie]

On a side note I did notice that one of the carb floats was a blue-ish color like it had been burned or something. Anybody know what that means?

[HondaMan]

On a side note I did notice that one of the carb floats was a blue-ish color like it had been burned or something. Anybody know what that means?

Usually that's because someone used the old-fashioned "gas preserver" that used to have formaldehyde in it. Once the stuff dried out, it stained the floats, and often the bowls. Avoid that stuff in the future: it doesn't work with ethanol-laced gas, makes a real mess of these carbs.