Author Topic: CB 400 starts....well almost (Read 4968 times)

Jonny Man · « **on:** July 28, 2013, 06:17:30 PM »

I have a 1977 Honda CB 400 which I've been customizing. It's been indoors for about two years. I just added a set of Accel coils. Dropped a new Balistic 2 evo, 8 cell lithium battery in it. Took the carbs off and have cleaned them twice now. The bike almost turns over with the electric starter. It stays strong for almost 30-40 minutes before the battery gets too low to continue. I give the starter a break before attempting again. If I spray starter fluid (Ether) into the carbs...I get momentary fire-up. My 4/1 Kerker gets warm....actually 3/4 of the headers (cylinder 3...not so much). Bike seems so close to starting but just won't lock in and kick over. I'm getting some back firing and sputtering. I tested the coils they were within the proper ohm's ratings. Pulled all 4 plugs...have strong spark. Seems as though I have fuel. So...SPARK, FUEL. The bike had strong compression when it last ran. So that seems out as a reason the bike isn't turning over. Could it be an ignition timing problem? I have new points, properly adjusted for the old, stock coils. I'm waiting on a new Dyna ignition which I'll drop in this coming week. Been fighting with her for a week now...to no avail. I'm puzzled? I'm not a mechanic but very handy and usually a quick study. She seems sooooo close, so ready yet won't turn over. Also the bike is indoors at the moment..so attempting to bump start it isn't an option at the moment. I've thought about air leaks...through the carb mount boots and or the 4/1 mounts but that doesn't seem like the problem either. Any insights or advice would help set me in the right direction....

phil71 · « **Reply #1 on:** July 28, 2013, 06:19:51 PM »

doesn't that bike have a kick start on it?

MoMo · « **Reply #2 on:** July 28, 2013, 06:42:58 PM »

good compression, spark at the right time and fuel/air in the correct ratio and it has to start. Don't assume, measure compression. Are the points opening at the F mark? Have the jets been changed? Air box still on? Make sure the spark advance is not seized...Larry

BobbyR · « **Reply #3 on:** July 28, 2013, 06:47:06 PM »

I think you mean it won't start. It turns over, but it doesn't run. The fact you can spray ether and it will fire points to a fuel problem. With carbs the jets need to be rodded out with some strand of copper wire. Carb cleaners as they are today, just do not work.

Jonny Man · « **Reply #4 on:** July 28, 2013, 07:20:19 PM »

Wow!!! Thanks you all for the speedy responses!!! Yes...correct it doesn't turn over....close but no cigar. I hear you about the jets. They seem (visually) clean to me. However, I'm waiting on a carb cleaning tool. Lost my old one. I'll have it this week. Jets were never changed. Cleaned and maintained a few years ago. Air box was removed back then and pod filters were added. Synched the carbs then... seemed to be running fine. Points are opening at the "f mark". Advancer is not seized as far as I can tell (Larry). Bobby R...if only one jet were clogged...wouldn't I still get more then I'm getting? Like I said.....bike seems so close to turning over.

Unfortunately, I've been battling the "Big C" for the last 6 months....lost 1/3 of my body weight and more specifically....MUSCLE. Kicking the bike over with the kick starter (Phil71) or bump starting not an option at the moment. Not looking for sympathy...is what it is. Just some advice. Thanks

MoMo · « **Reply #5 on:** July 28, 2013, 07:32:34 PM »

Where are you located in Philly? I may be able to help out...Larry

Jonny Man · « **Reply #6 on:** July 28, 2013, 08:08:05 PM »

MoMo,

My studio is in the Northern Liberties. I'm an artist (a painter)...teach college. I live in Fishtown, USA. Same neighborhood as "Philly Throttle". The bike has been great therapy for the illness...but need to get her running.
There are some electrical issues as well. Had a buddy...a mechanic who did some work on the bike when it got dry docked. He removed the 70's handle bar switches...put 90's Honda switches on the bike. Told me "it would be better". In doing so, he disconnected about 20% of the wiring. I've been figuring out....slowly...what it was that he rewired....but am concerned about shorts, etc, etc. I no longer have access to my bud to help me figure out what it was that he did exactly. Pisses me off...because he owes me. Thus....the "slowly" part. The original ignition switch was gutted. I have it wired to a "on-off" toggle switch at the moment. One way or the other...(whether I keep it or not)...I'd like to drill the switch into the back of my headlight bucket....or put a shallower ignition switch into the bucket. Like that look. Can use any help I can get.

MoMo · « **Reply #7 on:** July 29, 2013, 03:12:05 AM »

I also added latter model switches to the 400 I am working on but did not have to touch the harness. I cut the plug ends off the switches, used the Vintage Connection tool, a large schematic and a days work. I did that because I did not have any switches from the era and did not want to spend a couple hundred dollars for new ones when I had something that I knew I could make work. The bike for want of a better term will be a cafe style similar to this

I built that a couple years ago.

Do you teach at Tyler?

Wish I could help somehow. I pretty much have a full shop here, which is Gap, 17527...Larry

Jonny Man · « **Reply #8 on:** July 29, 2013, 06:48:50 AM »

Hey Larry,

That's a beaut!!! Love the Norton style lettering on the tank!!!Nice paint too!!!

Yep, taught at Tyler for 10 years. Couldn't have been closer to my place in Fishtown either. I was at Temple main campus is less then 10 minutes from my house. I took a better offer from Penn State Brandywine (out near Lima/Media, PA. Been building their "studio art components" for about 3 1/2 years now. I like getting out of the city a few days a week. Real nice campus!!!

Bobby R seems to think I have a fuel issue. I've had the carbs apart 2-3 times now. Didn't seem like the jets were clogged but I am waiting on a carb cleaning tool. So...I guess I'll clean out the slow and main jets again. Still seems to me....If one jet were partially clogged. I'd get more...? More engine turnover.....then poor idling because of a rich or lean mixture...? Right now, I have a slightly, thin, dark residue on the plugs. Implying a slightly rich mixture. The plugs are relatively new with almost no mileage put on them. No pits or damage to the plugs.

I'm starting to wonder if I don't have the spark plug wires routed correctly. The stock coils were wired (right coil) to cylinders 4 and 1 (right side and left side cylinder). The left side coil (stock) was wired to the 3rd and 2nd cylinders (the middle two). The new Accel coils I installed said to be mindful of the original cylinder order. I was certain I'd done that.....hmmm. I pulled all four plugs individually. Had strong...blue-ish sparking from all four.

Late yesterday, I did notice something that I hadn't caught before. I didn't think my buddy had wired the run/kill switch. Hitting the starter button....the engine would turn over but not catch. I thought everything sounded the same whether the run/kill switch was in either position or not. Then I

Jonny Man · « **Reply #9 on:** July 29, 2013, 07:27:29 AM »

Then I noticed that the coughing and sputtering only occurred when the run/kill switch was in the "run" position.
Will go at it again when I get to the shop/studio today...with a freshly charged battery.

I've had pod filters on the bike for a few years now. Never had to change the jets. Now I'm starting to wonder if I'm getting too much air...?

Love working on the bike...bikes. However, some times one variable changes...and it becomes a can of worms.

Really trying to avoid pulling the carbs again (for now). Getting them into the manifold boots and re-seated evenly is a bit of a #$%*!!!

MoMo · « **Reply #10 on:** July 29, 2013, 06:16:06 PM »

A heat gun will aid the removal and installation of the carbs, and since you have pods removal is way easier without the air box. Did you clean the midrange emulsifier tubes?
I used to live in Media while I taught photography at DCCC so I know exacty where you are working. I assume you stay in the area when you teach rather than commute?....Larry

BobbyR · « **Reply #11 on:** July 29, 2013, 06:37:09 PM »

Before tearing the carbs off I would like you to try something. Since you have pods, take them off and squirt a eyedropper full of gas into each carb throat. Don;t go nuts. If it fires you know you have a fuel delivery problem. It could be in the float bowl with a level so low, the vacuum cannot suck it in.

I say this because you need to eliminate things point by point without taking things off and wasting time and the risk of damaging something by accident.

If priming with gas works, you can concentrate from the petcock to the jets, one system to concentrate on.

Jumping from one thing to another all at once will just piss you off.

Jonny Man · « **Reply #12 on:** July 29, 2013, 07:58:02 PM »

Hey Larry and Bobby R,

Bike was soooooooo close today. I noticed when the cycle was coughing, sputtering and backfiring that the number two cylinder....while having spark....was cold at the pipe. Pulled the plug...and it was relatively bone dry next to the other 3 plugs, which were mildly damp...not saturated. I also noticed that I was leaking gas from that carb (number two) before my last clean. I solved that problem but Bobby got me to thinking that I hadn't done a thorough enough job of cleaning the jets. As mentioned, I'm waiting on some parts...among them is a carb cleaning tool. Curiosity got to me today. Decided to just use a few different gauge wires to clean out the jet holes. Overall, they weren't too bad but the main and slow jets in that second carb were seized in their respective ports. The other three sets of jets turned fairly easily and popped out without much work. Not carb two!! Also some of the micro jet holes were clogged....not massively but clogged nonetheless. Soaked the entire unit, after taking all the jets out, slides, needles, etc, etc. Will put her back together tomorrow. Hoping this solves the problem. Missed the delivery for my parts today. Should have them tomorrow. Dyna ignition install next after I get the carbs back together and try to turn her over again.

Jonny Man · « **Reply #13 on:** July 29, 2013, 08:10:16 PM »

Thanks for the tips guys. Just bought a new heat gun. Makes sense to soften those manifold boots beforehand.
Just getting the carbs evenly seated takes some finesse and muscle. That should help. Bobby...I'll try the eye dropper idea if I don't have any success with the carbs after this latest, more thorough cleaning. Larry...you probably had that photo lab across the hall from what is now the artroom/studio. I've seen the original blueprints and there used to be those tube-style, revolving doors...in what are now the tech offices. I realized that they were there for a photo-lab. Building probably hasn't changed much since you were there. Although the campus is now Penn State Brandywine...no longer DCCC. I'm usually there four days a week. I drive in from Philly. Generally about a 25 minute commute if traffic isn't bad.

Jonny Man · « **Reply #14 on:** July 29, 2013, 08:24:45 PM »

Aside from the frustration of....the bike not turning over. Made some additional headway with the electrical.
Got the headlight working, the beam indicator, high and low beams. Still need to get the turn signals (front and rear), horn, rear stop light, brake lights....working. Labeled some things and have a much better idea what the different wire colors are supposed to operate. I'm sure other problems will raise their heads!!!! Need to open up that 90's era..turn signal, horn and headlight (hi and low) switch. Figure out what the different color code is for those functions. It's definitely different from the stock, 70's switches. Have everything but the "turn signals" indicator light now working. Oil, Neutral and Beam. 3/4 ain't bad being how I just started tinkering with that can o' worms!!!

Jonny Man · « **Reply #15 on:** July 31, 2013, 05:37:14 AM »

Carbs have been thoroughly rebuilt, put back together. I'll bolt them back on this afternoon. Dyna ignition arrived yesterday. Hopefully, the bike will fire now. One problem at a time however.

Bankerdanny · « **Reply #16 on:** July 31, 2013, 07:47:00 AM »

I wish I had seen this sooner. A carb cleaning tool really isn't necessary. I went over to the local guitar shop and picked up a couple scrap pieces of guitar string, the E and B strings. They worked like a charm clearing the main jets on my 550 carbs.

Jonny Man · « **Reply #17 on:** July 31, 2013, 11:50:26 AM »

Thanks for the tip. Funny I play guitar and have a ton of strings kickin' round. I used various pieces of braided wire...unbraided. Worked well. My parts arrived and with it the carb cleaning tool. Works great. Some of the wires are ribbed so it gives you a little better cleaning power. Handy little device and very inexpensive.

Jonny Man · « **Reply #18 on:** July 31, 2013, 12:10:28 PM »

Well...bolted my freshly cleaned carbs back on and while I'm getting even more coughing,sputtering and much louder backfiring....#$%*er still won't turnover and catch!!! I keep thinking...."man she's so close"!!! Broke down and put brand spanking new plugs in properly gapped (for me new Accel coils). Didn't think that would matter all that much as the plugs that were in were not that old or worn. Three of the four plugs were very mildly damp. The number two plug...not so much still. Tried that gas/dropper technique and more starter fluid directly into the carb openings. Still the same coughing and sputtering. I know my compression is decent.

So.... I have "Compression, Spark, Fuel"....brings me to.."Timing". Here's the thing though....the timing was good before I put in the new Accel coils....this may seem like a really stupid question to you mechanics or veteran tinkers....but... Would the new coils radically or even mildly effect the timing or force me to readjust the timing? I have a brand new Dyna electronic ignition...just sitting here waiting to be bolted in..I'd like to bolt it in....but then I'd be adding more variables into the mix. Thoughts......

camelman · « **Reply #19 on:** July 31, 2013, 12:18:53 PM »

Sounds like your battery is too weak to power the coils.

Bankerdanny · « **Reply #20 on:** July 31, 2013, 12:27:11 PM »

If you still have the original coils I would put them back on and see if it starts.

Jonny Man · « **Reply #21 on:** July 31, 2013, 12:58:47 PM »

Just bought a brand new Evo lithium battery for the bike. Definitely enough juice there. Even after beating on the electric starter for 20-30 minutes (with breaks in between). Takes about that long before I have to put the battery back on the trickle charger.

Yeah...thought about bolting the original coils back on...but I'll be super pissed if it starts after all this work.
Would answer the question...."are one or both coils not working?". I'm getting pretty strong spark (blue-ish) when I pull a plug and let it arc. That's on all four cylinders too.

Any insights about a change in ignition timing with new, hotter coils? The instructions form Accel mention nothing about it.

MoMo · « **Reply #22 on:** July 31, 2013, 03:21:41 PM »

Timing only affected by position of the backing plate as well as point gap. Asked before did you remove the midrange emulsifier ?...Larry

camelman · « **Reply #23 on:** July 31, 2013, 05:25:58 PM »

Is your timing set to ''F'' or ''T''?

Jasondo · « **Reply #24 on:** July 31, 2013, 06:22:08 PM »

What plugs are you using? I also have Accel coils and you need to be running resistor caps or plugs in the 400F. I had a very similar starting issue I solved with changing from D8EAs (the factory recommended ones) to the DR8ES-Ls and saw a dramatic difference in how it started. I measured the total resistance from plug wire to tip of plug and was getting around 15k ohms. Also try to gap between .035"-.040". Otherwise to get a good starting point set your points gap to .014" with the little advance ears in the window and then time with a gun to the "F" at idle and dead in the middle of the two advance marks when at 2500 rpm. That would be a good start.

In my short career as vintage CB owner I have learned that the most trouble you will encounter to keep these things running strong lies behind the points cover. But once fully understood and maintained it becomes second nature. Also I would rethink the DYNA ignition, It may cause other issues you are not anticipating. I puts a lot of stress on your electrical system that the little 400 may not handle to well.

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Author Topic: CB 400 starts....well almost (Read 4968 times)