Topic: 1973 CB 500 Four - Starting issue

[Redline it]

I had the same starting issue recently with my 550. Tough to cold start, but then it ran fine. Easy to start once it was warmed up. I was going through the tune up procedure and isolated the issue to the points. Even with the points closed I was getting no continuity, but with them open, if I stuck a screwdriver between them and shorted them together I would get continuity.

Long story short, I installed a Charlies Place electronic ignition and it starts cold first kick now.

Hmm, it does sound really similar... How did you isolate the issue to the points? Just by doublechecking every other possibility?

It's one of two, either it was isolated after doublechecking every other possibilty, or before. Continuity helps the  points to work. I know that the 400f I'm having trouble with recently gave me strange trouble in adjusting the timing. It's never happened before, took long time to get it right. Sparks do look on the weak side. Now that it's getting warmer the bike is firing up and running better, if that's the case I'll wrap a plant warming heat cable around the motor and coils, for starts in the winter cold.

[Frijec]

I don't really see any seemingly relevant troubleshooting you have listed here at all.  What you've done isn't really where you should be starting.

To start you need:
1) Compression
2) Fuel and Air
3) Spark

That's it.

A.  So to actually troubleshoot, you should start with: compression check (probably not this since the issue from what you've presented is a cold starting issue).  If you don't have a compression tester, you can check the others.

B.  Squirt something into the cylinder and see if it has any change on starting.  Could be a squirt of starter fluid.  Directly in the cylinder via spark plug hole (good time to check what your plugs look like anyways), through the airbox side intake (after removing your airbox) or through your vacuum sync ports.  Most likely this will have an immediate effect.

C.  Verify spark by pushing the starter button while the plug is grounded to the head.

I'm not sure what you did or who did your carb work, but if everyone who did carb work just assumed that everything was perfect and never even entertained they could have a carb problem, then there would be a lot of people with non running bikes.  Looks like bowl screws have been stripped and replaced so it's not out of the question to assume they have been manhandled at some point.  Start there and report back-we will help you from there.

1) I've tested the compression today and it doesn't look good at all. 1: 75, 2: 60, 3: 65, 4: 53 are the PSI readings. They're supposed to be 155-170 psi to be up to standard. One of the neighbors said he has success improving this by squirting valve cleaner directly in to the air intake on the carb. So I might try that. Otherwise I will need to exchange piston rings and gaskets?

2) This is what my sparks look like, on the very lean side I would guess. So I am trying to up my jets to 105 and 110, and see how it looks. Otherwise the Slow jet also need 1 step up? What do you think I should do?



3) Is still an okay looking "yellow'ish" colors.

4) I also doublechecked the ignition points and timing. Should be correct now.

[harisuluv]

You might have done the compression check improperly.  It should be done on a warm engine and with the throttle held wide open.  If those were true compression numbers you would have more than just starting trouble.

[Frijec]

You might have done the compression check improperly.  It should be done on a warm engine and with the throttle held wide open.  If those were true compression numbers you would have more than just starting trouble.

Yes, it would seem I did it wrong. I missed the open-throttle part 

[Redline it]

You might have done the compression check improperly.  It should be done on a warm engine and with the throttle held wide open.  If those were true compression numbers you would have more than just starting trouble.

I have very comparable low compression results on this weird 400f of mine as well, as a matter of fact, i know the numbers are way off, well far enough that the bike wouldn't run very well, or smoke coming out the pipe and fouled plugs. It's one of the reasons I don't like doing the compression check, and to make things even more weird, my plugs look pretty darn good, like Frijec's, except without the carbon or oily look on the ring and the threads. 

[Deltarider]

Personally I've never managed to perform a reliable compression test on my CB500. Back then a mechanic tought me the 'thumb method'.

[Frijec]

So if we look away from the compression test.

Does the plugs tell you anything to the starter problem?


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[Kbecker]

I was checking the point gap and static timing with a ohm meter.  Even with the points closed I had infinite resistance on one set of the points, but not on the other. So I wondered if the surface of the points was contaminated and not allowing conduction. I filed them and still had an intermittent conduction between the points. So with the points open I put a small screwdriver between them and got conduction. During this whole test period I was able to compare the results against the other set of points, which were operating normally. So I knew there was an issue with one set of points. And trying to start the bike was an exercise in frustration!

I had good luck with the charlies place electronic ignition on my CL175, so I installed it on the 550. I set the timing statically after installation, then set it dynamically after I got the bike started. It now starts first kick and runs well.

There must have been something going on with the points-- a small internal fracture or something. When they got warm the problem resolved, explaining the fact that after the bike warmed up it was easy to restart. My guess is they were original points, so after 10,000 miles they must have clapped together about a billion times.

[Kbecker]

Here is a cold start video after electronic ignition installation. Note the tachometer has a little lag before it starts reading.

[attachment deleted by admin]

[Redline it]

here's a pretty good example of reading plugs http://honda-tech.com/forced-induction-16/***-basics-reading-spark-plug***-3063102/ which can be fairly easy or complex depending on what range of rpm is tested. I can't figure it out, my bike runs like it's lean and the plugs say rich. It seems like the more information I can access the more confusing it gets, and the more test I do, cutting into plain riding. So it's "let her develop," unless you have flames coming out of somewhere.

Note: I just noticed the link here leads to another forum, and the second sticky note is it. This forum might have the same info, somewhere.
 

[seanbarney41]

Maybe i am missing the logic here...successfully trouble shooted a faulty set of points, but then instead of replacing an expendable wear item, you need to replace the whole ignition system with electronic....

[Frijec]

You might have done the compression check improperly.  It should be done on a warm engine and with the throttle held wide open.  If those were true compression numbers you would have more than just starting trouble.

I got to redo the compression test today properly and it was really good. 1:165, 2:160, 3:170, 4:165. So I guess it isn't a compression issue.

Also I tried to pust a pair of 110 main jets in, and it actually ran better when I took a ride. It was stil bad in the lower rpms and when it have it full throttle. So to improve this, I guess have still have to increase a little in main jet, and maybe 1 in slow jet? Or how would I go about it? I am still unsure what the air screw and jet needle does to the behavior?

But all in all, this didn't help the cold start issue. It still starts instantly once it is warm, but cold it takes ages. Could it be an ignition problem as mentioned by Kbecker?

[Kbecker]

The electronic ignition is far superior to the point system, and although a more expensive repair in the short run, a long term investment in the bike as far as costs, time spent fixing it, down time, etc. is concerned. I have 4 vintage Hondas, all with electronic ignitions now.

[Redline it]

You might have done the compression check improperly.  It should be done on a warm engine and with the throttle held wide open.  If those were true compression numbers you would have more than just starting trouble.

I got to redo the compression test today properly and it was really good. 1:165, 2:160, 3:170, 4:165. So I guess it isn't a compression issue.

Also I tried to pust a pair of 110 main jets in, and it actually ran better when I took a ride. It was stil bad in the lower rpms and when it have it full throttle. So to improve this, I guess have still have to increase a little in main jet, and maybe 1 in slow jet? Or how would I go about it? I am still unsure what the air screw and jet needle does to the behavior?

just for sake of testing, and i hope i didn't miss it if you already have, install new plugs. I could be out there, again, but learning every minute, but possibly what slight ignition problems do to spark plugs is doing to yours. And at that point, hard starts are nearly in every category of diagnostic situation. I didn't know that, or at least I forgot. New plugs, checking the wire from the coil to spark plug is what I'll be doing on the to do list.   

But all in all, this didn't help the cold start issue. It still starts instantly once it is warm, but cold it takes ages. Could it be an ignition problem as mentioned by Kbecker?

[Frijec]

You might have done the compression check improperly.  It should be done on a warm engine and with the throttle held wide open.  If those were true compression numbers you would have more than just starting trouble.

I got to redo the compression test today properly and it was really good. 1:165, 2:160, 3:170, 4:165. So I guess it isn't a compression issue.

Also I tried to pust a pair of 110 main jets in, and it actually ran better when I took a ride. It was stil bad in the lower rpms and when it have it full throttle. So to improve this, I guess have still have to increase a little in main jet, and maybe 1 in slow jet? Or how would I go about it? I am still unsure what the air screw and jet needle does to the behavior?

just for sake of testing, and i hope i didn't miss it if you already have, install new plugs. I could be out there, again, but learning every minute, but possibly what slight ignition problems do to spark plugs is doing to yours. And at that point, hard starts are nearly in every category of diagnostic situation. I didn't know that, or at least I forgot. New plugs, checking the wire from the coil to spark plug is what I'll be doing on the to do list.   

But all in all, this didn't help the cold start issue. It still starts instantly once it is warm, but cold it takes ages. Could it be an ignition problem as mentioned by Kbecker?

Did I miss an answer or something? 

[jonda500]

You might have done the compression check improperly.  It should be done on a warm engine and with the throttle held wide open.  If those were true compression numbers you would have more than just starting trouble.

I got to redo the compression test today properly and it was really good. 1:165, 2:160, 3:170, 4:165. So I guess it isn't a compression issue.

Also I tried to pust a pair of 110 main jets in, and it actually ran better when I took a ride. It was stil bad in the lower rpms and when it have it full throttle. So to improve this, I guess have still have to increase a little in main jet, and maybe 1 in slow jet? Or how would I go about it? I am still unsure what the air screw and jet needle does to the behavior?

just for sake of testing, and i hope i didn't miss it if you already have, install new plugs. I could be out there, again, but learning every minute, but possibly what slight ignition problems do to spark plugs is doing to yours. And at that point, hard starts are nearly in every category of diagnostic situation. I didn't know that, or at least I forgot. New plugs, checking the wire from the coil to spark plug is what I'll be doing on the to do list.   

But all in all, this didn't help the cold start issue. It still starts instantly once it is warm, but cold it takes ages. Could it be an ignition problem as mentioned by Kbecker?

Did I miss an answer or something? 

yes - it's included in the quote ^

I just performed a 3000mile tuneup on my 550F as I have covered over 5000 k's since building it. Just to see if it would, when I started it after (new spark plugs!) I didn't do my priming routine, I just turned on the fuel, choke and ignition and it started first kick!!!
(The timing was almost right - strangely I just had to retard 1.4 slightly - the 1.4 points gap was still quite big so I just closed it a whisker. The valve clearances were all loose - some quite loose, others only very slightly)
John

[Frijec]

You might have done the compression check improperly.  It should be done on a warm engine and with the throttle held wide open.  If those were true compression numbers you would have more than just starting trouble.

I got to redo the compression test today properly and it was really good. 1:165, 2:160, 3:170, 4:165. So I guess it isn't a compression issue.

Also I tried to pust a pair of 110 main jets in, and it actually ran better when I took a ride. It was stil bad in the lower rpms and when it have it full throttle. So to improve this, I guess have still have to increase a little in main jet, and maybe 1 in slow jet? Or how would I go about it? I am still unsure what the air screw and jet needle does to the behavior?

just for sake of testing, and i hope i didn't miss it if you already have, install new plugs. I could be out there, again, but learning every minute, but possibly what slight ignition problems do to spark plugs is doing to yours. And at that point, hard starts are nearly in every category of diagnostic situation. I didn't know that, or at least I forgot. New plugs, checking the wire from the coil to spark plug is what I'll be doing on the to do list.   

But all in all, this didn't help the cold start issue. It still starts instantly once it is warm, but cold it takes ages. Could it be an ignition problem as mentioned by Kbecker?

The plugs are actually brand new, and I had already burned one of them, so replaced another one after. I haven't checked the wiring, but I am considering to change the coils, wiring, and plugcaps. Also thinking to change to a electronic ignition system at the same time...

[Frijec]

You would do well to test the stock plug wires, caps and coils before replacing them. You may well find the source of your problem is a quite simple fix covered by routine maintenance. Replacing components hoping for a resolution is a fools errand (not to mention expensive).

So to test these, I would refer to the maintenance parts in the manual? Or do you know of any guides to do this?

Thanks a lot for the help!

[harisuluv]

I don't really see any seemingly relevant troubleshooting you have listed here at all.  What you've done isn't really where you should be starting.

To start you need:
1) Compression
2) Fuel and Air
3) Spark

That's it.

A.  So to actually troubleshoot, you should start with: compression check (probably not this since the issue from what you've presented is a cold starting issue).  If you don't have a compression tester, you can check the others.

B.  Squirt something into the cylinder and see if it has any change on starting.  Could be a squirt of starter fluid.  Directly in the cylinder via spark plug hole (good time to check what your plugs look like anyways), through the airbox side intake (after removing your airbox) or through your vacuum sync ports.  Most likely this will have an immediate effect.

C.  Verify spark by pushing the starter button while the plug is grounded to the head.

I'm not sure what you did or who did your carb work, but if everyone who did carb work just assumed that everything was perfect and never even entertained they could have a carb problem, then there would be a lot of people with non running bikes.  Looks like bowl screws have been stripped and replaced so it's not out of the question to assume they have been manhandled at some point.  Start there and report back-we will help you from there.

We're on the third page now and I had everything laid out for you in the 3rd reply to your thread.  Looks like you have had the plugs off, did you not squirt something into the cylinder and see if it tried to start cold?  You have a problem with:  COLD STARTING.  It logically follows this is fuel related or CHOKE. 

[Frijec]

I don't really see any seemingly relevant troubleshooting you have listed here at all.  What you've done isn't really where you should be starting.

To start you need:
1) Compression
2) Fuel and Air
3) Spark

That's it.

A.  So to actually troubleshoot, you should start with: compression check (probably not this since the issue from what you've presented is a cold starting issue).  If you don't have a compression tester, you can check the others.

B.  Squirt something into the cylinder and see if it has any change on starting.  Could be a squirt of starter fluid.  Directly in the cylinder via spark plug hole (good time to check what your plugs look like anyways), through the airbox side intake (after removing your airbox) or through your vacuum sync ports.  Most likely this will have an immediate effect.

C.  Verify spark by pushing the starter button while the plug is grounded to the head.

I'm not sure what you did or who did your carb work, but if everyone who did carb work just assumed that everything was perfect and never even entertained they could have a carb problem, then there would be a lot of people with non running bikes.  Looks like bowl screws have been stripped and replaced so it's not out of the question to assume they have been manhandled at some point.  Start there and report back-we will help you from there.

We're on the third page now and I had everything laid out for you in the 3rd reply to your thread.  Looks like you have had the plugs off, did you not squirt something into the cylinder and see if it tried to start cold?  You have a problem with:  COLD STARTING.  It logically follows this is fuel related or CHOKE.

I did do the squirt directly in to the cylinder, and it helped it to start on 2nd or 3rd kick. I am looking into these scenarios on tuesday.

[harisuluv]

Good job, looks like you have a fuel problem.

[Frijec]

I had the same starting issue recently with my 550. Tough to cold start, but then it ran fine. Easy to start once it was warmed up. I was going through the tune up procedure and isolated the issue to the points. Even with the points closed I was getting no continuity, but with them open, if I stuck a screwdriver between them and shorted them together I would get continuity.

Long story short, I installed a Charlies Place electronic ignition and it starts cold first kick now.

And the winner goes to Kbecker. I did yet another full clean up of my carbs without success. So needless to say, it caused loads of frustrations, until I decided to order a electronic ignition system from PAMCO. Initially it didn't work, but I think my wiring was the cause. Until one moment of fiddling around and it fired up on first kick, and has for days since.

I need to adjust the timing of it (and figure out how to use a search light on a electronic ignition). But once that is done, I am pretty confident it'll run like a beast!

Thank you so much everyone for the feedback!