Topic: getting younger sibbling to cb550k - a xl250

[cb550fnewb]

Idle screw was out 2 1/2 turns.  i just got the carb rebuilt kit today so now it is back to stock.

This is what was in it:

main jet: can't read
Slow set: 38
Needle: was set to leanest setting


Now it is back to factory:
MJ:  120
LJ:   45
Needle: set back to factory
Idle screw: Set at 1 1/4 turns out (manual suggested)

I tried to start it with no luck today.  I have ordered a new coil, condenser and points that should be here Monday or Tuesday so trying not to kick it too much until I get them installed.  Spark seems to randomly fire so thinking maybe the condenser or coil resistance is off.

Only other issue I could see is that the stator (i think that is the right name for the generator).  There was a large amount of oil in the compartment with it so hoping it did not get ruined.  The other problem could be the ignition switch or kill switch which I believe if I unhook them it should remove them from the system, correct?

[cb550fnewb]

Research led me too the conclusion that the stator should have oil in it so I just need a gasket and seal it up better but I will worry about that after it is running.

[DustyRags]

Please don't take this the wrong way, but I always get alarmed when I see people throwing money at problems. If you're getting intermittent spark, then you'll want to do some testing to see exactly what's causing problems. First, it saves you money, and second, it's easy enough to make mistakes (and I mean tiny mistakes, like grounding or not grounding something), and now you've got an issue that you didn't have before you replaced a module you didn't know for a fact was bad.

You got the carb back to stock- awesome. That should give you proper fuel and air. You need fuel, air, compression and spark. Sounds like you definitely have a spark issue, so check into that. Have you checked compression on it? I'd do that, just for gits and shiggles, so you can safely rule that out. It doesn't sound like it's an issue, but if you happen to have a tester lying around, I would.

Then start testing your electrical components.

[becken]

The ignition system is basically a point magneto and is sensitive to the condition of the points. The contact surfaces need to be clean and bright to make a good contact. Also make sure the spark advance is working properly, an item very much overlooked on these bikes.

[cb550fnewb]

You got the carb back to stock- awesome. That should give you proper fuel and air. You need fuel, air, compression and spark. Sounds like you definitely have a spark issue, so check into that. Have you checked compression on it? I'd do that, just for gits and shiggles, so you can safely rule that out. It doesn't sound like it's an issue, but if you happen to have a tester lying around, I would.

Then start testing your electrical components.

Compression is 110 psi cold and probably a little wet with gas.  It did run for about 5 minutes before it fouled the plug so figured that compression is good enough to run.

The coil wire looks pretty rough.

The ignition system is basically a point magneto and is sensitive to the condition of the points. The contact surfaces need to be clean and bright to make a good contact. Also make sure the spark advance is working properly, an item very much overlooked on these bikes.

Is it correct that I can unplug ignition and kill switch to remove them from the system.  I read this on another forum.  How can I check the spark advance?

[cb550fnewb]

Got new coil and put in a new plug fired right up!!  Took it for a ride a few miles and other than me getting use to not bogging down the little engine seems fine.

Only issues are the speedometer is not functions at all including the odometer and need to get light functioning.  Also still need to get a gasket and some sealer for the stator case.

Here some photos: Oh and not sure I stated before turned out to be a '74 not '76

[DustyRags]

Oh, sweet! That's what my friend calls an "engineer's solution" (as opposed to a "scientist's solution"). In other words, you may not have pinpointed the exact problem, but you fixed it so who cares! 

Nicely done.

[DustyRags]

Oh, and info on the coil? I've got an XL350 waiting in the wings with a bad coil. Any info on that would be grand!

[cb550fnewb]

Oh, and info on the coil? I've got an XL350 waiting in the wings with a bad coil. Any info on that would be grand!

Just got it off ebay, seems to be plenty available in the $20 to $40 range.  Kind of sucks that the condenser is attached to the coil. I had to drill it off the old coil and have it zip tied for the time being.  I will probably put the new condenser on when it comes since I should be able to get a bolt to attach it to the coil.  Might be worth just ordering one that already has the condenser hooked to it.

My old coil wire and cap was pretty sad looking and shocked me a few times so even if the coil was not the solution I would have changed it anyways. 

Now I just have to get use to one cylinder.

[DustyRags]

Cool, thanks. I assume it's used Honda stock?

[cb550fnewb]

Cool, thanks. I assume it's used Honda stock?

Went with this

http://www.ebay.com/itm/Emgo-Universal-Motorcycle-ATV-Ignition-Coil-for-6V-and-12V-Points-or-CDI-/291297572486?pt=Motorcycles_Parts_Accessories&hash=item43d2b03686&vxp=mtr

Not sure how it can be both 6v and 12v but seems to be working fine with a bright spark.

After deconstructing my speedo today and teaching myself how it works, I got it functioning. I am sure the speed will be completely off but works good enough to pass inspection and I got the odometer/trip working again.

Now I just have to figure why all the lights running off the battery aren't working.  It is looking like a mess since all the ground wires coming out of the turn signals have been cut. So I think I will start by grounding them all and see where that gets me. All the other wires were replaced at some point.


 

[DustyRags]

Ace! Thanks, compadre, that's just the ticket!

[Tugboat]

Well done! No go ride.

[cb550fnewb]

So took it for a 30 mile ride a little cold driving on the pavement (40 degrees here) but once I got to dirt road was pretty pleasant.  I have encountered a new issue:

If I turn the head light on the bike starts getting random spark and backfires nonstop? It is when ever I encounter any type of incline and results in little power. 

The battery is completely dead and will not hold any charge.  The new battery will be here next week so hoping it will fix my tail/brake/turn signals.  Not sure if it will help with the headlight since I think the battery and headlamp/ignition are separate systems.

Anyone running without out a battery but kept their headlight or have any ideas of cause?