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It's a pass fail kind of thing, one of the symptoms of a failed one is that the bike won't go over 4000 rpm because it fails to advance. There's a guy selling them on ebay who has a full symptom list
 

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Discussion Starter #23
There's a guy selling them on ebay who has a full symptom list
Do you happen to have a link to this guy? I don’t know if searching from Canada is making it different but all I’m coming across are random pieces for different parts of the ignition system. But I’ll keep looking to see what I find.
 

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So I wasn't able to get my hands on a timing light to test that out. I'm heading off island tomorrow for a few days so I'll be able to pick one up and get that checked out.

I did however take apart the carbs to check them out, somewhat anyway. I just wanted to see if there was anything that jumped out at me with the jets. I didn't notice anything wonky with them. Put everything back and the bike is still running like it was, gets up to 4000 RPM and won't go any higher.

Hopefully I'll have a better update next week when I'm able to work on the bike again.

Thank you everyone for helping me out with this. Really appreciate all the advice.
 

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Here's the relevant thread for the ignition https://www.hondatwins.net/forums/64-electrical-discussion/50457-ignition-diagnosis-cb-cm-400-450-cb450sc-manual-trans-1978-1986-a.html
There are 2 choices for a CDI replacement. 1) CDI Magician on eBay and 2) Rex's Speed Shop in the UK
Biggest difference in them is Rex's is a plug-n-play while the other is a cut and solder your old connectors to it.
UK vs. US customs may come into play also since this is a Canadian destination

Timing can only be "adjusted" by swapping in different stators and CDI boxes,you're playing with resistance values.
If one wants to actually have adjustable and accurate timing, Honda's version isn't either one, then you would go with the Ignitech DCCDI-P2 unit
 

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Discussion Starter #27
Timing can only be "adjusted" by swapping in different stators and CDI boxes
So I get my hands on a timing light, test it to see if it’s out, if it is I pick one of these two options for purchasing one to replace the bad one on the bike?

Then later down the road if I feel like being able to adjust the timing I switch to a different system.
 

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I played with 3 CDI's and 3 stators and the advance was late on all combinations.
In checking the timing you're going to be looking for it to advance with the throttle. If it doesn't advance then it likely is the stator, not the CDI. Use your VOM and run thru the ignition tests in the thread I linked earlier.
 

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Discussion Starter #29
I played with 3 CDI's and 3 stators and the advance was late on all combinations.
In checking the timing you're going to be looking for it to advance with the throttle. If it doesn't advance then it likely is the stator, not the CDI. Use your VOM and run thru the ignition tests in the thread I linked earlier.
Sounds good. I'll post an update next week when I'm home again and able to work on the bike. Thank you!
 

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My 350 does exactly this, if I forget to knock the choke off once warm. The choke only has to be on by a few degrees too.....
 

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My 350 does exactly this, if I forget to knock the choke off once warm. The choke only has to be on by a few degrees too.....
I thought that might be the case too since my choke cable is stuck. But when I took the carbs off I just never bothered to reattach the choke. I’ll take another look to make sure it is seated properly and completely closed though.
 

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Discussion Starter #32
I played with 3 CDI's and 3 stators and the advance was late on all combinations.
In checking the timing you're going to be looking for it to advance with the throttle. If it doesn't advance then it likely is the stator, not the CDI. Use your VOM and run thru the ignition tests in the thread I linked earlier.
Looking to attempt to get this bike running again and I just want to clarify, the stator is the rectifier/regulator or is there another part?
 

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The stator is the large set of windings mounted on the lower left side of your engine primarily under the magnetic dome shaped rotor......
It contains both the alternator windings (to recharge the battery), and the ignition pick-up coil (exterior to rotor) and advance coil (within rotor) that trigger and control ignition timing........
Failures to rev past 4K are often due to the advance coil/winding failure...This is not a separate part and the stator is replaced as a complete unit......
The stator can be tested by verifying the Ohm readings are within the specific ranges listed in the factory service manual.......
Jim, (longdistancerider) has provided a good discussion topic detailing this procedure, and it can be found in the SOHC electrical section.....
 

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Jim, (longdistancerider) has provided a good discussion topic detailing this procedure, and it can be found in the SOHC electrical section.....
He’s posted the link to it for me already, I just wanted to make sure I knew which part we were talking about and I was definitely not thinking the right part. Thank you for clarifying this for me!
 

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Discussion Starter #35
I've gone through all the measurements on this thread and everything seems pretty good. I did however get these with the run/kill switch:

Ignition Switch Off = Infinity
Ignition Switch On, Kill Switch Off = -123

I'm not sure if I was just having issues getting the probes on there properly for those two or what, but it seems like since everything else was in then maybe the CDI might be my issue after all.
 

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So the bike engine will not rev past 4 to 5 k revs and it seems like a fuel issue, or a ht coil breaking down..........you have used the red neon plug caps so you can "see" the spark ( the red neons flash as they pass ht to the plug ) or spark loss.

The engine seems to surge at about 4 to 5 k revs and slows down a bit then re revs etc.etc.etc.

Have you check for proper ignition advance?

Have you checked acv outputs of the genny ign system wires?? as a rule all acv values should rise with increase in engine revs, rate of change.

disconnecting the cdi black/white wire will disconnect the cdi from the rest of the bike. earthing this cdi black/white wire kills the ign. Sometimes the handlebar dedicated kill switch can cause problems, especially when wet.

cdi's have been know to "die over night" which has happened to my sons 400, then a few months later the genny stator died.........

a multimeter will show acv and a pulse to the ht coil, but a scope will show much much more.....

you have a wiring diagram and know that the genny ign windings are on the same stator as the charging system coils but are completely seperate........the reg/rec is the black finned unit by the fuses........3 yellow, a black and a red/whiter from memory.......
 

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I've gone through all the measurements on this thread and everything seems pretty good. I did however get these with the run/kill switch:

Ignition Switch Off = Infinity
Ignition Switch On, Kill Switch Off = -123

I'm not sure if I was just having issues getting the probes on there properly for those two or what, but it seems like since everything else was in then maybe the CDI might be my issue after all.
Probably just a probe problem but you can open up that switch and clean the contacts since it's exposed to wet weather=corrosion
Before replacing a CDI it's useful to use a timing light and check the advance. It sounds like you're not getting any which is controlled between the stator and CDI.
 

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Discussion Starter #38 (Edited)
Probably just a probe problem but you can open up that switch and clean the contacts since it's exposed to wet weather=corrosion
Before replacing a CDI it's useful to use a timing light and check the advance. It sounds like you're not getting any which is controlled between the stator and CDI.

I checked the timing and it's on 'F' on start up. When I twist the throttle it moves towards the 'II' mark.

Do the marks need to be perfectly on the index mark? The 'F' appears to be a bit ahead of it on idle, and the 'II' seems like it struggles a bit to get to the index but it does get there. That's the point when it hits 4000RPM and won't go any further.
 

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I checked the timing and it's on 'F' on start up. When I twist the throttle it moves towards the "II" mark.
At what RPM does it move all the way to in-between the two marks? (in the middle of the II)?

EDIT....You answered while I was typing the question....
 

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Now the question becomes what is your idle RPM?....

AND YES, EXACTLY on the F mark alignment......
Sounds like you are starting out partially advanced at idle, and thus it can't fully advance the necessary number of degrees beyond that initial setting......

Have you checked for a damaged (crank to rotor) key or key-way?
(Which would shift advance timing slightly. making it difficult to smoothly increase in RPM, with incomplete fully advanced position causing the peak RPM limit/stoppage )

While the rotor is off to check that, look at the advance pickup coil to check for overheating as a short there would "read" erroneously to the CDI...(Although your prior Ohms readings SHOULD have told that tale......)
 
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