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Stator Removal for CM400A [SOLVED]

Yeah, mine didn't budge at all. I'm used to smaller bikes where they do come out and are easy to lose so I was going to take it out and set it aside before it fell onto the garage floor and got lost forever, but wouldn't budge so left it be. Was unaware it was interference fit, but good to know.

Admittedly, I did not check the torque this time around, but mileage has been pretty minimal over the past week. I'll give it a check tomorrow. Thanks for the reminder.
 
I'm guessing, but have no idea, that the advance coil probably plays a bigger role in the CM400T series bikes. But, if your 400T runs, just simply disconnect the advance coil on the 6 pin connector (pink wire only, need the green which is ground for the CDI), go for a ride and see if there's any real difference. You can carefully remove that connector with a non-angled pick tool or Vintage Connections/Sparck Moto sells the proper tool that makes it a lot easier.

Good suggestion, I should try that. It would be nice if I had a better strobe light I could rev it up and just verify it advances. Maybe I'll work on trying to get my DIY LED one bright enough to show this. And I suppose I can just disconnect the wire and take a drive and see what it feels like.
 
Yeah, mine didn't budge at all. I'm used to smaller bikes where they do come out and are easy to lose so I was going to take it out and set it aside before it fell onto the garage floor and got lost forever, but wouldn't budge so left it be. Was unaware it was interference fit, but good to know.

Admittedly, I did not check the torque this time around, but mileage has been pretty minimal over the past week. I'll give it a check tomorrow. Thanks for the reminder.

I thought you had the stator out sent off for rewind. Did you get it back already? Oh, maybe you put it back in without the 2ndary pulser thing ;) I suppose if it was not doing anything, why not.
 
Good suggestion, I should try that. It would be nice if I had a better strobe light I could rev it up and just verify it advances. Maybe I'll work on trying to get my DIY LED one bright enough to show this. And I suppose I can just disconnect the wire and take a drive and see what it feels like.

I know it sucks, but you really ought to just buy a real one at some point when you're able. If you want to keep these bikes running it's a necessary tool imo. I have this exact one and it works perfectly fine for verifying timing: https://www.amazon.com/INNOVA-3551-Inductive-Timing-Light/dp/B000EVYH72. This one works pretty well in daylight too. So you don't need to sit in a dark garage to find out what's going on.
 
I thought you had the stator out sent off for rewind. Did you get it back already? Oh, maybe you put it back in without the 2ndary pulser thing ;) I suppose if it was not doing anything, why not.

I only took the advance coil off the stator as the bike was running with it being open anyways. That got sent out, I put the rest of it back together (with new PVC sleeving because the old one was so hard and brittle from age) and still driving it. However, been pretty busy this week with the rest of the family on vacation and there's project the misses wants done around the house while she's out of town so I've been having to drive the car to pick up stuff.
 
Good suggestion, I should try that. It would be nice if I had a better strobe light I could rev it up and just verify it advances. Maybe I'll work on trying to get my DIY LED one bright enough to show this. And I suppose I can just disconnect the wire and take a drive and see what it feels like.

Another thing is you can check the resistance between the pink and green from the stator side and it should read between 120-180 Ohms for earlier CB400Ts and 126-154 Ohms for late model CB400T and CM series. According to the thread from Jim new it's about 129 Ohms and 135 Ohms is typical. If the reading is within spec it should work. If it doesn't work, then there's probably an issue with the 6 pin connector going into the CDI. There is a test for that too, the FSM test is accurate IF you use a DVM with a fresh battery. The values should read out in MOhms. Be mindful of the table though, because some pins read entirely different in one direction because of the diodes and SCRs. So if you probe some pins on it and they seem WAY off, don't panic, just swap the leads on the DVM and it's probably correct. The table is a bit confusing. I probably should make something a bit clearer one of these days.

EDIT: For the 6-pin on the CDI assuming a modern DVM with the positive probe on the Pink and negative probe on the Green it should read about 0.5 - 3.0 MOhms. It should also read the same with the leads reversed, according to the table.
 
I know it sucks, but you really ought to just buy a real one at some point when you're able. If you want to keep these bikes running it's a necessary tool imo. I have this exact one and it works perfectly fine for verifying timing: https://www.amazon.com/INNOVA-3551-Inductive-Timing-Light/dp/B000EVYH72. This one works pretty well in daylight too. So you don't need to sit in a dark garage to find out what's going on.
I think I will try to get one on the shopgoodwill site. This one looks tempting, but the shipping costs are a bit high: https://shopgoodwill.com/item/146757532 It does look like a classic!
 
I think I will try to get one on the shopgoodwill site. This one looks tempting, but the shipping costs are a bit high: https://shopgoodwill.com/item/146757532 It does look like a classic!

I tried looking for something similar like that before I bought what I had now. I ran into the same problem you had, where the shipping was making it hard to justify the purchase. If you want an old one then you're probably better off trying to go to estate sales or hanging out on facebook marketplace/craigslist and looking for "tool lots". The amount of work involved to find an old one at a deal you might as well just buy the one I have now, imo.

I will say that the one I have now I have used it many times to verify timing after adjusting points on the CB550, checking the CM400 and even used it on my dad's boat engines after he rebuilt them because the RPM was being restricted on the top end. I've used it literally at least 50 times and it's worked every single time.
 
Got the new coil from Custom Rewind today. Put it in and holy cow what a difference! You can actually accelerate quite a bit faster if you're coming from a low speed in '2'/'Hi'. It used to be that I'd use '1'/'Lo' and get it up to about 35-40 then shift to 2 and continue the rest of the way. Don't have to do that any more. I'll bet it will get better MPG as well. It averages about 37-40 currently.

Also, I did torque it down to spec this time. Book says 70-90 ft/lbs. When I checked what I thought was good, I was only at about 45 ft/lbs. So thanks for pointing that out to me or I would have been crying a year from now.

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If you'd like, can we modify this thread to say [FIXED]/[SOLVED] at the beginning of the topic? I don't think I have the ability to do so.
 
Final update: my speedometer is accurate, amazingly enough (theyre usually about 5mph too fast I've noticed on other old bikes). So took it up to the gas station, put ethanol free in it like I always do, reset the trip meter and went for a 30 mile ride on the highway. Did a small bit of bad boy sprints at 75mph but mostly cruised around 60-65. Got back and topped off, did the math and now I'm getting 47mpg up from 37mpg. Amazing how much difference it makes! It was even able to climb a large hill on the way back pretty quickly at 65mph. Usually it would top out at 50mph on that hill full throttle. My car can't even do 65 on that hill.

So long story short, ohm that coil, if its wrong go give custom rewind a call. You're totally robbing yourself of some power otherwise.
 
Timing advance plays a huge part in the production of power, often overlooked.
On manual trans models when the advancer coil is bad the first thing people notice is the bike tops out @50-60 mph in 5th gear and to pickup speed they have to downshift to 4th. This is also a bad CDI symptom if the stator ohms out good.
 
I'm guessing, but have no idea, that the advance coil probably plays a bigger role in the CM400T series bikes. But, if your 400T runs, just simply disconnect the advance coil on the 6 pin connector (pink wire only, need the green which is ground for the CDI), go for a ride and see if there's any real difference. You can carefully remove that connector with a non-angled pick tool or Vintage Connections/Sparck Moto sells the proper tool that makes it a lot easier.
So Maraakete I did pull the pink wire(secondary advance pulse) off and go for a ride. It was a sluggish ride, definitely very noticeable. Felt like I had to go full throttle and just had no pep, probably would top out around 60mph max it felt like, but I had no open road to actually try maxing speed out. So yes you must be thrilled with your advance fix.
 
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