Author Topic: 1975 Honda CB400 Four Project - Rookie (Read 317452 times)

britz73 · « **Reply #350 on:** March 17, 2011, 01:06:49 PM »

Hey Rick,
Finally finished a couple of days shift-work and about to get to those carb parts. They will be in the post today and you should get them by Tuesday. Forget the cost buddy, I've gained some valuable knowledge from your post that's worth more than a couple of bucks! I will email pic of parts sent this arvo.............Mark.

RickB · « **Reply #351 on:** March 19, 2011, 06:46:06 AM »

Took the bike back to the Matt the mechanics and worked on it into the evening. Now it's running super lean with a very weak spark. We're thinking it's the dodgy lathe work I had done to make the advance in the Dyna system work until the correct part arrives from the US. So I'm going to wait until that part arrives later this week before I give up completely.

Doctorlumen · « **Reply #352 on:** March 19, 2011, 02:12:49 PM »

Hang in there, Rick. With a fresh motor, the only two options for bad running are fuel and/or spark. I know from tinkering with my 400f that the carbs can be a bit tricky to dial in, and if they are far enough de-tuned, the bike won't run. Maybe I missed this in an earlier post, but what settings/jets are you running?

Good luck, man! This thread has been a real inspiration to finish up my bike.

fasturd · « **Reply #353 on:** March 21, 2011, 07:02:38 AM »

Jumping in late on this but I had a similar problem on a project bike. Dyna ignition, everything rebuilt... In the end the battery was too low on water. I know it sounds dumb and I was sure I had checked it many times but once I refilled the battery (it was a newer battery that had been recharged many times during the rebuild) the richness went away and it pulled hard all the way to redline. Super simple fix that had not only me stumped but two of my good mechanic buddies. We all smacked our foreheads when it was finally solved.

Good luck with all the final details you really deserve to get out and ride that thing after all the work you have done to get it going again!

Bankerdanny · « **Reply #354 on:** March 21, 2011, 08:22:51 AM »

Electronic ignitions are very sensitive to battery voltage. Upgrading the battery in my Enfield, which I had converted to EI, to sealed AGM made a huge difference in starting and overall performance.

RickB · « **Reply #355 on:** March 21, 2011, 08:56:23 PM »

Thanks for the advice lads.

I'm really starting to suspect that this is faulty electrics. I've got that dodgy advance adapter, a silicone rectifier that blows up if plugged in and a faulty charging system. So I'll just have to work through those issues I think.

The replacement advance adapter comes later this week, so I'll start with that.

As for getting a AGM battery, that is a great idea. Where I would find one suitable for a CB400F in Australia, I have no idea. The battery I have now is brand new and I even topped it up with distilled water. It's the charging system that is faulty, I won't change at even high revs. So I'm going to pull the vreg apart and adjust it according to the manual I think.

Thanks again guys.

Rick.

Hush · « **Reply #356 on:** March 28, 2011, 02:04:11 AM »

You've come so far with this project Rick, I love the work you have put into a bike that most told you was dump material when you looked at it.

I too was having major battery problems, replaced with a sealed battery from BESCO, I think they come from Aussie, anyhow one of the best batteries I have used, got one for my partner's bike too.

www.bescobatteries.com.au

RickB · « **Reply #357 on:** March 28, 2011, 02:30:18 AM »

Hush,

Thanks pal. I can always rely on you for encouragement!

I'll check out Besco tomorrow for sure. Spoke to my mechanic tonight and apparently the timing was way out on cylinders 2 and 3. It's still draining the battery way too fast and one of the spark plugs is not behaving (even though it was brand new).

So there's a serious electrical gremlin somewhere still.

Rick.

RickB · « **Reply #358 on:** March 30, 2011, 12:17:54 AM »

So I called Besco in Australia and the only battery they could offer me to fit in my CB400F was the Yuasa one. Which is a traditional lead acid one. Which I have. So that's the end of that I suppose.

I spoke to my mechanic today and he said he was able to get the bike running beautifully by hard wiring the battery directly to the ignition. So something in my electrics is draining the battery way too fast and causing the ignition to malfunction. I have no idea what, but after paying $600 to an overpriced auto electrician, I'm very frustrated. So Matt the mechanic is going to try and work backwards and see what the problem is. He thinks it could be something to do with the CB350F switch I have on the right side.

The saga continues. Oh and I've just noticed my image hosting has died on me. Nothing is ever easy!

Rick.

RickB · « **Reply #359 on:** April 08, 2011, 04:01:34 AM »

Ok and update.

Firstly, all my photos will be back online tomorrow.

Secondly, after getting relays put on the starter and right hand switch, the bike still doesn't run. It's running great with a full charge but then as the battery drains, it won't idle and then it fouls the plugs and then obviously won't start. I'd love to know why it isn't charging.

So I'm taking it back to the mechanic tomorrow to see what we can do.

So incredibly disheartening.

Rick.

fastbroshi · « **Reply #360 on:** April 08, 2011, 04:15:20 AM »

Maybe I missed it, but you tested the stator's output while running? Sounds like it's dead or your rectifier's gone.

RickB · « **Reply #361 on:** April 08, 2011, 04:20:39 AM »

I've sort of been relying on my mechanic to check this. He's pretty good, well has been so far. How would I test the stator and/or regulator? I have a multimeter.

MasterChief750 · « **Reply #362 on:** April 08, 2011, 04:26:52 AM »

should be in a service manual if you have one. you can do it with a multimeter. do you have the original rectifier or a replacement. also i had an issue with charging on my 750 until i adjusted the gap in the regulator

RickB · « **Reply #363 on:** April 08, 2011, 04:43:42 AM »

I have the original regulator and rectifier. I took the regulator apart and from what I could tell, there's no adjustment to be made. It's the black thing with green, white and black going into it. I have the Clymer and Haynes manuals.

MasterChief750 · « **Reply #364 on:** April 08, 2011, 05:05:45 AM »

the cover should come off and there should be a metal"switch" inside of it. might be different on the 400, check your manual it should say whether or not there is adjustment to be made

Doctorlumen · « **Reply #365 on:** April 09, 2011, 09:36:46 AM »

What a bummer, Rick.

Here is a link to a guy in Oregon who makes Regulator/Rectifier units for your bike. I know a ton of folks at least in the Seattle area that run his parts and they all rave about them. In fact, I just purchased one for my 400f that I have yet to install.
http://www.oregonmotorcycleparts.com
Even if you don't buy one of his parts, his FAQ is very helpful as far as trouble shooting is concerned.

So, if all goes to hell and you find yourself in need of a rectifier or regulator or both, shoot me a PM. You can have mine, and I know for sure that they work.

Industrial Rat400f Killer · « **Reply #366 on:** April 10, 2011, 06:25:06 AM »

Quote from: Doctorlumen on April 09, 2011, 09:36:46 AM

What a bummer, Rick.

Here is a link to a guy in Oregon who makes Regulator/Rectifier units for your bike. I know a ton of folks at least in the Seattle area that run his parts and they all rave about them. In fact, I just purchased one for my 400f that I have yet to install.
http://www.oregonmotorcycleparts.com
Even if you don't buy one of his parts, his FAQ is very helpful as far as trouble shooting is concerned.

So, if all goes to hell and you find yourself in need of a rectifier or regulator or both, shoot me a PM. You can have mine, and I know for sure that they work.

+ 1 for Oregon Motorcycle parts, I believe the ability to run a super under powered small battery is because I have the REg/Rec unit on my bike. Plus He has the best customer service ever. Email you problems to him and he'll either tell you how to fix it or suggest you buy from him.

fastbroshi · « **Reply #367 on:** April 10, 2011, 11:56:23 PM »

Rick, the regulator is adjustable, but it is not recommended. The rectifier should have a testing procedure in the manual; you can do it with a parts store $5 multi-meter. This little vid should clear up how to tell if your charging system is working. Make sure your battery is fully charged!

http://www.youtube.com/user/cycleadam#p/u/12/VFp8Uvr70zc

RickB · « **Reply #368 on:** April 11, 2011, 12:50:51 AM »

Thanks guys.

I flooded the engine yesterday and couldn't get it started. I left it was the plugs out and charged the battery overnight. I polished up the rectifier terminals. I have yet to test it with a multimeter.

Today I swapped in fresh plugs, put in a replacement starter motor as the old one was shorting out and it started right up. It seems to be missing a cylinder at low RPM's, which makes this alternator problem more pressing.

So I did the tests on the regulator suggested here. It's showing 0.3 ohms resistance, well within spec given the accuracy required to measure that low. I did try adjusting the regulator per the instructions in the Honda shop manual but got no noticeable increase in charging voltage when bending the armature arm.

I then tried testing output on the alternators three yellow wires when revving the bike. Nothing. I may be jumping the gun, but I think it's dead. The three yellow wires are rock hard and one has been broken and soldered back together. To my tests, it just doesn't seem to be outputting any power. I've ordered a second hand part from a wrecker in Sydney. The starter motor he gave me was great, so I've got confidence this will be too.

Rick.

fastbroshi · « **Reply #369 on:** April 11, 2011, 01:12:09 AM »

Rick, when you were testing the output from the stator and the three yellow wires, did you have the multimeter set to AC or DC? This will make a difference.

RickB · « **Reply #370 on:** April 11, 2011, 02:12:23 AM »

Nope, I had it DC. Yep, I'm an idiot. I'll try it again tomorrow in AC.

RickB · « **Reply #371 on:** April 12, 2011, 04:26:03 AM »

Hi guys,

I posted this in a CB400F Charging Issue thread I have going over in the 'SOHC/4 Bikes' section. I'm also posting it here for anyone that's interested as it pertains to this build and I feel like I should keep it all in one place.

Ok so I spent all afternoon going through the instructions some of you helpful people have given me. Here's my results:

Battery was charged all night. When I took it off the charger it was 13 volts and dropped down to a holding steady 12.7 volts over 5-10 minutes. With the key off it held 12.6 volts. When I switch the key on it held 11.78 volts. I have the headlight disconnected and have the Dyna ignition and 5ohm coils with appropriate relays. Apart from that, the wiring is stock.

The resitance between the white and green wires is 4.5 ohms.

I now tested the stator wires from the harness side of the unpluged rectifier. I had the meter set to AC. The photos above show 0.00 but that's because I don't have three hands. When I revved the engine to 4000 RPM I got these approximate numbers:

1: 19 max, 16 approx holding.
2: 16 max, 13 approx holding.
3: 16 max, 12 approx holding.

The numbers were jumping around so I did my best of figuring what was the highest and what was the average. There were higher values but I tried to be conservative.

Then I 'full field' the field by jumping the black and white wires on the regulator. I then did the above test again.

1: 16 approx holding.
2: 15 approx holding.
3: 15 approx holding.

I also tested resistance between the white regulator wire and the chassis ground. That was 4.6 ohms.

This is a far as I know how to go. Does this provide any insight as to why my battery is not charging?

Thanks again for all the help guys.

Rick.

MoMo · « **Reply #372 on:** April 12, 2011, 04:36:46 AM »

Rick , that is not a conclusive test for the rectifier. I do not have it handy but the shop manual has the full test, and my off the top of my head memory is insufficient

. you need to check each diode in the rectifier and the multimeter is in the correct mode. My experience is the rectifier is most often the culprit in charging problems. When you get a chance could you either post or pm me some closer photos of the mounting for that Commando style exhaust. I really to like that and it would be a nice touch for the Norton style CB400f that I have. Thanks...Larry

RickB · « **Reply #373 on:** April 12, 2011, 04:46:42 AM »

Larry,

Yeah I thought there might be more to the rectifier test. I'll go over the manuals I have and try again tomorrow. I've removed those photos just to save anybody the same mistake.

For sure I'll take some photos of the muffler setup for you. I'll also do that tomorrow. I'll post them here.

Thanks Larry,
Rick.

RickB · « **Reply #374 on:** April 12, 2011, 04:46:51 AM »

So when I haven't been dealing with my battery refusing to charge, I've been getting some popping out of the aribox/carbs. I've probably pulled the plugs 20 times trying to read the tea leaves.

I've yet to ride the bike, this is all at idle. When it pops out the air filter the clip on cover almost pops off and the engine bogs down.

I know these plugs look a bit sooty but having seen similar photos from other 350Fs and 400Fs I think this is pretty good. Except for that real clean one!

#1 doesn't even appear to be firing.

#1

#2

#3

#4

Everything is stock besides the muffler. It doesn't have any direct baffling (ie you can see straight through it).

The Dyna S ignition is firing the plug, I've tested it with a plug in it grounded against the engine and shocked myself more than once. I've tried a total of 5 different plugs in it too.

Could this be related to my battery not charging? Like the Dyna S system needs above 14 volts at the battery to trigger all the plugs? Perhaps at idle there's not enough power to fire the plugs?

Rick.

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Author Topic: 1975 Honda CB400 Four Project - Rookie (Read 317452 times)