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Stampie
Stampie PowerDork
7/22/19 5:02 p.m.

In reply to maschinenbau :

Is that something you could take to an old school alternator shop and have them rebuild it?

maschinenbau
maschinenbau SuperDork
7/22/19 7:59 p.m.

In reply to Stampie :

There was a guy in Alabama who used to rebuild them, but apparently he's out of business now. Maybe an old-school shop could do them but I'd have to find one around here.

I did a lot more troubleshooting and I'm pretty sure it's stator and/or rotor. I cleaned off the rotor slip rings much better with sandpaper this time and now the rotor resistance is too low around 3.0 Ohms. I borrowed a much nicer multimeter to read AC voltage from each stator lead and I'm only getting like 6 VAC instead of 50ish, but that's only at starting speed since the bike is too torn apart to run. So it could be either or both. I'm just not sure what's worth doing at this point. New rotor/stator pair from highly rated shops could top $300, but those are high quality units I could trust. ChinaBay would come in around $150. I'll have to see what a rebuild shop costs. 

maschinenbau
maschinenbau SuperDork
8/1/19 11:02 a.m.

Forget the charging system for now, I want it to at least run again. I bought 2 coils for a 2.2L pushrod Cavalier and 2 generic HEI modules. The stock location for the coils is just under the fuel tank, but these are much bigger and won't fit.

This bracket came with the coils and has threads for the mountint bolts. I also want it to secure the battery from moving around.

Nice battery-sized notch.

Coils will hang off the under-seat tray, powered from above by wires and HEI housed inside the tray. I had to cut the connectors off the OEM ignitor units so this system plugs right into the stock harness. 

It all mostly fits. Some generic Rockauto spark plug wires complete the kit.

Barely even noticeable. Might need a shield or something to keep the coils dry from the tire.

I'm happy to say it fired right up! Of course the carbs have sprung a leak at the fuel tube that connects #1 and #2, so the rack needs to come back off. Charging system is still not functioning whatsoever, but it should at least be rideable this weekend (for a short while).

maschinenbau
maschinenbau SuperDork
8/3/19 2:18 p.m.

Alright I'm calling the ignition upgrade a success. Actually I'm calling it TOO successful, and please check my logic on this:

The bike has pod filters, which are way less restrictive than the stock airbox. This means given the same engine speed, more air is going in, fuel not really changed, so it runs lean. Before the ignition upgrade, sometimes it would pop and bog (sign of running lean) and sometimes it would run fine, but only with the choke pulled. When riding on the road, the choke was basically always pulled about halfway. So that would be lean, but not so extremely lean that I couldn't ride. Idle was all over the place and I was constantly adjusting choke and idle screw though. 

Now that the ignition is crazy powerful, I think I'm getting full complete combustion, which means the real problem is even more apparent - lean condition. I was able to get it to idle very nicely without any choke by blind-balancing the carbs (no vacuum gauges yet) and letting the idle mixture screw out just a bit (richer). But now it won't rev past 4000 at all, maybe a little higher with some choke, and starts popping. I opened the carbs (again!) and found a 42 slow jet (stock is 35) and 90 main jet (stock is 92). Other internet sources recommend 42 and 120 when running pods and a less restrictive exhaust like mine, so that 90 main is probably my rev limiter. 120 jets are on order so fingers crossed. I've also heard shoving a universal PCV grommet inside the pod filter creates enough restriction to act like the stock airbox, so I've ordered those too. 

Here's a photo of the main (biggun') and the idle (litlun') jet. I considered drilling the jets until I realized bits smaller than 1/16 aren't sold anywhere.

barefootskater
barefootskater Dork
8/3/19 5:26 p.m.

I’ve never had much luck with pod filters. But on my old Honda shadow when I removed the “snorkel” from the stock intake I had to take the main jets from like 105 to 140 iirc. And the only change I made was before the filter, so I’d imagine you are in need of much bigger jets to deal with all that extra air. Possibly needing to modify the emulsion tubes as well. 

Just my thoughts from my experience but hopefully somewhat helpful. Take it slow, read the plugs and experiment. You’ll get it. 

Edit- you can buy jet drilling kits online, I have one in my bike stuff but don’t remember where I got it from. 

maschinenbau
maschinenbau SuperDork
8/3/19 6:05 p.m.

In reply to barefootskater :

Thanks for the tips. I've just never owned so many carbs before.

pres589 (djronnebaum)
pres589 (djronnebaum) PowerDork
8/3/19 6:16 p.m.

I think I'd just play with jets and not drill anything but I also have a bad habbit of slowly accumulating old parts due to this mindset.  

wawazat
wawazat HalfDork
8/3/19 6:32 p.m.

I’m playing with the jets in the S&S carb on my old Harley now.  Mine is clearly rich (black tar in the pipe!) but this over rich situation is also acting as a rev limiting function.  Taking the (one) carb apart now for re-work.  

ebonyandivory
ebonyandivory PowerDork
8/4/19 7:37 a.m.

Isn’t the fact that it wouldn’t idle without choke a sign your idle jet is clogged? Unless it’s new, it’s pretty likely. I do realize you blew them out once already. 

 

Ive been advise to take a brass bristle from a brass brush and poke it into the holes on the jet. Cleaning and compressed air won’t always cut it.

rollinchicane
rollinchicane New Reader
8/4/19 8:34 a.m.

Really enjoying your build and am rooting for you to sort all of this out.  

Since it looks like you have the carb stripped down it might be worthwhile to take an inventory and make sure you have everything you should. Lots of small parts that a PO might have misplaced while trying to make it work.

When rebuilding my first street bike, a $250 Rebel 250, I had major carb issues. It would start and run poorly on choke only.  The very helpful Honda forum peeps would reply “it’s not clean enough. Tear it down, clean it again!”  

After the third or fourth rebuild something clicked and I laid all the parts out on the workbench exactly as it appeared in the diagram from the manual.  Sure enough there was a whatsit in the picture that I didn’t have. It had creeped out of the chemdip basket and was in the bottom of the bucket.  Once reassembled with all the requisite parts it ran perfectly. 

captainawesome
captainawesome Reader
8/5/19 8:57 a.m.

I'd buy the stock airbox stuff off of someone wanting to put pods on their carbs and call it done. The engineering of the shared chamber was top notch for the day, and is better than you will ever manage to get close to usable trying to jet it. Right now you have 4 carbs pulling different air from each with varying results. The inner carbs don't see as much cold air as the outside carbs and so on. Even modern sportbikes share an intake chamber for this reason. It may not look as cool as pods, but it's the right thing to do for functionality.

 

 

maschinenbau
maschinenbau SuperDork
8/19/19 8:00 p.m.

I put the big jets (120) in place of the original 92 or whatever. Also put a restrictor orifice (PCV grommet) inside the pod filters. Ignition is definitely good and advancing like it should be. I've been checking it and changing it with a timing light. It responds as it should to advance or retarded timing. 

Still can't rev this turd past 4500. Top speed is 45 which means no real riding.

I'm kinda lost now. I'm guessing I need to shim the needles, which assumes the problem is still lean. I've heard the main jet upsizing only helps at WOT, which I can't even get to, so that's why I think the needles need to come up now. Or it just needs a better cleaning. Very open to advice now, including taking it to a shop.

Also the fancy new rotor didn't fix the charging system. Guess I need to buy the stator and reg/rectifier next.

barefootskater
barefootskater Dork
8/19/19 10:04 p.m.

Shim those needles! Easy to do, easy to test. Just be careful not to go too far, they can come out too far when you open the throttle and jam it wide open. Not fun. 

¯\_(ツ)_/¯
¯\_(ツ)_/¯ PowerDork
8/20/19 5:39 a.m.

When it stops accelerating at 4500 rpm, is it popping and making all sorts of nasty sounds or does it just softly refuse to go any further?  What happens if you give it a little choke?

You say you can't even get to WOT- does it bog and die?  If so, at about how much throttle?

AxeHealey
AxeHealey HalfDork
8/20/19 7:19 a.m.

In reply to maschinenbau :

Maybe I've missed something and I don't have a ton of experience in these parts but wouldn't you want the restriction in the pod if you didn't re-jet? Or were the specs you found the 120 with the restriction? From what you wrote it sounded like the restriction was to help the stock jetting with pods.

Sounds like you were able to get more fuel into it (4,500 v. 4,000 rpm) but maybe now you've cut off the airflow?

maschinenbau
maschinenbau SuperDork
8/20/19 7:36 a.m.

When it stops at 4500, it has tons of popping and bad noises, which is why I think lean. If you keep cranking it slowly to WOT, it just stays there all tormented. Maybe bogs a little, but keeps popping.

These mechanical slide carbs mean you have to fully separate the rack just to get to the needles, including springs and all that. The same tedious process that keeps me from fully cleaning the carbs like I should. Guess I'm out of options though.

On the pod restrictors - I've heard they go with the 120 jet. Some say they are still lean at 120 and this helps get it right.

Pulling the choke a little while revving helps only a tiny bit.

¯\_(ツ)_/¯
¯\_(ツ)_/¯ PowerDork
8/20/19 7:42 a.m.

In reply to maschinenbau :

That sounds lean to me too, although I'd look closely at the float height and that sort of stuff- if the problem was just the needle position I'd expect it to be closer to OK than it sounds like it is.

captainawesome
captainawesome Reader
8/20/19 7:53 a.m.

Have you checked plugs yet to see what idle/mid range mixture looks like? What kind of voltage are you getting in the upper rev range?

I still think you should just put a stock airbox back on, or make some sort of air chamber they can share.

 

maschinenbau
maschinenbau SuperDork
8/20/19 7:56 a.m.

This bike is so far gone down the modified path I don't even know if a stock box would fit. The seat and battery tray are all modified or aftermarket. And it's not like I'm the first to put pods on a CB650...though folks do often have issues.

It does idle pretty amazing right now though.

captainawesome
captainawesome Reader
8/20/19 8:06 a.m.

Fair enough.

If you are going to mess with jets though, you need to be pulling plugs to see what kind of mixture you are getting. Especially if ignition advance looks accurate based from a timing light. Definitely check that you are getting good voltage at higher RPM as well. You should see ~13-14+ volts when charging properly.

maschinenbau
maschinenbau SuperDork
8/20/19 8:09 a.m.

In reply to captainawesome :

Charging system isn't putting anything out right now at all. Constant battery voltage when running.

maschinenbau
maschinenbau SuperDork
8/25/19 5:30 p.m.

Gave the needles 2 shims each and still not revving! I have no idea what to think anymore. I can't imagine the charging system would rev-limit it, especially since the whole ignition system is non-Honda. 

Slide throttles do open fully. 

Plugs look black, but that could be from a rich idle.

Hard to tell exactly what's happening when it stops at 4500 RPM.

wheelsmithy
wheelsmithy SuperDork
8/25/19 6:00 p.m.

My opinion:

Do not take it to a shop. You are a much better mechanic than most shops I have dealt with. Party on. You'll get it squared away.

mazdeuce - Seth
mazdeuce - Seth Mod Squad
8/25/19 6:27 p.m.

What is the advance mechanism? If you change fueling pretty radically (which you did) and you get no change in running, then I tend to think the problem isn't fuel. You made the spark hot, but I'm wondering about it's timing now. 

TurnerX19
TurnerX19 HalfDork
8/25/19 6:45 p.m.

Are the spark plugs the correct heat range? The abrupt RPM limit at WOT points that way, especially if black.

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