81 xj550 project

In practice it's a test from almost every factory service manual I've ever looked at.

 

Thanks. I didn't come across it in my manual yet but maybe because I read an online version and not my actual book.

Well that sucks then. I don't get a magnetic field. But good in respect that i now know where the issue seems to be coming from and where to look first.

 

I saw the post in another thread just now. Your stator is bad.
The rotor is likely good, but if you an snag one as a package deal with a stator (and not overpay) it wouldn't hurt to have one.
Replace the stator.

 

Thanks. I'll start a conversation with Len.

 

New stator came in from Len but no good.
Just to make sure I am not doing something wrong when reading the resistance. The meter has to be set like this, correct?



So, on the new stator, I am getting 1.0 across all three white wires. This is still out of spec, no? It's supposed to be in the 0.5 range.
On the rotor, I am getting 5.5 across the two rings. I couldn't get any reading on the connector today for whatever reason. I did two days ago.
The brushes are clean but might be short. They are only about 1.2cm but I haven't found specs for length in my manual yet.
I wanted to remove the rotor for a visual inspection but didn't manage because it kept rotating. Need to build or order a tool.

Not sure where to go from here since the two parts (rotor and stator) are out of spec but stator is new and should be fine?

Edit: I didn't measure the brushes end to end (just realized) and according to the wear line, I have plenty left.

 

And just for the completeness of the info, the rotor does spin when engine runs.

 

Stupid question:
Does the rotor get any power from somewhere or is this not needed?
Just trying to think if the issue is somewhere else.
It just spins when engine is running which then creates a magnetic field because of the stator? And that is send over rectifier to battery.

 

18 resistance at brown green wire. Which indicates something is up with the wiresor brushes. At the rings, I had 5.5.
I will also check the multimeter. I was thinking that if, for whatever reason, the ohm readings are off by .5, everything would fall into specs.
But this still wouldn't explain not getting a magnetic field that can be tested with the feeler gauge - unless, hence my question above, if it actually needs a power supply first. Which would then lead me away from the alternator in general and look for something else.

And my apologies for all the posts, just trying to think through stuff and write it down as additional info

 

Digital multimeters like that one may not be very accurate at low resistance readings.

The spinning rotor must be engergized (voltage fed to it) for it to create a magnetic field.....the rotor is really an ELECTRo-MAGNET, i.e. it doesn't become a magnet, nor produce magnetic fields, when no "electro" is fed thru it....and the delivery of electricity to it is the purpose of the brushes which ride on the copper rings on the face of the rotor.....the brushes carry/transmit voltage to (and ground from) the rotor, thus "energizing" the rotor and creating a magnetic field within it. No voltage to the rotor = no magnetic field.

The spinning action of the rotor merely takes the created magnetic fields in the rotor and rotates them past the stator. Non-moving (or, more precisely, non-fluctuating in strength) magnetic fields don't do much for the generation of electricity; VARYING STRENGTH magnetic fields will induce an electrical current in a conductor (i.e. a wire, or a big mess of wires such as the stator). The "varying strength" of the magnetic field(s) is due to the fact that the rotor is rotating, thus bringing (and then removing) a magnetic field past the stator's wires. Of course, this magnetic field isn't very strong, but it does not have to be: there are lots of wires in the stator, and each one of them gets a "to-and-fro" magnetic field strength from the rotating magnets/magnetic field in the rotor, and so in total it adds up to the required voltages needed.

The amount of voltage applied to the ROTOR is controlled by the voltage regulator; the lower the voltage of the battery, the more voltage it applies to the rotor (via the brushes, thru the commutator rings) and thus "amps up" the magnetic field strength of the rotor. The higher the magnetic field strength of the rotor, the greater amount of voltage flow is induced in the stator and thus fed from the stator, to the voltage rectifier (which changes the AC current coming out of the stator to DC current), and then to the battery.

 

Get a resistor that you know the value and tolerance of. Read the resistance with the meter.

I have the same meter as you do (as a spare) and it's pretty close to my Simpson, but then part of what you pay for when buying an expensive meter is consistency and repeatability from every meter they manufacture. I may have goten lucky with the particular Actron meter that I have.

 

Ooookkkaayyyy...
Thanks guys.
So basically:
Verify the multimeter is giving correct numbers
Check wires to/from brushes
Check regulator/rectifier and all wires there

I'll do that over next few days
Thanks again

 

Got myself something nice (and expensive).
Arrived yesterday

 

I'm drooling

 

Best you can do when measuring the stator is subtract the resistance of the leads and contacts from the actual reading. So, touch one of the stator wire terminals with both leads with the leads not touching and note that reading - wiggle the leads a bit to get the lowest reading. Then measure the stator resistance as instructed in the FSM. Subtract the first reading from the second to get very close to actual stator resistance.

Be sure to use a thin feeler gauge to test for rotor excitation. About a 1/4 inch away from the AC generator cover and when the key is turned on the feeler gauge should pull towards the cover. The rotor should be receiving maximum excitation when the engine is not running. 12V ignition on the brown wire, and approximately 1.8V on the green wire. The regulator controls the low side (green wire) and will raise and lower the voltage based on internal voltage sensing within the regulator.

Reading a higher resistance (up to about 20 ohms) at the brown / green wire connector is not all that unusual. I get a reading of about 18 ohms on mine, but if I insert a current meter and check current the actual resistance calculates to about 5 ohms.

 

Well, I guess mine (speedo) is wrong. I could have sworn I did a lot of research and came up with this number. Maybe I ended up ordering the wrong one.
Mine already shows 8 miles on it and I didn't even ride it that much.

 

8 miles isn't very far. A tour around my block is almost a mile.

 

And the Oscar goes to: hogfiddles

Dave suspected the rectifier right from beginning.
I had a new one on there but it was no good. Received my new part yesterday and just put it in. Feeler gauge is getting attracted now.
I haven't checked the voltage going to battery yet but it looks promising.

Only thing left now is the front brake.

 

I have to say, every time I turn on the bike, I am amazed how well it idles and sounds after I did the color tune back then and a second carb sync.

Unfortunately, I haven't been able to ride it since due to the battery charging issue. And yeah, not having a working front brake is an additional concern...

 

Nice video! Nice bike, too!!!

 

thanks Len. still need to put everything back together and route the wires from when i installed your stator. but that's a quick job.

I'm more worried about the front brake. I'll dig into it on the weekend and maybe open a new thread or so. i wouldn't know what to look for at the moment. or maybe it is not related to the brake itself and just my inability to fill and bleed an empty system. Dave already mentioned to make sure there is enough fluid in the reservoir. so i will tilt the bike a bit to make up for the angled sitting reservoir.

 

Do you have a vibratory sander?
Use it to shake the bubbles up to an out of the master cylinder.
Start at the calipers and work your way up.

 

Good idea. And yes, I do. I'll give it a try.

 

Or just a vibrator... Lol

 

You know how mad wives get when you clean parts in the dishwasher.......

 

Matti not needed here?!

 

Oh, We were just waiting to see how quickly you would jump in on this thread

 

Between this and that other carb cleaning thread, I'm pretty busy.

 

I assume the brake lever has to be pulled in (zip tied)?

 

I'm gonna leave the reservoir unscrewed for the day with the lever zip tied. Hopefully this will help, seemed to have worked for others. Maybe I'll tap it a few times in between. In case it works, I will bleed the system with fresh fluid - not sure how fast brake fluid absorbs moisture.
So close to actually riding Major Pita...

 

Yes.

 

I think it's my Chinese ebay master cylinder that's causing the issue..
Removed the brake line at MC and put my finger over the hole. Pumped a few times. There was little pressure but not much fluid moving. At some point the opening should be filled with fluid, no?

 

Son of a b...
Swapped MC for the previous one (for which I couldn't find a shorty lever) and I have firm brakes within 2 minutes..

 

Good parts are worth paying for.

 

Just like my "new" rectifier..
The bore is not the correct one but just took her for a ride and it behaved fine. I'll keep an eye on it.

 

Now I have to change the connector to the brake switch on the MC, hook up the rear brake to brake light and get a mirror. That should be it to get an inspection. Too late to get it done today, so I guess the longer test ride has to wait.

 

The clutch cable routing could be better too. Overall it looks and sounds really nice.

 

Yes. That's still to do.
I want to take the front fender off to repaint it. That's when I am going to drill a hole for the clutch cable guide. I already tested.
I focused more on getting it run right over the last few weeks, more detailed cosmetics are next. Also want to do some simple side covers to complete the look.
And I decided to go for a longer test ride in the morning. The fine is not that bad in case they stop me. But have to hook up the brake lights first.

 

That's why I don't get the cheap Chinese parts........

 

Me either. If I have to buy something from Asia it's either Japanese, Tiawanese, or from a good Chinese factory (there are several, but it's so difficult to find out which are and which aren't).

 

It was the only MC of the correct size and with shorties. Oh well. Works for now and I'll figure it out later.

 

First test run was a success. Only went 5 miles or so because lots of traffic already and constant stop and go. Didn't want to leave my area either in case bike breaks down. But all good.

Once fully warm, I think the idle is a bit high, need to adjust. Bike shifts through all gears smoothly, and has a good pickup. All of my previous bikes were 1000cc, so I'm quite happy with that actually-not-so-little 550.
Major Pita smoked like crazy afterwards. Think it's the engine paint and exhaust wrap burning and curing. Should be gone next few times. Definitely had that unpleasant smell that I know from other bikes.

 

I'm gonna put it up for sale for a (too) high amount of money - maybe it gets some interest while I enjoy riding it. In NYC, you never know...

 

IMO you should easily get a decent price. It's a well sorted bike in a very popular style. I'd give you a few grand, or a dusty dented xj750rj for you to start over with

 

IMO you should easily get a decent price for it. It's a well sorted custom in a very popular style. Some jerk with too much money will pay up! If I had too much money, I'd pony up a few grand. How bout a straight up trade for a dusty, neglected 750rj?

 

thanks for that. yeah, selling takes time that's why i already posted. i want to focus on the 88 FZR that i have, i also have a completely disassembled and boxed up GPZ laying around.
i am going to get the Major inspected today, brakes are all wired up and working. should be no issues. i threw on one of those side mirrors while the regular mirrors are being shipped today.
well, the bike will be around for a while, just let me know. btw, the vibrator is not included.
and i actually have no idea how to price the bike - or trade in for a buell xb (yeah, i still miss mine after all these years)

at some point and for a weekend project, i want to hook up the neutral switch again. i have a little light on the aftermarket control switch which will be perfect for it. if i get fancy, i also have a cbr front end in my garage which i could try to put on. but again, FZR is my priority.

 

Yeah, I was always interested in Buell. Either that or a Sportster with the Buell swap. Would've been cool if they could have done more with the Rotax engine they had...

 

Street legal. Woo hoo

 

Major Pita is now tested on the highway as well. And both bike and rider are still well.
Ride to get the inspection was about 20 miles in total and had everything in it, stop and go's as well as highway cruising.

Two things I need to look into:
Once bike is hot, idle is higher than it should be. I am on the higher idle setting side anyway, will adjust there first.
Second, the bike stalled on me at a traffic light. As if not getting fuel. I prime, nothing. I open the lid to check on fuel, try again and voila, fires right up. I think I saw a thread on here where I guy suspected that no fuel was running after a while because it had created a vacuum inside the tank (or something of that sort). Could it be that? No issues on last mile after that little incident.

 

Think the breather valve inside the tank lid needs a cleaning. Thanks hogfiddles.