Archive for February, 2007
Charging System Troubleshooting
Posted by Randy in Motorcycle on February 26, 2007
How does this work?
Remember Choose Your Own Adventure books? Same idea. You can’t effectively read this page from the top down. You have to skip around using the links at the bottom of each test/question.
If you prefer something you can print out and take to the garage with you, download the original charts; they’re really useful. If you feel comfortable with choosing your adventure as you go, skip to start.
This page is based on charts published by Eletrex USA
Very Important:
This fault-finding chart assumes that the user has knowledge of the basics of electricity (Voltage, current, resistance, etc.), and about electrical systems on motorcycles in general. If you do not have this knowledge/experience, find someone that has and let her/him check the charging system on the bike. The use of this fault-finding chart is entirely at the risk of the user. The author cannot be held responsible for any damage that could arise from the use of this fault-finding chart.
Fully charge the battery. If the battery is not fully charged you may get wrong results using this fault-finding chart. You could just replace it with a battery off another motorcycle that has a good functioning charging system.
Use an accurate digital multimeter! RR means Regulator/Rectifier. This whole fault-fining chart only works if you have a bike with a combined regulator and rectifier (= regulator/rectifier) in a single case.
Take Notice of the Following:
Suzuki used on the older GS models three different colors for the three output wires of the stator. They were the only manufacturer doing this. The only reason for this can be to cause confusion, because the output of all three wires is the same. The colors on the wires from the stator are Yellow, White/Blue, and White/Green. On the Suzuki RR for these models we’re talking: Yellow, White/Blue, and White/Red. Just think them all being yellow, and then go on with the tests below.
Let’s Get Started
Switch the multimeter to DC Volts (DCV or Vdc). Switch the range to 20 or 50V. Connect the multimeter leads to the battery terminals. Start and rev the engine up to 2500 rpm. Check the battery vo
ltage.
[ Higher than 13.5V | Lower than 13.5V ]
Rev the engine up to 5000 rpm. Check the reading on the meter.
[ Higher than 14.8V | Lower than 14.8V ]
Charging system perfectly OK. You could still disconnect most of the connections on the bike and spray them with contact cleaner or WD40. This could prevent problems in the future
Count the Wire Colors
Count the number of different wire colors emerging from the RR. If there’s a yellow wire on a Yamaha RR, don’t count it. (It is a special output wire for switching the lights on and off.)
[ Four or Less | More than Four or No RR on the Bike ]
Permanent Magnet System
You’ve got a permanent magnet alternator system. Let the engine idle, and connect the black multimeter lead up to the battery(+). Connect the red multimeter lead up to the red (or white/red = Kawasaki) output wire of the RR. Leave the RR connected up to the bike. Check the reading on the meter. Leave the engine idling!
[ Less than 0.2V | More than 0.2V ]
Bad connection in the positive lead from RR to battery(+). Check the whole lead (suspect the connectors as well as the fusebox and fuses). Good connections are extremely important in this high current lead. Solve the problem and return to [start].
Connect the red multimeter lead up to the battery(-). Connect the black multimeter lead up to the negative output of the RR (Honda: Green, Suzuki: Black/White, Yamaha: Black, Kawasaki: Black, Other: Normally Black). If you can’t find a negative output wire, then the casing of the RR is normally the negative lead to the frame. Check the reading on the meter. Leave the engine idling!
[ Less than 0.2V | More than 0.2V ]
Bad connection in the negative lead from RR to battery(-). Check the whole lead to the battery(-). If the RR doesn’t have an output lead but uses the case as connection to the frame, clean the area where it is bolted and use new screws. Also check the connection between battery(-) and frame. Also suspect the plate on which the RR is mounted (sometimes it is rubbermounted and uses an extra cable frome this plate to the battery(-) or frame). Disconnect all suspect terminal and clean. Best solution: connect the RR straight up to the battery(-) with an extra lead. Solve the problem and return to [start].
If you have an RR with four different wire colors emerging from it find the switched +12V supply input. (Normally Honda: Black, Suzuki: Orange, Yamaha: Brown, Kawasaki: Brown, otherwise check the wiring diagram for the extra wire coming from the ignition switch). Connect the red multimeter lead to the battery(+) and the black multimeter lead to the switched +12V input wire (the one you just found). Leave the RR fully connected up to the bike and let the engine idle. Switch on the lights. Check the reading on the meter
[ Less than 0.2V | More than 0.2V | Less than four different wire colors ]
Bad connection from the battery(+) through the ignition switch to the switched +12V supply input on the RR. Check the whole electrical circuit. This is one of the most difficult faults to find. Suspect the ignition switch itself, the fusebox and its connections. The RR thinks the battery voltage is too low while the actual voltage is correct or too high. Disconnect all terminals and clean them with contact cleaner. If you have solved the problem, return to [start].
Stop the engine. Disconnect the wires emerging from the stator. These are usually three yellow (or white = Yamaha) wires. Switch the multimeter to Ohms, the lowest range on the meter. Measure the resestance between all three wires coming from the stator, so you need to take three readings.
[ At least one reading is greater than 2Ω or less than 0.5Ω | 5Ω > all readings > 0.5Ω ]
Bad Stator
Stator is at fault. Replate the stator and return to [start].
Connect one of the multimeter leads up to one of the three yellow (or white = Yamaha) wire. Connect the other multimeter load up to the engine casing. Check the reading on the meter. Make sure the connection to the casing is good!
[ No Reading | Anything between 0-100Ω ]
Switch the multimeter to AC-Voltage (Range at least to 100 Vac). Make sure you DON’T switch it to DC-Voltage (DCV or Vdc). Connect the multimeter leads between two of the three yellow (or white = Yamaha) wires emerging from the stator. Start the engine and rev it up to approximately 5000rpm. Check the reading on the meter. Switch one of the multimeter leads to another yellow (or white) wire and check the reading again. Switch the other meltimeter lead to another yellow (or white) wire, and check the reading again.
[ Three Equal Readings. All Higher than 50V | Not All Equal or One is Below 50V (AC). ]
Regulator/Rectifier Positive Test
Disconnect the RR from the bike. Switch the multimeter to the DIODE-TEST function. (The reading on the display will be in Volts now, not in Ohms!) Connect the Red multimeter lead to the Red (or White/Red = Kawasaki) output wire of the RR. Connect the Black multimeter lead to one yellow (or white = Yamaha) wire. Check the reading. Repeat this procedure for the two other yellow wires.
[ 1V or Lower on At Least One Test | 1.5V or Higher on All Tests ]
Bad Regulator/Rectifier
RR is at fault. Replace it with a new one and return to [start].
Reverse Regulator/Rectifier Positive Test
Connect the black multimeter lead to the red (or white/red = Kawasaki) output wire of the RR. Connect the red multimeter lead to one yellow (or white = Yamaha) wire. Check the reading. Repeat this procedure for the other two yellow wires.
[ Lower Than 0.2V or Higher than 1.0V on At Least One Test | ~0.50V on All Tests ]
Regulator/Rectifier Negative Test
Connect the black multimeter lead to the negative output wire of the RR (Kawasaki: Black, Yamaha: Black, Honda: Green, Suzuki: Black/White). If there is no output wire, connect the black multimeter lead to the RR case. Connect the red multimeter lead to one yellow (or white = Yamaha) wire. Check the reading. Repeat this procedure for the two other yellow wires.
[ Lower Than 1.0V on At Least One Test | 1.5V or Higher on All Tests ]
Reverse Regulator/Rectifier Negative Test
Connect the red multimeter lead to the negative output wire of the RR (Kawasaki: Black, Yamaha: Black, Honda: Green, Suzuki: Black/White). If there is no output wire, connect the black multimeter lead to the RR case. Connect the black multimeter lead to one yellow (or white = Yamaha) wire. Check the readiing. Repeat this procedure for the two other yellow wires.
[ Lower Than 0.2V or Higher Than 1.0V on At Least One Test | ~0.5V on All Tests ]
Bad Battery
As this was the last test, the only thing that can be at fault is the battery itself. Replace it with another fully charged one and return to [start].
Do You Have a Regulator/Rectifier?
Is there an RR on the bike? (Somewhere on the frame under the bodywork)
Integrated Generator
You have an integrated generator (car-type, with built in regulator and rectifier). Most of the problems with this kind of generator are bad connections, from generator to battery (battery doesn’t change), or a burned out regulator (battery-voltage too high). Sometimes, the generator itself is at foult. You could check the resistance of the fieldwinding (around 5 Ohms) and the state the brushes are in. Otherwise, leave it to an expert. After solving the problem, return to [start].
High RPM DC Test
Switch the multimeter to DC-Voltage (DCV or Vdc) Range 20 to 50V. Connect the multimeter leads to the battery terminals. Start the engine and rev it up to approximately 5000 rpm. Check the voltage reading.
[ Higher Than 14.8V | Lower Than 14.8V ]
Stop the engine. Disconnect the block connector to the generator closest to the engine. This connector must have at least three yellow (or white = Yamaha) wire in it and one or two extra ones. Switch the multimeter to the lowest Ohms-range. Measure the resistance between the two other wires, or between the single extra one (apart from the yellow ones) and the engine casing
[ Between 4 and 6 Ohms | Lower Than 3Ω or Higher Than 10Ω ]
Fieldwinding & Brushes
The fieldwinding in the generator or the brushes to the rowor are at fault. If there are any brushes inside the generator, disconnect them and measure the resistance between the two copper sliprings on the rotor. These are the rings on which the brushes run.
(If there are no brushes inside the generator, replace the fieldwinding or if that’s not possible separately, replace the whole stator and return to [start].
[ Between 4 and 6 Ohms | Lower Than 3Ω or Higher Than 6Ω ]
Bad Brushes
Wiring to the brushes or the brushes themselves at fault. Replace the brushes, check the wiring to the brushes and return to [start].
Bad Rotor
Rotor at fault. Replace it with a new one and return to [start].
AC High RPM Test
Connect one spare wire to the battery(+) terminal and connect it up to one of the extra wires that are in the block connector, apart from the yellow (or white = Yamaha) wires. Connect a second spare wire between the battery(-) and the other extra wire in the connector block. If you have only one extra wire, only connect the battery(+) wire to this one. Make sure the battery(-) is still connected to the frame. Switch the multimeter to AC Volts, range at least 100V (ACV or Vac). Start the engine and rev it up to approximately 5000 rpm. Connect the multimeter leads up between two of the yellow (or white = Yamaha) wires. Check reading on multimeter. Switch one of the multimeter leads to another yellow wire and check the reading again. Then switch the other multimeter lead and check the reading again.
[ All Readings Equal and Above 50V | Not All Equal or At Least One Below 50V ]
Stop the engine. Switch the multimeter to DC Voltage (DCV or Vdc). With the block connector disconnected as above, connect the multimeter leads up to the two extra wires in this connector (apart from the three yellow wires), this in the connector block emerging from the wiring loom, not the other side going to the generator. If there’s only one extra wire, connect it to one multimeter lead and connect the other multimeter lead to the engine casing. When you switch on the ignition, check the reading.
[ No Reading or Reading Less Than 10V | Higher Than 10V ]
1978 CX500 Front Brake Unstick
Posted by Randy in Motorcycle on February 26, 2007
There are a few things that will tell you that your front brake is stuck:
- Engine feels strong, but the bike is lacking pep
- After a short jaunt around the block, your front disc is burning hot
- The bike has been sitting for any prolonged period of time
To prove once and for all that your brake is stuck on, put the bike up on the center stand. Have a friend (or some other source of 200 lbs) sit on the passenger seat to get the front wheel off the ground. You should be able to easily spin the wheel by hand.
Whatcha gonna do about it?
This repair is much easier than you would think. Steps are as follows, pictures coming soon.
- Put the bike on the center stand.
- Take out the two bolts that attach the brake cylinder to its bracket.
- Slide off the brake cylinder.
- Push the pressure cylinder back into its housing
- Put everything back together
- Pump the system back up.
In theory, this isn’t necessary, but I would be afraid to work on the bike on the side stand.
There are four bolts here. Two hold the mounting bracket to the fork. Those aren’t the ones we’re looking at. The other two attach the cylinder itself to the mounting bracket.
This is probably the hardest part. The harder your brake is stuck on, the harder this is going to be to remove. Sometimes you can shake it loose. Trying to jostle it along the circumference is much more productive than perpendicular to the plane.
On my CX500, it came off in a couple seconds just jostling by hand. I did a CB450SC a couple months before and it required persuasion with a rubber mallet. Do not use a hard-faced hammer as you could mar the casing or worse, miss and mar the disc. Once you’ve got the cylinder out of the way, this is a good time to check out the brake pads.
The reason the brake is locked is that the pressure cylinder isn’t returning back into its housing when the brake lever is released. Generally, if you push it back once, it fixes the problem. If not, you’re looking at a brake cylinder rebuild which is beyond the scope of this document.
You can press the cylinder in with a C-clamp and some wood blocks or rags to avoid marring the surface or you can try neat leverage tricks using only a couple of wrenches.
That’s it really. The cylinder should go back on much easier than it came off now that you’ve pressed the cylinder back into its housing. Make sure the bolts go back in tight. This is your main brake, remember.
Moving the cylinder manually usually screws up the pressure in the system. Pump on the brake lever until it is once again firm and feels like a brake.
Jacobsen Sno-Burst Carburetor Overhaul
Posted by Randy in Small Engines on February 26, 2007
A few months back, I picked up a Jacobsen Sno-Burst on Craigslist for $20. Surprisingly enough, it ran when I got it home. I used it happily for the first half of the season and had no problems up until today. I was slogging my way through the five inches of slush that was dumped on Milwaukee last night when the thing just died. It wasn’t its normal bog-out-and-die, it was just pum-te-pah—dead. Well, as normal, I ripped on the cord a couple of times. Unlike normal, I got nothing. After a little common troubleshooting, I determined that I was going to have to tear down the carburetor. I figured I could go online and get myself a manual, but found no such luck. Since there was no such luck, I figured I would fill the void. Please read this whole guide before starting work. It’s written in my order of operations and I came upon better ways of doing things part way through.
This is a Jacobsen Sno-Burst. If your snowblower looks like the one in the picture, then you’re probably in the right place.
The first thing you need to do is take off the top cover. In the case of my old beat-up unit, there was only one screw holding the cover on. I took it out and had a look at the engine. The carb is the little metal box on the front left from the driver’s position. On initial inspection, it looked like it was going to take some wizardry to get the carb off, but I think I handled it pretty easily.
Before you can do much else, you have to detach the paraphernalia from the carburetor. The choke cable is removed by simply unscrewing the phillips head screw that secures the cable, then weaseling the little hook out of its eye-hole by hand. If your machine has been in service as long as mine has, the fuel line is going to be a pain to remove.
(Don’t forget that you’re going to have gas running out when you disconnect / puncture the line. Even if you siphon out the tank, you’re never going to get the gas that is in the line itself. I chose not to siphon out the tank, but rather had a connecting hose on hand to let the gas run into a collecting tank.)
Unscrew the hose clamp and get it out of the way. I wound up using a pair of vice-grips and ripping the fuel line apart to get it off. Even so, it left a chunk of line still on the tap that I had to cut off with a pair of dikes. Other than being fused to the tap, the fuel line was in great shape and plenty long, so I just used a sharp knife and fashioned a new end for it.
I decided that the best approach for carb removal would be to remove the carburetor and flange assembly intact from the intake body. There are two 3/8″ bolts that hold the flange to the intake body. Unfortunately, there is a little bit of difficulty getting to them. On the left side, the galley cover is in the way. (In the picture, you can also see the clear tube running from the fuel line to my collecting tank.)
On the right side, the diaphragm cover is in the way.
There isn’t a lot of room to work around the engine so getting the galley cover off required the use of a simple jig that I assembled out of a 3/8″ box-end wrench and a flat-blade screwdriver bit from my hand impact driver.
Once the galley cover was off, there was just enough clearance to fit a socket over the left-hand flange bolt.
To remove the diaphragm cover, I used the long, flat-blade screwdriver that I use to tune the carbs on the bikes.
Once the diaphragm cover is off, there is clearance to get a socket over the right-hand flange bolt as well.
Although you can get a socket on the bolts, there is no way that you’re going to get a socket wrench in the tight space, so once again I made a little jig. This one is a 1/4″ wrench, a 1/4″ hex-to-square adapter for a multi-bit screwdriver, and a 1/4″ drive, 3/8″ socket for the bolts.
Once you’ve got the bolts out, you may think you’re home free … but you’re not. The automagic throttle is still connected to the bottom of the carb. The linkage between the vacuum actuated throttle and the carburetor is flexible plastic, so you can flip the carb over with it still attached to get access to the circlip that holds it on.
The circlip (like all snap-rings) is a pain in the ass to get off. A circlip remover won’t even help you as there are no attachment dimples and the ends are too far apart to use inverse pliers. I lucked out and after a while one end of mine jammed in its galley so all I had to do was jam my trusty carb-tuning screwdriver into the circlip galley and pry out the other end.
As of now, you should be able to remove the carb from the engine completely and take it to your bench.
Be sure to put the flange bolts somewhere where you won’t lose them.
At this point, you should make sure that both your choke and throttle butterflies work easily as expected.
Also, the fuel tap may fall out. This is no big deal as it’s just a press-in part. Just be sure to put it back later.
Before we can really clean anything, we need to get the diaphragm out of the way, mostly to avoid damaging it. I had no intention of replacing the diaphragm, so I used a very sharp knife to slowly work around the edges and separate the diaphragm gasket from the carb surface. This takes time and patience. If you cut or tear the diaphragm, you’re looking at hard-to-find new parts.
Once you’ve got the diaphragm loose all the way around, you’ll notice that it’s still connected in the middle. This is the connection to the “float needle”. You can safely bend the diaphragm back a little bit so that you can see which way you need to slide it to disengage the needle. Don’t worry, nothing is going to fall out.
Once you’ve got the diaphragm off, you can start honestly cleaning the carb. Spray carb cleaner or WD-40 into every hole you can find (you need the straw) and make sure it comes out somewhere else. Pay special attention to the big hole at the bottom of the carb. That nasty brown thing is a fuel strainer. It may fall out on its own; you may need to help it with a wire or screwdriver. Clean it well and make sure the passage below it flows. Don’t forget to put the screen back when you’re done.
The trickiest and most important (read: likely to get clogged) are the tiny holes in the track above the diaphragm. One of them connects to the “bowl” under the diaphragm. The other connects to the main air passageway where the butterflies are. Make absolutely sure that these flow as they should.
That’s really all there is to cleaning the guts of the carb. If you want to separate the flanges, you can do so by taking out the two big screws by the choke butterfly.
Because of this separation, you can reattach the flanges to the engine first, and then attach the carb to the flanges with the two screws. I didn’t trust myself to line everything up well enough, so I just assembled in the reverse order of removal.
First, I reattached the flanges to the carb assembly.
Next, I reattached the diaphragm to the needle.
Next, I reattached the throttle and circlip taking care to twist the throttle linkage such that it would be properly oriented once the carb was righted.
Next, I righted the carb and bolted it back to the intake with the flange bolts, taking special care not to hurt the diaphragm which is now only loosely attached to the carb.
Next, I screwed on the diaphragm cover using my carb-tuning screwdriver.
After that came the galley cover with the screwdriver jig …
Finally, I reconnected the choke cable and the fuel line. (I forgot to take a picture with the fuel line connected. You get the point.)
Put the cover back on, put some premix in and give her a rip. Mine fired right up and ran like a dream. I hope you can say the same.
Carburetor Cover?
Evidently, these machines had a carb cover from the factory. Mine was gone when I got the machine, but Tom was nice enough to send me some pictures of his:
