just bought a seca and it is acting weird.

Ok, I just bought this 1982 xj 750. On Friday when I got received it, it ran fine for about 6 hours then died a block from my house. I took my voltmeter and tested the battery and noticed it had a crappy low charge even when the bike was running (12.2 volts). I replaced the battery the next day and the readings were at 12.5 volts at idle and 13.4 volts with the throttle on. Bike rode great all day. Yesterday, she was having some cold start issues but when I got some starter fluid and let her sit for a while she started right up and ran great. Today I went out to ride to class expecting some cold start issues and she refused to turn over, even with the starter fluid. Someone claiming to be a bike mechanic stopped by and said that I the spark plugs were not sparking. She tried to turn over on my first attempt but it didn't hold and from then on it was just the sound of the starter.

My theory is that I may have flooded the engine initially and then run the battery down when trying to start her later. Would she not spark if I had drained the battery by trying to start her? Is this plausible? Or am I staring at a world of hurt and repairs on the budget of a poor college student?

A bike mechanic (or someone claiming to be one) drove by did a quick look at the plugs with a plug wrench and said it was not sparking. He recommended I replace the cdi outright. said that is 1 of the 3 components that usually cause that. Is there a way to test my cdi before I do that?

Any advice available on this subject would be greatly appreciated.

 

Before you replace the TCI, I'd check a few things first. Check and make sure your stop switch is working right along with your kickstand switch. Check battery voltage before and when cranking it. Check your plug caps, coils and pickup coils resistance.

If you put in your location you might find someone close to help you...

 

Thank you. I will post my results. Sadly I need to study this week so my time is limited but I will definitely follow that advice.

Thx,
Cole

 

To be more specific about the structure of your ignition system:

there are two coils, one for 1/4 and the other for 2/3. If you're not getting spark on either pair of plugs, it's pretty unlikely that the coils are the problem.

The checks mentioned by rpgoerlich are definitely a good place to start.

FWIW, my bike reads similarly in voltages to what you've seen.

 

Ok, I just went out to check the ignition since I have been charging her. She turned over which should imply spark. Letting the battery charge all night and then I can check it in the morning.

Am I wrong in this thought process? Also if anyone has some directions for how to check a stator I would really appreciate it. Battery was reading a little low which might be because she wasn't charged all the way when I started her or that the stator is actually bad.

By the way I am a brand new rider who is getting into this in order to experience motorcycles as well as to learn about how to work on them. Please dumb it down for me as much as possible. I hope the presence of such an inexperienced person here doesn't offend.

Best,
Cole

 

How many miles does this bike have on it?

MN

 

With 13.4 volts running I bet the charging system is working. Sounds like the choke passages in the float bowels are clogged.

 

Cole,

I suspect that what you are lookiing at is not serious. These bikes are notorious for hard starting when cold because the enrichment circuits (kind of like a choke) are usually grossly neglected over the years. You probably flooded the bike and then ran the battery down. I would change the plugs, charge the battery and then try it again. My wager is that it will start. You will have to play with it a bit from that point on to get a method down that will work for you to start the bike when it is cold until you have time to go through the carbs and clean out that enrichment circuit. When you get that far ask questions and the folk on this forum will guide you from there.
Best wishes

 

If the battery is low when he trys to fire up when cold, the spark could be weak and that is enough to cause trouble. These bikes need a real good battery to fire up when cold.

MN

 

Awesome guys, thanks for the responses.

The bike has 30.5 K miles on her. She has sat for the last seven years and was recently rebuilt and sold to me.

I will let everyone know what I find.

Best,
Cole

 

It IS possible for the battery to have enough of a charge to spin the motor (quite vigorously) but not have enough left to fire the ignition system. (Wouldn't have believed it if I hadn't experienced it.) I would fit a brand new set of plugs and fully charge the battery and I'll bet it fires right up.

 

Until you sort things out, you can park uphill and bump start it. I helped Charlie3 with this problem by just adding a headlight off switch to his butchered wiring harness.

You may need to go thru your starter. Also, plan on cleaning every electrical connection on the bike.

 

Not so padwan, only a spark at the spark plug will confirm that.

Not in the least, we all start somewhere. Welcome aboard.
You can do a quick charging system test with a multi-meter.
As you've discovered, your battery was a little low at idle. Charging it up is a good start to fixing that problem. Just bear in mind that the battery will discharge itself over time, usually a few weeks so ride often to keep it in good shape.
I would start by checking the static voltage on your battery. Being new and freshly charged, you should see about 12.8 volts (this is not a hard number, somewhere around that should be fine).
Start the bike and look for a voltage reading close to the static number (12.2 is ok here too). This measurement should be done at idle.
Now bring the rpms up to 5000 rpm and take another measurement. You should see at least 13.8 volts. The current curve on the chart shows that this measurement should reach about 13.4 at about 2400 rpm but this isn't what the manual instructions suggest. If you see less, you might have a rectifier/regulator problem.
Let us know what you find out.

 

I had a similair problem. Bike started normal with no problem for a while when working on it. When i finaly went to put on the road nothing. would turn over but not start. Put new plugs in and a new bat started first try and has been running with no problem for 700km. Good luck the people here will get you on the road.

 

Thanks. Gonna have to take a couple of days off of her as it is now raining and I have managed to catch the evil cough from hell. I will begin looking at all of these suggestions hopefully this weekend.

You guys are awesome.

Cole

 

my bike's "cold start" woes that led to flooding were as a result of leaking float bowl gaskets.

Also, look for vac leaks. They were also giving my bike some starting troubles.

 

Took readings on battery and this is what I have found.

At a cold engine battery was reading 12.25

at idle battery reading 12.45

at 24-2500 rpms battery at 13.4

at 5000 rpms battery at 14.08

Bike once again did not want to cold start but after careful negotiations and just a little bit of starter fluid she started right up and is working. I am thinking that my usage of the bike is not enough to really charge the battery so if I can't effectively ride her at a high rpm for a little while each day it would behoove me to place the maintainer on her overnight.

This all points to my theory that the other day I flooded her out and then drained an already low battery.

Please tell me what you guys think.

 

Inspect the Alternator Brushes for proper length.
10mm Min. (look for wear bars)

Inspect Quick-connector fm Voltage Reg. to Harness.
Special attention to plastic surrounding solid RED Wire.
Evidence of overheating indicates possible damage to Regulator.

In some cases the connector overheats ... releasing the Red Wire.
Place the Red Wire back into the Connector
Tack-weld it in place with epoxy.

 

Took her for a decent ride around Reno today. She was riding beautifully. Took her down one of our 55 mph hwys and at a light she just up and died. Rolled her to a gas station, checked the plugs, she had spark. Let her sit for a bit while I got a ride to kragen and got some more starter fluid. She started right up. Rode her home and parked her.

Noticed that when I got home she was idling at 4000 rpm. Turned her off and let her sit for 5 minutes. Turned her back on and she was idling at normal (just about 1000 rpm).

Will be checking the above mentioned red wire on the regulator after class tomorrow.

Also took another voltmeter check once I turned her off and the battery is still above 12 volts.

God she is moody.

 

Volts?
Hey, there's 9 Volts is a Smoke Detector Battery ...
But, a Smoke Detector Battery isn't going to run the Bike.

You need to bring the Battery to a Parts Store and see what the AMPS are.
Charge the Battery.
Bring it in.
Break it down for Cranking Amps.

 

I'll bet you have a two-pronged problem, and I think this symptom right here is the clue to the second "prong." It sounds from this like you've got a hanging carb slide, which means a good cleaning is in order. That, coupled with riding habits that don't keep the battery fully charged is doing you in. A bike with one slide stuck is going to be a bear to start as well.

You also may want to take a real good look at the fusebox, a known XJ Achilles' heel. Replace the fuse clips with similar ones from Radio Shack or retrofit to a contemporary blade-type fusebox.

 

whats your starting procedure ?
cold, choke at full or half and push the button.....no throttle at all
warm, push the button..........no throttle at all

 

Ok, weather has cleared up and I have been given some time to try and work on her. Now she just wont start. Starter makes all the starter sounds but she just will not turn on that beautiful engine of hers. At the moment I am completeyl lost for words on this. Any suggestions?

Oh and is anyone in Reno that would be willing to help me out here. This is a nightmare and a half.

 

Any coughs, or just nothing at all?

Have you checked for spark?

 

Yesterday she coughed once. I was in the process of releasing the throttle and inadvertantly killed any chance of keeping her going. She has not coughed at all since then. I took a key and checked for spark from the 2 outer spark plugs. left one seemed week as I had to actually feel the key to know if I was getting anything but it was there. Right one I could hear the spark.

 

Both of the outer cylinders fire from the left coil. You should check spark on #2 or #3 to make sure the other coil is firing as well.

It's also strange to have differences in spark between two plugs on the same coil unless the plug itself is misgapped, or dirty, or bad. Might try cleaning up that #1 plug.

 

Thanks. I will give it a better look tomorrow.

 

See if it will run on a generous shot of Starting Fluid.
That will "generally" clue you to if its Fuel or Ignition.

If it will Pop on Starting Fluid ... (Just spray some in the Airbox opening) you can work looking for the trouble or start on the Carbs.

 

Polock's got it right.


If you open the throttle with the choke(enrichment) on, it bypass the choke. The choke runs off the idle circuit. As soon as you come off idle, the air/fuel goes through the main jets.
I normally just barely put tension on the throttle cable, but don't open the throttle, full choke, hit the starter. As soon as it fires, I tickle the throttle a bit and back down the choke somewhere between half and full until it will run with no throttle, and let it run for a couple of minutes while I get my gear on. Then I kill the choke and take off.


Just remember the NO THROTTLE when using the choke.

 

i think i have a theory as to why your bike is giving you trouble. its probably because you go to UNR baaahahaha!

 

Thanks for the heads up lopez, I am sure that my choice in a superior school (references recent Cannon game) is part of my karma induced engine problems. LOL.

Thanks c21aakevin and polock for that start up procedure, I am new to this bike so that does help me understand a little more on the choke (enrichment circuit) for this seca. I am still waiting on my manual to arrive.

Rick, Starter fluid has been my primary method during the previous cold start problems. Seems not to be working. I will start fiddling with her when the weather clears up.

 

Ok, on break now from school and have been working on the Seca. With the previous spark issues I have replaced pretty much every aspect of the starter mechanism. Came upon the fact that the ignition coils were bad and replaced them. Now I am getting spark in all 4 spark plugs.


With the screaming that the engine was doing when it got hot, I did a clunk test and the slides were definitely not clunking in right. I replaced them with my friends carb slides and they now clunk properly. Though the 5000 rpm idling seems to still be continuing as when she warmed up it was right back to the screaming again.

She did backfire rather badly yesterday and blew out the cap on my muffler about 6 inches. I will attach a picture of that. The muffler cap has been slid back in to the pipe. Also, the Incident in which this happened with starter fluid as it was not yet starting without fluid. Today starter fluid was used and seemed to catch but the gas didn't seem to ignite. After a number of tries the gas seemed to ignite on its own, no starter fluid needed. and the backfiring seems to be continuing only not as violently.

Any further advice on this matter would be greatly appreciated.

 

If your slides were not clunking properly and you put your friends slides in and had an improvement, your carbs need a good cleaning. What was restricting your slides will not be specific only to this area, but throughout the carbs. See rickomatics carb cleaning tutorial!

 

I've been where you are, and from everything I've read about your bike, you have crudded-up carbs. There are four separate air/gas circuits inside EACH carburetor, PLUS the rubber vacuum diaphragm has to be intact, PLUS the slides have to be free in their bores, PLUS the float level must be set for each carburetor, PLUS the float valves must be seating properly ...

Do the math: we're up to 32 things that can be worn, torn, clogged dirty, or set imporperly - And any ONE of those 32 things can mean a bike that's tough or impossible to start, gets bad gas mileage, is unpleasant to ride, and may actually be dangerous (do you really want the engine to surge or stall in the middle of a sweeping turn, at speed?)

And there are all these things, on a bike that you know for sure has NOT received proper maintenance through the years. The odds are flat-out against you, man.

There are no shortcuts, there are no spray-can fixes, and no simple 'check this or do that' which can solve your problem. You have to take the carburetors off and completely go through them, per the master RickOMatic and his detailed Old School Carb Cleaning gig.

And realize this: a few decades ago, an engine design with one carburetor per cylinder was the province of Formula-1 racing cars. And now we have this design on our 550cc street bikes, where many have turned more than 50,000 miles with irregular maintenance and are now over a quarter of a century old! It's a technology marvel that these bikes were reliable in the first place - let alone 25 years down the road.

Oh yes, and my other 2-cents: You can never really be sure about rust in the gas tank on these old bikes. Smart money says to add an inline fuel filter between the tank and the carbs. I got one at NAPA auto parts for about $3. It's clear plastic, and over the next few thousand miles, I will KNOW for sure if there's rust in that tank - just by looking at it. Real cheap insurance against more crud going into the carbs.

Keep the faith, and keep us posted on how the project goes.

 

Thanks guys. I got her to work on her, and work on her I shall. I look forward to this carb battle! I am concerned about the backfire earlier though. It was rather violent and sent that cap out of the pipe about 6 inches. Any thoughts on that? It happened while using starter fluid and the gas wasn't igniting at the time.

 

You blew the baffle out when a big cloud of starter fluid flashed in the pipe.

You have to be a bit judicious with starter fluid, imagine what a blast like that at the INTAKE would have done to the rubber manifold! Like an M-80 in a plastic mailbox...

+1 This is the hard truth; there ARE NO SHORTCUTS. You either do it right or keep doing it until you do. THAT can get frustrating; better to just go all-in to begin with. Honest.

 

The carbs the carbs its always the carbs...what Chico Jim and bigfitz said
do it right the first time (hopefully) and don't forget the Throttle Shaft Seals,it works.

 

No short cuts!!
This may seem anal and repeditive but true.
Most of us tried them at some point on something only to have
wasted a lot of time/money.
Think of it this way, one tiny clog in one carb and no matter how
clean the others are it wont run right.
Do it right once and you will be smiling all day.

 

Rehabilitating an Old XJ-Bike to have it deliver peak performance to you is going to be a Multi-Project and Time Consuming endeavor.

You'll have obstacles to overcome during each Phase of restoring the Bike. It's best to tackle them one at a time and begin eliminating the reasons why the Bike won't run.

Replace the Fuse Panel.
Check the Battery's ability to Deep Charge and provide power.

Thoroughly clean your Carbs:
> Fuel Bowl Enrichment Circuit Well
> Siphon Tube
> Jets, Passages and Emulsion Tube
> Flush Passages; Inc. Pilot Mixture Passage
> Re-finish, Clean and Polish "Slide-piston" Bores

Once you are confident that all the Systems are Hunkie-Doorie; you can get-on to addressing the Fine Tuning.

You'll take great pleasure in doing the Fine Tuning after assuring that you've done everything necessary to allow you to Fine Tune and expect the Bike to respond to being Finely Tuned and made to Start quickly and run great.

 

then the carbs it is. Though I am also sure that I had a starter issue. Damned 2 pronged faults. Also, is it possible that the non factory exhaust pipe I have could be messing with my back pressure? All 4 pipes are being routed into the one pipe I attached earlier in the picture.

 

Generally most back pressure is created at the collector (where the 4 pipes converge). Your mufflers have little effect on this.

 

Ok wanted to try something before I did the carb cleaning. I have a bike that is the exact same as the seca except the non factory exhaust on mine. I have been using this bike to swap parts out and trouble shoot and have just swapped the carbs. The bike now starts. It also now immediately screams up to 5000 rpms when it starts. I know these carbs to work fine on the other bike as i have ridden it many times this last week and it did not do that on it.

I have also attempted to adjust the idle and I have also tightened the fuel mixture screws as well.

Any thoughts?

Also, I intend to fully clean my carbs out as they look better than his so I can't have some beat up engine parts sitting on my pretty bike.

 

5,000 rpm's mean the Throttles are OPEN.

Look to see if you got the Throttle cable Linkage stuck-up under the Head.

If you did ... Welcome to the Club!

DON'T Pry it.
Loosen the Carbs and FREE it.
If you Bend it ... it will Break.
If you Pry it ... You'll have Linkage Binding to worry about.

Next time you mount the Carbs ...
Tie-up the Throttle Cable Linkage Device to the Choke Activation Rod until the Carbs are secure inn their Manifolds.

 

+1

my carb linkage got caught on a clamp turned to the side..

 

Ok I am looking at the throttle connection on the carbs and I dont see anything stuck. It adjusts position accordingly with the use of the throttle. I did notice however that I used to have significant play on my throttle before it reached the point where it opened up the throttle itself. This play has all but vanished.

But yes, looking at the throttle on the carbs everything is moving and nothing appears to be stuck. Then again, I am a complete amateur and could be looking at the wrong thing since I seem to do this often as well. The part I looked at was the throttle connection to the carbs and it does adjust when I use the throttle control.

 

hold on... im going to go snap a pic, and explain stay on

 

shoot man, I was going to go and take a pic of where the throttle lever and such hits the idle screw...

but I cant see it, or feel it...

sorry

i was wrestling with a hot engine though, maybe you can trydisconnecting the cable from the arm, and keep pulling on it, and in the middle, feel for it hitting something.. if its a bolt, then you're good

 

If the cable is now tight where before it was loose you may have a
routing prob. recheck how it's run and make sure theres some slack.

 

Sorry I had to log off. Thanks for the help. I know the arm moves when I engage the throttle I just dont know if something else is keeping it open. hmmm.

 

They can be touchy.
If the cable sheath is not given enough room then it will cause
the cable itself to pull against the throttle shaft. Even more so when turning the handlebars.
Happend to me the first time I put the cable back. It looked fine
untill I moved the bars,then up came the idle.
By the way hows the weather in Reno?
I drive rigs and have been to Sparks many times.

Ron