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.