Need help solving this problem

Hello everyone

Cylinders 1&4 are not firing
First off, I've used the "search" feature before creating this thread. I've found a few related threads but nothing exactly related to my problem.

The best I can describe the problem is just a lack of power, it feels like I'm riding a moped now compared to what my XJ650 used to be like.

I rode the bike one evening and it ran excellent, just how it has been all summer.

Parked the bike that evening (outside), stormed/rained pretty hard all day the next day, then the following day after everything dried up I started the bike and it started just fine but was running really rough and took awhile for the engine to rev.

Tried to ride the bike even with it running strange, and the bike has no power!

What I've done so far:

Replaced spark plugs

Put the petcock into the "Prime" position

Checked air filter

Still runs poor.

Can anyone help me? The season is coming to an end for us in Wisconsin and I've gotta ride as much as I can before the winter sets in.

The bike is a 1981 Maxim 650

Thank you,

Paul-MaximXJ

 

I'd try replacing the gas. Maybe you got some water in the tank.

mikeg

 

I should have added that I topped off the tank yesterday with new gas (3/4 of a tank worth)

 

coils got wet possibly?
check your spark

 

Checked spark already and all plugs spark good

 

Water is heavier than gasoline. Topping off the tank won't do anything if there are "blobs" of water floating around in the BOTTOM of the tank, getting sucked into the carbs along with (some) gas. I would put the bike on the sidestand and then leave it TOTALLY STILL for an hour or so. Then disconnect the fuel line from the petcock, hook up a bit of appropriately-sized hose, and put the petcock on "PRI" and drain out a quart or two of gas. You'll probably get the lion's share of the water. Follow it up with some Sea Foam to "dry" the remaining water and you should be good. (Assuming it's not simply a wet wiring problem.) If it is water in the fuel, you might want to consider rebuilding your gas cap.

 

Sure sounds like something is wet still or has corroded. Try checking all the electrical connections - starting with your coils, the pickups, the TCI, Battery etc...

Make sure they are dry and clean.

 

Excellent idea. I have a feeling this is my problem.

 

I will be going through this tonight as well, hopefully with the combination of getting rid of the water if the gas (if that is my problem) and checking the electrical components I should have a properly running bike by the end of the night.

 

If you're going to be parking your bike out doors, you may want to invest in a bike cover. Just a thought.

 

Ok well I don't think it's water in the gas

I took the bike for a ride and checked the exhaust for heat

The outside two are hot/warm

The inside two are really hot!

I have spark on all 4.

 

park the bike in full sun all day.

 

It has been for two days :/

 

Have the float bowls been emptied ?

 

Try This,
Pull your plug wires off and blow out the caps & boots with compressed air. Take your plugs out and look to see if there are carbon tracks down the insulators to the metal. Put alittle dielectric grease on your plug boots pop the plugs and wires back on and see what happens when you fire it up. Moisture can stay in your boots for along time and may be shorting your plugs out. Maybe that will help. Good Luck

 

are there still puddles around the inner (2 &3) spark plugs? I would also try draining the carbs, maybe whatever water WAS in the tank got sucked into the carbs already, and it will do the same thing, lay in the bottom...

 

IF WATER RAN DOWN INTO YOUR AIR FILTERS AND SOAKED THEM, THEY MAY NOT DRY OUT UNDER THE SHADE OF THE SEAT.... ???/

 

I'm with Fitz - check the bowls

 

If you drain some fuel from the tank into a glass jar, and let it sit for a while, any water that is there should settle out and you should be able to see it. You can also start the bike at night in total darkness and look for sparking around the coils and plug wires. Should you see any, you can try using starting fluid to evaporate the moisture with the bike off, restart the bike, and re-test. Make sure that all of the ether evaporates before restarting, or you will have another issue to address!! That should help you determine if the storm was the source of the problem or merely coincidental to the start of some other problem.

Hope that helps, Mike

 

Well I think it's not a fuel issue.

I'm thinking I have a problem with the TCI unit

"Yeah, if only #1 isn't firing, it isn't a TCI or Coil issue. Both #1 and #4 fire at the same time from the same TCI signal so one cannot work without the other, unless there is a wire issue. What you should do is switch the signal wires (primary if you will) and also switch the plug wires (1&4 to 2&3 and visa versa). The dead cylinder should move to #2 then if it is a wire issue. I would also try replacing that spark plug also, it isn't unheard of for a brank spankin' new plug to be bad. If the dead hole does switch to #2, unscrew the cap, trim back the last 1/8" of plug wire or so and screw in the cap onto new wire. Make sure that the copper wire is at the end of the insulation and not playing hide-and-seek. While you have the cap off, check the resistance through the cap, I can't remember the spec though, but they are resistive caps."

^From another thread I was reading, since 1&4 are dependent on one another with the TCI unit, I'm thinking this is my best guess