Maxim-x running only on two cylinders

So 1 and 4 run fine, 2 and 3 no joy.

Here is what I have done:

12 volts to both coils.
3.2 or 3.3 ohm between poles on both coils.
Sparks on all wires using same plug.
13(some) K ohm between plug wires on same coil with boots removed.
All boots were removed, approx 1/4 in rubber removed to expose wires. Dielectric grease forced into space with wires, applied to screw on boot, and then reattached.
Plugs one and four both removed and verified DE8x, can't get center 2 right now, need to get a jointed extension for ratchet. Both sooty.

Cylinders 1 and 4 are running very rich and idle very high, courtesy of PO and haven't messed with such yet. Carbs have pods and supposedly rejetted and properly mixed per PPO, but suspect PO messed things up trying to correct "problems" incorrectly.

Suggestions on how to proceed greatly appreciated.

 

I went threw the same problem when I though I needed to put pods on my X.It ran like yours with stock jets,35 pilots,105 mains. I ended up with 47.5 pilots and 120 mains.It ran good,but not as good as the stock set up that I changed it back to. If you need a air box for it I have one I'll sell you cheap. STOCK IS THE BEST.

 

did the PO have it running okay and this just started?
are the plugs getting wet when you let it idle for a few minutes?

 

I would have guessed a coil problem but it sounds like you checked them correctly.

Be interested to see 2&3 plugs.
I wouldn't be concerned about the sooty 1&4 with it only firing on those two. The mix is all screwed up since those two have to stuggle to get the crank over the hump.

Did you measure the resistance in the spark plug caps? I believe they are supposed to be 5K

A possible theory might be that the coil for 2&3 is on the weak side and if you are running very rich, that coil couldn't produce enough spark and the plugs are fouled.

Have you had it on the road since you got it or just been wrenching so far?

 

I just got my 86 x running right about 20 mins ago. No. 2 wasn't firing after a complete redo of the stock carbs. It was doing the same thing with another set of carbs. I couldn't remember if I replaced the plugs. I checked and nope, I didn't. I looked up the plugs (d8ea) and the ones in it were completely different. I think they were dr8ea-L, which I've never heard of. New plugs and she fired right off the bat on all four. Now I just have to figure out the charging problem. I'm pretty sure it is the stator. I'm not getting but 13.2 V at 4k rpm. Battery is only a year or so old too.

 

Hi folks:
When the PPO sold it, it was spinning like a top.

Then the PO got it.

The PPO had replaced the original coils with auto coils and they were originally suspended up under the fuel tank. They had slid out of the zip ties holding them and ended up on the engine block where they were shorting out on the bike, making it run rough.

Somewhere along the line, the barrel clip piece on plug # 2 had come off, making it so plug 2 wasn't making good contact. So it was running rough and in the PO's attempts to resolve things (without ever looking at the coils ... ), he had removed the pods as well. Gee, no wonder it didn't run properly ... Shop told him it needed a TCI ... pretty stupid since it turned over ... so I don't know what the PO did for certain and what was done by the PPO who is the one who salvaged the bike from a trip to the junk yard.

For the most part, he did a pretty good job, but he wasn't concerned with keeping it OEM, so I am gradually getting it back to OEM. I haven't gotten the airbox in yet, right now just dealing with the cylinders.

 

I will replace all 4 plugs tomorrow.

I forgot to say, yes, I have had it on the road. I consumed the greater portion of a tank of gas going 50 miles ... I knew it wasn't running right, but I was hoping running some seafoam through it would help ... it did, but it was still very anemic for something that was supposed to be like a thoroughbred race horse. That was when I did a spot check of the pipes and found 1 & 4 hot enough to vaporize spit and it just laid on 2 & 3 ...

 

here are my thoughts after thinking about this for a bit.
the pods are on, jets are changed to accommodate the extra air... 2, 3 dont fire. 1,4 run very rich, right?
a cylinder firing is independent of the other 3. it knows nothing about the condition of the other 3. it's only source of vacuum to pull air and fuel is through its intake and carb. it can only pull a finite amount of air and fuel at one time. if the carbs are adjusted and set right as you believe they might be, you will not run any richer or leaner on 1 and 4 if 2 and 3 are firing or not.
this leads me to think that the issue is the in the carbs for 1 and 4
2 and 3 may be a spark issue. have you tried swapping the coils around? if the problem follows, it's the coil. if it doesnt change, it's air/fuel or the sensor in the crankcase.

 

I didn't actually "swap" the coils - that is easy enough to do tomorrow.

As far as air fuel mixtures and such ... I know they *WERE* good before the PO bought it, ran it for 2-3 weeks, the screwed the pooch.

I am willing to live with his screw-ups though. He paid $1200 for the bike, spent over $300 at an incompetent/lying repair facility, lost the title, and sold it to me for $400 as a parts bike. He did get a temporary registration, which I subsequently took to BMV and got the information of the titled owner, contacted him, and got him to get a duplicate title and send it to me. It took almost 3 months, but I finally got it a few days ago. I just had to straighten out the coils to get it functional. He could easily have screwed up carbs though, I just don't know. I had them apart at one point and they were nice and clean, plungers passing the clunk test, air passing nicely through all the ports. He never had them apart so anything he did was on the outside.

I have a few other minor electrical things to figure out, such as getting the tach working, but I was thrilled to get her running (even on two cylinders) so relatively He easily.

 

Tach working?? ... The tach simply monitors the pulse signal from the TCI so if No-pulse, no tach. Weird thing is that the diagram shows it monitoring #1&4 pulse wire not 2/3
When I first got Plum on the road I had the exact same problem. Lost #2&3
I fought with it for a while and ended up taking the coils out to check them and I put the originals back in (just laying them on the valve cover) and It fired right up (which made no sense)

I put the dynas back in and bolted everything back down and it has been fine ever since (about 2000 miles)
I attributed it to a loose coil mount bolt that had shorted out the pulse signal but I was never positive of the problem.
It was running perfect on the way to the gas station and bam, no tach and no fire on 2/3...still curious to this day what caused it.

 

Well, that does bring up another issue I was going to address later: The Tach does not work and I wanted to figure out how to get it working. Additionally, there is a toggle switch to turn the radiator fan on and off. I am not certain that the thermostat itself is working either, so eventually will need to replace the fan control sensor and find a way to test the thermostat. Another wiring issue to address ...

The ideal thing would really be to replace the wiring harness on this as it has been modified in a number of places and I don't know what all was done and it is rather difficult to trace as the wiring harness was subsequently wrapped up in electrical tape most of the way ... Availability and cost being what they are, I don't see that happening soon, unless someone miraculously comes up with one they don't need any more ...

 

The thermostat is easy to test.
The hard part is getting it out!
Once you get it out, you can just drop it into a pan of water and heat to boiling. You SHOULD see it open before the water boils....and it should open completely.

While you have the thermostat housing off, you can pull the thermo switch (the big brass one with two wires)
Heat that up to boiling also and the switch should make contact somewhere around 195 degrees.
It's normally open.
If the bike is wired correctly you can jump the two posts of thermo switch and the fan should come on.

I used a heat gun to test mine but be careful.

I'm not sure if I'm ready to part with the harness I have on the shelf...but I'll think about it.
They come up on E-bay occasionally and usually don't cost a lot.

 

that sounds like a fantastic idea. Mine doesn't come on until the needle is gets to the red....at which point my radiator fluid will just about be boiling....I'd love to be able to flip a switch and cool it down. How is that all wired up? Any pictures?

 

It would be best to leave the fan hooked up as stock (with the switch) and then add the toggle swith in parallel with the existing switch.
Run a wire to each wire on the thermal switch (brown wire and blue wire) and attach to switch.
That way if you forget and don't turn on the fan, the stock system will do it for you. Also if you forget and leave the switch on the fan will stop when you turn the key and you won't have a dead battery.

 

Stumped: Maxim-x running on only two cylinders

So, here is where I am: My auxillary tank started to leak on me and I couldn't get it fixed until today.

All 4 plugs replaced.
Previously, 1&4 pretty black, 2&3 shiny but wet.

I used a lighter to burn everything out of the cylinders.

Knowing the coil/wires for #1&4 is good, I swapped the input wires to the coils and then swapped the plug wires so that the left coil was now running 2&3. 1&4 not connected, not even plugs in cylinders ( I didn't want to foul them with fuel. Tried to start 2&3, no go. I used ether/starting fluid in addition to the gas, still no go. Added plugs to 1&4, connected to coil normally used for 2&3, 1&4 fired, 2&3 stayed cold.

Swapped the coils back, 1&4 fire fine, 2&3 still cold: diagnosis: problem must exist before coils, right? Both coils and wires measure out correctly as far as ohms, enough voltage going to and through the coils as both can run cylinders 1 & 4.

I can't remember for certain right now, but I recall testing the volts and ohms coing through the wires to the coils, but couldn't swear on it.

So, assuming those wires are good, what would cause a problem where the bike would signal 1&4 to fire and not 2&3?

As noted before, although tech docs state that the tach runs off of 1&4, it appears like the tack runs off of 2&3.

I can really use some help here as am getting rather frustrated.

 

I believe I have an explanation of the DR8EA-L. I believe that they were either platinum or Iridium versions of the plugs, so would have worked fine, if they weren't otherwise fouled. I believe that the latest part number for those is DR8IEX, or something very close to that. Historically, the 'R' would indicate that it was a resister plug, but this is not the case.

As an interesting note to all, in some of my reading I have come to understand that the Maxim X wants between 5K and 10K ohms to work properly. The plug wires provide 13 Ohms between the two of them or approx 6.5 ea. Therefore, shouldn't the machine run properly with just the plug wires and without the 5Kohm resistance in the boot?

 

have you pulled the plugs and checked for actual spark? I wonder this because after I read your last post, I was thinking that maybe the cdi is bad?
speaking of cdi, what color is yours? It should have a yellow tag on it. If you don't know it is behind the left hand side cover on the opposite side of where the rectifier is. One other thing you may want to do is check all, and I mean all of your connections. Clean them and hit them with dilectric grease. Just another thought, how is your side stand relay switch (on the same panel the rectifier/cdi are on). I believe that if it isn't connected correctly, you will have no, zip, zero spark, but it's worth a try.

 

I'd have to say if you swapped the coil pulse wires and the plug wires with no joy, you must have a bad TCI.

After you swapped, did you check for spark? Sounds like #2/3 isn't getting a pulse to fire.
It has to be a spark issue. It's hard to imagine anything else that would only act on #2 & #3 without affecting something else.

Check the connections closely on the TCI and clean them up.

Just for kicks, pull the crankcase cover off the left side and look at the pick up coils and wiring. If the TCI isn't getting a signal from the pick-up it won't fire the plugs either.
Those wires are tucked in along side the oil pan so they'll be hard to look at but any damage should jump out at you.

TCIs have failed before so that's a possiblity too.

 

I haven't rechecked for spark, certainly can do that.

I'll check that and the pick-up coils/wiring after I get back from a little trip am leaving on today. I had understood that if the tci failed, it wouldn't start at all. I didn't realize it could fail for a cylinder pair.

 

I'm no expert on TCI failure....but from my understanding, it's a split circuit.
I wonder if it could have gotten damaged by the basket-case coils that were installed before?

 

That would *REALLY* suck ... but I wouldn't put it past him ...

 

When I got my xj750 It was only firing on two cylenders. I traces things down and found a short between the TCI and the coil (which ended up being the tach that had a short in it). Replaced that wire bypassing the tach and it runs great now. You may try disconnecting the tach...just a thought.

 

Sounds like a plan. I have an aquaintance back home who used to do detailed electrical work - circuit boards and such - back before it became cheaper to throw the old and purchase new. I will see if I can prevail upon him to help me.

 

I haven't yet had a chance to crack one open yet, but I would highly doubt that the TCI is a completely segregated circuit system for each pair of cylinders. I suppose this would be possible, but, as the ignition advance/retard circuit would apply to both sets, I would suspect this circuitry is common to both sets and may be the link between them...

The point, I really doubt your TCI is messed up.

However, I could totally see you not getting a signal to fire from the crank sensor. Is there anyway you can swap those sensors or perhaps flip their wiring before the TCI to see if your 3/4 start firing? (obviously pull the plugs so you don't fire on the wrong stroke)

I would also trace out your tach issue. That is too close to the problem to be ignored, you might just find by fixing one you fix the other.

 

hey, wdenny, what part of Ks you from?
I am from Hays but live in Overland Park now

 

I am from Topeka...

Worked in Kansas City (9400 Ward Parkway)

On Assignment in Canada

Hays eh? Not a bad little place... Been through several times on my way to go skiing...

 

it's gone downhill in the last couple years, but I still like visiting.

 

It is still a huge step of from Tipton.

I have relatives there, and its a big night out to hit Hays. So, its got that going for it eh?

 

Don't know if the newer model is the same as an 81 - 83 XJ550 but it might be. I traced the schematic and the coils get battery positive through a red/white wire when the key is turned on. 2 & 3 are fired when the grey wire is connected to negative through the ignition unit. Removing the grey wire and quickly touching the frame or block should produce a spark at the plugs. If it does the coils and plugs are OK. The ignition unit is signaled by a reluctor passing the pick-up coil. This is located in the engine right side cover. A volt meter connected to the grey and brown wire should deflect as the reluctor passes the pick-up coil. If it does the problem is more than likely in the ignition unit.

 

shopping at the mall and then hitting taco grande was my life in high school

 

what is the story with this bike?

I just wanted to pass on a piece of information I came across this weekend. After much troubleshooting, I think I found the problem. This maxim x had it's carbs done very well, but the fuel enrichment circuit was not cleaned. When I would go to start the bike up, it would stutter, stumble and just run like cr@p until warm. I figured, ah, what the heck, and started it sans 'choke'.

It's just as cold natured as other max x's I've had, but it actually runs on all four from the git go. I've had four max x's and I'll tell you, each one has shown me something different.