Max-xj700x Refurb

k-moe, I recently purchased an '86 Maxim (water cooled) X, and both coils test open circuit. I have spares from a donor bike, but do you know if these CB750 coils would also work on my Maxim X? (I like the convenience of replaceable wires) -Thx

 

just to be sure when you tested coils it was primary wire to primary wire then spark plug wire to spark plug wire?

also if the spark plug wire was the open did you remove the caps for the test? the caps could be bad

 

XJ550H, I have only tested the secondary side of coils. But I took the plug caps off (they tested good), and for the coil test, I inserted one lead into the No. 1 plug wire and No. 4, then tested wires 2 and 3. The bike was running only on cylinders 2 and 4. -Caps tested well at 9.6k - 11k ohms.

Sidenote, I'm running non-resistor plugs (D8EA NGK)

 

if bike was running on 2 and 4 . coil pack controls plug 1 and 4 other coil pack runs 2 and 3.
I would trim back the plug wire just a little to see if it fires on the offending cylinders. ends of wire may be corroded.
I would also swap plug wire from 2 to 3 to see if the problem follows the wire.

could be a bad plug so next would be to swap non fire plug with firing plug to see if the issue follows plug.

you do this test before buying coils.
in above if the issue follows swaped part it will help confine the trouble spot

 

your caps are out of spec
1986 SX/SXC models: 15K +/- 20% = 12,000 to 18,000 ohms per cap acceptable range
plugs should be resistor type for an 86
1986 SX/SXC models: 5K ohms per plug

are you sure of the year?


XJ700-X water-cooled models:

Pick-up coils:
120 ohms +/- 20% = 96 ohms to 144 ohms acceptable range


Ignition Coils:

Primary side (input from main wiring harness):
2.7 ohms +/- 10% = 2.43 ohms - 2.97 ohms acceptable range

Secondary side (spark plug wires, without their end caps):
12K ohms +/- 20% = 9,600 ohms - 14,400 ohms acceptable range


Spark plug caps:
1985 XN/XNC models: 10K +/- 20% = 8,000 to 12,000 ohms per cap acceptable range
1986 SX/SXC models: 15K +/- 20% = 12,000 to 18,000 ohms per cap acceptable range


Spark plugs:
1985 XN/XNC models: 0 ohms per plug
1986 SX/SXC models: 5K ohms per plug

 

XJ550H, my build date is 08/85 (but vin decal shows 1986 and shorty vin lists 1NW00), but I also noticed that the coils have salvage yard writing on them, so it's possible these are the from an '85 donor bike. I even took a couple caps apart and tested the resistor core values.

I was under the impression that 10k caps with non-resistor plug was used in '85 and total resistance for '86 years should be approx. 15k per cylinder if adding up plug, cap and wire resistance.

I like your idea of shortening the wire a bit to get a better connection, if there's enough length.

 

you cut off about 1/8 inch

85 and 86 coils do cross fit so that is good.

there are plug wire splicer out there ngk and ngk style I have used the ngk style (not NGK brand) with good results half the price of NGK and comes with plug wire

MODEL NAME: XJ700XS
STREET NAME: 1986 XJ700 Maxim-X
MODEL ID CODE: 1NW
FRAME ID: 1NW
SERIAL NUMBER STARTS AT: 000101

as to the caps and plugs yes a total resistance of wires and caps and plugs is ok to use.

add plug wire to 2x caps and 2 x plugs if it comes between all the plus and minus specs it should be good.

my problem is your caps are out of spec at Caps tested well at 9.6k - 11k ohms. unless thwy are 10k caps so that may be an issue

Spark plug caps:
1985 XN/XNC models: 10K +/- 20% = 8,000 to 12,000 ohms per cap acceptable range
1986 SX/SXC models: 15K +/- 20% = 12,000 to 18,000 ohms per cap acceptable range
while 9.6 to 11 k ohms is in spec for 85 it is out of spec for an 86.
if they are 10 k caps they are good but if they are 15 k caps they are out of spec and I would question if the caps are working properly

issue with non resistor plugs
you have zero ohms vs the 5 k ohms speced for your year

you are down 5 k on caps and 5 k on plugs

your tci is the same so I do not know why the 2 years are speced different

after you trim wires back se if you are firing on all cylinders. if not, then do the wire swap to see if problem follows wires.
you can try the caps next if the problen follows the wires
this will test wires and caps
if problem does not follow wires do a plug swap to see if the problem follows the plugs if it does replace the plugs.

you may also test spark against the cylinder with the spark plug out only 1 plug per coil at a time leave the second one installed.
a sparking plug out of motor may not spark in motor.

if you find you have spark across the plugs and the issue does not follow the wires or plugs you may have a different issue

if issue remains the same could be a fuel issue or valve spec issue

 

at this point if you want to go deeper I would suggest starting a thread on your bike. maybe a moderator will add the conversation we have had to it .

after reading the xj4ever catalog I do not think the cb 750 coils will be a direct bolt on

 

Thanks 550, I appreciate your time and advice. I will dive further into troubleshooting the coils and plug wires, like you mentioned. Fortunately, I have a complete '85 Maxim X parts bike that the coils tested good (just in case I need to swap).

 

@Max 700-X New thread created.

 

Thanks k-moe, so to give everyone reading this thread some background, I recently purchased a 1986 Maxim XJ700X, and was fortunate enough to find a complete non-running '85 Maxim X parts bike for a great price. My intentions are to get this '86 fully functional and road-worthy. I haven't had the bike for very long and I never tinkered with bikes much, but I've been a car mechanic and hobbyist for a long time so I'm optimistic I'll catch on quickly.

Some issues about the bike: previous owner stated it has a charging issue and runs on the battery only, which I'm hoping is nothing more than a case of dirty contacts, need of new brushes. or maybe a rectifier. The carbs are in poor order and someone ditched the OEM airbox and installed inexpensive pods (fortunately my parts bike has the box and boots I need to reinstall), and right now the engine's only firing on two cylinders (when I can even get it to light), so I'm currently troubleshooting spark. The rest is somewhat cosmetic or minor, for example the clutch and front brake handles are both broken, mirrors and side covers were missing and someone spray painted everything black.

On the plus side, the bike is in good shape, tires are good, all gauges appear to work and light up, (when the engine starts) I get no odd sounds or smoking, seat looks to have been reupholstered well, brakes work, battery is new and tank isn't beat up.

I've done an oil change already and have spent some time cleaning up the bike on days when the weather allowed. I'm sure I'll have many questions as I tackle the problems, one by one, and want to say thanks in advance for any help with questions I may have. There seems to be a great wealth of knowledge here and helpful members!

 

once you get the charging system fixed I think your issues may subside. these bikes like a full charge on the battery to start

this link has good info on the charging system and its repair
The Ultimate Relay, Switch, Sensor, and Diodes Guide

 

Very good info, and I agree that re-establishing charge back to the battery will go a long way in helping any electrical woes this bike has.

I hope to perform a compression test this weekend with a fresh battery and TCI disconnected. I'm expecting a cold engine (in cool weather) might deliver slightly less cranking compression than the std. 159 psi, however, I'm more concerned about variation between cylinders at the moment.

 

Air temperature won't affect compression enough to show up on a gauge.

 

So this past week I've removed the rear fender and 'Maxim X' side brackets to sand and paint. While everything was disassembled, I decided to add better condition rear turn signal lights and aftermarket rear brake light. I'm not a fan of the bulky OEM brake light, but will be wrapping up the original so I can return it to stock if I want later. The new one's smaller and less obvious so as to not distract from the lines of the rear fender. I also took the side covers from the parts bike and prepped and painted them. I'm using a dupli-color paint called graphite mica metallic and light clear coat to compliment the black frame, engine, and wheels. I'll try to take some progress pics

 

When you get rear-ended cuz someone didn’t see the dinky little brake light, you’ll wish you kept the bigger one on.

 

What he means is that your safety is more important than style.

Tony

 

There are more stylsh brake lights that are big enough to be seen.
The "lizard brain" that keeps us alive (usually) by warning us of threats is triggered by two things. Perceived velocity of an object towards us, and size of the object.
We can trick that part of the brain into percieving a threat in advance by adding brightness (in essence the opposite of camoflauge). Reducing size from that equation makes any bright object seem further away than it actually is, and conversely increasing size makes it seem closer (a greater threat).

I've nearly hit other motorcyclists who had dinky tail lights because they were too small to trigger the fast-reacting "lizard brain." In each instance I was not following too closely, but they were braking hard.

 

I appreciate everyone's concern, but, rest assured, I have no desire of sacrificing my safety.

By 'less obvious' I meant a brake light that would protrude less from the fender, not one that would make the brake signal harder to see. My hopes are the new light will be brighter and easier to see than the hazy, incandescent, 35 year old.

 

Took my carbs off this weekend and started disassembly. Was pleased to find that the intake boots were fairly pliable. Since my bike didn't have an airbox, I made quick work of removal.
Carbs were very dirty, as expected, but as I removed the first fuel bowl, I was surprised at what I saw (or didn't see). Continued removing the remaining three bowls......anything jump out from this picture?!