1985 xj700 maxim x water cooled desperatly needing help.

:cry: :cry: [hi , can anybody help? i bought my maximx over 3 years ago, took it all apart , had the frame powder coated black the tank and guards candy apple red, i needed a new exhaust so i got a mac performance one from the states along with a workshop manual on cd. put the bike back together, eventually got it running but it never ran right, i was convinced that it was the carbs, so after many times on and off the bike, balanced and stripped down it still didnt run right. all this was over a period of 18 months, i gave the bike to a garage to put on a diognostic machine. the bike ran when i gave it to him and didnt when i got it back and was told there was something wrong with number 3 cylinder . i had already had the engine in pieces, cleaned all valves and ports and put new gaskets on , so the thought of taking it apart again, the bike went back in the shed untill recently when i managed to get hold of a engine from a breaker in scotland. i fitted it , but it wasnt running right, only on 3 cyclinders,2,3 and 4 so new plugs, no differerence .took air box off, put hand over each carb whilst engine running to make sureit wasnt fuel all seemed ok there. the next time i started the bike it was only running on 2 cylinders, 1 and 4 so now num 1 was working. i went down to my local bike shop and asked what it could be, he said he thinks it could be electrical because of the different cyclinders working then not. i came back checked all the wireing, cleaned all contacts, started the bike and it only was fireing on num 4 pot. i took a spark plug out of one that wasnt to check it was sparking, i put the plug on the engine casing turned the bike over, there was no spark across the gap but if i hold the plug 3/4 of an inch away from casing the spark would jump across to the casing and was very strong . so it looks like when the plug is in the engine its not sparking , could this be the case and if so what causes it. not rode the bike yet, really looking forward to it just need this ongoing problem sorting out once and for all, many thanks marq=left]

 

Assure that the Engine Case has a Ground (Earth) Wire to the Frame.
Fabricate a Ground (Earth) Wire from the Frame to the Battery.

Clean the Ground (Earth) Connections from the Coils to Frame.
Use 320 Sand Paper. Clean - Shine the Wire End Connector.
Make the Points where ALL the Connection of Earth Wires to the Frame prepared by sanding away any paint or powder coat to INSURE that there is NO Resistance at the Earth Connections.
Paint or Powder Coat will need to be removed to INSURE the Connections are free from resistance.
ALL Earth (Ground) Connections to the Frame.

(A sanding Disc in a Dremel Tool will remove material down to bare metal without making a mess of the Paint Job.)

 

I heard the same issue with another maxim owner. Check the end of the plug wire connecting to the connector..you may just cut off an inch and screw it back in for better contact..that solved the problem in his case.

 

I had nearly the exact same issue with my X. I couldn't get spark to save my life. I'll spare you the story and tell you that my main ground (towards the rear of the coils) was loose. That fixed that problem. I had another issue on the spark on another X. This turned out to be ALL side stand relay related, all of it. I'd have spark, wouldn't touch a thing, then I'd have spark, no spark etc, etc. I finally got a good connection, doused the connection in dilectric tune up greast , made sure the connection was sound (wrapped a zip tie around that and the relay) and voila, no more issue. On my father's X, I had an intermittent spark, couldn't figure that out, that is until I employed the aforementioned zip tie trick to the cdi, and again, voila, no more issue. Hope it is that simple for you. The mac exhaust will make the bike run very differently, my suggestion is put in the time, find a stock exhaust and run that. Mine ran better stock than with that exhaust on it. Cheers

 

You might have a problem inside the spark plug caps if you get spark to arc to the engine but can't make a plug spark.

Unscrew them from the plug wires and check the resistance from the little wire screw post to the "snap receiver" that slips over the spark plug threads. And, BTW...make sure the plugs have the threads exposed on the tops (some come with a screw on cap).

They should be around 5 ohms resistance IIRC.
if not>
Take the spark plug caps off.
Pop the orange rubber boot off the end.
Unscrew the "guts"
The part that snaps over the top of the plug will unscrew.
There are three parts. The part that snaps over the top of the plug threads, a small resistor cylinder and a spring. Odds are the part that is supposed to make contact with the plug is rusty, and it's quite possible that the resistor core is not conducting any juice, and the spring is possibly rusty.
Measure the resistance of the core (its about 3mm diamter and maybe a half-inch long)
Clean the brass parts and spring and screw it back together if the resistor is close to spec.

If the resistor is toast, I have heard of others replacing that part with a section of aluminum rod the same size, but then you will have no resistance and will need a resistor plug.

But first off, take a couple readings and post back.
If you need some pics, drop me a PM and I'll email you some pics of a cap torn apart (I have four on my bench right now).

 

Mike I'd like those pics, never attempted to play with my caps.

dpawl31@comcast.net, and thanks!

 

Sorry guys, couldnt get to the pics today.
dpawl> The spark plug caps I speak of are unique to the X (water cooled 700 from 85-86)

From what I have heard they are the only bikes that used the caps...maybe the FZ700 which had a very similar engine with the 5 valve genisis head.

The plugs are buried down in the head (the tops don't even stick out)
So the caps are extra long to get down there.

HAP has a photo of them on his website and used to have a write-up about testing them.
http://www.maxim-x.com/service.html

 

hi, thanks for all your suggestions on my maximx re the spark problem , ive tested the spark plug caps and the readings are showing between 4.7 and 5.4. i,m now working my way around the bike cleaning of any powdercoat so the electrics are earthed out properly. ive seemed to of miss placed/lost my copy of the xj manual cd, how do i get to buy another one? thanks

 

HAP has done a complete write up on these plugs, but his hard drive crashed. He emailed it to me if anyone wants it drop me a PM with your email address.

Here are some of the pics that is included in the very long cleaning procedure that he did.
http://www.maxim-x.com/pix/plugcaps/1-m ... _parts.jpg
http://www.maxim-x.com/pix/plugcaps/2-m ... rparts.jpg

Then make them look like this
http://www.maxim-x.com/pix/plugcaps/spa ... ploded.jpg

But, it sounds like yours are fine Nige...spec is 5K Ohm

 

i,d taken them apart aswell just as precaution and all of the componants were like new. yesturday afternoon after cleaning all the earths on the bike that i could find and it still only fireing on no4 pot i took out no4 plug and put it in the plug cap, earthed it on the engine casing and it sparked across the gap as it should then i tried the same plug in the other three caps and it sparked as it should, strange. then i tried it with the other plugs they wouldnt spark unless i held the plug away from the casing. mmm i wonder if the new set of plugs i,d bought were dodgey. took them back to bike shop and explained everything he said if the bike is running to rich it fouls the plug very quickly and makes them not spark across the gap, he comes across it all the time when repairing bikes . so i bought a new set of plugs, not pup them in yet but fingers crossed it solves that problem.
the bike shop to set the mixture screws so that it runs weak. i had set them at 2.5 turns out. does it let more air in if i screw them in? what should i use as a starting point?

 

Screwing them in leans the mixture, screwing them out makes it richer.

 

thanks joe