Engine Runs A Short Time Then Stalls

[Laitch]

black coils . . .now only an intermittent spark

Your moto is stalled until you do something about this. New orange-top coils cost upwards of $200 per two-cylinder unit. Used orange-tops can be had for as little as $30 per two-cylinder unit right now on eBay. If you're certain the connections to the coils are providing enough current, then replacement is your only option.

Where are the coils from the other engine?

[Laitch]

. . . my radiator is full and catch can is half full . . .

That container is not a catch can and should not function like one. It's a coolant reservoir; the cooling system is designed to draw coolant from the reservoir into the radiator when necessary. If the hose outlet inside that reservoir is not fully immersed in coolant, you're defeating the system. Of course, that doesn't matter right now because your moto doesn't run; however, it will matter when your ignition system allows the engine to run long enough to get hot.

[Paul_Waterloo]

I am late to the party, but I would bring a timing light with me when I did a ride, and when it dies, put it on all four spark plug wires, one at a time, to determine if they are all dead.

Reading this thread it almost seems like you have a cold solder joint somewhere, like in the Motoronic unit, once it heats up, it open circuits and cuts the control circuit for the spark.

Like I said, late to the party, just offering some advice.

[volador]

^ kudos Paul did you read this thread? http://www.motobrick.com/index.php/topic,13767.msg123295.html#msg123295   

[85killzillaRS]

Paul, you may be late to the party
but as the saying goes
better late than never
thank you for tip
as said about cooling, ﾏ won稚 need unless it actually runs 
motor came without coils or alternator
ﾏ would have attempted to sell those separately also
thnx for now

[85killzillaRS]

ﾏ do know the can actually gives and takes as in a lot of 4wheeled vehics,
was slightly easier to call it that though
RESERVOIR

[volador]

Paul, you may be late to the party
but as the saying goes
better late than never
thank you for tip...
thnx for now

Potius Sero Quam Nunquam

How ironic you should say

We chip in for Paul's Aerostich shirt

[Laitch]

Reading this thread it almost seems like you have a cold solder joint somewhere, like in the Motoronic unit, once it heats up, it open circuits and cuts the control circuit for the spark.

Irregular sparking is one of the symptoms of coil failure but it seems like in the heat of an El Paso summer, coil failure, cold solder joints and cold cuts could all be likely candidates. 

[The Mighty Gryphon]

In the time I've been hanging around these forums, I've seen a fair number of those early coils fail on other bikes.  There is a reason the design of the coils was changed in 1986 and the earlier version was discontinued.

[85killzillaRS]

bought a pair of orange tops today, cheap, Thanks Laitch
i値l be riding again real soon, for a few miles anyway   

[Laitch]

i値l be riding again real soon, for a few miles anyway   

It's too early for a victory dance. Party on general principle and send out an early invitation to Paul_Waterloo. 

[85killzillaRS]

ﾏ got some k11 igniting coil packs. same size and cover mounts. spade terminals are gone and theres a plug connector for the two hookups and the ground mounts to frame instead of back through wiring. that was easy enough to connect. needed new plug wires for new different coil terminals. ﾏ sent back, free returns, just paid return shipping. so ﾏ did get proper coils. bike runs good now. was just about to go for ride and ﾏ noticed the fuel rail has a small leak at front end and is spraying fuel. So ﾏ pulled it off and have started searching online for replacement. Apparently i知 not riding this weekend.
If anybody has a fuel rail, let me know!!!

[Laitch]

ﾏ noticed the fuel rail has a small leak at front end and is spraying fuel.

Clean the leak area with lacquer thinner. Sand it with emery cloth. Let it dry then apply JB WaterWeld over it according to instructions. Let the JB cure for a couple of days in the Texas heat then see how that works for you while you're waiting for a rail to turn up.

It'll be exciting!

[The Mighty Gryphon]

If it were mine, I'd remove the rail and take it to a welder to have it brazed.  Heck, silver solder may work as well.  JB Weld under pressure would make me a little nervous.

[Laitch]

  JB Weld under pressure would make me a little nervous.

That's the exciting part. 

JB claims WaterWeld resists the effects of gasoline and 900psi. I used it on a pinhole pressure line leak in the 5.0L F250HD and it has worked for two years. It's an elderly F250 though, so there's really nothing to lose.

[Laitch]

You can get a new one from Max for about $85, zilla.

[85killzillaRS]

it痴 already off, i知 going to cleanit really well then braze the ends. a good soldering sounds good too👌