losing top end power

Hoople

The color of the arc gives you an idea of how much "spark duration" or millijoules of spark energy you have.
Faint blue sparks are weak. Thick orange sparks are Healthy. This is simple but effective way to see if your ignition has a healthy "reserve" spark. Remove both plugs so the engine will spin easily while cranking. Take an old spark plug you have laying around. Set the gap to .060" or some very wide gap. Install it into one of the plug wires. Place the shell of the plug against the engine and crank the starter. Look at the spark. It should be easy for the coil to jump that wide gap and with a .050" gap it should be a nice thick orange color.

It is only a basic test but it may give you an idea of what is going on.
Of course you have 2 sides to test. When you test one side, it is a good idea to have the other spark plug wire (the one not under test) shorted to frame ground.
Now just mirror image what your doing to test the other side.

Hoople

I just noticed the year of your bike. Does this engine have points or were they solid state in that year?

softail 88

i meant twin fire coil and crane cam HI-4 igintion

softail 88

it is a solid state coil

glider

Do you have the selectable curve HI-4 ignition?

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softail 88

yes just had them all adjusted after the problem

Hoople

Sorry. I know nothing about Crane HI-4 ignitions. My fault. I thought you were somewhat stock.

But I have been to their factory & Dyno testing labs. They do make some very High Quality products.

Would you be able to explain.
What is your tach Red line. What RPM do you shift at under racing conditions.
If you were to put the bike in 2nd gear only and sweep your RPM under Full throttle (100%) from 2000 to 5500 (or your shift point) would the engine "break up" or back fire?

If you were to maintain say 5000 RPM in 2nd gear, would the bike "nose over" or start to fuel surge?

Hoop!

softail 88

i believe red line was just moved up to 6500 i shift at about 6000 under normal conditions but it starts to back fire around 4500 5000

Hoople

I am not knowlegable on the Crane system but....

1) How is the Crane unit TRIGGERED. Hall effect or inductive pickup. ?

2) How is Spark Advance introduced? Is it done through programming in the Crane Box.

It almost sounds like you have "Spark Scatter" at high RPM. Would you happen to have a Good Quality timing light like a Snap-On MT241 ?
If you do, you would be able to see spark scatter just sitting in your garage.

Hoop!

glider

You have an 1988 softail which is an EVO and is from what I read basically a stock engine with the exception of some ignition parts which aren't needed on that engine and the rev limit is set at 6500 and you mention nothing about if you have any settings on the Hi 4 ignition box or what they are set at as far as ignition curve.

I suggest that you are killing the motor running it over 5 grand and this may be part of the reason for your problems.

[PDF] HI-4 MOTORCYCLE IGNITION

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