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losing top end power

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

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.

it has been back firing on top end if i dont get on it runs great once i try to race i lose power on top end

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!
 
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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
 
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!
 
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
 
Wow, Great PDF. Your Amazing Glider.

Softail,
So looking at Page 4 Figure 4, I assume this is the setup you are using. If you are, there are lots of things to check. Notice the #9 Rotor. It does not state that the windows cut into the rotor are used for an Infra-red chop or ferros metal density (reluctor) identification but I would take a look and clean whatever method they use. If Photo beam method is used, crankcase oil vapors coming in contact with photo beam path would be a killer.

Questions I have:
1) Does page 4, Figure 4, resemble what you have installed on your bike.
2) Are you using the "Green" wire (Vacuum Switch for improved economy) or is it taped off.
3) Which coil are you using (can be single stock <4 ohms, or Crane 8-3006, or 8-3005 or Duals etc)
4) I assume you are using the brown wire for your electronic tach. At ANY time does your tach get erratic, jumpy, when engine starts to back fire?
5) Did bike just start breaking up like this on its own or was some change or modification made at the time this started happening.
6) Do you have access to a Good timing light.
7) Remove the access cover to the HI-4. What position are the dials in for MODE & ADVANCE SLOPE.


Hoop!
 
Wow, Great PDF. Your Amazing Glider.
What position are the dials in for MODE & ADVANCE SLOPE.


Hoop!

This is what I was referring to a while ago :D

Possible when the mech raised the rev limit he redialed in the advance curve.:33:
 
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