Full throttle cutting out : V-Twin Forum: Harley Davidson Forums

blt93932 · 07-31-2009, 08:25 AM

My 94 Fat boy is cutting out under full throttle once I hit 2nd gear and above. It almost sounds like it's starving for something. It doesn't cut out for a long time, just split seconds, then ok, then cuts ok, then ok.

It has a crane HI-4 ignition, not sure what else has been done to it. The front cylinder spark advance dial is turned all the way to the right. Plugs are gapped at around .042. It has an aftermarket cam, not sure which one. S&S Shorty carb. Straight pipes.

The other thing I noticed was pretty bad mileage. My first complete fill up sine I bought it yielded 33 mpg.

**baggersport** · 07-31-2009, 08:51 AM

Probably the straight pipes....install a cheap baffle or a homemade "lollipop" type of reversion thingy....see if that helps.

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Dr.Hess · 07-31-2009, 08:54 AM

33MPG isn't too bad, depending on a lot of things like wind, etc.

Did it always to this cutting out thing or is this something new? The main jet could be clogged up, especially if the bike has sat for a while. The S&S carbs will plug up the main jet pretty easy. Fortunately, it is easy to get to by just pulling the plug, catching the gas that will fall out, then removing the main jet with a short fat screwdriver. The S&S main jet remover tool makes it really easy, but a screwdrive will work just fine. Clean out the main jet really really well. I usually run a wire or something through it, even though they say not to, but that's the only way I can ever get all the crap out of it.

4XLT · 07-31-2009, 05:49 PM

also you might want to check your petcock filter just in case

blt93932 · 07-31-2009, 10:03 PM

I've only had the bike for a month so I don't know how long it's been going on (I also don't know whats been done to the bike

)

I was going to switch it to points from the HI-4 since I've heard some bad things about the HI-4.

I'll look into the things you guys have told me, the only bad thing is as of now I don't have a work area indoors, just outdoors, so before I get into any projects I have to make sure the weather will be perfect.

By the way, any problems putting on a bigger tank? Any you would suggest?

**DBChoppers** · 08-01-2009, 11:24 AM

The HI-4 is a piece of junk, but before you start replacing a bunch of parts check your charging system and try another known good battery.

Beemervet · 08-02-2009, 12:31 AM

Quote:

Originally Posted by blt93932

I was going to switch it to points from the HI-4 since I've heard some bad things about the HI-4.

No need to go to points. Get an ignition from Dyna or similar. You should never have to fuss with it again,

Besides, matchbooks aren't as easy to find these days.