backfire when cold

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Jul 14, 2017 | 01:43 AM

TRACTA1

Thread Starter

Stage II

Joined: Jul 2017

Posts: 2

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From: Rendelsham

backfire when cold

bought my first Harley it is a 1998 fatboy softail 1340 has had a top end change to screaming eagle barrels and heads mikuni carby with hypercharger air intake 2 into 1 vance and haines pipes 107k on clock had the change over to screaming eagle at 70k was back fireing when cold as had to stuffed plugs and out of tune carby replaced plugs and leads tuned carby as best I could still backfires when cold exhaust is as black as hell and have leaned it off was going to try shifting the needle down also or changing back to a cv carby any sugestions

Jul 14, 2017 | 04:46 AM

Dan89FLSTC

Seasoned HDF Member

Joined: May 2008

Posts: 21,208

Likes: 12,796

From: South Carolina

Quote:

Originally Posted by TRACTA1

any sugestions

Yes...

Use some periods.

Jul 14, 2017 | 06:47 AM

Tom84FXST

Seasoned HDF Member

Joined: Nov 2009

Posts: 15,706

Likes: 22,738

From: Farmington ,MS

Quote:

Originally Posted by TRACTA1

still backfires when cold

Out the exhaust or "carby"?

Jul 14, 2017 | 04:24 PM

daven9113

Road Master

Joined: Aug 2007

Posts: 942

Likes: 323

From: Grew up in Texas, moved to AZ

Congrats on your new bought bike. It will give you many fun miles.

Backfiring from pipes is probably an exhaust leak or running too rich.

Backfiring from carb is probably a lean condition or intake leak.

Start from there, before you make too many changes.