I just picked up a thunderheader for my 1987 heritage softail.It is all stock.Do I need to rejet for the thunderheader or will it be ok?If I need to rejet any ideas what jet size to start with?The carb has a part# 27029-86a on it if that means anything.Thanks for the help in advance.

 

First off, depends what size of jets that you're currently runnin'. I'd just run the bike as is; it may not need anything. Adjust accordingly. Check your plugs periodically. They should be a llight tan color. If they're white then your jets are too lean, if the plugs are black colored then you're too rich.

 

I just got the bike about two weeks ago and have been working on it since I got it.Tires,oils,just the general stuff.I did notice that the bike had a popping noise out the stock pipes when you let off the gas and the plugs are alitle on the white side.I may need to go fatter on the jets.I have never messed with the jets on a Harley.I guess I will have to pull it apart and see what is in there now.I am waiting on my manual to show up.Just thought someone may have the same set up and give me a starting point.

 

I think that it's primarily a trial and error type of thing; Since you know that you a little on the lean side, you probably want to fatten it up some as you say. Get several sizes of jets and experment until you find the combination that works for you. At any rate that's how mine has been. In reality it all works together, cam, carb, pipes, ignition module, coil ,pistons, and head work if you have any. Stock evo's are a pooch out of the box.
52-57 HP.