Issues after Big Bore Kit

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Jul 14, 2015 | 02:26 PM

#11

mudsplasher

Intermediate

Joined: Dec 2014

Posts: 36

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From: Rossville, GA

Check for an intake leak.

Jul 14, 2015 | 02:29 PM

#12

Joe_G

Stellar HDF Member

Joined: Jan 2013

Posts: 2,721

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From: St. Louis, MO

Quote:

Originally Posted by Next In Line

Did you mix up the spark plug wires?

The Twin Cam has a specific firing order unlike previous Harleys.

Another good guess and certainly easy to check. I did that once (forgot my key and had to theft proof the bike somehow so I put the wires in my pocket) and had similar results as I think about it. Had a 50/50 shot and guessed wrong. lol

Jul 14, 2015 | 06:35 PM

#13

greybeard122

Cruiser

Joined: Jun 2007

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From:

I agree it will need to be remapped, but it should still start and idle. Did you reuse the same pushrods or adjustable? Is it carb or efi? If efi, make sure everything is hooked up properly, map, tps,IAC engine temp etc. Chances are its something simple.

Jul 14, 2015 | 06:40 PM

#14

greybeard122

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Joined: Jun 2007

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Forgot to mention, check and make sure you hooked up all your grounds. One wire not hooked up will make you pull your hair out!

Jul 14, 2015 | 09:05 PM

#15

Joe_G

Stellar HDF Member

Joined: Jan 2013

Posts: 2,721

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From: St. Louis, MO

Quote:

Originally Posted by misfitJason

You have two things working against you right away. Your pipes are a bad power choice and a velocity stack is a horrible thing to tune. No remap! Don't even try to start it without a remap. You are going to burn your motor up!

All due respect, but the tunes aren't so dramatic different from the stock tune that you'll burn your engine up just idling it or even riding gently. A drag strip run you might be lean enough to do some damage but even then I doubt it. I don't think we need to scare the OP like that.

But I do think he has a mechanical issue. I hope it's as easy as the plug wires reversed. And that he chimes back in to let us know what it is.

Jul 14, 2015 | 09:37 PM

#16

misfitJason

Seasoned HDF Member

Joined: Dec 2010

Posts: 6,849

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From: Florida

Issues after Big Bore Kit

Yes it is ^. A stock Harley runs a defined timing map with efi. Combine that with the fact that a stock bike runs extremely lean and then add a larger size combustion that would require more fuel and your starving it creating heat. Heat with new rings and unbroken in walls and new components is a very bad equation. Can lead to toasting a new motor by baking it. A tune can be a little off and that's ok. But using a tune for an 88 with timing for an 88 on a 95 is not the same as a little off. Oh and I do agree with you that he has something mechanically wrong but this can be a very large reason why

Last edited by misfitJason; Jul 14, 2015 at 09:40 PM.

Jul 14, 2015 | 10:31 PM

#17

Joe_G

Stellar HDF Member

Joined: Jan 2013

Posts: 2,721

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From: St. Louis, MO

Idling engine is under a lot less stress than an engine under load. Tune wouldn't cause what his problem is, nor will it blow his engine up idling. I've been tuning cars for 8 years. Not an expert but this I know.