Won't start after big bore install

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Mar 6, 2015 | 06:09 AM

#11

98hotrodfatboy

Seasoned HDF Member

Joined: Mar 2010

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From: Poolville

we all. ooopppsss....

I remember when I had no clue what the difference was between single and dual fire.... I found out. The hard way....... a real head scratcher......

Mar 6, 2015 | 08:59 AM

#12

Ultra 99

Cruiser

Joined: Jun 2006

Posts: 246

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From: Oakville, ON

Crank position sensor gone bad maybe?

Mar 7, 2015 | 12:55 PM

#13

Jameson

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Joined: Feb 2007

Posts: 551

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From: Fort Bragg, NC

Thanks for all the input guys. I haven't had a chance to look at it as I've been in the the field. Hoping to check it out tomorrow.

Mar 8, 2015 | 08:45 AM

#14

RHillbilly

Road Warrior

Joined: Jan 2008

Posts: 1,446

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From: greenwood, mo

Make sure the wire to fuel inj is plugged back in behind air cleaner,after doing my big bore that's why mine wouldn't start

Mar 8, 2015 | 05:05 PM

#15

Jameson

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Joined: Feb 2007

Posts: 551

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From: Fort Bragg, NC

Plugs are fine and the plug wires are good. It's getting fuel and spark, it'll back fire sometimes. When it does its out of the pipes and sometimes it sounds hollow. It's carbureted too. I'm going to have to tear the damn thing apart again. I'll check the cam timing and stuff. I used stock push rods. This is my first build and I did everything by going off FuelMotos videos. It literally just turns over and may pop but mostly just turns over. I have no clue.

Mar 8, 2015 | 06:34 PM

#16

prodrag1320

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Joined: Sep 2009

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From: deland,florida

I hate to keep going back to this,but how have you verified the plug wires on on right? (not just "good",if their backwards,you`ll still have spark,it`ll just pop & spit like yours is doing).looking at your coil,the top wire should be the rear cylinder & the bottom the front

Mar 9, 2015 | 09:35 AM

#17

Jameson

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From: Fort Bragg, NC

Sorry, that's what i meant by the wires are good. They are not swapped or backwards.

Mar 9, 2015 | 10:40 AM

#18

djl

HDF Community Team

Joined: Jun 2006

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From: san antonio

Quote:

Originally Posted by Jameson

If fuel and spark are there, the motor should run, not just backfire. Usually this sort of problem is always something simple, like fuel valve on the off position, no fuel, plug wires crossed, etc. Pushrod adjustment (I know, stock pushrords) can be way off an the motor will still run, just poorly. Cam timing can be off a tooth and the motor will still run, poorly but it will run. Disconnect fuel supply to carb to make sure there is fuel flow. Are you seeing a good solid fuel stream in the carb venture when you twist the throttle? Before you start tearing everything apart, check compression and see what you get; go back to basics and run all the traps first.