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Backfires out carb

Started by Rommel, June 06, 2019, 08:23:51 PM

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Rommel

Ok so set timing to dot on flywheel, installed new pushrods, had a bent one. So fully closed opened them till snug on furthest downward position. Gaped spark plugs to 38, timing off dot to right of view hole, kicked over easy but e very time starts out with loud bam and smoke, mechanic here said try retard it 20%, now wont even kick over, it's an 80-81 fxef shovelhead, been sitting 20yrs in a convex box. HELP need it for work but no go.... been at this for almost a month...

Brrrap

Many others with greater knowledge than me will certainly pipe in, I'm pretty sure a few things could need to be addressed further than what you've described. First, be aware lifters need to relax (or pump down) when adjusting them. Opening them until snug isn't correct with stock hydraulic lifters. Second, with a bike sitting that long, real hard attention should be given to the fly weights behind the timing cover.
82nd ABN INF B.Co.1st 508th '78-81<br />1923rd Comm Group, ATC, Kelly AFB '82-86

Rommel

Ok I'll look into that thanks, oh and I have solid rods no hydraulics to old for all that cool stuff

Mule

If it had a bent push rod ,it may have had valve to valve contact and bent an intake valve.

Burnout

Stock Shovelhead hydraulic lifters get adjusted from the bottom up, not top down like EVO.
When doing this setting you must allow time for the lifter to leak down to find the bottom and to avoid valve to valve or valve to piston contact.
Take your time to do this right.
They don't call me Ironhead Rick just because I'm "hard headed"

Rommel

 
Quote from: Mule on June 07, 2019, 09:27:10 AM
If it had a bent push rod ,it may have had valve to valve contact and bent an intake valve.
Yeah we never did look into that I'll have to check that, also I have solid lifters, and with that do I tighten push rod till the lifter stops moving or do I need to pull up and just make em snug, like I already have, super nub here, I'm getting advice from all over and I think that's causing me more issues then good results

JW113

Indeed you need to get the valves readjusted correctly. But sitting for 20 years? Can you provide any more details what de-mothballing you've done besided mess with the timing and valve adjustment. How about the carb and intake gaskets?

A bent push rod, that seems like a bit of red flag if you ask me. They don't "just bend". I suspect you have a few gremlins to flush out before you have a running bike. JMO.

-JW
2004 FLHRS   1977 FLH Shovelhead  1992 FLSTC
1945 Indian Chief   1978 XL Bobber

Rommel

Quote from: JW113 on June 07, 2019, 04:34:30 PM
Indeed you need to get the valves
readjusted correctly. But sitting for 20 years? Can you provide any more details what de-mothballing you've done besided mess with the timing and valve adjustment. How about the carb and intake gaskets?

A bent push rod, that seems like a bit of red flag if you ask me. They don't "just bend". I suspect you have a few gremlins to flush out before you have a running bike. JMO.
Yeah so messing with it and all of a sudden no power to points, burned up second coil, while I checked valve issue, none that I could locate. Also with mothballing tire down to bottom end replaced pretty much everything, put her back together, come to find out, the bent rod, was to long completely closed, so idk how it worked before, but was told it ran great when it ran, idk seams to be one thing after another. Hopefully got most hammered out, now gotta figure out y coils keep going bad, they get hot then dont work on the out put side, have new spark plug  wires as well, so I guess replace all the original wireing and go from there. Re add lly sucks to cause it's my only transpo right now and cant just have it towed to a shop. So I learning as I go.. oh the joy of it all!! Goid thing though when I do ride her I'll feel like I accomplished something!! Lol
-JW

JW113

Sounds like you need to do a systematic inspection of pretty much everything. The usual cause of coils burning up is because of electricity constanly flowing through them. For example, the breaker points closed, and the ignition left on. OR, the wire from the (-) side of the coil is shorted to the frame. This is a 1980, right? So it has the early electronic ignition unit, right? You need to make sure that it is working correctly. Or is there some other ignition system on it?

So you took the top end off, what does that mean? Just replaced gaskets and back togther, or had a valve job and new rings? A stuck valve can cause a bent pushrod.

Did you pull the carb apart and do a thorough inspection/cleaning? What carb is on it, by the way?

Dunno man, if that is your only transpo, I think it's time to invest in a bicycle. Hey, it's summer!

-JW
2004 FLHRS   1977 FLH Shovelhead  1992 FLSTC
1945 Indian Chief   1978 XL Bobber