As some will know did top end rebuild on a 1986 FLST, valve re-grind, cylinders re-honed, new rings, oil seals etc, fitted an ev27 cam and rebuilt the S&S Super E carb.
Bike starts and goes great also ticks over ok, but, the bottom pipe, (front cylinder) has a lovel steady thump thump. The top pipe, (rear) has a more lumpy thump and not as smooth or steady and will give a definate THUMP every cycle, also, the top pipe sounds louder....
Tried swoping leads in coil and plugs, no difference.
The exhausts are porker pipes with Big City Thunder baffles and the top one is considerble shorter, would the difference in lenght cause this?
I did mark ignition well and think the timing was set up as before work, but if timing was off (or need re-timing) could this be the cause?
It is not a major problem, and I think it was the same before work, (which makes me think it might be pipe lenght) but I would like to know why.
Any ideas, as usual, deeply appriciated.
Thanks
Tony.

 

If it fires up quickly when you crank it over, Chances are that your timing is good. i do wonder if your running adjustable push rods though, & if you are, have you double checked the clearances??
Plug gap is important on that mid 80's era & should be between .038 & .041.
If they are too close, your bike will run like a moped.
Warm it up, do a compression test with the throttle wide open for max air.
What kind of oil are you using & how have you been riding the bike while the rings re seat?
Hatch.

 

Hi Hatchetman, that was quick.
Standard push rods, did check plug gap, set at .040, would hope that compression is ok after fitting new rings using standard Harley 20/50 non synthetic and have only about 40 miles on bike since work and to be fair, found it hard to hold back ALL the time......... but never over reved.

 

Sounds good so far! For the next 800 km, try to use the throttle on & off, not steady. This will help in seating everything. Like riding through town where your always working the throttle.
What happens when your on a highway for a long time is your set to 1 throttle position. The bike is up to speed & very little effort is needed to hold it there. Your throttle is steady & the bike begin's to lean out on it's fuel air mixture. That should be avoided for a while until it's had a chance to wear in.
Keep your ears open for changes in sound & performance for the next few weeks!
Keep us posted on your progress!
I am just starting to put mine back together & I am doing exactly the same work on mine that you have just done!
Hatch.

 

Thats cool Hatch.
Hope your re-build goes as smoothly as mine.
Will keep it easy for 800km or so, (if I can).
Perhaps all will be ok when everything beds in. Would like to change exhausts but with the Celtic Tiger well and truly extinct, will have to wait awhile.
It is a great feeling when you do a job like this that when you go to fire her up all works ok,
It is half the enjoyment of an older bike, not like the newer ones where it is a sensor for this and a sensor for that and you have to be a computer whizz.
Will let you know if things settle down ok.
Thanks
TC