missfire/banging in the exaust starting just around 3200 rpm

[jayh]

Has paso.org been offline for a couple of days ? or was it just at my end.
Sorry Higgy can't figure out what we missed ?
it will probably be something blatantly obvious as usual J

[bobst2]

hi havent been able to log on for a couple days. to give more info. yes it the orininal air box, just did the coil upgrade so ground & connections seem to be fine. have run my hands along plug wires dident get zapped. will pick up another set of plugs & try that after i cync carbs by method above. the tool i used was a special tool bought for weber carbs(my brother works on old twelve cyclender multi weber carb cars)so i borrowed it. i will use the oil & hose method(to be shure)
i still question weather there there may be another issue mainly because around that rpm is where the spark advance comes in i have tryed a couple of digiplex boxes no change mabey pick up coil going south?

last time i checked valve clearence it was ok but getting near the tight end of spec that was mabey 200miles i will also recheck
1)RECHECK COMPRESSION
2)RECHECK VALVE CLEARENCE
3)CHECK INSPECT/REPLACE PLUGS
4)SYNC CARBS OIL TUBE STYLE
DOES ANYONE KNOW A GOOD TEST METHOD AT HIGHER RPM TO TEST PICK UP COIL


thanks it will be a couple of days before i can spend some serious time on the bike
will check back to see if there are any other ideas
thanks

[bobst2]

and i cleaned tank filter also when i changed inline & carb filter thanks

[bobst2]

and i cleaned tank filter also when i changed inline & carb filter.but seeing tank is off i will recheck flow also
thanks again

[higgy]

One idea

Make sure your vacuum lines to the ECU are in good shape and not collapsing.
Did you open up your plug gap to get the most of your coil upgrade ?

[jayh]

I replaced the wiring to the pickup coils on my 600 pantah motor with some silicone coated wire from an appliance repair store.The insulation has a habit of breaking down over time in the hot oil and is a known problem with them,then they can short out inside the altenator casing.My 500 pantah sometimes develops a miss up around those rpm which I can fix by jiggling the pickup wires at the gland nut ,so that is due for the same treatment.There is no backfiring though. Not sure if this is a known issue with the later paso wiring or not,but pickup air gap to flywheel could be an issue as well as timing alignment.The pickups can also attract loose metal filings.

On the Weber side of things ,a problem that gets worse with engine temp is usually a rich problem,I have played around with the jetting a hell of a lot over the past 12 months but I have never had any backfiring under acceleration before,only under deceleration.If is running rich from the accelerator pump it will miss around 2500 to 3500 rpm as well as down lower
but it will just feel like you should drop it down a gear,it just feels really sluggish until the rpm gets up high enough to cope with the extra fuel.I have the conti cans fitted to mine as well.A dangerous lean problem could cause the backfiring,but this should improve with engine temp not get worse.Thats why I tend to lean toward the electrical side of things.A low float level or fuel restriction(maybe faulty fuel pump) could cause this lean condition.

The reason I mentioned the coil wiring is that the upgrade mainly focuses on supplying a good strong positive supply to the coil ,a good earth is of equal importance,and that includes where the earth wire connects to the chassis,no paint,corrosion etc. J

[bobst2]

thanks i did directly ground coils & fuel punp to the battery. do you have a gap # you might suggest after coil upgrade. i very much am concerned that my problem originates with the pick up coil end of the igntion.
but i have yet to find a propper test process. going to get back to work on the bike either later today or tomorrow will keep posting results

[higgy]

depends on the plug,most have a range.
With the dynacoil gap it to the max range

[jayh]

Bob, This is an extract from the US version of the workshop manual which is a free download ,courtesy of the guys that run this site.The pickups can be adjusted for air gap,and the whole pickup mounting plate can be rotated for ignition timing.Follow the links at the top of the index page and download,lots of other important info there too. J.

[higgy]

not likely to be the pickup
they generally work or not

airgap maybe

plug gap most likely

[bobst2]

my bike has the digiplex igntion with a single pick up coil not the two pick up set up.
i have been reading from a lot of sources about pick up coil issues and a lot of the issues they list are excatly what my bike is doing.
1 driving down the road and just dies for no apprent reason
2 after it dies wait a couple of min,s & it starts right up
but will only run under a 3200
3 seems to be heat related

all of these types of problems have been in the stuff i read. i found a source of replacement pick up coil
for a very good price 30U.S. i just ordered a new one i am going to leave the bike alone untill it arrives

[ducinthebay]

The symptoms you stated sound like a pinched hose. Try riding with the gas cap open to see if you get the same thing. I had a pinched vent hose that gave me similar symptoms. The vacuum of pumping fuel out of the tank was stronger than the fuel pump, it just ran dry in the carb.

Cheers,

[bobst2]

i have been out of town working for a couple of weeks, but got a chance to work on the bike
yesturday.
i bought a new pick uo coil a few weeks ago install it yesturday & bingo the bike works normaly again

[higgy]

GOOD NEWS

[Reale]

What kind of pipes you have Bob
Makes a difference.........

And is that running or ridding with leds ?

I had the same kind of an issue, and keeps bothering me like hell, so I have to take proper steps in resolving the issue as soon as possible