Bucking issue under load?

[Gary Lewis]

So even after all of this, including replacing the plugs and swapping carbs, it is still missing?

If I remember correctly you have swapped the DS-II module. But you haven't replaced the pickup module. I think that would be my next step as it is the last of the common items.

As for "laying down", I do understand that when things go quite lean. But in my experience you don't get the bucking that you are experiencing.

I think I fixed 1 thing but caused another in trying to fix the bucking.

Here is my take:

Yes I did try a used DSII box, no change, everything else is in good shape.

Changed out the coil, no change. Swapped plug wires from bad plug with another plug and will keep an eye on the 2 plugs to see if the wire was the cause or ????

FYI I pulled the metal plug end out of the good wire when I did the swap so the wires will be replaced at some point.

In trying to fix the bucking I installed a Ebay carb I have had for a year or so.

It runs a lot leaner than the old carb and this may be the cause I have now that is more of a miss than bucking like before.

When I changed the plugs this stopped the bucking but now feel a miss just about all the time when driving.

Being the AFR is running in the mid 15's to mid 16.s and some times I have seen 17's I think I am feeling a lean miss. I want to richen up the needle and jet to see if that helps the miss.

If not I will pick up a pick up coil and change it out.

I had seen it posted some where a bed coil was causing a PITA and once out of the dist. he found a crack in the unit.

Still trying to fix this.

Dave ----

That makes sense. How about just swapping the "original" carb back?

[AmericanSavage]

So even after all of this, including replacing the plugs and swapping carbs, it is still missing?

If I remember correctly you have swapped the DS-II module. But you haven't replaced the pickup module. I think that would be my next step as it is the last of the common items.

As for "laying down", I do understand that when things go quite lean. But in my experience you don't get the bucking that you are experiencing.

I think I fixed 1 thing but caused another in trying to fix the bucking.

Here is my take:

Yes I did try a used DSII box, no change, everything else is in good shape.

Changed out the coil, no change. Swapped plug wires from bad plug with another plug and will keep an eye on the 2 plugs to see if the wire was the cause or ????

FYI I pulled the metal plug end out of the good wire when I did the swap so the wires will be replaced at some point.

In trying to fix the bucking I installed a Ebay carb I have had for a year or so.

It runs a lot leaner than the old carb and this may be the cause I have now that is more of a miss than bucking like before.

When I changed the plugs this stopped the bucking but now feel a miss just about all the time when driving.

Being the AFR is running in the mid 15's to mid 16.s and some times I have seen 17's I think I am feeling a lean miss. I want to richen up the needle and jet to see if that helps the miss.

If not I will pick up a pick up coil and change it out.

I had seen it posted some where a bed coil was causing a PITA and once out of the dist. he found a crack in the unit.

Still trying to fix this.

Dave ----

Hey Dave,

This is what I was thinking—it is one of the few I found on this issue. I do not think there would be evidence of oil burning from the tailpipe—the amount is so small that leaks, it is burnt ash and therefore, can go undetectable without pulling the plugs.

https://bikerestart.com/ash-deposits-on-spark-plugs-causes-color-solution/

I also read something somewhere, that the “new” coolant does not build up as much to leave a deposit if there is a leak into the chamber. I am not sure that is the final word tho.

Keep us up to date! I am leaning toward a small leak past the guide.

[FuzzFace2]

That makes sense. How about just swapping the "original" carb back?

I might do that but I can still feel a miss it just is not bucking like it was before.

I can also feel it when the AFR is in the 13's when first taking off from a stop like a little old lady.

I think I got to fix the miss first as that has to be throwing off the AFR then deal with the carb.

I forgot I got a box of Carter YFA carbs & parts so I might be able to get the needle & jet from that supply and pop it into my old carb as I know there was something missing on the needle assy. but the carb ran good so never worried about it.

If I get out some what early tomorrow I will stop in Raleigh to pick up the pick up coil as that was the only place that had it in stock.

I also made a small screw driver that fits the hole of this new carb but I cant tell if I am hitting the screw and turning it so I try, ride, try, ride and repeat as it has not changed much so I am done for today.

Dave ----

[FuzzFace2]

Hey Dave,

This is what I was thinking—it is one of the few I found on this issue. I do not think there would be evidence of oil burning from the tailpipe—the amount is so small that leaks, it is burnt ash and therefore, can go undetectable without pulling the plugs.

https://bikerestart.com/ash-deposits-on-spark-plugs-causes-color-solution/

I also read something somewhere, that the “new” coolant does not build up as much to leave a deposit if there is a leak into the chamber. I am not sure that is the final word tho.

Keep us up to date! I am leaning toward a small leak past the guide.

I guess it could be a small oil leak in to the hole and being burnt?

That is why I also swapped plug wires because if that one was weak it may not fire strong enough to burn it off. So I will keep an eye on them 2 plugs and see.

As for coolant IIRC it was the 50/50 mix I picked up at HF as it was cheap so cant say if it the "new" type or not LOL

Right now I want to fix the miss it has after the plug change as that will change the AFR.

Then I will deal with the lean carb or may see about fixing the old one, I found a box of carbs & parts, and put that back on?

I will keep this up to date till it is fixed.

Dave ----

[FuzzFace2]

Hey Dave,

This is what I was thinking—it is one of the few I found on this issue. I do not think there would be evidence of oil burning from the tailpipe—the amount is so small that leaks, it is burnt ash and therefore, can go undetectable without pulling the plugs.

https://bikerestart.com/ash-deposits-on-spark-plugs-causes-color-solution/

I also read something somewhere, that the “new” coolant does not build up as much to leave a deposit if there is a leak into the chamber. I am not sure that is the final word tho.

Keep us up to date! I am leaning toward a small leak past the guide.

I guess it could be a small oil leak in to the hole and being burnt?

That is why I also swapped plug wires because if that one was weak it may not fire strong enough to burn it off. So I will keep an eye on them 2 plugs and see.

As for coolant IIRC it was the 50/50 mix I picked up at HF as it was cheap so cant say if it the "new" type or not LOL

Right now I want to fix the miss it has after the plug change as that will change the AFR.

Then I will deal with the lean carb or may see about fixing the old one, I found a box of carbs & parts, and put that back on?

I will keep this up to date till it is fixed.

Dave ----

Lets start with the coil, I have changed out the high tension coil the other day with no change.

Cant remember if I did that before or after the plugs? but it is "new" And we all know about new parts but I cant see it a cause at this point in time.

BTW I was told to check the voltage to the coil IIRC it was

+ = 8.75 - 9.5 maybe a little higher

​​​​​​​- = 6.75 - 8.25

The other and only coil I have not done anything with other than buy a replacement is the pickup coil inside the dist.

The new one, a Standard Products one, is sitting on the seat of the truck.

So I did ALL plug wires. I used a little dielectric grease on the plug end of the wires so hope they come off easier when I have to remove them. 

The plug wires may have helped a little as I can still feel a little miss at times.

I think before I swap out the pickup coil I will try and get the AFR up to a safe area as it is in the 16 to 17 range and that can cause a lean miss and that now can be what I am feeling?

Thing is to adjust this they only give you a 1/8" hole to put the regulator screw driver thru and then you got to feel to get it on the screw.

I may wind up removing the top of the carb a few times to get this adjusted we will see.

Dave ----

[FuzzFace2]

Lets start with the coil, I have changed out the high tension coil the other day with no change.

Cant remember if I did that before or after the plugs? but it is "new" And we all know about new parts but I cant see it a cause at this point in time.

BTW I was told to check the voltage to the coil IIRC it was

+ = 8.75 - 9.5 maybe a little higher

​​​​​​​- = 6.75 - 8.25

The other and only coil I have not done anything with other than buy a replacement is the pickup coil inside the dist.

The new one, a Standard Products one, is sitting on the seat of the truck.

So I did ALL plug wires. I used a little dielectric grease on the plug end of the wires so hope they come off easier when I have to remove them. 

The plug wires may have helped a little as I can still feel a little miss at times.

I think before I swap out the pickup coil I will try and get the AFR up to a safe area as it is in the 16 to 17 range and that can cause a lean miss and that now can be what I am feeling?

Thing is to adjust this they only give you a 1/8" hole to put the regulator screw driver thru and then you got to feel to get it on the screw.

I may wind up removing the top of the carb a few times to get this adjusted we will see.

Dave ----

Well I fatten up the carb from high 15's to low 17's to high 14's to low 15's just where I think it should be.

I can still feel a miss thru out the truck but at this point I am going to hold off on the pick up coil till I get a good run in like to the next town over on the high way and then back roads home, and see how it dose.

I still need to put the adjustment plug back in the carb so it will not leak out gas and install the air filter assy.

But it should be good to pull the trailer for the food Hall get together at the end of the month.

Dave ----

[FuzzFace2]

Well I fatten up the carb from high 15's to low 17's to high 14's to low 15's just where I think it should be.

I can still feel a miss thru out the truck but at this point I am going to hold off on the pick up coil till I get a good run in like to the next town over on the high way and then back roads home, and see how it dose.

I still need to put the adjustment plug back in the carb so it will not leak out gas and install the air filter assy.

But it should be good to pull the trailer for the food Hall get together at the end of the month.

Dave ----

I got to thinking if doing plugs & wires, I broke one wire and other felt because of age 8 years but only really used 4, that is also best to pick up a cap & rotor even that the old ones looked good.

This way I know from coil, yes coil too, to the plugs are all new for a "tune up".

Tomorrow I will change the cap / rotor and see if that changes the miss.

My son did the air filter, gas filter and breather not long ago even changed the oil & filter too.

Dave ----

[Gary Lewis]

I got to thinking if doing plugs & wires, I broke one wire and other felt because of age 8 years but only really used 4, that is also best to pick up a cap & rotor even that the old ones looked good.

This way I know from coil, yes coil too, to the plugs are all new for a "tune up".

Tomorrow I will change the cap / rotor and see if that changes the miss.

My son did the air filter, gas filter and breather not long ago even changed the oil & filter too.

Dave ----

I agree. Good luck!

[FuzzFace2]

I agree. Good luck!

I have not given up on this.

When I was doing the other work I was taking care of my wife who week ago Mon went for a medical procedure for Afib then got Covid Wed. between the 2 that really knocked her out.

Well Fri before bed I was not feeling good so Sat. morning I was at Urgent Care. Tested neg. for Covid but could be to early, it was as I tested pos. with a home test and it knocked me out.

I do have the cap / rotor and pickup coil for the dist. just need to feel a little better before I swap each one out and fingers crossed no more little miss under light load.

Dave ----

[Gary Lewis]

I have not given up on this.

When I was doing the other work I was taking care of my wife who week ago Mon went for a medical procedure for Afib then got Covid Wed. between the 2 that really knocked her out.

Well Fri before bed I was not feeling good so Sat. morning I was at Urgent Care. Tested neg. for Covid but could be to early, it was as I tested pos. with a home test and it knocked me out.

I do have the cap / rotor and pickup coil for the dist. just need to feel a little better before I swap each one out and fingers crossed no more little miss under light load.

Dave ----

I was feeling bad on Friday a couple of weeks ago but tested negative. On Sunday I tested again and within 2 minutes I had a bright red line saying "Dude, you have COVID!" So yes, you can easily test too early.

I got Paxlovid and it was a miracle drug. Worked very quickly but leaves a horrible taste in my mouth. Glad to be through with it yesterday!

Hang in there and get well!