Low idle/slow off idle after timing advance?

[benwjj42]

Today I modified my timing plate based on instructions here: https://www.fjowners.com/index.php?topic=4292.msg38140#msg38140.  After the timing advancement, the bike idles at about 500rpm.  It also bogs off idle when given throttle (1/4 turn) when in the advanced position.  Adjusting the idle screw results in a slow return to idle but does not affect idle speed.  Any suggestions?  Perhaps I am exacerbating a carb problem which was already there and needs to be addressed?

Background:
This is a new bike to me, but it has stock exhaust, airbox removed with a single foam filter for all 4 carbs, and a K&N stage 1 kit done to the carbs from the previous owner.  Instructions for the k&n kit attached.

[ajacstern]

I can't remember exactly what happened when I did my timing advance mod, but iirc I didn't have to do anything to the carbs or if I did it was only turning the throttle stop a bit. I know there wasn't any bogging off throttle. I was on upsized Yamaha jets and I am now on the Dynojet kit.

It would make sense to me that if you were running lean already with the K&N and are now running advanced you would require even more fuel, thus exacerbating a carb problem or something like that. Possibly you could try raising / lowering the needle and seeing if there is improvement.

[fj1289]

Today I modified my timing plate based on instructions here: https://www.fjowners.com/index.php?topic=4292.msg38140#msg38140.  After the timing advancement, the bike idles at about 500rpm.  It also bogs off idle when given throttle (1/4 turn) when in the advanced position.  Adjusting the idle screw results in a slow return to idle but does not affect idle speed.  Any suggestions?  Perhaps I am exacerbating a carb problem which was already there and needs to be addressed?

Background:
This is a new bike to me, but it has stock exhaust, airbox removed with a single foam filter for all 4 carbs, and a K&N stage 1 kit done to the carbs from the previous owner.  Instructions for the k&n kit attached.

#1 How did the bike run before adjusting the pickup plate?  Did it have the off idle bog?
#2 When adjusting the idle - are you using the large adjustment knob under the rack of carbs (really good placement for burning your hand if you don't have a 90-degree screwdriver!).  Or have you messed with one of the balancing adjustment screws?
#3 Are you sure you slotted the pickup plate in the correct direction?  Looking at the end of the crank, the engine rotates counter-clockwise; so the pickup plate needs to rotate clockwise to advance the timing.
#4 if you rotated the pickup plate in the correct direction, did you go too far?

Overall, I'd expect the idle speed to INCREASE not decrease if the timing is advanced.

As an aside - this is one of the tricks you use to help create a smooth idle on an engine you convert to EFI (especially if you don't use an idle air control) - set the idle speed timing a couple degrees LESS than optimum, then add timing to the table BELOW the desired idle speed to help accelerate the engine back up to the desired idle speed if the engine idle "sags" a little for some reason. 

[benwjj42]

Today I modified my timing plate based on instructions here: https://www.fjowners.com/index.php?topic=4292.msg38140#msg38140.  After the timing advancement, the bike idles at about 500rpm.  It also bogs off idle when given throttle (1/4 turn) when in the advanced position.  Adjusting the idle screw results in a slow return to idle but does not affect idle speed.  Any suggestions?  Perhaps I am exacerbating a carb problem which was already there and needs to be addressed?

Background:
This is a new bike to me, but it has stock exhaust, airbox removed with a single foam filter for all 4 carbs, and a K&N stage 1 kit done to the carbs from the previous owner.  Instructions for the k&n kit attached.

#1 How did the bike run before adjusting the pickup plate?  Did it have the off idle bog?
#2 When adjusting the idle - are you using the large adjustment knob under the rack of carbs (really good placement for burning your hand if you don't have a 90-degree screwdriver!).  Or have you messed with one of the balancing adjustment screws?
#3 Are you sure you slotted the pickup plate in the correct direction?  Looking at the end of the crank, the engine rotates counter-clockwise; so the pickup plate needs to rotate clockwise to advance the timing.
#4 if you rotated the pickup plate in the correct direction, did you go too far?

Overall, I'd expect the idle speed to INCREASE not decrease if the timing is advanced.

As an aside - this is one of the tricks you use to help create a smooth idle on an engine you convert to EFI (especially if you don't use an idle air control) - set the idle speed timing a couple degrees LESS than optimum, then add timing to the table BELOW the desired idle speed to help accelerate the engine back up to the desired idle speed if the engine idle "sags" a little for some reason. 

1. It ran reasonably before the timing advance. Idle was a little low (800rpm) but I hadnt addressed that yet because  I could hear a slight imbalance between the carbs at idle, but no major bog off idle.
2. Using the large screw between the middle carbs.  ouch.  I wouldnt mess with the individual carbs until I have some time to hook it up to my vacuum meter and get it all syncd up.
3. Looking at the images linked in the instruction post it looks like the slots were made in the clockwise directions, allowing the plat to rotate in the counter-clockwise directions.  Am I wrong here?
4. I have an engineering background and can assure that the plate was note rotated more than 4deg. Good ol maths and protractor to verify.

[RPM - Robert]

Looking at your number 3, it appears you have retarded the ignition instead of advancing. You should have slotted counter clockwise and rotate the ignition plate clockwise.

Start there but it could be a pilot circuit problem. It is common with a clogged pilot circuit for it to die when rolling into throttle.

[Bones]

The advance mod wakes it up a bit down low not deaden it so I'd say you slotted it the wrong way. The holes need to be slotted to the left so the plate can rotate clockwise.

[fj1289]

benwjj42 - any follow up on this?