Topic: Exhaust 2 and 4 much cooler than 1 and 3?

[ChopSticks]

Youre right Gene.

His IMS are on the airbox side, so they meter air into the idle circuit.

Chop...if your vacuum sync was done properly, using the lock nut and screw on top of the carbs, then great.  leave it.


The IMS now need to be adjusted for each carb to get the proper air/fuel mixture. 
If the plug for carb 1 is Darker than you want, turn the IMS for carb 1 OUT about 1/4 turn, and retest/repeat until the plug is med brown.
(If the plug is too white, turn the IMS IN .25 turn, retest/repeat until the plug is med brown)

Repeat this for each carb/plug....but you gotta be certain the vacuum sync is done properly...first.
revisit it if you are uncertain.

Alright just to confirm

Buy new plugs
Install into Carb #1
Let bike idle
1/4 out
turn off
inspect?

How long should the bike idle for between each plug check?

Also any idea why exhaust 3&4 temp would change if the IMS was never touched between the adjustments?

[flybox1]

changes in vacuum will have an effect on temps.
idle plug chop:
Set all IMS to 1 turn out
Put new plugs in ALL Cylinders.
Put a fan on your engine.
Start the bike and let it idle 4-5 minutes with no blipping.  Just idle.  turn off the engine.
Pull out the plugs and post a picture of all of them, side by side.  1-2-3-4.

[ChopSticks]

changes in vacuum will have an effect on temps.
idle plug chop:
Set all IMS to 1 turn out
Put new plugs in ALL Cylinders.
Put a fan on your engine.
Start the bike and let it idle 4-5 minutes with no blipping.  Just idle.  turn off the engine.
Pull out the plugs and post a picture of all of them, side by side.  1-2-3-4.

Since all the vacuums should be the same now via carb sync what else would cause temp differences?

Also should I look to purchase the plugs in bulk? I know I'll eventually have to do a plug chop when I get it on the road, do I have to use new plugs then or could I reuse old ones?

[flybox1]

A/F mixture issues
Unseen vacuum leaks
Weak spark (check your plug caps with an ohm meter)

I try to start my idle plug chop on the lean side, and work up to brown from there.
Once they are rich/black, they're only good for riding unless you can blast them.

[ChopSticks]

Haven't been able to do a idle plug chop since other things have been popping up but I did solve the cooler 3 & 4 exhausts. Their respective idle screws were completely blocked (probably from using auxiliary gas tank while tuning), couldn't even get it out with air. I've soaked them in cleaner but had some spares laying around.

Now 3 & 4  warm up perfectly, but 1 @ 2 are suddenly cold...  the left exhaust also backfires on idle. I checked the pilot jets when I did 3 & 4 and they were clear... any ideas?

[ChopSticks]

In case anyone stumbles upon this same issue here was my solution:

While trouble shooting this and other things I noticed that the pilot jets were clogged (couldn't see light through the main hole at the bottom) switched them out for different ones I had lying around that's when the other exhausts were cold instead of the original.

Then after other issues, I finally decided to pull the whole rack, disassemble the carbs entirely, and do an ultrasonic clean. I'm assuming the clog was me not being the greatest about making sure the auxiliary gas was debris free, also there was a bunch of crust and crud on the bottom of the carb bodies. I ordered new OEM pilots and mains. Reassembled everything, mounted them, and now all 4 exhaust appear to be running at similar temperatures.