Topic: carb synch/tuning question for 750k

[kopptl]

i spent about an hour running the syncho on the bike cant seem to get them all the same..   im runnig with a kerker 4-1 header exhaust and a stock airbox. i have the stock jets..   if im missing anything let me know.
-tom

[dave500]

youll never get it exactly,but a darn sight better than if you didnt,make sure all the ignition and tappets are spot on first,if you havent got those adjustments perfect the sync will be a waste of time.

[DYSKORD]

i spent about an hour running the syncho on the bike cant seem to get them all the same..   im runnig with a kerker 4-1 header exhaust and a stock airbox. i have the stock jets..   if im missing anything let me know.
-tom

You should be able to get them almost perfectly spot on. Follow these instructions I posted to a similar question: http://forums.sohc4.net/index.php?topic=87117.0
So you need to constantly adjust your idle screw (the large screw with spring on linkage) when you are doing the sync.. When you adjust them the idle will be directly effected. You MUST keep the idle between appr. 800-1300. Letting the idle get too high will negate the adjustments because your carbs will be operating outside of the idle circuit. Adjust one, wait a few seconds for the idle to differ, then adjust idle back up/down to range previously mentioned, then continue with syncing adjustments constantly bringing the idle speed into the appropriate range when necessary.
1. To continue from where you are now, I would go ahead and lean out your mixture screws first at 1/8 turns just until smoking stops.
2. set all nuts on the carbs where you were adjusting during the sync so that 2-3 threads of the screw are showing above the nut.
3. Adjust number #1 carb to #2. Make sure to adjust idle speed after back down/up
4. Adjust #4 carb to the same vacum as #3 carb. Adjust idle.
5. Adjust #3 to #2. Adjust idle.
Repeat sequence until they are all reading the same vacum. Adjusting in this sequence will keep you from going in circles since adjusting one will effect the others.
Once you have them synced you can fine tune your idle mixture (rich/lean)

Remeber, you must have valves in adjustment, cam chain tensioned and a clean air filter before you sync the carbs. It will do you no good to sync them if this hasnt been done FIRST.

Hope this helps

[dave500]

your ignition adjustment must be perfect first,this is the most critical of the adjustments,go slack here and it causes a chain of errors!use a timing light,static will not do,,static timing gets the engine running.

[kopptl]

i have a brand new air cleaner.  not sure about the valve adjustment or the cam chain tension. havent checked either.   
anybody know what stock air screw setting is  and what it should be for a header application?

[DYSKORD]

i have a brand new air cleaner.  not sure about the valve adjustment or the cam chain tension. havent checked either.   
anybody know what stock air screw setting is  and what it should be for a header application?

You didnt state what year your K is so nobody can tell you the the stock air screw setting. However, the stock air srew setting is just an initial setting for most carbs (except newer models) from which you make further adjustments ie: 1+/- 1/4 turns out. Note the +/- 1/4. Your manual should tell you this setting.
Note: making any carb adjustments (syncing or air/fuel mixture) without first cleaning airfilter, setting valve clearance, tensioning cam chain, adjusting points gap, checking plug condition, settining timing is a complete waste of time. Fair warning.

[nancy]

I'd also suggest being totally sure that all your carb to head rubbers are airtight/leakproof. I had synching probs - I have a nice Morgan Carbtune kit - it's easy. But each time I ran the synch I found I was getting No 1 cylinder to be erratic. It would climb higher inexplicably. I suspected a vacuum leak at the carb rubbers. So I sprayed WD40 with the motor running and watched for motor changes and noted nothing. Tightened the band clamps up. Tried another synch = still not quite right on no 1. So I bought a compression tester. Measured within 2 to 3% variation across all pots - so that was good. Gave up.
Two days ago - after the bike had sat idle in the shed for 2 weeks I fired it up and noticed a "hiss" or "Spit" from no 1. I had heard this before while riding. Took a good look and noticed a "poof" of vapour coming from No 1 rubber!!!! Bingo! Undid the band and shone a torch in there - sure enough, a split righ through where the band sits. Now fixed while I await new boot...then I'll do another synch and hope for better.
regards
Mark

[kopptl]

thank you guys for your input!!  i got it!!

i grabbed my manual reset the air screw to 3/4 of a turn out, installed brand new ngk's corectly gapped, and just had patiende and took time. got it so all the carbs are within 1-2  degree's of each other!! she runs like freaking MAD!!!   
now i just gotta re bleed the front brakes hahaha..... puts it into perspetcive when your hauling ass and you hit the brakes and nothing!!!     

thanks again!!