Topic: #4 Not getting hot - Swapped 4 and 1 wires and #4 still not working.

[briancwynn]

Cal, I will take a picture of all plugs and post.  Thank you.

[disco]

Hi Brian, I've had a bad plug brand new out of the box before. It can happen. It's either that or you've got a dicky connection on the plug lead.

[briancwynn]

Okay all new information.
I did the following on #4.  I changed the air/gas mixture out half turn.  I put the pod cover back on the carburetor.  After I added the pod, the exhaust started to get very hot again. So hot I know its firing. 

Does this mean this all goes back to jetting?   When I drive the bike now with the Pods back on, previously I took the pods off as riding with them off the bike ran great for sometime.  Maybe dirt got into the carb and clogged something? 

I am now going to take off the carbs and replace the jets as advised but and additional help would be great.  Thanks all for the help so far. I'm glad it was not the motor. 

[flybox1]

Wait....you were testing the bike with everything not reinstalled each time? 
What jets do you have in there now that you need to swap them for something different?

[briancwynn]

When first riding the bike, the bike runs much better without the pods, no bogging initially at all.  Then I started having the issue with #4.  I then swapped the cable connections between 1 and 4 and no change.  I then tried a new plug and no change.  #4 stayed cold.  I then opened up the fuel air mixture and put on the POD and boom its running hot.  But now with the pods on the bike, all 4 are on the bike now and the bike does not run well.  WOT causes it to bog down. If I slowly add throttle i can get up to speed kinda but it wants to bog down.   

I will take off the carbs and re-jet but I have never done this before so this shim stuff is not clear to me. 

The jets are screw out and in so I am good there.  My carbs are set for what is in my signature.  I honestly don't understand what half of that means.  =)
But I am not scared to work on it. 

Thanks.

[flybox1]

Glad it runs hot on all 4.
Yes, now you are on to jetting, and as i mentioned in my first post, your stock pilot jets are too small.
You'll need at least 38's.  (40's are better IMO as they allow better fuel screw tuning range)
Start with bigger pilot jets.  I also suspect your 125 mains are too big.

Your bike runs ishtty now as your idle circuit is really lean, and then closer to WOT you are rich.

...and keep your pods, on.  Put everything back on just as you want to ride it, or it skews your plug chop results.

[briancwynn]

Flybox1, Thank you.
Is there a brand of pilot screws you recommend and from where?  CB750 Vintage parts has them.

[flybox1]

Flybox1, Thank you.
Is there a brand of pilot screws you recommend and from where?  CB750 Vintage parts has them.

OEM Keihin.  Nothing else.

www.jetsrus.com


Edit...IIWY, id go with 40/120's.  It should be REALLY close.  Similar to 700504's setup.
From there, you'll just need fuel screw and shim adjustments to get it dialed in.

[briancwynn]

Roger,
I am going to order 40's
I will put them in and reset the fuel screw to 1.5 turns out from 0 on all 4.
I dont know what the Shim adjustment is.
Put them back on and test with PODS installed.

Thank you.

[flybox1]

The Carbs have been professionally restored and cleaned.  The settings are 125 main jets, stock slow, and 2 shims on the needle

you should know...you wrote it 

[briancwynn]

I wrote it here but I did not do it.  Harrisluv did the restore on the carbs and made them perty. 

[flybox1]

the difference between 77 and 78 PD carbs......77 carb slide needles had adjustable needles.  you could move the needle clip to different slots to change the needle height.
78 PD carbs had fixed needles.  one slot.  not adjustable....so, to raise the needle height, you slide on one or more M2.5 washers under the needle clip.  the washers should be measured equal, and around .2mm

[briancwynn]

Roger that. I will crack open the carbs and take a picture and confirm what I am looking at.
Thanks again for the follow up.  It is getting too warm to not be on the road. 

[briancwynn]

Okay all, new information.
I took off the carbs and adjusted the fuel/Air mixture screw.  I set 2 and 3 to 3 turns out and 1 and 4 to 3.5 turns out and the bike is starting and running smoother than before. No more pops or spitting.  With that said I still cant roll on the throttle fast up to approx 40mph or 5k rpm.  If I roll gently i can get up to speed but if I push it, it bogs down immediately.   
Still going to replace the Jets but making sure this does not change 40/120 new jets assessment. 

[flybox1]

Plug chops at idle first please now that you've modified your carbs. That is the proper determination for your first jet change. Then chops at WOT. This will tell you what jet change to make next.

Guessing and hypothesizing will only delay your regular riding.

+1
...with NEW plugs.