Cold running questions

Maybe there was a miss understanding, I always run it NO choke, any choke caused problems, even cold

 

When Cold, I had to open the throttle to make power, below 2k rpm it would want to die. But even cold, if I opened the throttle and let out the clutch without letting it dip below 3k or so, it would do fine and cruise fine, just if it went below that I either had to open the throttle OR let go of the throttle to keep it from dieing.
I had my mixture screws out almost 5 turns though (based on colortuneing) with a very wide blue range. (which seemed strange)
It ran good, but would carbon up the plugs real fast at idle. If I got the bike moving right away, the rest of the ride would great and I had really good plug color. But I would have to get the bike going RIGHT away or I would have the problem listed above...and dead cold you can't really get going right away...so...Chacal and I (I bought a bunch of parts from him and used him as my sounding board for a while) thought it was just flowing a lot more air than expected due to the exhaust and the KN filter and that while the main jets had been up-ed 4 sizes, I was still making up for improper jetting with the mixture screws. But I couldn't get around this rich at idle issue as leaning it out for idle would obviously cause problems at the top end...
Anyway, I got some foam backing for the filter now and made sure it is installed correctly.
I did some runs yesterday with it for a short distance with my screws back to around 3 turns and there is promise, but I may have to get new plugs as the old ones (which are only a month old) might be too far gone.
Was going to drive it to work today and do another colortune and sync (I can tell the airflow is a lot different with the filter in place) but weather didn't cooperate. Maybe I can work on it tonight. great running bike as soon as I can get this low rpm cold running issue fixed! I think I am well on my way!

Thanks for all the input!

 

Sorry I didn't read the Post more closely.
OK.
5 Turns Out and still needing Throttle means the Pilot FUEL Jet you are running isn't allowing enough Gas up through the Passage to get the AIR~FUEL Mixture:
1. Rich enough to keep the Bike running at Idle
2. Keep enough Gas available to let the Mixture get adjusted within the degree of Richness to BOTH Idle the Bike AND provide Supplemental Richness to maintain a Rich ENOUGH Mixture to Maintain Combustions for the, ... brief ... just 6 or 7 rapid eye-blinks ... of on-rushing fresh air into the Cylinders when the Bike comes ... OFF-IDLE ... when the Throttles are OPENED ... and, the Bike transitions from IDLE <>Pilot Jet Fuel <> to ... Main FUEL Jet supply.

Finding the right Pilot FUEL Jet Size can be problematical.

 

I had the same cold running problem with my xj. Took it a good 8-10 miles to fully warm up. It would start fine but when I would try to take off it would putter badly until warm. I think it is just a quirk of these bikes. I found that when I first started it, it was best to let it idle for at least 5 minutes when it was completely cold.

 

Well, it only takes about 1 mile, maybe two for my bike to warm up and run right. If I let it idle very long, the plugs will foul up pretty good and then I'll have to get it revving pretty good to burn the plugs clean and the bike to run right.

I was thinking the pilot jet was were I needed to be looking, but my prayer is that once I get my airfilter issue addressed (basicaly done now) I can get it tuned right and not need to mess with my pilot jet.

The 5 turns out and still needing throttle is a qualififed statement. Only when cold, and it idles fine, revs fine with no hickups, just won't develop power below about 3k untill warm. So, here I am sitting, idling, smooth, I decide to go and start letting out the clutch and adding some throttle and the bike will start to give me problems and die...and it will die unless I either add alot of throttle OR just pull the clutch back in and let go the throttle...it will immediately drop back to idle and be smooth again.

As I said, I think it was just all that extra air flow that was throwing everything off.
tonight it's pouring rain, so maybe tomorrow I will give it a wrench.

Again, thanks everyone!

 

You usualy don't mess with pilot jets if all you have is the 4-1 exhaust right? Just usualy go up 4 main jet sizes...correct?
(If I understand correctly, stock main jets are 120's...mine are 124's and I have a 4-1 exhaust)
I wish these carbs weren't such a bear to pull off, or do jet swaps with them in place...

Thanks all you guys for contributing, I like to learn and hear different ideas!

 

The K&N Filter might require a Jet bump.

 

That would be a bummer.
Well, let me see if I can at least get this cold issue fixed with what I know is a current problem and then we'll see how it runs.
When you say jet bump, you mean main or pilot?
I would probably rather just go to a paper filter if that was the case...don't really need to mod the bike...

Another nasty day out...man I need a garage!

 

cool runnings was a good movie

 

Geej, I personally say go back to stock airfilter and if possible get stock exhaust setup 4/2. Definitly start with your filter. K/N kills my bike. Stock for life on these old bikes.

 

I probably wouldn't mind going to stock exhaust (get my center stand back!) but as we all know, stock exhaust isn't all that common, let alone in the great state of AK! (And I'd hate to see shipping on those up here)
If anyone in AK has a good condition stock exhaust setup, let me know.

As to going back to stock air filter, I was afraid of that...I might still try cleaning and re-oiling the filter and see what that does. The weather isn't so bad, maybe tonight I can try and re-tune the bike...we will see if it works out. About to go out of town for a week...

You say the KN kills your bike...where you having similar problems to me? Were you running stock exhaust or a 4-1...how were your carbs jetted?

If I'm lucky, i'll have a report tonight...or tomorrow, otherwise it will have to wait till next week.

Thanks!

 

Well, I'm stumped... (how do you make an angry face on here)

So, i serviced my K&N...cleaned, dried, oiled, etc.

made sure it was installed correctly w/ foam on the back to avoid any air leaks. Hooked up my carb sticks and fired it up. (Had mixtures 3 turns out)
Sure enough, this time it needed some choke to run cold and as it warmed up it settled into a nice idle NO choke.

YICS tool installed.

SYNC'd the carbs up real good.

THEN....Colortune.

Man, I just cannot seem to get the color tune to work right. I have this HUGE blue range and have to turn almost wide open to get orange flame.

I again checked my choke system...but if the choke was still on I should be able to get a rich indication really fast, so that can't be it. If i had some air leaks, then i should be able to get a lean indication pretty easy.

I ended up going back to pretty much 3 turns on all carbs, the color tune seemed to show that ok and sometimes it would throw a little orange tint.

the only thing i can think of is maybe my idle was too high when colortuning? When i first started, things seemed to be working, but then I checked and my idle was like way below 900. In the 1100-1200 rpm range is where I did the rest of the tune...for that matter maybe it was a little higher than that? Hmmm... at what point does transition to jets happen?

I would really feel stupid if that was the case.

Ran good, now to see how it starts and takes off cold....

 

was the bike ridden for 15 minutes before doing all that?

as for my KN, I am pulling it tonight and replacing it with a stock UNI filter

 

No, but it was up to operating temp. I am about to go out and crank her up for a ride into work. We'll see how she does.

 

This is bad, I'm dominating my own post...

*Ride Report*

Well, nothing really new, performed as it has with one exception.
Now (for those of you wanting my bike to need choke cold) it needs choke till warm. I started without choke, but it wouldn't stay running without throttle. I re-started full choke and was able to lean it to half choke pretty quick, and maybe 5 minutes or a little more till I was off choke completely.
Mixtures at 3 turns.
Filter oiled and seated properly.

I was encouraged by how it started and warmed up, but starting out, I had the same problem. Had to really coax it to get moving and then it would spit at me for the first 2 miles as well as slight power surges when trying to hold constant RPM. This was telling me that it loaded up again during warmup and was burning the carbon off the plugs.
Once I was past that initial Ride-warm-up, she ran great. I *think* I could even tell a bit of a difference with the filter on right.
A plug check when i got to work was a bit hard to read as I DID NOT replace the plugs, but seemed to indicate I was not overly lean, nor overly rich. But I should really buy new plugs and go for a ride and chop.

So, thoughts on my cold fowling problem (seemingly)? Is it just since I have plugs that have been abused one too many times, they will fowl very easily and new plugs will be the answer?

Argh.......Any of you geniuses going to make a trip to Alaska? It's beautiful here!

 

If you have the Idle Adjustment Rod holding the Throttles OPEN >> Even a little Bit << then, you can't expect much of a change because you are letting IN more AIR than you have FUEL for.

Back-off the Idle Adjust Rod.
Close the Butterflys
ColorTune >> The PILOT System
Make the Bike Idle on Pilot Mixture Screw Adjustments >> Alone.

 

oooooohhhhhhhh.......
How did I miss that? I thought I distinctively remember reading posts where you want to have the bike idling a bit higher even during colortuning....
so, that is why it was looking like i was getting a proper reading when it was barely idling. And it was showing rich at 3 turns.

So, I have to back the idle adjustment rod all the way off and let the bike lope just barely running (and hope it stays running?)

Now I feel stupid.
THANK YOU
I leave for a week tonight on a trip, so it will have to wait till then i think.

 

NO!
Adjust the Pilot Mixture Screws to provide you with an Ideal Air~Fuel Mixture and the Bike will purr and Idle like a sewing machine.

The trick is to use the ColorTune Plug to get within the "Window of Fine Tuning" ... and then, move the Pilot Mix Screws to just the right amount to Idle the Bike forever with just enough Supplemental Richness to sustain Combustions ...

For the brief ... less than 2-finger snaps ... moment when the Throttle Plate OPEN and Fresh Air gets drawn into the Engine.

If the Supplemental Richness is correct ... The Engine rolls-on Power without a hiccup or a delay.
Too Rich >> Bogs it out and will Foul and/or really darken the Plugs.
Too Lean >> And you get a Hesitation or Backfire.

The Fine Tuning Process involves "Orchestrating" all the adjustments.
Having the Idle Adjust Rod available is one source of adjustment.

The process ... long before there were Ganged Sync Tools and ColorTune Plugs ... got done "By Ear"
Adjusting the Pilot Mixture Screws ... listening for RPM's to Rise.
As they do ... DECREASE RPM's by backing-off the Idle Rod.

Once you get over to Number-4 ... The Bike's Idling and the Throttles are closed.

 

I've been all through this thread and only find ONE mention of float levels, which causes me to have a question (and think "we" might be barking up the wrong tree.)

How did you check your float levels? Statically or with fluid?

Have you checked and adjusted the valve clearances yet?

 

Yup, fluid levels were checked WITH fluid and all are spot on. Also all the valves were checked and re-shimmed as needed. Carbs were cleaned and serviced very well as per all the instructions found on this site. I tried to leave nothing undun