Something just isn't right! Startup and warmup issue

[incarceration]

I've got the carbs finally synced up really close together. But I'm still having this strange issue.

When I started the bike up this morning and it was fairly cold out, it started right up, I had to let it warm up like always and then took off.

When I got out of work, it took a few seconds but then started up, let it warm up, and it was eh ok.

Went to class, at around 5, and it was starting to act weird on the way there. I got to my destination and checked the plugs, they are SUPER clean - no cloudy gray look, no black like it's rich, SUPER clean. I'm guessing it's running too lean? It has also puffed out on the left side like it's shooting off NOS or something on a couple occassions lol

Going back to what the condition is, it's not the stock exhaust, it has a MAC 2-1 exhaust. I've done a total carb work job on it. Swapped out the main jet to #130 (up from #115 before exhaust mod) and I HAD #47.5 pilot jet, but someone recommended to go back to stock, which was #45, so I did.

When I was leaving after class today, it REALLY did not want to go, if I let go of the throttle at all it would just die. Once I let it warm up and took off though, it was running fine, at lights, etc - no dying.

Does this mean the pilot air screw needs adjusting? Is it the pilot jet? When I took EVERYTHING out of the carbs and did the chem dip, i just put the pilot air screw ALL the way back in until pretty much finger tight, what is it supposed to be at with the current exhaust config if not what it's at now? Should I put the larger pilot jets back in, #47.5, that have the small holes on the sides of them (as opposed to the stock, that's #45, without the side holes on them?)

I don't understand why the starting up when it has been used frequently, (because prior to today, I hadn't used it for a few days, yet it started up, just needed to warm up a bit) makes it start up and warm up like crap.

Thanks in advance!

 

[tom203]

Sounds like fuel starvation in idle circuit at times. Is petcock vac hose on tight? I'm unclear on where you have your pilot air screw (idle/air mixture?) at.

 

[incarceration]

I drove around the other day adjusting it periodically; it's probably close to 3 turns out from fully in

 

[tom203]

I'd have to guess one carb has plugged idle passages- despite your carb cleaning- maybe something from tank or some bad fuel. You should not have to fiddle with idle/air mixture "periodically" and 3 turns should be in ballpark.

 

[incarceration]

What i meant by periodically was that I had just had done all that work so I had to adjust it, it was my first adjustment after changing out the carb jets. I wasn't just doing it for kicks lol

 

[chuck hahn]

So you have CV carbs with nthe 1 screw at the top back of the bores and you state its "all the way in finger tight"...back it out 2 turns from lightly seated at the bottom. thats the fuel / air ( MIXTURE ) scew. think of it like a water faucet. the farther you turn it OUT the MORE mixture gets to the cylinders. The more IN..obviously the LESS fuel gets delivered.

Yes. like others have said. its fuel starved. But not from dirty carbs...from misadjusted ones.

 

[incarceration]

The fuel\air mixture screw on the top, front side of the carbs (intake side, not air box side) are ~3 turns out already. The ones I was talking about that were all the way in about finger-tight are the pilot air jets, the ones that are inside a hole on the air box side inlets but bottom left of the edge

Here's a picture to kinda help:
http://img541.imageshack.us/img541/6033/9n7t.jpg

 

[Guest]

The air jets you are pointing at are not adjustable... they should be snug.

Install larger pilot jets to richen the pilot circut.

 

[incarceration]

Ah ok, yeah I thought it was supposed to be snug, cause that is what I thought i remembered it was at when i took it out before the chem dip awhile back.

I will put the #47.5 pilot jet back in and reset the pilot jet\mixture screw and see how it goes this weekend.

Thanks!

 

[chuck hahn]

I understood exactly what you were talking about..my comment was in that the way your post read "to me " was that the MIXTURE screws were all the way in.

And yes you need to tighten the air screws becuse they will vibrate and fall off..may get sucked into he engine or may fall into the air box. By tight i mean give them a good tightening twist to be sure they dont back out.

At 3 out on the mixture screws your probably too rich. Has been my findings that 2 out ( even on an 850 ) is about perfect. may need a 1/8 adjustment one way or the other though.

I suggest you get a peek at the carb throats and 1, be sure the air jets are all there and 2, tighten them up. Set the mixture at 2 and adjust from there.

EDIT...Went back and it does say pilot air screw. My misread.

 

[incarceration]

Chuck, I'm curious why you think it's too rich considering the scanario i described in my OP. Other than the pilot jet mixture screw being about 3 out, the plugs are super clean and it's difficult to crank up at times unless i roll back on the throttle

 

[chuck hahn]

Because of exactly what you just said!! Its getting just a tad more AIR when you tweek the throttle..which helps the over rich fuel inginte easier. It doesnt mean its so rich the plugs will foul..just means its too rich to start easily.

If its too lean youll get the same symptoms ( in a way ). Set them in and see what it does. Better yet, start it and go take a sniff of the exhaust and see if it smells gassyat an idle!!! If it smells gassy, then youll see what i mean. By sniff I mean stick your face in and have a good whiff.

Where does it idle at now? Should be around 1000 to 1200. I like mine at the 1200 area.

 

[incarceration]

I actually have been smelling the exhaust as i have been on this nightmare journey because it used to be super rich i smelled it at lights (not exhaust but while on it), when it was warming up, and when it was sitting idling; I'd also smell it after it got nice and hot when it would die on me (at a light and while sitting on it) or almost die on me unless i rolled back on the throttle, which it would then sound muddy, slow to react, and like its drowning. I would pull over if i could and had my socket wrench and looked at the plugs and one would be black with unburned fuel and the other would be super clean and running lean (imo). I replaced the 2 float needles and seats, put the pilot jet from 47.5 back to stock 45, and then resynced the carbs (for the first time since i have acquired it). Now this is happening.

I'm thinking it just needed the sync and new float needle and seats, but not the pilot jet swapped back because now both plugs are super clean (even with my pilot jet screw\mixture screw way out) which represents running super lean, right?

 

[chuck hahn]

On CV carbs, the mixture is premixed in the carb bowls via the pilot circuit... and the air jets doing their thing.

At the mixture screw all your doing is metering the actual AMOUNT of pre mix is getting into the cylinders. So, like i said before, its like a water faucet. The more you turn the screws out, the more mixture is let thru..just like the more you open the water knob the faster the water flows...see what I mean her?

So you need to get it stuck in your head...turn the screws out = richer.
Turn them in = leaner. Its that simple.

Float hts are important too...Too low and the carbs run LEAN..Too high and they run rich. I always set floats at the middle of the manuals stated range..period. I dont ever have float ht problems either.

 

[incarceration]

Oh **** that's right I also equalled the float heights to what the cv carb PDF I found that had the complete tear down said to do. I have a digital caliper, what should my heights be?

It seemed no matter how much I backed the mixture screws out the plugs were still super clean

 

[chuck hahn]

And dont have the vents capped off and be sure they are open. Atmospheric pressure helps equal fuel hts AND makes it possible for fuel to be efficiently sipped up the main jets and needle jets.

 

[chuck hahn]

Click on the STICKY at the very top and cruise around there and see if anyone had posted that bikes info.

 

[Gorminrider]

...interesting- I have the same carbs but my "pull-choke" knob is on the left. oh well...
You haven't mentioned the "Choke".If the bike is too lean this is a way to add a bit of gas. It's the wrong way at running temperatures, but may give a better clue than tweaking the idle-mixture.
...given that everything is air-tight and clean, are you are adjusting your idlemix screws for "best running" and then add a 1/2 turn or so?.. If you are able to do this, noticing a change in the engine as you lean or richen, I don't think you can do more with them and perhaps should look elsewhere....if you changed the main jets, I'm out of my depth but you might look into checking the adjusted height of the (vacuum-operated ) throttle jet needles.