TOPIC:

So, I felt like I have been messing with these darn carbs since I bought the bike a year ago.

After taking OMR's advice on jetting, since we have similar set-ups, the bike is running a lot better than when I first got it, but still need fine tuning.

I feel the jetting is spot on, but I'm still getting some backfire on decel. Not too horrible, but more than I want. My air screws are only turned 1/2 turn out! I don't have much more to turn in. Does that mean bigger pilot jet needed? Or turn another 1/8th or 1/4 in?? Anyone else with this set-up that can chime in??

Either way, I'm about to drop the $250 for the Yoshi MJN drop in tube kit to see if that helps any with these touchy carbs!

Any help is appreciated!

Are they synced? Valves adjusted?
Steve

Yes and Yes.

Was reading up...I could try raising the needle (or lowering the clip, whichever) one notch as well to adjust for the lean condition???

Yes in the midrange.
Steve

Right, ok...

Just rode home from work and it was almost 20 degrees warmer than this morning and it rode worse.

So all the symptoms lead to, step up in pilot jet size, but what am I missing here? OMR is running a very similar setup and this is what he's running with it even being more on the rich side....I'm losing my patience with jetting these flippin carbs.

Go one full step up. Example 20 to 30. Not 20 to 25. Don't adjust anything until the pilots are right.
Steve

I'll try that, but I was running 52 pilots and 112 mains all summer and never had this bad of lean pop and backfire until I switched to 55 pilots. Doesn't make sense.

I'll put the 65 pilots back in and try from there. I mean, all the symptoms lead to try that anyway sooo...

Thanks SWest

Pic of the plugs?
Steve

BOOM_FIST wrote: I'll try that, but I was running 52 pilots and 112 mains all summer and never had this bad of lean pop and backfire until I switched to 55 pilots. Doesn't make sense.

I'll put the 65 pilots back in and try from there. I mean, all the symptoms lead to try that anyway sooo...

Thanks SWest

Why would you go up 5 SIZES ON PILOT JETS???? One size makes a BIG differeance.

Keihin CR pilot jets go 50,52,55,58,60,62,65,68.

I have had CR's on my bikes since back in 1981, and I have NEVER had to go up 5 sizes at any time.

I got 65 pilot jets in my 33CR's on my 1105cc motor!!!

SWest wrote: Go one full step up. Example 20 to 30. Not 20 to 25. Don't adjust anything until the pilots are right.
Steve

Dr. Gamma wrote: Why would you go up 5 SIZES ON PILOT JETS????

Well, because another member suggested it this way....plus I have 65's in my possession and I just ordered 2 sets of jets just last week to include the 55's that don't seem to be working and I really didn't want to order more jets again.

Are you suggesting that I go with 58's or 60's instead?

I rode in again this morning after a plug cleaning and it ran just about the same. I'll pull the plugs when I get home and report back.

One remote but conceivable possibility is that the previously installed non-popping pilot jets had been "drilled out."

Good Fortune!

Patton wrote: One remote but conceivable possibility is that the previously installed non-popping pilot jets had been "drilled out."

Good Fortune!

Well I'd hope not as I bought them new from JetsRus!

Please bear with me as I'm still a NEWB to these bikes and carbs! I don't think I mentioned that the pops are coming out of the exhaust, not the carbs. After researching and trying to find what my exact problem is, it seems that I haven't been setting the air idle screws correctly. I thought the symptoms of the popping exhaust were because I was running lean, when in fact I'm running rich? Am I correct in saying that?

Rode home from work and could tell the plugs were fouling up by the way it sounded and felt. I pulled them last night and 1 and 2 seemed good, but 3 and 4 had some black on them. 4 more than 3, but neither completely sooted up. And I kept smelling the rich mixture every time I came up to a red light/stop sign. Duh...should have known just by that alone that I was running rich.

But every time I back the air screws out to try and lean 3 and 4 out, it starts to run like crap. I'm also getting a little surging in the low end while cruising...very similar to when I first bought the bike and had the 65 pilots in. Slow cruising speed was very choppy. Again, symptoms of running rich, not lean.

With all of this, it seems I'm running rich still and I'm wondering if I need to swap back in the 52 pilots and reset the air screws and tune again? Anyone agree?

Thanks again for all of the input you guys, it's much appreciated!