FCR tuning

[terse750]

So, after a complete tear down of my bike, (twice )
I'm looking for input on tuning my new FCR's.

Bought from CA cycleworks for a 750 with their stock setup.

155 main jet
200 main air jet
60 slow jet
EMT needle
3rd from top clip

On the first test ride she sputtered on full throttle twists.
Came home and sat for a few hours to cool and she wouldn't start. Pulled the plugs and set my gap to .045 from .060 and she likey!

Never before has she pulled the front wheel off the ground with just throttle...now she does. ( I'm 240lbs )
And, no more sputtering! She seems to like the smaller gap for cold starts also, which is night and day difference from before FCR's.

I have noticed that 90% of the time on downshifting, she is mildly popping in the exhaust.
It's quite nice actually, but thats just my personal opinion. Sounds like riding a rocket or something of that nature. 

I do believe that some light grumbling backfire-ish sounds to be somewhat the norm for ducati. Is this correct?
My plugs look perfectly light coffee colored but I have not checked immediatly after a hard pass at high RPM's.

I'd like to know if the grumbling/ popping is something to be concerned with?

Setup: FCR 39mm's / CA exact fit coils / NGK 9's as suggested for the coils / pod air filters with dry charge covers /  new to me full size 41cm ish long slip-on exhaust, pretty wide open bore
(much more quiet than my chopped GPR cans on startup, very bassy on idle)


And to anyone on the fence about getting some FCR's.... DOOOO IIIIT NOOOWWW!!!!! 

[koko64]

The plugs sound like they are a good colour. At least one part of the jetting circuit is close. Think in terms of idle, 1/4, 1/2, 3/4 and WOT. WOT is hard to test safely and legally.
Do you know how to do an old style plug chop?

[Speeddog]

What's your air screw set to?

[terse750]

No sir, I've never heard of a plug chop.

I think my slow air screw is set at 1-1/2 turns.
And fuel mixture is at 3/4 turns

What is the hand turnable one called...sets idle speed? I find for a easier start it likes to be turned up and as I ride and come to stops I work it back down to less idle.

[ducpainter]

No sir, I've never heard of a plug chop.

I think my slow air screw is set at 1-1/2 turns.
And fuel mixture is at 3/4 turns

What is the hand turnable one called...sets idle speed? I find for a easier start it likes to be turned up and as I ride and come to stops I work it back down to less idle.

You need to use the idle speed adjustment to start. On a cold engine turn on the fuel and open the throttle about 4 times. Turn the idle speed adjustment all the way in and crank. Adjust the idle down so it doesn't stall at idle when warm.

You do have a manual petcock on this bike...correct?

[koko64]

^ as you can see, you develop a starting routine as there is no choke/enrichener. It's the only thing the oem carbs have over FCRs.

Plug chops are when you ride at a set and steady rev range/throttle position then hit the kill switch while simultaneously pulling the clutch and roll to a stop with a still motor. You then examine the plugs for colour for that rev range/throttle position. Of course you need a safe place to do it. It's a snapshot of the AFR for a particular rev range/throttle position. You can mark the throttle for the increments.

Speeddog has tuned his 750 with FCR39s, so he will have good advice for you.

[koko64]

Hows it going?

[terse750]

Hows it going?

Haven't been able to do any tuning yet this week.

Hoping today will be a good day to do so.

Although the bike has brought me to and from work all week! Which is a 60mi round trip on back highways following a curvy Bayou.

I avoid the interstate as much as possible.

I'll try some of the suggestions you gave koko.

[koko64]

 

[koko64]

How's it going T?

[terse750]

Sorry I went MIA.

First issue has presented itself!

On my way to work this week I finally went for a WOT for a brief climb in high RPMs.

Felt ok  only getting her to 107 then backing down to 80. Fifty yards later... sputtering out like a spark plug is down.

Wouldn't restart rolling so I pulled off at the end of a quiet exit/entrance to the highway, lights and blinker staying on.

Got off the bike (still dark 6am on interstate) checked my spark plug wires I thought one may have been loose.

Waited a minute than crancked...she catches for a few rotations, dies...backed off the Idle Speed Screw, I think...

I was worried I had foaled a plug so I didn't want to over feed it gas at this point. Cranks up strong so I pulled off.

Little bit down the road (75mph road) gassing it to 80 for a pass and...boom, same shtuff.

So I limped to work trying my best to keep it in the lowest rpm on the highway. 



Now every time I go above 75-80 it acts up within minutes, I back off, it fades...

Still pulls hard as ever in low speed WOTs but I need my 0-100.  I need to know it will shit and get when I tell her. 

Thats the update: I was avoiding the obvious and loving the new power of the FCRs, which need some TLC.

I'll check back on this thread and order some new slow jets as was recommended to start.

Then float height may be off? Either starving it at high rpms, (which I doubt) or flooding?


Where is the best place to find FCR parts/ jets?

[koko64]

The plugs would have a story to tell once you have come to a stop from the hi speed problem. Thats not a slow jet issue at 100.
It could be fuel delivery at that speed. Maybe. Dont hurt your motor if its lean.
The float level is 9mm on those FCRs. SUDCo, powerbarn, jets r us, CCW (sponsor) are worth a try for jets. Be worth checking for fuel blockages and delivery issues. Mind you 110 mph sounds good but it could be either choking on fuel or starving if it isnt another issue. The issue sounds extreme from either cause. The plugs will say alot. It may be safest in many respects to get a dyno tune.

[terse750]

So after checking my plugs it appears I am running lean.

They were white with a hint of brown...just a very little bit

[koko64]

Glad you didnt hole/melt a piston.
Based on Speeddogs jetting (iirc) and since you have pods, try needle posn 4 or 5 and 160 main jets and see what the plugs say about it. Thats based on the assumption the plug porcelain is white all the way down to the base of the plug and it was a high speed plug chop. Are there coloured bands on the porcelain as you look down into the plug?
Some lift the needle until they get the roll on power at its best and then do a plug chop at half throttle to ensure its not too rich at cruising speeds. You can tune for slightly lean cruise and let the accelerator pumps help when you whack open the throttle.
What kind of pods are they?

[ducpainter]

I don't ride in my winter.

I quit when temps get down around 8-10 of yours