Topic: Patina Hyena - 550/650 674cc Hybrid Cafe Build

[riverfever]

Dave...the place I do my chops is on the way up a smaller mountain pass. There's a section that's 2.5 miles long but I do not think it's enough because my plugs show rich and chops showed super lean. That section is close to the house and straight enough that I feel comfortable doing them on. The rest of the pass has too many drop offs and rock walls. Wish there was a mobile dyno service that could come up to altitude and deal with squirrel. 

[DaveBarbier]

Ok so did some more plug chops. I wanted to see the state before I go do another few dyno pulls.

I honestly don't know what to think. I'd like to know how many of you actually use plug color to determine mixture. What my plugs show doesn't make sense to me. I've read many people (on the forum and elsewhere) saying that you can't reliably read plug color any more with today's gas. Is this true? Does different gas (octane and Mobil vs Shell vs Cumberland Farms) make any difference?

This was my idle plug chop in the middle of July. Plugs were fairly even in color.


This is the first idle chop today with the same mixture screw settings and same pilot jets as before.


2 and 4 look very lean. 1 looks perfect. Then I decided to do another chop with fresh plugs after adjusting the mixture screws. I actually forgot that these screws are out for leaner and in for richer. As you can read in the picture I went OUT on #4 all the way to 1 full turn out and it shows a darker plug...? I'm confident my idle chop is done properly.


I was confused so I put the mixture screws back to 1/2 turn out, put new plugs in and went for a ride to do a pilot jet plug chop at just above 1/8th throttle. This is where I'm feeling some burbling, I was assuming it would be very rich. 1-4 left to right.


After seeing this, I turned the #2 mixture screw in 1/4 turn and it ran worse. Right now, all my settings are back to where they were at the start of the day (1/2 turn out). I didn't seem to make any progress, haha.

My bike idles nicely at 1500rpm, though with current mixture screw setting. Any thoughts on the above? Sorry for the rambling.

[SOHC4 Cafe Racer Fan]

At which settings does it run best in terms of power/throttle response?

Since you do not have a built in AF meter, are you planning to dyno tune it using an external AF sniffer?

[DaveBarbier]

At which settings does it run best in terms of power/throttle response?

Since you do not have a built in AF meter, are you planning to dyno tune it using an external AF sniffer?

With the mixture screws at 1/2 turns out it idles nicely. I believe my pilot jets are still a bit rich which is making around 1/8 -1/4 throttle burble and hesitate.

I am planning on going to a local dyno and getting an a/f map done. The guy doesn't help tune, only gives me a print out. Planning on posting here and have you guys tell me what to do, haha.

I can totally see the benefits of having a 4-4 exhaust to measure what each cylinder is doing.

I just don't see how or why you'd have to adjust the mixture screws wildly different. They should be all around the same setting if not exactly the same, no?

[Camrector]

Dave I remember reading somewhere on here that a member had different jets for 2-3 and 1-4. It was for a race bike, but maybe a solution.

[DaveBarbier]

Could be a solution. I read that FunJimmy had different air jets for the inside carbs vs the outside.

I had an amazing opportunity to spend some time at Twinline Motorcycles with CR Master, Doctor_D and Jeff, AKA Tower.
These guys know CR carbs and dyno tuning like no one else in the PNW.

When I arrived my CR26 Carb jetting was: 

Pilot 60
Main 105
Needle YYO
Clip #2 (5th slot from top)
Air Jet 220
Air screw open ¾ turn


Post dyno tuning:

Pilot 65
Main 105
Needle YY8
Clip #2
Air 220 Inside 230 Outside
Idle Screw 1 turn

These jetting changes combined with a little ignition timing made big differences in throttle response and crispness.
Idling was a different deal. The bike just wouldn't hold a steady idle and required 1500rpm+ to stay lit, but that was found to be cam timing and an intake leak.
Not a fault of the carbs.

 


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[sinister902]

have you played with the different timing curves on the ignition yet?

[DaveBarbier]

have you played with the different timing curves on the ignition yet?

I haven't, I could try that out and see what happens. I haven't found what the curves look like nor which wires apply which curves when grounded.

[DaveBarbier]

Contact Paul then do that while at the dyno without changing jetting to see effects.

Yup, sent him an email a little bit ago. And maybe I'll make a little temporary switch to toggle between the timing curves so it's a bit easier.

[DaveBarbier]

From Paul at C5 Performance:

With both wires grounded max timing is 39 degrees if memory serves me correct. Each drop after that is about 3 less degrees (at max ramp up).
In my experience if the carbs are set to provide 13-13.5:1 AF ratio (using wide band O2 sensor) your engine probably would perform best in map #1.
Does that help?

Both wires grounded = map 1

only brown grounded = map 2

only blue grounded = map 3

none grounded = map 4


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[sinister902]

From Paul at C5 Performance:

With both wires grounded max timing is 39 degrees if memory serves me correct. Each drop after that is about 3 less degrees (at max ramp up).
In my experience if the carbs are set to provide 13-13.5:1 AF ratio (using wide band O2 sensor) your engine probably would perform best in map #1.
Does that help?

Both wires grounded = map 1

only brown grounded = map 2

only blue grounded = map 3

none grounded = map 4


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that's fantastic info.

[sinister902]

I mentioned the timing curves because the symptom reminded me of HondaMan's description of the stock 550 advance mechanism going to full advance a hair too soon leaving a lull in the powerband that can be "fixed" by trimming the advancer springs short by one coil.....

[DaveBarbier]

I mentioned the timing curves because the symptom reminded me of HondaMan's description of the stock 550 advance mechanism going to full advance a hair too soon leaving a lull in the powerband that can be "fixed" by trimming the advancer springs short by one coil.....

Right, but as far as I understand it, the timing curves only change the total amount of timing not how soon the advance comes in. Doesn't hurt to try obviously!

[DaveBarbier]

Ok, so I just got back from the dyno. Very good experience and I have info I need to order jets. I didn't change the timing curves on the dyno, I know I know. It's $65 for three pulls and that would up the price, but when I go back after the jetting changes I'll see what the guy says. He's super nice and got me in right away. I highly recommend him. He's in New Milford CT so any south western NY and CT guys can go, pay $65 and he'll show you exactly where your mixture is at a given throttle position. He doesn't claim to be a carb master but he'll give you suggestions. Sooo much better than doing plug chops.

I marked my throttle in 0 - 1/4 - 1/2 - 3/4 - WOT and we put the bike on and he showed me that I'm very rich just before 1/4 throttle and it tapers to a very good mixture at 3/4 then goes rich again at WOT. Pretty much what I thought, so that's good to hear.

Here's my dyno sheet not that it tells you what mixture is at a given throttle but, hey it's fun to share:


Here's my current jetting:
50 pilots
YY6 needle 4th position down
112 mains

I'm going to order a few jets but I'm thinking I'll be closer to 42 pilots and 108 mains. I may get leaner needles too (YY7), might as well just so I have them. With a dyno, tuning is actually fun!

Here is the CR Special tuning guide.

[Camrector]

Wastes no time! I like that!

[DaveBarbier]

Wastes no time! I like that!

Haha, he's 30 minutes from me and it's a beautiful ride! I might be hanging out there often.

But seriously, anyone in the area with a bike just ride over and for $65 you can get an a/f map and see what power you're running. So worth it

[Stev-o]

Great info Dave, wish he was closer.

[DaveBarbier]

Also looking for brake upgrades, haha. With this power increase I do feel that brake is a bit lacking, even with my dual disk setup. Let's start simple, what pads are the best for grip? Anyone have recommendations? I believe I have EBC Kevlar organic pads in there now.

Maybe in the winter I'll do a fork swap...maybe. I've been reading about R1 swaps and GSXR swaps, what's the easiest but gives incredible braking performance?


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[DaveBarbier]

Hmm, interesting. Beringer dual disc would be nice. Haven't seen a price and if it actually works with stock spoked wheels. So far it looks like I'd need the caliper(s), caliper bracket(s) and disc(s). I'll talk to Don and see what he says. He has nice friends!


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[DaveBarbier]

Just saw the price, never mind, haha! Just under $3k for a dual disc setup, about $1700 for single, I'm all set. I'll just get some semi sintered pads and see how that goes


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[SOHC4 Cafe Racer Fan]

  sticker shocker but they are amazing.

I bet Scott S has comparable or maybe even better stopping power with his R6 front swap.

[DaveBarbier]

Yeah, but the Beringer stuff looks incredibly well made. I'm jealous! I ordered some new semi wintered pads for about $60. That's more like my budget, haha. Do these discs get glazed easily? Is it good to try and rough them up every once in a while?


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[bwaller]

I use an old front hub, mount a disc to it, mount it in the chuck and turn the lathe slowly. Use an old slow electric drill.

Get a medium grit, they work well.

http://www.newmantools.com/flexhone/fh4r.htm

[DaveBarbier]

Damn, I like that. I'd have to find a larger lathe, though. Mine is too small. Maybe the shop down the street will let me use their brake lathe...probably not, haha.


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[DaveBarbier]

I use an old front hub, mount a disc to it, mount it in the chuck and turn the lathe slowly. Use an old slow electric drill.

Get a medium grit, they work well.

http://www.newmantools.com/flexhone/fh4r.htm

I ordered one of the 120 medium grits. But that site had them for over $100, I found the same thing on eBay for under $40. I'll rig up something to spin the discs, won't be too complicated. Thanks Brent!