big_sur's Race Build

[KTMGene390]

Word back from dynotjet, consensus was correct: The stock O2 sensor must remain active and in the exhaust (even if using Auto-tune). Auto-tune can only be effectively used in the 80% and 100% throttle columns or any throttle position above 7500 RPM.

That's crazy! IMHO, makes Auto-tune near worthless for the RC 390. I actually like the PCV a little better than Bazzaz because you can change ignition timing but in this case I don't like DynoJet's lack of effort on this one. The one good thing about the Bazzaz unit is the Quick Shifter and Z-AFM O2 sensor which works from 3k to redline (Does not read below 3k by design).

I think a proper test is in order by someone? PCV vs Bazzaz.

 

[big_sur]

That's crazy! IMHO, makes Auto-tune near worthless for the RC 390. I actually like the PCV a little better than Bazzaz because you can change ignition timing but in this case I don't like DynoJet's lack of effort on this one. The one good thing about the Bazzaz unit is the Quick Shifter and Z-AFM O2 sensor which works from 3k to redline (Does not read below 3k by design).

I think a proper test is in order by someone? PCV vs Bazzaz.

If this were a street bike I might care, but this bike will spend 98% of its life above 7500rpm so that should be fine. I would be interested to see a dyno of the same setup with the PCV\Autotune and the Bazzaz\Z-AFM.

I was looking at all the extra parts from the Arrow box where they're expecting to mount to the passenger rearsets and noticed there were a few Al spacers in there that line up pretty close. I got some Al bar and plan to cut down the mid-pipe so as to tuck it in closer for cornering clearance in addition to lining up the hanger.

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[KTMGene390]

If this were a street bike I might care, but this bike will spend 98% of its life above 7500rpm so that should be fine. I would be interested to see a dyno of the same setup with the PCV\Autotune and the Bazzaz\Z-AFM.

I was looking at all the extra parts from the Arrow box where they're expecting to mount to the passenger rearsets and noticed there were a few Al spacers in there that line up pretty close. I got some Al bar and plan to cut down the mid-pipe so as to tuck it in closer for cornering clearance in addition to lining up the hanger.

I'll let you in on a little know serect (if you don't already know) about the supplied wideband O2 sensors for both the PCV & Bazzaz, they go bad pretty quickly. They last anywhere from 50-80 hours of use with no definite time frame. You are supposed to remove them after creating a custom fuel map though this is not required. Mine has already burned out after not much use at all but at least it did its job while it lasted. Your current bung location will make changing out a new one much easier than the stock location though.

Nice. Getting the ground clearance right will be a little tricky, but I would look at the Akrapovic exhaust as a guide and improve upon it's mid-pipe design for more cornering clearance.

 

[waveriders]

I appreciate your comments and documenting the install of the Arrow GP2 exhaust. I was notified yesterday that the little brown truck is delivering mine with a PCV tomorrow. Looks like I know what my plans are for the weekend.

 

[big_sur]

So I cut down the mid-pipe 9/16ths and made my little exhaust hanger, complete with speed holes for extra hp, and it seems like it might work. I think it really needs to be a single bent\welded piece of metal, but in the interest of getting it done, it's there. I imagine over time that it'll fatigue near the mounts since the bottom mounting point is getting torqued when the exhaust pulls down. It'll do for now though and I'll keep an eye on it. Honestly the exhaust is pretty solid without the hanger so I'm not overly worried about it.

 

[big_sur]

Got the PCV and autotune installed today in a little over 2 beers. You have to take the tank off but other than the overhead, it's not too complicated. I took it around the block and it ran okay, but without a map change it's backfiring on decel with the exhaust change and generally lean. I verified USB connectivity and got an AFR so it's looking good to get some auto-tuning in at the track on Sunday.

For the autotune, I needed a hot, switched wire so I used one of the accessory plugs and found that the blue one is switched, the yellow is not.

 

[big_sur]

Got some track time in today at HPR and tried out the autotune. I made a map tuned to 13.1 AFR (>7500rpm\>60% throttle). I did notice it smoothed out the bottom a lot as well which I assume is the O2 optimizer thing richening the closed loop up. I'd like to see what it makes on a dyno and try different AFR's but it's fine for getting going.

The hanger survived the day but I think I need to drill the clamp lower so it can't loosen its grasp on the can.

There were kind of a lot of people at the track and there was a large speed disparity which made it tough to get clean laps but I was getting down to 2:08's when I could avoid traffic. My best of the day was a 2.08.345, so considering the track record for the class is 2:07.237, I'm hoping it'll be pretty competitive once the suspension and other little things get done.

 

[psych0hans]

God luck! You seem to be making great progress

 

[tecknojoe]

Jesus you're already down to 2:08? Must have been running north course, ha.

I raced this weekend. The stock suspension is hell. I can't wait to get that fixed

 

[big_sur]

It really does suck, especially the rear. I should've left a session earlier, but last session of the day I took 10 a little wide and the rear unloaded on me hard when I tried to get on the gas. I then got to explore its KTM dirt roots.

 

[tecknojoe]

That's a scary place to stand it up, and exactly why I held back so much this weekend. The bike would wobble was I trail braked and put weight back onto the rear in corner entry, and would also wobble as I got on the gas.

In other news, I was pitted next to fosbinder, he said stock front and 44T rear is the right combo for all three tracks, so I'm getting that on order.

 

[big_sur]

I could definitely see that. I ordered up 44-46, but it probably does just need to be a bit taller. I'm hitting the rev limiter at the bottom of the dip before the brake markers at HPR now. I'd like to get down to pueblo and see how that feels with the tires and gearing there but I doubt I'll ride it again until I get the shock and then it'll likely go to Dave for the forks.

 

[Asher]

What did you use to log that data?

 

[big_sur]

What did you use to log that data?

This app - https://play.google.com/store/apps/details?id=com.trackaroo.apps.mobile.android.Trackmaster&hl=en

with this receiver - Amazon.com: Qstarz BT-Q818XT 10Hz 66 Channel Bluetooth GPS Receiver: Electronics

My only complaint is the companion website for the app to analyze all this stuff online doesn't work for me so I might try a different app next time.

 

[big_sur]

I didn't want to re-make the hanger so I took the easy out with the exhaust. I will say that whatever that hanger is made out of is tough.

Also, I was noticing I got these kind of "rings" of abnormal wear on the tires. The back kind of looks like a hot tear?

 

[Asher]

Slight hot tear but I don't think that's too bad, the raised lip on the back of your tread pattern suggest your rebound is too fast too.

 

[big_sur]

Hmmm, maybe I'll try a little higher next time. I was definitely following dunlop's 33/30 off-the-warmers recommendation so maybe the tire just doesn't like its current role of suspension part two. Hopefully most of that clears up when the suspension goes on.

 

[big_sur]

The RC actually made it off the work bench and sat around for a little while but a fresh round of parts showed up yesterday. The initial cheapy e-bay lever was too short on the clutch side and I was getting some pain in my left hand so new cheapy ebay levers came today and I replaced that side. I left the shorter brake lever as the new longer ones were kind of close to the brake lever guard. I couldn't get it to contact and interfere, but it was a little close for comfort and I only use two fingers on the brake anyways so the shorter one should be fine. I also couldn't decide on color so now I have lots of spares.

All of my Tyga stuff showed up as well and I'm pretty pleased with the quality. The fairings in particular are much more polished than the dutch ones were. I'm going to try and run into town and grab a chain to get the gearing on tonight.

 

[big_sur]

The shock came Friday so that, the new chain, and the 44t sprocket made it on. Unfortunately, the weather has gotten a little gross recently (and I bought a project sumo) so it might just be headed to get the forks done next and all this stuff will go into hibernation until Spring.

 

[OldVet]

Dang I wish you would have did a step by step picture tutorial