Yosh exhaust,PCII still stumbles @ 2500 too 3000 rpms?

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OB_Tangram

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I've got the Yosh RS-3 Stainless system with a PCII. I've also got stage1 yosh cambs and a modified airbox, so although you're welcome to the map I'm using, I don't know how good it'l be for you.

Looking at the base maps available on the net the M304-006.map file has the Akropovic exhaust system (not too unlike the RS-3 so I'm told), with Stock air filter, which sounds like a good place to start. The changes I made for my bike where...

1) at 3000 accross the range on table 1 (AAP) the fuel was WAY too rich. Pulling down the values from 10 to 100 % throttle range smoothed out the hump which is evident on the dyno (TTS - Silverstone). This made the power delivery much smoother at the 2500 - 3000 point. It still had a tendancy to cough when going from a trailed to a nailed throttle in 1st or 2nd gear at around the same point (2500-3000), but this appeared to be a problem in the low-throttle/low revs area.

2) Having spent a month running around with a laptop on my back tweacking the map, some changes where made which proved to be succesful in making the power delivery feel better. This was confirmed as a possitive improvement in delivery on the Dyno too. This for the most part has cured this hesitation when nailing the throttle.

My stock bike did this stutter thing as well, though it's better now then it was. I would guess that this is the fuel-filter mod, or rather lack of said mod, which is causing this one for me.

If you want the maps to try out, mail me your address.
 
I just zeroed my Yosh box changes, plugged in my new PC2 with the 006 map and did 150 miles trying every conceivable combination of gear, revs and throttle.

Not a stumble or hiccup anywhere. Perfectly smooth and hard running in every situation from easy launches to 6th gear roll-ons from 15 mph right up to the rev limiter (I have a 16 tooth front). Seems to pull harder in the mid range.

I have an Akra, full box mod, PAIR off and a BMC.

I'm delighted! Lookin' forward to a dyno run. :)
 
I have a stuble around 2-3000 rpm on my busa also I have a yosh RS-3 stainless full, system cams, and more. It is very irratating. Other than this spot witch happen mostly leaving a light and then clears up at around 3500rpm it runs Awsome. but leaving a light smoothly make a lot of differnce when you do a lot of stop and go to and from work.
 
DP-<<I have an Akra, full box mod, PAIR off and a BMC.>>

If you have a "Full box mod", why do you have a BMC air filter in there? There is absolutly no way that filter can filter any air for you. If you have the full mod with the floor totally removed, the filter has nothing to seal against! It's useless to have that type of filter in there on a full mod. Also, the air needs to roll around in the box and with that filter in there disturbing air flow, it could hurt performance?
 
Anyone running a Yosh Duplex system with stock airbox? Downloaded the map into the power commander but it still stumbles/ surges around 2500 to 3000 rpms? How do I get the stumbling to go away? Any help would be appricated!
 
I put the PCII with map2 on Sunday, rode to Willow Springs to watch the club races where I found that L&L Motorsports had their DynoJet dynamometer set up.

My Busa, with 2Bros slipons and no other modes, did 162, 161.9 and 160.8. Tuner showed me how it was running way rich at the lower end, basically off scale on the air-fuel mix at one point. He tweaked it with the PCII buttons and it was better, but it was rich the whole range. I'm going to go to the shop soon for a full dyno map session that will produce a custom map for my bike. $200.

The symptoms have been hesitation and roughness, which started with the slipons and dealer setting mixture rich with Yosh box. He reset it back to zero and it improved, but still never as good at low end as it was stock.
 
I've got a similar setup. Full Yosh 4>1 RS3?, stock airbox and filter, and the PC2 with the prescribed map. I still have the stumble just off idle. It happens when I crack the throttle then it clears up and pulls fine from 1/8 throttle on up to full open.

I got rid of some of the stumble by going one "bar" rich on the "low" range using the manual adjustments on the PC2. It's still annoying though.

I have not checked the TPS, is it something an average joe can do with a screwdriver and a monkey wrench?

BTW, taking off next weekend for a shred in the Ozark mts. Put a new set of D207s on and will let you all know what happens.

Thanks all,
W
 
Have you played with mixture in the low end? Have you retarded ignition in the low end? Every Busa is different, so the Dynojet map may not be right just as is. That's why they provide the ability to dive into the map and modify it for your bike/weather conditions/riding style.

Please stay in touch with us on your progress.
 
I'll take my Busa out after work and figure out at what throttle position the stumble occurs and at what rpm is on the tach. Just got my PCII yesterday and still haven't figure out what the charts mean. Can anyone explain in simple terms what the charts mean?
 
Find a Yosh box,Use the map they recomend for that pipe.Adjust the TPS sensor first.All you need for that is a paper clip and a 20 torx bit.I have the same pipe and cant improve it without a dyno or E.T. SLIP.Its that good."BOB" showed all this to me ,it works,give him the credit.
 
I've got the same setup and I've been fiddling with it for awhile (see other posts). I've got nearly the same conditions and my TPS is right plus I've ruled out screens though I haven't checked them recently. I tried the Yosh box remaps and couldn't get it right with that so I got the PCII. It was better out of the box than I had it with Yosh, but still needed work. I think the Dynojet map is pretty good mid and high (though I've still made some changes), but the low end needs work. I started looking at some of their other maps for big differences from the 004. The Acro map has some timing changes (4k-5k @ 10%-20%) and they all seem to be leaner (vs stock) at 2500'ish and richer at 3000'ish and have a TP adjustment at 3000 (explanations anyone?). Someone earlier suggested retarding timing, but the PCII doesn't allow timing changes below 4k (I was trying the + side though). The Force map and the 004 map are very similar. The Acro map seems to be leaner down low vs the 004 (maybe duplex diff?). I've managed to make mine much better, but I still feel small hesitation when rolling on the throttle in the 2500-3000 range (it was there a little bone stock) -- very liveable though. Mine had a worse one at 3000-3500 that was very irritating, but now gone. I haven't had the time yet to do all the testing I want like tring large rich and lean swings to see which direction to go with it (wish I had a dyno). I'm guessing the 2500 thing is just a tradeoff of the aftermarket pipe and maybe a function of the quick lean/rich transition (maybe the flapper comes into play?). I know there are others who have similar complaints, but I haven't seen anything absolute and no one has shared a map. You are welcome to try my map (at your own risk of course -- larue@nwlink.com).
 
I would also like to try your map too. E-mail ame at : kzz1@voyager.net
Thanks!
BTW, My stumble happens around 2500-3000 rpms 1/8 throttle using the Yosh Duplex map with stock airbox. Other than that it pulls fine after 2500-3000 rpms.
 
May I also please take a look at you maps I have a Yoshimura R-22 full system and K&N airfilter with small airbox and PAIR mod. I had it dyno tuned but there is power surges in 3-4k ranges seems running rich.
 
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