4000 RPM surging/stumble

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T.RexRacing
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Joined: Fri Nov 01, 2013 8:34 pm
Location: back in the hills

Re: 4000 RPM surging/stumble

#16 Post by T.RexRacing » Sun Oct 22, 2017 4:28 pm

I prefer to sneak up on things rather than just throwing radical tuning changes at a bike. I did say it will be interesting to see how it pulls through under load as well as the TPS being the key.

Hmmmmmmm..........wonder if a MAP sensor would work? Anyone ever try one on a reed valve smoker? You could install a manifold pressure gauge (before the reeds) and see what differential it stumbles at before fitting the sensor.

You cold always drive a few hundred miles and we'll toss it on the dyno. It's slow season 'round the Harley dealer and we can always use the work. :smt005
There is only one difference between a madman and me. The madman thinks he is sane. I know I am mad.
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MK
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Re: 4000 RPM surging/stumble

#17 Post by MK » Sun Oct 22, 2017 4:40 pm

I also doubt that it'd work without a TPS.

MAP in my engine was between 90 kPa at idle and 100 kPa at WOT.
And it's not much use for stumbling effects (even if you logged & viewed it with the Megasquirt software). The pretty radical ignition retard had the most effect next to leaning out.

If you can put it on a dyno, it'll certainly be the most effective way to get rid of it.
Bye
Martin

savethe2strokes
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Re: 4000 RPM surging/stumble

#18 Post by savethe2strokes » Mon Oct 23, 2017 9:40 am

Video should be working now.

https://youtu.be/AeZEHtgkrzo" onclick="window.open(this.href);return false;
85 RZ350-Messed up wiring

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jumjum01
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Location: Denmark

Re: 4000 RPM surging/stumble

#19 Post by jumjum01 » Wed May 31, 2023 12:47 pm

MK wrote: Sun Oct 22, 2017 2:45 pm "A few" deg likely wont do the job. As I mentioned I run as low as 7deg in that low rpm / low tps region.
MK you just gave me the last missing puzzle to my EFI bike. It had the 4-5k rpm surge.
I took and punched in 7 deg. in 8-20% tps range at 3500-5000rpm in my ignition map and now the surge it gone. Night and day difference. :smt038
Having the EGT monitor, you can really see a lot more heat going to the pipe when retarding the ignition.
Guess the more heat in the exhaust in this rpm area changes the pipe pressure return waves speed to where they are more in "tune" with the engine cycle?

MK
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Re: 4000 RPM surging/stumble

#20 Post by MK » Thu Jun 01, 2023 7:42 am

You're welcome.
For the non believers, here's a couple of onboard videos from my EFI application.
https://youtube.com/playlist?list=PLVfL ... 7h1Up3tlK8
Bye
Martin

savethe2strokes
Posts: 513
Joined: Tue Jan 24, 2006 6:35 pm
Location: Kansas City, MO

Re: 4000 RPM surging/stumble

#21 Post by savethe2strokes » Tue Jun 13, 2023 8:24 pm

jumjum01 wrote: Wed May 31, 2023 12:47 pm
MK wrote: Sun Oct 22, 2017 2:45 pm "A few" deg likely wont do the job. As I mentioned I run as low as 7deg in that low rpm / low tps region.
MK you just gave me the last missing puzzle to my EFI bike. It had the 4-5k rpm surge.
I took and punched in 7 deg. in 8-20% tps range at 3500-5000rpm in my ignition map and now the surge it gone. Night and day difference. :smt038
Having the EGT monitor, you can really see a lot more heat going to the pipe when retarding the ignition.
Guess the more heat in the exhaust in this rpm area changes the pipe pressure return waves speed to where they are more in "tune" with the engine cycle?
Did you buy a kit for the EFI?
85 RZ350-Messed up wiring

savethe2strokes
Posts: 513
Joined: Tue Jan 24, 2006 6:35 pm
Location: Kansas City, MO

Re: 4000 RPM surging/stumble

#22 Post by savethe2strokes » Tue Jun 13, 2023 8:24 pm

MK wrote: Thu Jun 01, 2023 7:42 am You're welcome.
For the non believers, here's a couple of onboard videos from my EFI application.
https://youtube.com/playlist?list=PLVfL ... 7h1Up3tlK8
Was this a EFI kit? Also your fairing setup looks nice? Any other pics of the bike? I hate how much my full fairing setup shakes around while riding.
85 RZ350-Messed up wiring

MK
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Re: 4000 RPM surging/stumble

#23 Post by MK » Wed Jun 14, 2023 7:53 am

No kit.
Based on Stephe Murphrees work (aka Smurf on this Forums).
R6 throttle bodies, walbro fuel pump, mega squirt based controller.
Bye
Martin

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