The Sportster and Buell Motorcycle Forum - The XLFORUM®
 

Go Back   The Sportster and Buell Motorcycle Forum - The XLFORUM® > SPORTSTER MOTORCYCLE & BUELL MOTORCYCLE FORUM - GENERAL DISCUSSION > DYNO Charts and Result
XLF Blogs XLF Arcade XLF Disclaimer/Privacy Statement/Terms Of Use

DYNO Charts and Result Post your dyno charts and results here.

Active Threads
0 Keep & Kill
Last Post: Tim The Grim
Posted On: 6 Minutes Ago
Replies: 14,319
Views: 804,349
0 question about new trans door
Last Post: Iron Mike
Posted On: 25 Minutes Ago
Replies: 10
Views: 142
0 XL IR EFI to those that asked
Last Post: Iron Mike
Posted On: 31 Minutes Ago
Replies: 24
Views: 949
0 Full face, Half or skull cap?
Last Post: mikeLI_77
Posted On: 50 Minutes Ago
Replies: 502
Views: 93,360
0 98 Stator Removal / Inspection / Installation
Last Post: 60Gunner
Posted On: 1 Hour Ago
Replies: 17
Views: 571
0 This week on Craig's list
Last Post: IXL2Relax
Posted On: 2 Hours Ago
Replies: 4,455
Views: 544,295
0 Still got your upper drive belt guard??
Last Post: Ireeman
Posted On: 2 Hours Ago
Replies: 111
Views: 19,446
0 Crusty's Travels
Last Post: Davo_137
Posted On: 2 Hours Ago
Replies: 2,588
Views: 341,587
0 Multiple timing marks?
Last Post: needspeed
Posted On: 2 Hours Ago
Replies: 35
Views: 19,068
0 Where were the IronHead sportsters Made.
Last Post: NLXL
Posted On: 2 Hours Ago
Replies: 8
Views: 362
0 Hottie of the day, no nudity.
Last Post: Stairman
Posted On: 5 Hours Ago
Replies: 15,022
Views: 1,422,437
0 Hot Chicks on Hot Bikes
Last Post: trainman
Posted On: 5 Hours Ago
Replies: 10,385
Views: 1,818,953
0 BMW reverse trike build
Last Post: Stairman
Posted On: 6 Hours Ago
Replies: 4
Views: 113
0 Anti reversion “muffler”
Last Post: 60Gunner
Posted On: 6 Hours Ago
Replies: 31
Views: 1,331
0 Cometic Valve Stem Seal Install?
Last Post: BlackBikeDave
Posted On: 7 Hours Ago
Replies: 12
Views: 222
0 diagnose noise in engine after rebuild
Last Post: Nibelungen
Posted On: 9 Hours Ago
Replies: 13
Views: 488
0 Handlebars
Last Post: decman
Posted On: 9 Hours Ago
Replies: 2
Views: 107
0 .551 Cams in an EFI 1200
Last Post: Tomcatt
Posted On: 9 Hours Ago
Replies: 76
Views: 4,433
0 Roads I'd like to ride.
Last Post: Stairman
Posted On: 10 Hours Ago
Replies: 2,573
Views: 219,403
0 Best Battery Maintainer and/or Booster?
Last Post: stikflote
Posted On: 10 Hours Ago
Replies: 29
Views: 1,156
0 1200 conversion
Last Post: Folkie
Posted On: 11 Hours Ago
Replies: 2
Views: 125
0 Do you blip the throttle when downshifting?
Last Post: 60Gunner
Posted On: 11 Hours Ago
Replies: 462
Views: 79,713
0 Derby cover
Last Post: RussW
Posted On: 13 Hours Ago
Replies: 5
Views: 157
0 THE Hockey Thread
Last Post: XL Ed
Posted On: 14 Hours Ago
Replies: 4,038
Views: 270,380
0 Iree's late night cafe
Last Post: Maxeffort
Posted On: 14 Hours Ago
Replies: 1,335
Views: 169,944
0 Official XL Forum Random Image Thread (NO NUDITY!)
Last Post: Graywolf
Posted On: 17 Hours Ago
Replies: 45,493
Views: 7,182,658
0 Sportster Crankcase Pressure / Engine Breathing / Wetsumping and Mods
Last Post: harley506d
Posted On: 18 Hours Ago
Replies: 860
Views: 35,187
0 What got you into bikes?
Last Post: Ireeman
Posted On: 20 Hours Ago
Replies: 28
Views: 1,244
0 White Letter Tires
Last Post: Ireeman
Posted On: 21 Hours Ago
Replies: 23
Views: 8,011
More...
Members Birthdays
vlmuke, wazza (48), Grizzwold (44), roaldtm (39), redtacoma31 (34)
Sponsored Links
Reply
 
Share Thread Tools Display Modes
  #1  
Old 15th May 2017
aswracing's Avatar
aswracing aswracing is offline
A Million Facts & Figures
 
Join Date: Jan 2005
Location: Famous Potatoes
Posts: 10,072
Sportster/Buell Model: XL883
Sportster/Buell Year: 2007
Sportster/Buell Model #2: Buell Cyclone
Sportster/Buell Year #2: 1999
Reputation: 2674312
aswracing has a reputation beyond reputeaswracing has a reputation beyond reputeaswracing has a reputation beyond reputeaswracing has a reputation beyond reputeaswracing has a reputation beyond reputeaswracing has a reputation beyond reputeaswracing has a reputation beyond reputeaswracing has a reputation beyond reputeaswracing has a reputation beyond reputeaswracing has a reputation beyond reputeaswracing has a reputation beyond repute
Default Somewhat interesting 1275 result



2003 XL883R owned by a Valued HAMMER PERFORMANCE customer, equipped as follows:
Very good result for STOCK Thunderstorm heads. Back in the day, when Buells came with these same heads and cams, a good one would turn 90hp, I tested tons of them on this same dyno. So to get 96ish on a Sportster, with it's heavier flywheels to boot, is doing well. The 1275 kit has a bit to do with that.

As is plainly visible in the chart, the pipe is reverting badly below 3000 rpm. The torque is low, and with a small measurement lag, the AFR goes fat. Those are both sure signs of a pipe that's reverting.

What happens is the pipe pushes back during the overlap window, i.e. when the exhaust is connected to the carb. The intake charge that's sitting in the ports and manifold get shoved right back out the carb. Then the piston goes down and sucks it back in again. So you get a charge that's been through the carb three times - in, out, back in again - picking up fuel each time, and the motor goes rich. Plus you get a big hole in the torque curve because the cylinder fill is so bad. One tell-tale sign that you're reverting is a fog of fuel standing outside the carb.

The above chart was done with a 165 main in the Mik. On the right side of the chart, it wanted more main jet. In fact, with more main in place and taking it to 6800, I hit 98hp and 92lb-ft of torque a couple times. However, putting anything bigger than the 165 into the carb made it shoot ducks in the reversion. I didn't want to deliver the bike with that going on, so I settled on the 165. That was the biggest jet it would take without breaking up in the reversion.

Being a pipe issue, the right way to fix this is on the pipe side. There are ways to try to address it on the carb side, for example Thunderjets with less main, but at the end of the day that's a crutch. It's really a pipe issue.

Makes you appreciate EFI. You can't fix the reversion with EFI, but you can at least keep it from going fat.

The pipe follows the reversion with a real hard pull through the mid range, dying on top. In other words, not real great diffusion. A lot of pipes behave this way.

I'd be surprised if I couldn't hit 100 with a Patriot in place, with it's big top end punch.

(Hey Folkie ... there's no sticky reference thread for 1275's ... hint hint)
__________________
Click Here to Contact Me

Reply With Quote
  #2  
Old 11th July 2017
TT60 TT60 is offline
Chief Harley Engineer
 
Join Date: Nov 2010
Posts: 536
Reputation: 68455
TT60 has much to be proud ofTT60 has much to be proud ofTT60 has much to be proud ofTT60 has much to be proud ofTT60 has much to be proud ofTT60 has much to be proud ofTT60 has much to be proud ofTT60 has much to be proud ofTT60 has much to be proud ofTT60 has much to be proud ofTT60 has much to be proud of
Default

Looks like my Winter project will be 1275 kit

Just gotta save my pennies now.
Reply With Quote
  #3  
Old 30th September 2019
Highly-Dangerous's Avatar
Highly-Dangerous Highly-Dangerous is offline
SPANIARD
 
Join Date: Apr 2019
Location: 17130 Spain
Posts: 507
Sportster/Buell Model: XL 883
Sportster/Buell Year: 2006
Other Motorcycle Model: Big Dog K9
Other Motorcycle Year: 2006
Reputation: 1083150
Highly-Dangerous has a reputation beyond reputeHighly-Dangerous has a reputation beyond reputeHighly-Dangerous has a reputation beyond reputeHighly-Dangerous has a reputation beyond reputeHighly-Dangerous has a reputation beyond reputeHighly-Dangerous has a reputation beyond reputeHighly-Dangerous has a reputation beyond reputeHighly-Dangerous has a reputation beyond reputeHighly-Dangerous has a reputation beyond reputeHighly-Dangerous has a reputation beyond reputeHighly-Dangerous has a reputation beyond repute
Default

Wow!!! Those were very good numbers!!!

I am in the process of ordering the 1275.... I keep wondering about my stock heads... I am worried about regretting it in the future.
__________________
CLICK->>"Maintenance is as much art as it is science"<<-CLICK

Reply With Quote
Reply

Bookmarks


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump



Sponsored Links
All times are GMT +1. The time now is 04:32.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2019, vBulletin Solutions Inc.
XL Forum® - Linson Media LLC