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Discussion Starter · #1 ·
I love getting "free" Horse power and torque
and after reading much here about the restrictor plate removal
both pros and cons and I especially appreciated Venturi's posts
I decided to give it a try...but I wanted to dyno it before and after
here is what I have:
a BLUE 2006 Thruxton all stock except jetted with 125 MAINS
no other jet changes and the side snorkel is removed
Stainitune slip ons and it runs great. So I got a dyno today
It maxed out at 59.67 HP and 49.37 torque
It was a bit rich according to dyno guy
I went home and removed the restrictor plate
went back for #2 dyno with restrictor plate removed
This time it had 62.98 HP and 51.92 torque.
The HP & torque curves were the same until
4000 RPM when things kicked in.
There is no down side to this modification,
it runs the same through all RPM but pulls alot harder
there is no mid range problem or flat spots
I would highly recommend removing the restrictor plate.
I'm doing this step by step...so bottom line is I gained
3.31 HP and 2.55 pounds of torque for free and the
seat of the pants dyno confims this!
 

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HP/ Torgue

I am gonna DX the rev limiter. She loses that little xtra little git @ the last few sec's! Bums me out when that little "break-up" starts just when shes callin for it! Not much- just that last 1000 rpms. Not lookin to win drag races! Just want the last bit of potemntial shes got.
Other than that- ya gotta love it!!!
 

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Great for you!:D Feels a bunch better, don't it?:D

Now ditch the Staintunes for a really free-flowing exhaust, and add a pair of carbs to the mix and, see what you get.

Prob. minimum 10 MORE HP.:D Wanna know what that gets you? Trouble, if you're not carefull! Since I added the carbs to my mix, I have been putting ALOT of miles on my bike.

With light until about 9PM Pacific time, Iv'e been doing about 75 miles after work. There's a much bigger thrill in riding her.

Bravo! on your mods.:D
 

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Enlarge the inlet hole by 1/4" all the way around. Go up to 132.5's

Another jump up, probably a bit more than what you just did.
 

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Discussion Starter · #5 ·
Captdon,
you mentioned the rev limiter...I agree with you it was almost commical how the dyno would run up the rpm and THEN it would go FLAT when it hit the rev limit...
I will get a different ignition box soon...I heard there is a decent one out there that changes the ignition timing to what it should be and increases the rpm, some JUST increase the rpm but I want to advance it...the little black box will be my next thing...
 

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Discussion Starter · #8 ·
HP and rich

Since you asked about it running rich on the first run and you asked would it have still gained HP?...I think YES!
YES, it did bring the a/f ratios closer to ideal but it is STILL a bit rich but it runs so good I'm not changing it right now but I will be adding a UNI filter soon which may lean it up a bit...we will see. You know 3 HP does not seem like much but you can really feel it in the seat of the pants when getting on it...I only brought this topic up because for a long time I didn't want to mess with the airbox but it is worthwhile and I wanted those other scardy cats to know...someday maybe the entire airbox will go but it is good for now. I am dreading taking off the tops of those kehin carbs to reshim...I did lots of old style mikuni and Amal carbs but that rubber diaphram scares me to mess with BUT I will get around to it...
 

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me thinks that guys dyno reads kinda high.dyno runs can change 3 hp with out changeing a part.63hp on a bone stock bike with just pipes is about 5 hp to high.You cant hardly feel 3 hp what you feel is more torque.lets see the dyno sheets.
 

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Discussion Starter · #11 ·
You might be right

Miki, you might be right...
If I had a scanner I'd post the graphs...but I gave the best of the best runs of 6 runs total it's the torque like you said... I can feel its a very good improvement and it is a very noticable improvement ABOVE 4000 on up...below that no difference really till then BUT I think their dyno is accurate, it might be optomistic like you said...those guys dyno $75,000 race bikes and if it was high or not it had a noticible 3 HP difference in runs just 2 hours apart...maybe getting the jetting closer to that magic 13 a/f was part of it too but I have ridden alot of bikes over the years and IF and WHEN I get this Thruxton to LOFT the front wheel by GASSING it ONLY then I will be completely happy with it...My question to those reading is WHAT do you think it would take to do that...lofting the wheel?
I have been considering the FCR carb$$ next but I want to get a ?pieman? ignition box first...and see what the box does...advancing the ignition.
 

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Now ditch the Staintunes for a really free-flowing exhaust
me thinks that guys dyno reads kinda high.dyno runs can change 3 hp with out changeing a part.63hp on a bone stock bike with just pipes is about 5 hp to high.You cant hardly feel 3 hp what you feel is more torque.lets see the dyno sheets.
Me thinks maybe people that have never run Staintunes don't realize how much they actually improve performance. It's not all about how "free-flowing" an exhaust is. If that were the case, no mufflers would be the way to go.
 

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Me thinks maybe people that have never run Staintunes don't realize how much they actually improve performance. It's not all about how "free-flowing" an exhaust is. If that were the case, no mufflers would be the way to go.
I will bet you money my 2into1 D&DS will make more hp .I have yet to see a dyno with any big numbers with those pipes .I dont care what pipes 63 hp on a bone stock bike is a little on the high side.should be high 50s at best a stock bike is 49 to 52 at the rear wheel .
 

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to get one of these to power wheelie on demand you need 70ft/lbs or more .You will need a big motor to do that or run a 17th on a 904 or 988 motor .To get the big low end power the stroker motors are the way to go.You will need big flat slide carbs to get the power you want ether buy 39s or 42s.making hp makes the bike fast making torque makes it feel fast.I had a 989 stroker motor with some after market headers it made 70 ft/lbs and 75 hp .when i went to the 2onto 1 pipe hp whent to 89 but torque droped off some the 2into1 pipe was way faster but the other pipes felt faster .The best butt dyno test to see if you gain hp is to run the bike to redline in all the gears speed shift every gear and see what the rpm drops to on up shifts the less it drops the more hp you are making.When they are making hp they only drop maybe 500 rpm every shift.
I think my 904 is making near the hp the 989 was .Last dyno bike was way lean it made 84.67 hp and 63.89 ft/lbs .Since then i put a pieman box on it and bigger mains It feels faster now but wont know till i get it back on the dyno.
 

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Discussion Starter · #16 ·
It Is Like Crack

OK so I want torque...so where do I get this pieman ignition. The ignition is what I want to do next. I'll post the dyno when I get a different ignition box. After that I'll do cams. SO for TORQUE which cam??? Then maybe FCR carbs...the carbs are last cause they are alot of $$$. And sounds like a STROKER is what I need. I'll research the stroker info but please give your opinion on stroker kits also...thanks for the input.

This is like CRACK...thank GOD we are not into that.
 

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dump the air box get some real carbs and be ahead of the game.Why waste time and money on a patch when the fix is all ready there lol.
 

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dump the air box get some real carbs and be ahead of the game.Why waste time and money on a patch when the fix is all ready there lol.

Oh Mike!!
Now where would be the fun in doing that!!
:)



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