FCR velocity stacks - Page 8 - Triumph Forum: Triumph Rat Motorcycle Forums
Air Cooled Twins Technical Talk Technical Talk for Hinckley Triumph Twins: Bonneville, Bobber, T100, Speedmaster, America, Thruxton, and Scrambler.

Sponsored by: Triumph Twin Power Ltd

LinkBack Thread Tools Display Modes
post #71 of 74 (permalink) Old 11-12-2012, 11:48 PM
Senior Member
Main Motorcycle: 2010 Triumph Scrambler
Join Date: Oct 2010
Location: San Jose, CA
Posts: 290
I have a bad habit of feeding the trolls. =)

Originally Posted by steventhechef View Post
Can I play too? Can I play too?

Shaneduc, stop trolling or you'll be called a wanker
casida is offline  
Sponsored Links
post #72 of 74 (permalink) Old 11-13-2012, 03:25 AM
New Member
Production 125
Join Date: Jun 2008
Posts: 9
Originally Posted by ShaneDuc View Post
Then you were doing something wrong. What your friend and you are attempting to sell, sounds more like smoke and mirrors. No dyno's comparisons with different filters; Uni-Filter vs K & N's or other brand, with and without his velocity stacks....

Let's just say, "I'm very skeptical."

..........And the dyno you displayed is for the KTM, not the Ducati. Two totally different engines. Carburetion vs Fuel Injection, there's another a big difference. You're trying to compare apples to apples and in this case doesn't work.
I guess my subscription to this thread is flaky as I only seem to get an update every few weeks instead of days.

Anyway, I shouldn't have posted anything until Chris tested on a Triumph - but then again that's how he got started looking for one. He was arranging that when Sandy hit and he and much of NJ and the NY metro area have been without power for several weeks. Anyway, he's got a Bonnie lined up and will do the work to see what can be done. He's not selling anything here or to Triumph owners until he's worked it out and tested it.

As far as me and my KTM - my dyno chart that I posted is two runs before and after with no other changes other than the stacks and the main jet. The filters in the first run are the stock K&N's that come with the kit that Sudco sells and the second run are also K&N's but larger for the stacks. Not exactly sure what your problem is with that - same bike, same carb, one part swapped and the dyno chart is pretty easy to read. It's as apples to apples as Granny Smith gets. It's even more obvious on the road where I actually ride.

Like I said, I hope he can find as much with a Triumph kit - until it's done we won't know but I just want to set you straight on my bike.

sakurama is offline  
post #73 of 74 (permalink) Old 11-26-2012, 08:05 AM
Senior Member
Formula Extreme
Main Motorcycle: '04 Thruxton
agro's Avatar
Join Date: May 2004
Location: Gawler, South Oz
Posts: 488
Originally Posted by beemerrich View Post
I hear where you're coming from Agro...for about $35 per pair of velocity stacks and $100 of dyno time, I can test all 4 of the RS velocity stack lengths for my machine for less than $250 and have a induction length tuned to my motor's exhaust/cam timing.

My personal experience reflects your result, which was dialing in the tuned intake length ws beneficial in backfilling a hole in the midrange. It did nothing for me up top on either the CVKs or on the CR carbs.


Yep, midrange torque rules!!
Long stacks will fill in holes that the 2 into 1 creates. Also long stacks will fill in the holes big cams with long duration and large overlap like the 813, Irrespective of carbs used, CR, FCR, CVK.

By the way Rich, what main jet size were you using with CVK's stacks and Uni pods?
Had 135's now @ 150's, think it still needs more?

Have tried smooth and polished 790 manifolds with 50mm and 70mm stacks with 135 mains 42 pilots. The 70mm stacks felt good with this main.
Today tried 865 manifolds, no spacer, 50mm stacks, 150 mains, 42 pilots, felt very strong in the mid range.
Tomorrow, will try this combo with 70mm stacks.
Then i'll try the polished 790 with 150 mains and the 50mm then 70mm stack
Should get me a smart phone and get the "Smart Speedometer" app.... I'm having way too much fun...

"Whale Oil Beef Hooked"
agro is offline  
post #74 of 74 (permalink) Old 11-26-2012, 03:48 PM
Senior Member
Pole Position
Main Motorcycle: 2004 Thruxton
Join Date: Jan 2008
Location: Grand Rapids, Michigan
Posts: 3,861
Other Motorcycle: 1954 BMW R25/3
Extra Motorcycle: 1971 CB350
Originally Posted by agro View Post
By the way Rich, what main jet size were you using with CVK's stacks and Uni pods?
Had 135's now @ 150's, think it still needs more?
I was running 150 mains with thruxton needles/no shims. 42 pilots. This was optimal on the dyno using Uni pods over 50mm velocity stacks, 790 cams, and D&D slip ons on stock thruxton headers.

Best way to check if the main is big enough is to go full throttle for a bit and then let off to 7/8ths throttle...if she picks up, its running lean/the main is too small.


beemerrich is offline  
Sponsored Links

Quick Reply
All posts must adhere to Forum Rules

Register Now

In order to be able to post messages on the Triumph Forum: Triumph Rat Motorcycle Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter your valid email address, that can receive an automated confirmation message. Otherwise, you won't be able to gain full access.

Email Address:


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode

Similar Threads
Thread Thread Starter Forum Replies Last Post
Boddington Velocity Stacks BigAl8295 Hinckley Classic Triples 3 03-03-2010 10:28 PM
Short Velocity Stacks & Unifilters LOOSE - 60mm Open Velocity Stacks WIN robnobrakes Air Cooled Twins Technical Talk 5 01-29-2009 03:59 PM
velocity stacks pz1 Air Cooled Twins Technical Talk 1 10-18-2007 08:12 PM
velocity stacks?? blue-thrux Club Cafe' 13 05-06-2007 09:34 AM
DIY Velocity Stacks TBSstunta Hinckley Classic Triples 8 10-28-2006 09:01 PM

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
Trackbacks are Off
Pingbacks are Off
Refbacks are On

For the best viewing experience please update your browser to Google Chrome