VortecCPI wrote on 06/24/16 at 10:07:47:

Aside from actual study and dyno work, safer to include a bell mouth of some sort.  Similar to our bike, people put pod filters on the cb750 and they perform terribly... until they separate the carb and filter with a small bell mouth.

verslagen1 wrote on 06/24/16 at 10:28:46:


I can not disagree on "safer" but it is not necessary and space makes it very difficult.

Poor performance with pod filters is almost always because the pod filter flange covers CV air bleeds at the carb bell.  This is a huge issue with cheap/junk pod filters.

Examples below:

http://www.choppercharles.com/2013/12/jetting-made-easy.html

http://www.xs500forum.com/index.php?topic=1357.0

Versy , I'm curious have you ever dynoed your beast? Your kinda tight lipped with your engine mods. The rest of us would like to know. Give us a  HP goal or what's in that top end. When I'm done testntune mine is going to see the dyno guy across town!

I think it is a good idea, when you get a bike that is new to you, to pull the carb and check to see what jets are installed and if everything is clean inside.  If you are going to tune the bike/adjust the carburetor, then you need to know what the condition of it is before you start.  
That just makes sense.

Lancer , What about you ever dynoed your bike? Or will you tell us what's in your top end ?

I will likely mount the velocity stack I have for the performance runs.
In the book that was discussed in another thread, about 4-stroke performance, the charts on motorcycle speeds/times a velocity stack in the 4-6" range out performed every other type of intake.
There is some interesting stuff in that book.

"Performance Tuning in Theory & Practice"  by A. Graham Bell

Thanks for all that info Michael that gives me an idea where mine will be. My teacher Dima Elgin made us design a engine around a cam, the megacycle cam I won from a friend in a drinking contest , boy did I pay for that hungover for days. Graph the cam,bore & stroke,comp ratio,carb cfm, exhaust length all came together as one fast SR500 but never was put on a dyno. All from math from that book. But with the Ryca I did none of that , I just got together some parts & built it. As follows a Web cam STD has alittle more lift & duration than stock & hard faced the rockers, ported the head myself and removed all sharp edges in combustion chamber, 10:5 97mm wiesco & Boretech coated , 36vm mikuni with UFO,quad Wingy thingy,dialajet with a heat shield between head & carb,2" header 1 7/8 ID
With a muffler I built, repackable, Barnett clutch & springs , Versy's tensioner & plug. So far so good, guess the gearing is higher than I thought, should pull right past 100 mph easy. On One real hard run it barked rear tire & carried front tire for 30 feet on a first to second shift , she's got some big nuts that's for sure,seat & paint and she'll look as sexy as she is fast !

[quote author=283731362B2C1D2D1D25373B70420 link=1464235388/75#86 date=1466973426]he charts on motorcycle speeds/times a velocity stack in the 4-6" range out performed every other type of intake.


Does that include a filter ?

It seems I got a couple of charts mixed up together.
One was for cars in which an "air horn", or velocity stack I assume, was used.  For the car the velocity stack did out perform all but one, and that was very close, like839 to 853 cfm.  There were a total of 10 catagories
.
The other was a chart for an SR500.
The SR had 4 categories;
1.  34mm Mikuni carb with air filter & air box;
2.  carb with 2 filters + mod. box;
3.  carb + 2 filters;
4.  36mm Mikuni carb

** NO velocity stacks on these as I thought earlier.

In this case 2, 3 & 4 were nearly identical, with 1 being 1 hp ahead between 3-4500k rpm, all even at 5k, and from 5500-7500 from 1-3 hp behind.

Does anyone remember the SR500 having a redline of 7500 ? ?
I sure don't, but ...

My apology about the misinformation earlier.