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secondaries

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Tasi

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Most of us believe life is better with out them .
Trouble is ,you get left with that 6mm bar that does nothing but turn the sensor on the LHS of the throttle bodies .
I'm not exactly sure of the tb opening size but its around 44mm-+ .So with 4 of them ,total suck in area is 176 mm.
Trouble is ,the 6mm rod, robs you of 24 mm of clean air suck .Not entirely true because the air goes around the rod but you get the idea .
In other words ,IT GETS IN THE WAY .
I'm no mechanic so I could be totally wrong but the rod seems to be a hindrance , agreed ? (agreed )


The tb's are actually two halves joined together ,the secondary servo thing is in the middle .
I decided the sensor on the LHS of the throttle body's could be placed into the servo leaving the rod 20mm long (less than 1 ")instead of 300mm?
inside the TBs .Servo is now not attached to the tb's .
Holes for rod are plugged with Epoxy Steel .
Tbs now look as they should .
Waiting for epoxy to dry so a smooth finish is obtained ..
IMG_0175_zpsf68d4126.jpg


IMG_0181_zps05866567.jpg
 
No shaft at all ., Servo motor lives on it own with sensor directly attached .
Ive gained 24mm of smooth air intake , no error codes or fi light .
 
Thing is I'm not sure about the impact; after all the seccondary shaft is inline with the primary so is it really blocking a significant amount of flow? I would expect that the effect is much less than the calculated value because of this. Would love to see a b4 and after dyno run to verify
 
dekenai said:
Thing is I'm not sure about the impact; after all the seccondary shaft is inline with the primary so is it really blocking a significant amount of flow? I would expect that the effect is much less than the calculated value because of this. Would love to see a b4 and after dyno run to verify
Click to expand...

Very good point dekenai.

The standard procedure to follow when performing engine mods to increase HP/ torque is to first perform a before baseline dyno run, then install whatever part your putting on such as a slip-on, or adjust only one thing at a time such as a fuel manager, and then perform a follow up dyno run to validate what HP/ torque improvements if any the mod made.

My gut feeling is also that removing the secondary butterfly shaft is going to have such a small improvement in performance if at all, that the only way you would be able to find out the effects of removing the shaft is with a before and after dyno run. ;-)
 
I agree on the dyno , probably only a very small increase .
Exactly what I was after .How much do we normally pay ($) for that . (lots)
Just knowing that useless 6mm rod isn't there puts a smile on my face .
One thing I know , the rods not going back in .

I can not see this becoming a common mod but it is an interesting option .
A dyno run by someone who had one would be an interesting read .

I just can not get the size of the rod out of my mind ...6mm X4 = 24mm blockage ..that's huge .
 
Yes, and it should also blow more… out the tail pipe that is! (At least if it is effective).

However we should examine the idea, which I think is prima facie a good one and see how it stands up.

IMO the first test is that it should do no harm? Well, I can’t think of any apart from a small chance that it will work too well and cause an overly lean mixture that cannot be accommodated by the ECU.

Next, does the change introduce new potential risks. A small risk that the filler could drop out maybe. I know that Gus is a former bike mechanic and so would expect that his familiarity with the filler in the same or similar situations would mean almost no risk there.

However, we could further mitigate this risk by designing a plug that was say similar to a push-pin (drawing pin in Oz), we could then seal that with a smear of silicon RTV. The other side we could fill/shape, (someone handy like Scott could do a kit).

Next, will it provide a benefit? That what I was hoping to quantify; I’d reckon yes, especially up top where the B1250 runs a little flat.

Well, based on the above I’d give it a go, but would probably want to be taking the TB’s off anyway.
 
Ive never been any sort of mechanic , I just like pulling thing apart .:doh:

The epoxy filler is a mushroom shape on all the holes so its not coming out .That is a dummy bolt head in the last picture .It is just
hiding the mushroom shape head . Epoxy is the same shape as a allen head metal thread .
Removing the secondary disks just seem like doing half the job to me .
Dek, if you ever ride past my place you better call in and give it a test ride.
It could be worse for all I know .:rider:
With more than one bike you kind of forget what it was like stock .

Perhaps you could leave the holes empty and just plug the outer LHS like the RHS .(brass Plug)
We need a spare tb with no rod ,Dek at one of his trackday .
I'm getting very quick at removing the row of 4 .
 
Oops, sorry mate...at least it wasn't anything insulting like accusing you of being a ex-lawyer...bahahahaha

Anyway, sounds good would love to do the b4 and after; probably wait till after the Yoshi cams go in as:

1. Since the expected benefit will be up top, and the cams should push the breathing further up the rpm scale;

2. When the cams are being done will install Scott's pair block off kit and tidy up that area to improve accessibility.

Of course, even after having done that the result is really only applicable to another B1250 engine with the same mods! The effect may be bigger, smaller or non-existent in another engine, e.g. expect next to no difference if you haven't modded the air box lid.

Would love to take you up on the test ride offer and you are welcome to give mine a try; just that ol' tyranny of distance thing (we'd be close to 3000 miles apart). But if you find yourself in the area....
 
I would think that by removing the bar it would be benificial to airflow, however the actual affects would be difficult to tell. Is it helping or hindering air turbulence, does it diminish eddies thus improving overall air flow ? Will it require a retune as the A/F mixing parameters have changed ? I agree that it would have to be done in conjunction with mods to the airfilter lid.

On raw figures the bar is approx 17% of the sectional area of the venturies. As a way of demonstrating this size of blockage I have blanked out 17% of a K&N SU-6505 airfilter to visualise the effect. Actually it is probably the opposite in that there is 17% more surfce area, very simular to the 1200 filter.

6505_v10.jpg


Whilst I am not saying there should be a 17% improvement in all areas, I would expect a slightly more responsive throttle and if lucky maybe an extra hp or two, for the cost of an afternoons work thats not a bad return especially if you do it as part of the butterfly removal process.
 
I just had my secondaries removed on my 2011 FA. Rods are still in. I am not going to remove them either, I just don't think it's gonna make that much difference. I would have to see before and after dyno data to be convinced.

Having said that, all I can say about taking those secondaries out is - WOW! She runs like a totally different bike now. Just smooth as silk, nice pull all through the band now, and that darned on/off throttle "jerk" is all but gone. So I figure I'll leave well enough alone! :mrgreen:
 
And a lot of people believed the earth was flat , and a Koala is a bear .:-P
If it was an easy mod we would all be riding with it removed .Unfortunately
it's a bit awkward .(but free)
 
No ,its not a bear .Like a whale is not a fish .(sure looks like it to me though )
I'm with Raptor , the earth IS flat , surly .
 
Another really nice thing about doing this is that I do not appear to have taken any real hit in fuelly! Usually anything you do to increase performance exacts a price in fuel economy. But so far I have not really noticed any. A pleasant surprise indeed!

The nicest thing by far though has been the drastic reduction in that on/off throttle "jerk". The Suzuki guys said there was no fix for that, but I guess we found it!
 
I've been threatening to do that for 5 years and 70K miles. I hope I do before I sell it one day. Course , in the last two months, I've rode the bike for 10 minutes around town. 1st time since my wreck at the end of May. ;-( Still be awhile before I can get it up on the lift with my shoulder's shape. ;-(
 
RaptorFA said:
The nicest thing by far though has been the drastic reduction in that on/off throttle "jerk". The Suzuki guys said there was no fix for that, but I guess we found it!
Click to expand...

Indeed! Got rid of most of it but once you go stage 1 or 2 the rest goes byebye too and she transforms in a whole new bike! :rider:
 
Yessir, Stage 1 kit is next on the list. I wanted to go Stage 2 but I really don't want to cut my fairing to fit the header. I know, I'm chicken! :eek2:

But I figure a Stage 1 kit with a nicely perforated air filter cover is gonna be a nice "next step", one that I am looking forward to for sure. I gotta say, I just love this bike! She's just a great all-rounder that is comfortable but still has a kind of sport bike feel to it.
 
You don't need the headers for Stage 2. It's Stage 1 plus less airbox lid plus secondaries out. The difference is startling even with the stock headers.
 
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