Ducati Monster Forum

Having run and dyno tested an open air box on a carbed 900 Monster, I settled on a good set up with shortened velocity stacks which thickened the power and torque curves rather than gave any major top end power at the expense of mid range and bottom end. Tuning theory leaned towards the latter happening but it didn't. The inlet manifold are a mile long anyway..

The conlusion I reached because of this was that the velocity stacks were too close to the filter element making an inefficient air box even more so. Shortening the velocity stacks improved the available volume in the air box. The shorter stacks mitigated a shallow air box design to some extent. The location of the filter, available space between the filter and the stacks and the location of the carbs on the air box are all part of the equation. I'm no expert on this for sure but look at a modern air box on a GSXR and see the difference.

What about trying pods? The K&N RU 1750s have been shown to flow enough air to make over 100hp in worked carburetor desmodues. They also drop 1.5 kilos in weight and make servicing easier. I have a friends bike which runs very well with them, a 944 Superlight with FCR39s, a little porting, dialed cams, Dyna coils, Igniteck Ignition and Ti valves. This bike does 3rd gear wheelies down hill. It only required a change in needle position when changed from an open air box (#5 to #6). I did this mod on the bike as I owned it before by buddy. I painstakingly tuned this bike over six months.

I got my kids and Math teacher wife to help me calculate the filter area of the pair of pods compared to the K&N flat filter. The pair of pods had about 30% more filter area (roughly), I can't remember exactly. There was significantly more. Their shape concerned me and whether there is a good radius inside to give a velocity stack effect. If Jako and MBP have used them to good effect then I shouldn't worry too much. (Anyway Chris Kelley don't sell crap).

When I am well I will conduct road testing and then whack the old girl on the dyno. If I get 81-82 hp and no losses in the midrange or bottom end then I will keep them.

By the way she has JE high comps, advanced stock cams on Vee Two pulleys, Termis and some porting on the inlet side. There is also Kelley coils, Igniteck module, Vee Two/Barnett clutch (-1.9 kilos) and 1 kilo lightened stock flywheel. Going nuts with being ill with the flu at home, I got out of bed and carefully weighed all the stock components removed or replaced with lighter stuff and have dropped a whopping 16 kilos from the empty tank weight as weighed by Sportsrider in 1995-1996. From 186 to 170 all fluids sans gas. Pity I can't afford light wheels. As an aside, the sprung weight is low but the unsprung weight is heavy with the stock Brembo wheels, and I feel it in the handling as the unsprung weight is a bully to the chassis. The sprung and unsprung weight are out of balance to me.

With Pods servicing is easier and with a Shorai battery I have fitted the coils and ignition all into the battery box which I have seperated from the air box. Removing the ignition bracket removed another 200grams. That's 3 kilos off with the Shorai, 1.5 kilos off with the pods and 200 grams off with the ignition bracket.

I'm concerned about crankcase breathing which I will have to deal with (see the other thread)!

I'll get well and report soon.

Cheers. [drink] For medicinal purposes.


 

I have been toying with pods for my M750.  I haven't made the leap because of having to create a way to mount coils & battery AND all the tuning that goes into me setting up for the pods.  Currently, my crankcase has a tiny K&N style filter clamped in for crankcase venting.  Bike is running very good with the exception of an off-idle grumpiness.

JM

Get well soon!  [beer]

Who the hell gets the flu in July?

Feel better soon!

Middle of winter Down Here mate...

Yup hope you're back on track soon Koko64 (looking forward to seeing how you go with this....)  [thumbsup]

Thanks for the good wishes guys. Should be able to start testing in a week when I am well enough. It is snowing in the nearby hills...

 Back to the sofa and granny blanket. Never thought I'd say this, but bring on global warming!

Ah.  Got it.

Good luck!  I'm curious at the results!

After three weeks of illness, I'm back on deck. Back to work tomorrow.

Will arrange for a dyno test next week as I can get it cheap including dyno diagnostics for A/F ratios at idle, 1/4, 1/2 3/4 and WOT for 80 bucks (which I don't have due to being off work). I'll see what deal can be arranged.

I will do the road testing first if it isn't raining (damn cold though). Haven't ridden the bike in nearly a month!

Based on doing this mod in the past I suspect no significant difference in power with the appropriate tuning. It's not like I have removed a really effective air box.

It's good to get off the couch..

I'm definitely keeping an eye on this thread  [popcorn]

First ride in a month! Had to richen idle mixture screw and will fiddle with the slow air jet. Pods seem to flow more air at idle and sub quarter throttle, I'm getting a lean spot off idle. Interesting.
Might have to increase slow fuel jet.
Bike is very responsive otherwise. Its running fine on the street. A lttle more responsive. Half to 3/4 throttle rich spot is resolved.
We will see what the dyno says.

probably a truckload less restriction for those pods

I think thats correct from the seat of the pants. We will see with A/F ratios are on the dyno.

One big issue the dyno isn't going to tell you about is that generally engines like to breathe from a large volume of relatively still air.

So pods on a dyno may work fine, but when exposed to a 60 MPH blast of air they'll make less power.

My local shop prefers the open airbox to pods on their race bikes.

Personally, I think pods look and sound great and I don't miss the few extra HP they may be costing me.

My view is that a correctly designed air box is the best way, eg ala Jako.

I wonder what you'd get if you kept the bottom of the airbox with no filter and modified the horns to take the pods... 

I have considered an air box mod like that, but if MBP and Jako can run pods and make over 100 hp, then I thought why bother? My next rebuild will be incorporating some of those tuning mods. Mind you Jako has a carbon air box that gives about 110 hp.

How much of that 110 is due to the airbox?

Pods were at 102SAE and carbon air box toward the 110SAE mark. Jako normally uses ps hp so you take a couple off.
Check out the site its interesting. I know you speak French (smooth move), the Jako site is in German. I winged it and found some dyno graphs. The air box appeared to work well but would be pricey.  I would be happy with the Jako 100 hp kit!

Now that's an interesting idea! So are they basically using some kind of "shield" to protect the pods from the airstream?

Off to check out their site (and brush up on my German)

I saw one air box that had pods in it with possible ram air and another that looked like it was custom made for split FCRs. Jv might chime in, he told me about the site and had been looking at the carbon air boxes.  Jako have been using Del'Ortos and seem to have alot of experience with them.
Unfortunately my German is limited to what I learned from Hogan's Heros.  [laugh]

Are you thinking about this one?
http://www.riding-house.com/products/ducati/fiber_parts/dfm020.html (http://www.riding-house.com/products/ducati/fiber_parts/dfm020.html)

Very nice. There is so much more available for the S4R/S4RS.
Have you seen the Jako air boxes? Jako cater for carb desmodues.

It's my day off and I have been doing overtime (gotta claw it back)!

We have a break in the weather, a sunny but cold 15-16 deg C. Any lean spots in the fueling will show up today!

Will test slow air screw settings for 1/8-1/4 throttle operation and general road testing for responsiveness, etc.

Will post my impressions.

EDIT.

I went for a two hour ride thru the local hills. The response up to half throttle and 3/4 was impressive.
There is a little dip in the power at 1/4 throttle (on the lean side, well feels like a lean dip) and then an improvement at 1/2 throttle from before where it was on the rich side.

The climb out of the dip has the front wheel lifting easier than before in second and this occured with a gradual rolling on of the throttle climbing a hill. This surprised me as I was overtaking a car on a switchback corner in the overtaking lane, the road was greasy and I was leaning the bike!

My take is that a couple of slightly rich spots (1/2 and 3/4 throttle) have evened out nicely and I believe I now I have a lean spot at 1/4 throttle. I will continue the bottom end tuning with the slow air screw as it overlaps at 1/4 throttle with the needle pos-n, needle diameter and slow fuel jet. When I tune out that lean spot it won't feel as rippy but will actually be faster.

Rolling on hard to WOT from 3500-4000 rpm and 50mph (80kph) was a little cleaner and more immediate. Nice.

We will see what the dyno says as to any measurable change in power. I wouldn't be surprised if a lost a pony or two in some places and gained a pony or two in others. I couldn't hazard a guess for peak power.
Main thing is that there are no ill effects. I reckon "much of a muchness."

Like any intake mod, it's just a matter of tuning.

I'm sure it's from years of experience...but, how are you determining the difference between lean, rich, and normal spots in your throttle?

You know we could have a separate Tuning tips/Tuning Principles thread dealing with that question.

Thanks for your interest.
It's so much easier (or less difficult) responding to a specific tuning issue or set of symptoms. There are a number of very qualified and experienced people on this forum who could contribute to such a thread. Some related threads already exist. Try the search function and enter the inputs relating to your bike.

Before we go there how about checking out the following sites?
Brad Black's "Bike Boy".org site and his articles on Dyno Tuning and Carbed Monsters/SS,
Factory Pro's Tuning guide on their site,
Patrick Burns Keihin FCR Tuning site (you can also get to it via Chris Kelley's Ducati Tech site,
Dynojet's site.
Keihin's site for tuning it's range of carbs.
Doug Lofgrens Motorcycle Performance Services site.
You could even Google Motorcycle Carburetor Tuning (I'll have to try that).

I would read up on these and then consider a separate thread on general tuning tips and Principles. If your bike is displaying specific symptoms put a querie in the Tech section.

Wow... I hope I didn't bite off more than I can chew  :)

I don't have anything wrong with my bike, I was just curious to what specifics you were using to diagnose your situation.

I would love a thread dedicated to tuning, it would help a lot. For now, I'll start digging through the links that you posted, thanks for the info.

start here:
http://www.bikeboy.org/performance.html (http://www.bikeboy.org/performance.html)

Still dealing with a lean spot at 1/4 throttle.
The needle won't fix it without buggering up the 1/2 and 3/4 throttle fueling. Could change needles but will look at the overlap of the slow circuit before I consider a needle with a smaller root diameter or less aggressive taper (depending which way I would want to go). Another tuner who deals with dirt racers that use these carbs suggested some tuning of the accelerator pump. He feels a common problem is a lack of fuel from the a/p with a leaner/smooth/cruise setting.
Those adjustable accelerator pumps are am option also.

It's a matter what angle to attack from without buggering another fuel range.
By the way, the pods are loud. I swear the engine/intake note from the seat has changed, it's a little harsher with a more strident edge to it.

I richened the slow air screw/jet and the lean transition to 1/4 throttle is solved. The bike was running on the rich side, but not hurting it at 1/2 and 3/4 throttle (12 and 12.5 a/f ratio). I figure if the pods flow more air this will be leaned out a little closer towards the theoretical optimum for power. Maybe raising a/f ratio half a point which would be fine. We will see.


Will do a couple of customer jobs and then i'll dyno it. The sun has finally emerged. :D

fun catching up on reading this after being away for awhile; that riding house ram-air lid is bfa! One day I will master fiberglassing/carbon-fiber'ing and make some type of gonzo airbox for my 900

Great to see you've emerged from study, hope you went well.

I'm finishing a job on a big Gixxer ex racer turned street bike. It literally has more than twice the hp of my Monster by quite a margin. Test riding is interesting.. Oh dear! [leo]
The Monster is more fun on the street.

That Gixxer probably has triple the air box volume of a carburetor-ed Monster with the velocity stacks at one end and the air filter at the other after the intake tubes for the ram air. There is a huge volume of space in between.

I will have the Monster on the dyno soon.

My bike has a pc of hoddy sweater zipped tied over the intake stack . it is a 2001 ss750 FI.

Time will tell: Don't find results out till November!


Awhile back I acquired a set of the Febur / CM Composit carbon upper "intakes" (these:)
(http://www.bursievolution.com/media/catalog/product/cache/1/image/5e06319eda06f020e43594a9c230972d/p/1/p1010144.jpg)
(http://www.bursievolution.com/media/catalog/product/cache/1/image/5e06319eda06f020e43594a9c230972d/p/1/p1010142.jpg)


...and eventually I'd like to work something similar to (here's a three-way combination for you):

(1) BMC 748/9*6/998 Air Filters Set-Up:
(http://www.ducati-john.co.uk/ducati/bmc1.jpg) (http://www.ducati-john.co.uk/ducati/bmc2.jpg) (http://www.designcorse.co.uk/lg_images/748_916_996_998_BMC_Air_Filter%5B2%5D.jpg)

(2) Streetfighter "Ram-Air" Carbon Intakes (mine in the form of the CM Composit Intakes I've got)
(http://www.shop.goaz.com/images/12950023081671373321653.jpeg)
(http://www.oppracing.com/image.php?image=p1050082_p183442_6ee6a9.jpg)

(3) Jako Airbox for split singles
(http://www.jako-motorsport.de/images/SuperDue3.jpg)

("4") "END Result" similar to: Bursi Evolution Carbon S4RS Airbox with Ram Air
http://www.bursievolution.com/multigallery/detail/index/id/18/monster-s4rs-corsa.html/ (http://www.bursievolution.com/multigallery/detail/index/id/18/monster-s4rs-corsa.html/)
(http://www.bursievolution.com/media/multigallery/p1010340.jpg)
(http://www.bursievolution.com/media/multigallery/p1010341.jpg)
(http://www.bursievolution.com/media/multigallery/p1010345.jpg)

you can do it easier than you realize.  there are some great videos on youtube.  i made a mold for the stock airbox but broke it accidentally when moving.  I should try it again.  Even with plain fibreglass it is going to be around half the weight -- no reason to use carbon unless you just have it lying around.

because its just so pretty! i'm going to put glitter in the resin!   

(http://www.emofaces.com/en/buddy-icons/%5B/buddy-icon-in-love.gif)

(http://disney-site.com/disneypics/fairy-21.jpg)

NEW.TANK.LOGO.LOCATED!

Hey you're onto something, I've got a couple of daughters who want a Monster for their first motorbike! :D

I was thinking of possibly making a carbon shroud to shield the pods beneath and each side to calm the air a bit and keep out water. Since the pods flow enough air to support over 100hp, the largest barrier to 100hp is now lack of valve area and the long manifolds. A beaut air box would just add to the performance, and most likely right through the power curve.

That is a very interesting set up you are looking at j v. It is going 10/10ths to extract all the available performance for sure, which must be why Jako went that way on their racer.

How to mold something with enough volume to fit a Monster with all those frame struts will be interesting. The struts relocated to allow for split single FCRs could give the room you need, more like an SS. Notice on the Jako site there were only SS bikes with split singles?

The split singles on short manifolds may come when I do the next full refurbishment including painting the frame. Then I will do the full MBP style heads with big valves and raised ports. Damn it that I prefer the look of the older Monsters I only want 100 air cooled hp!

 

but i'm doing it because i'm terrible at managing my money... [laugh]

Do it all now before kids! :D

Yep.  Buy all your toys and extras before you have kids.  Once you do, you better win the lottery because time and money are not in surplus anymore.

i'm trying a variety of delay tactics.  among them, moving 600mi twice in 3 years and getting a ferocious house cat.

Update.
Had to delay dyno test due to the dyno requiring a service and rebuild. I am concerned that having been refreshed, the dyno may read different. Have a booking for next Tue, so will report back then. I will discuss with the dyno guy whether the dyno rebuild will change the readings and if so by how much.

Honestly, I don't expect there to be much difference between pods and an open air box, (for old two valvers), as long as both configurations receive the appropriate jetting. But that's why we test things. We'll see.

[popcorn]

(http://www.sherv.net/cm/emo/smoke/smoking.gif)

G'day fellas, I got back from the dyno. [evil]

The pods when compared with an open air box and stock length velocity stacks with same main jets and needle position gave the same 80hp. Peak torque was down less than a ft/lb, 62.43 to 63.29.

The dyno lines trace each other with very small differences. What stood out was that the pods made the bike run leaner below half throttle and richer from half throttle. The half and three quarter throttle runs were unacceptably rich 11-12! It was rich enough to start killing power.
My assumption about filter area was incorrect at higher rpm.

The open air box with short stacks was significantly stronger in torque and hp through the rev range than both the pods and open air box with stock stacks. 81hp and 65 ft/lbs but 1-2 more all the way through.

I went back to the open air box with short stacks when I looked at the a/f ratios as I believe this set up flows the most air and helps the runt of the air box litter work a little better. The a/f ratio was consistenly richer with pods at WOT than the short stack air box with the same jetting. The open air box with stock stacks was leaner than the pods until 6500 rpm when it too took a dive in the a/f ratio on WOT runs. They would both need a smaller main jet. Again rich enough to start killing power
causing it to flatten off the torque and power peaks. The short stacks let me run a fatter main jet to get the gains everywhere, while the smaller mains with the pods and long stacks restore the peak power, but without the thicker midrange torque.

With more fine tuning I could get another peak hp and fill the dips in the torque
curve. Just matter of tuning.
So much of muchness. You aren't doing much harm running pods, just be prepared to tune. I would run pods over an open air box and stock stacks and tune accordingly. If I were to run the open air box I would definately shorten the stacks. This gave the thickest power and torque curves. Imagine what a bigger air box would give.
Forgive the scrappy report, its from a smartarse phone as the pc is down.
As for now, those K&N 1750s have been put back in their boxes for the big day of MBP style heads and split singles...(one day).

Thx f sharing!  :)

Maybe you`ve killed the neverending pods/box debate.....  ;)

Now put some short manifolds on with split FCRs and tell us.... :-)

After some more ruminating over the dyno sheets, I noticed some characteristics of each set up.

The air box with stock stacks and pods appear more sensitive to any over rich points in the a/f ratio. It seems that those set ups required a more precise jetting with less room for error. The short stacks seemed to tolerate both rich dips and lean bumps in the a/f trace without harming the power and torque curves.

The pods ran with the most rich a/f trace on the same jetting at WOT. The pods run richer at WOT and above 1/2 throttle hurting the torque peak, but below 1/2 throttle run leaner and wanted more fuel/less air. I had to experiment adjusting the slow air jet and IMS to get rid of a lean condition from 1/8 to 1/4 throttle. I have to say, this was opposite my expectation, considering the pods have 20-30% more filter area. I really thought the pods would lean out the top end. However, the pods do not have a nice bellmouth/velocity stack type radius inside. It's pretty basic in there. The pods combined volume would be significantly less than even the runty carbed air box.

Now I have to decide if I can tolerate the extra 1.5 kilos I put back on the bike with the air box or continue to tune the pods set up. I suppose I have to wait for j v to start producing a carbon air box! Maybe an air box extension that can be clipped to the existing air box going up to the height of were the snorkles would be on a stocker..

In the end, between the stock long velocity stack open air box and pods, there was very little in it. Both wanted a smaller main jet.
The open air box with short stacks gave the best performance. It allowed a bigger main jet to support power over the rev range at WOT without choking the top end power or peak torque.

I'm keeping the 1750s in hope of doing that one day. Just a little keepsake for the future.. ;)

Thanks for the info/update I don't pretend to follow you 100% but I understand plenty enough to make a decision and leave the tuning to my local Duc shop. Thanks again gotta love the cold hard facts.

Gday g m

How did you find it tuning the pods? Your M900 looks like it has pods from the picture.

i actually left it to a skilled tuner w a Dyno.

Most fiddling done w idle & off idle response.
No good idle yet w either 55 nor 60, but 1.5 half turns on air screw I find really good f off idle response.

That's interesting. The air box with short or long stacks wanted 1.5 turns on the slow air jet screw, 1/2 a turn on the idle mixture for best response. I run a 52 slow jet for easy cold starting, thats why the IMS is only 1/2 a turn out,. Ideally I could use a 50 slow jet, but with no enrichening/choke circuit and cold winters here (not as cold as where you are!), the 52 slow jets help.

With the pods I needed the slow air jet screw turned in to 1 turn to avoid an off idle lean spot. The pods required me to maybe go a richer, thinner needle root diameter.

Conversely,I needed 160 main jets with the pods and long stacks/air box, but 165 main jets with the short stacks/air box.

Both long and short stack air box set ups worked well with needle position 4, but I could have gone to needle position 3 with the pods.

A race car tuner I know told me we have strange fuel here, so I don't know how relevant my jetting is.

Think I have needle in 4th, 162.5 is my mains.
Pods w Kämna stacks.

Very similar jetting to be sure.

The Kamna stacks sound interesting. Can they be used with the standard air box?

Ideally I would like to use some stacks like the blue Keihin ones in a nice carbon air box. Does Kanma make air boxes?

Maybe they`ve done one-off boxes f their specials.

This is what I have:
http://www.kaemna.de/cms_en/katalog.htm?&view=artikel&artikel=1012 (http://www.kaemna.de/cms_en/katalog.htm?&view=artikel&artikel=1012)
My friend bought FCR kit from them, he used airbox and these where left over so I guess they don`t work w the box.

The site says those adaptors fit the stock air box.
They look like a more radiused, "ported" version of the Keihin air box adaptors. I wonder if they work better.

May be thats the reason the pods rich out on WOT ?
KN have filters with velocity stack built in.

For sure a good velocity stack in the pods would have to help air flow. Are the Kaemna stacks usable with other pods or only one type? I would like to use something like that in a custom air box.

Dunno in details why the Kämna adapters didn`t fit airbox. To me, they look like they wouldn`t fit air box only w/o any more rubber fittings.
Friend fiddled 3 long nights w the carbs & ended up w stock airbox & stock rubbers.

I have a 2002 620ie dark. I want to take out my air box and replace it with two K&N's. I was looking at it this morning and noticed a hose that is attached to the air box and runs to the back of the seat into a plastic bladder/box. I was wondering if I need to or should add a fitting that would run into a spacer between the filter and the velocity stack. This may sound strange but I will take pics. Does anyone know if this will work for my 620? Thanks.

That is your crankcase breather setup. For best performance, it ought to be there - but you can do away with it all together to clean things up. More info on it can be found by searching: crankcase, breather, vacuum, Pressure, vent, oil, mist, etc

Thanks JV! How you been? Did you leave Texas? When do you find out the test results? I was thinking that I could add the crankcase tube to the tube that I will add to the adapter to fit the K&N's to. Kind of a t-bar effect. the hose would be breathing into the velocity stack. Does this make sense?

dont most use a 1 inch hose with a KN mini ?

they do until the oil pressure sprays a bunch up into the filter.  if you have to use that setup, it should be with as long of a hose as you can put under there. 

I was thinking that I would keep the length the same and just add a K&N mini like suggested above. Do you think this would work? I was going to mount it in the same area as the air box.

that is better than trying to branch it into the pods/velocity stacks - the v-stacks are supposed to be uninterrupted flow area - smooth flow from there, through the carbs/throttle-bodies (whichever applies), through the shortest straightest intake manifolds into the heads where it is again, the smoothest, straightest path to the back of the valve (ideally).   the "in" for the intake air path is the velocity stacks, which should gradually taper into the throttle bodies - think of the "bell-mouth" of a trumpet.   Likewise, the "out" for the intake air path (into the head/cylinder's combustion chamber) should get a nice smooth 'bell-mouth' shape (hence 'multi-angle' valve jobs for performance) - again like a trumpet/tuba/baritone/trombone's bell. Not like the abrupt ending of a flute.

Good to have you back on deck j v.

I was thinking about a T piece into pods at one stage with the hose entry into the plastic face of each pod. But I went nah, I"ll put the air box back on and stick a mini K&N on the oil seperator box. Clean air into the air box, and with shortened stacks the best performance.

In the end I tested and decided.

The next best set up is a bigger, better air box. I want see if I get the filter to be at the very top of where the stock air box lid would be. I'm going to get an old air box lid and see if I can glue/plastic weld a filter frame into the top of it before I open it to get some more volume.. It'll be a cheap experiment and reversable with bits from mates and the wreckers.

Thanks guys(JV) I will take pics of my progress. I just bought a mini filter for the crankcase line and will get the filters in the mail on Monday.

i'm doing some learning about the setup on the 851-888-926 (corse/corsa models and factory models) and will divulge what i learn promptly.

Will there be some transferable mods considering the similar frames?
[popcorn] [popcorn] [popcorn]

So for EFI does this effect me as much as the carbs? Also what is the easiest setup if I want a loud annoying monster...

Cut your mufflers off :)

Cut your exhaust headers down to about 2" -- 2" from the exhaust port.

Weld a kazoo on one port, and a duck call on the other port.

It will be the loudest, most annoying monster EVER!

I stand corrected. This would net a more annoying monster.

If you are after a harsher sound, I found the pods combined with free flowing pipes like Termis, Leo Vince, Arrow, etc made for a more strident engine note. I found the pod's intake sound quite harsh and not as deep as the open air box. It actually started to annoy me. So if you want a harsh sound, less weight , a tough looking intake,  easy access to servicing your carbs and  possibly less restriction of air flow to the rear cylinder, then fit pods.
In the end I went with the open air box and modified velocity stacks.

Hey j v, how's that air box going?
What about you Tiz, made a fibreglass box yet?

I haven't extended the stocker yet, waiting to see what you guys come up with.

Nothin doin over here right now. frowny face.