Billet FCR Velocity Stacks

Despite the worst of what mother nature threw at us the first round of Billet FCR Velocity Stacks has shipped! Extra thanks to all that ordered sight unseen and had patience to be the early adopters. I'm also ready with low tension throttle springs, a TPS sensor mounting kit and also the entire FCR upgrade for those who are still running the stock CV carbs. I'm still working on a clever solution to adding a choke that requires minimal modifications.

Click on the link below in my signature and you'll be taken to the online store. Its a bit sparse now but it works. Sakurama is busy taking some glam shots of the parts so we'll jazz the site up a bit soon but I wanted to get it online ASAP.

Hopefully we'll have some glowing reviews posted as these parts get delivered, installed, and tested.

Just checked out the online store for your wares!
Nice looking selection of specialty parts for our rides.
Looking forward to seeing and installing those stacks!
Congrats on making it to market.

Chris got his stuff back and before I put a set on my bike I promised to give him some nice photos so after I wrapped up my shoot yesterday I put the carbs on the table. I was planning on getting the black stacks but now that I've seen the orange on my carbs I have to do that. I'm going to try to get it all mounted up this week and take the bike out for a ride Saturday or Sunday.

Anyway, Chris is also a Sudco dealer now so you can buy a whole kit from him with the reduced pull springs, the TPS bracket, the stacks, filters and cables plus the jets and vent filter. Here's the whole kit:



Nice work Chris.

Gregor

Nice photo Gregor!
Youse mus' be sum kin' o' perfessernel...

The whole shebang looks really good as a package.
Orange is the only color that matters, of course, but I can understand the guys wanting blacked out, er..., a stealthier color.

I have a few questions, since you have my undivided attention.

I have a Ducati M900 (Monster), and have installed FCR 41mms. The usual 'stacks that come with them are the flatter (I think) 35mm versions. The blue 'stacks are 50mm, but don't accommodate any filter. Basically, the longer the runner in the Pantah / Monster / SS engines, the better torque and usability. Shorter stacks are great too, but for top end.

So, my long-winded question is if you make different lengths of velocity stacks or at least 50mms which would help me a lot.

The work I see looks phenomenal, thanks for the initiative.

Hillbilly,

Thanks for the compliments. So far I am making stacks for the KTMs and ones for the modern Triumph twins are in the works. Depending on the under tank space either or both of these may fit on the Duc. One downside to that approach is that the KTM and Triumph are optimized for each particular engine. If there was a market for these in Ducland I would prefer to make a M900 specific set and as you say a nice fat torque curve is preferrable to a couple of extra Hp at the very top.

Whereabouts are you?

This may be all the incentive I need to run FCR39's on my 07 Triumph 865/270...

Some feedback.

Beautiful engineering!

I have a 990 Super Duke engine (with an adventure gearbox) in a 2004 adventure chassis. I am using the 950 headers with a free flowing aftermarket exhaust.

I have spent 2 sessions on a dyno with a very experienced operator to get to where I am now.

Used to have a 150mm unifilters with foam skins setup on the OEM FCR carb. I had 142 140 main jets, 52 pilot jets in it. This was setup by the same dyno guy.



When the velocity stacks arrived, I mounted them with 155 mains that were supplied. It was way too rich. I went back to the 142 140 with the needles on the 4th clip from the bottom and then sent the bike off to the dyno.

What I came back with and am at the moment;

140 front 138 rear main jets
Needles second clip from bottom
50 pilot jets
198 air jets
2 ½ turns out on the air screw bleed
1 ½ turns out on the fuel screw bleed.









I have left the outer foam socks on until my filter skins arrive. (we dyno’d the filters with the foam on and off – it made negligible difference to the AFR’s)

The billet throttle position sensor works very well and looks factory;



Starts instantly, even when cold. Seldom have to re-thumb the starter button. Very torquey and snappy. Angry even. With my 95kg’s and 25 litres on board it was roll on wheelies in 2nd. Precise throttling. Some patience is needed balancing the carbs both at idle with the adjusters and at 5k revs with the cables. Slow technical riding is brilliant, it will tractor through at low revs and is very hard to stall. This is very cool as I am short and having to dab from a stall always means a trip to the ground. The rear tire is not very happy.

My dyno guy has been a bit slack (too busy) in sending me the dyno charts, but will post them up when I get them.

We are not sure why there is such a discrepancy between the USA main jet experience and my South African one. I am the only one I am aware of that has these stacks here so can’t explain why. Unless you have a dyno with exhaust gas analyser, or, you have huge experience and skill in tuning, then these stacks are maybe not plug and play. In anycase, I can’t imagine anyone would buy these carbs and not expect to have to go visit a dyno. Not doing so, in my opinion would be foolhardy.

It has been a long road with these carbs and I am done fiddling now… I think… I spied a 2 wheel drive project somewhere?

I know that it may be a very strange question to ask about this setup, but how much mpgs suffer, if any on 950? Now I have 35-40mpg with headwinds setup on 950.

Do you need longer mixture screws, so they can be adjusted without gas tank removal?

I remember converting 640 to FCR and actually improving mileage a little and adding excellent midrange.

I am not the best to answer, not much time on them in this configuration. They are very sensitive to abuse. Baby it and they can do comparable figures to the CV's... I believe. But I seldom, if ever baby it and twist it's ear a lot and often ride in thick sand - worst I've seen is 9 km/liter, best I've got is about 14km/l but I haven't done much cruising on them.

I don't have the longer screws.

Andrew, thanks for the update and glad to hear some dyno work got it sorted out. I was thinking maybe the gas could make a difference? In the US there are various percentages of ethanol blended in to the gas depending on the season and location. Do they do this in SA?

I was hoping for a plug and play solution but with anything but a completely stock configuration it may be hoping for too much. As you say a dyno tune is a good idea whenever changing components anyway.

>>but how much mpgs suffer, if any on 950?

Our only data point so far is for Flanny changing from a Sudco FCR setup to my FCR setup and it increased gas mileage for his trip from NYC back to the Great White North. YMMV quite literally. CV to FCR? Good question.

>>I think… I spied a 2 wheel drive project somewhere?

Yes, that is about to start in earnest. Keep tuned to Sakurama's 950 refresh (yea, refresh!) thread.

For street riding, my FCRs are now getting the same mileage as my stock CV carbs were at 17 kms/litre or just about 39mpg. I think I can squeeze a little more out, because I think it's a bit fat on the pilot circuit still.

Off road all bets are off. Economy can get down to 12kms/l or about 27mpg, but then again, usually when we're doing that kind of riding, I'm not the least bit concerned with fuel milieage, and more concerned with just staying alive...

Getting the velocity stacks improved fuel mileage by 10% based on the before trip to NYC and the after trip from NYC under the same conditions (I was getting 35mpg on the way down). For transparency sake, this is probably not 100% attributed to the stacks/filters because of the small jetting changes we also made on the main, but my guess is that the intakes did contribute a lot to better steady-state cruising mileage...

Quick question: On an 04 950 Adventure would you recommend the 39s or 41s?

41's really let the motor do its part and are worth the torque...

Yup, in our tests the 41's were worth 1-2hp all across the range. There was no torque gain with the 39's anywhere but this was with an SMR 990 engine so we haven't tested a 950 with both back to back. I think the results would be the same.

Snowhawk - how's it going? Did you ever get them mounted up?

Gregor

It's taken a bit of fiddling and 5 dyno runs but I am quite far from where I was before. In my part of the world, jets for these carbs are scarce. Lot's of road runs changing the jets on the same piece of road to check



The difference was way more marked in the fuel consumption than the power.

It was very heavy on fuel when I began this journey. This was not because the main jets were rich but the idle circuit plays a really big role in fueling almost across the entire usage range.

Currently I am on the suggested 155's, needles on the 3rd clip (mid way)
38's idle fuel jet 1.25 turns out (it is slightly rich on idle and steady load @ 5% throttle, I might go to 36's)
No air jet, left them clean out. Screw 1.5 out. (this was a surprise, though there is some evidence on thumper forums of this being needed. It might be something to do with Super Duke cams?)

It is very very strong low down, the front pops up in second no clutch, even with a full fuel tank. It runs out of puff at 210 indicated. I just can't seem to keep the front wheel down. It is very tractor-able with lots of response. I think is is about the same as a normal bike very high in the revs.

Starting is a bit of a ritual if the ambient is . 3 cranks of the throttle. No throttle start. It bursts to life for a second or two then dies.

Do this twice and then catch the burst of revs with a 1/5 throttle to get the revs up to 3000. Leave it there for 10 seconds. After that it will fire up instantaneously.

A major bonus is not having to deal with the airbox.

Andrew,

Great to hear you got it worked out and are happy with the results. It's really weird that leaving the air jet out was the best result.

Hopefully we'll get the choke upgrade working and then it will be easy start and easy wheelie!

I just rode mine on a 2000 mile trip up to Northern Quebec and back, and I was worried about the choke situation, as the nights were cold and wet (about 5-8 degrees celsius).

Have not touched the jetting - it was set up at Chris' shop/dyno in New Jersey by Flanny et al last fall. I was pleasantly surprised by how easy it was to start.

3 cranks of the throttle, fires up and usually dies after a few seconds. Repeat the process, usually idles nicely on the 2nd try. Never had to do it a third time. On the third day, cold morning at about 7 degrees, it fired and idled on the first try.

I can't recall how the stock carbs run on these bikes, but there is ridiculous amounts of power and near-instantaneous throttle response. 100km/hr throttle wheelies are the norm.

Averaged 39mpg on a steady 120km/hr drone down the windy highway home. Typically I would get 260km before the reserve light came on.

Only issue was that the seat cutout is still pushing against the pod filters - I have to trim it back a bit further. Otherwise, I am very impressed and my greatest worry was the choke situation - so far in my experience at 5 degrees C and above, it's really a non issue.

The power and throttle response is truly addictive.

dc

I cant remember reading whether there are any clearance issues with the bigger filters on the 950SE - are there?

Not sure on that either. All the testing that I am aware of happened on an ADV. I know this setup will not work on an SM, that is my issue. Could be the same issue with the SE.

Chris mentioned to me he was going to try and find a smalled or slanted fiter for the one side that touches the tank on the SM...I am hoping that a solution will be found so I can install these over the winter, along with the choke.