Originally Posted by Tangai
I’m waiting for someone who has installed one of these on their 950 to give us a comprehensive report on how it runs and the fuel consumption.
Have you ever
known a freer-breathing engine to get poorer fuel economy?
Originally Posted by Sporting Wood
I installed a filter and tuned a friends bike yesterday.
It had Akras on it, no quiet tip. A 70 idle air jet, 45 slows and tiny mains(148 & 152) had been added along with a Uni pre filter dealio. I 'think' the needles were stock but couldn't tell for sure. They had been moved to the 3rd clip.
I set it up with 172 mains. Guessed that the richer bottom end would compensate somewhat and wanted to keep it from gasping at elevation...plus I didn't have a set of 175's. Adjusted the floats to 4mm from 3mm. Also didn't have any 50 idle air jets to set the slow mixture back to stock, so I got creative. Swapped air cut offs to 90's from 80's and put in 40's in place of 50 idle air jets. Total air is the same but it seems to backfire a bit when the throttle gets closed.
. That'll get swapped back once some 50 air jets get ordered!
The bike ran like a raped ape, not rich or lean anywhere in its range. It remains to be seen how it runs at elevation (roughly 1000' here). I've always had a hard time getting the 45's to work on the mountain.
He is I and I am him. I made it up Mt. Mitchell, along the BRP yesterday - 6,500'-ish, and it still runs like the proverbial raped ape, thank you very much. I did the same thing we did with it that Saturday - 4,000 rpm, full-throttle loaded runs out of 2nd and 3rd. It's strong as an ox and, with those silly silencers out of the Akras, I'm sure I saved a coupla dozen lives.
To Tangai's (indirect) request, I made certain to note gps trip odometer readings at fill-ups yesterday, and calculated mileage: 185 miles on 4.5 gallons = 41.1 mpg. I can't claim that my riding style reflects a concern for fuel mileage, so I'm sure it could do better, but I was too busy wringing it's neck and doing wheelies to care. I doubt that qualifies as "comprehensive," but it's enough for me to be satisfied. As for "how it runs" - again, I'm not certain what you're looking for, but there's no doubt the mid-range and top-end are significantly stronger. The thing just rips.
Originally Posted by Sporting Wood
Also, when I installed the filter on this bike I noticed what could be a potential issue. I can't say for sure as I've put these on several bikes with no fit problems, they've always been tight. There's also lots of folks who've made their own with the same grommets who've not ever reported a fit issue. This bike is the first early production version (2003) and has been through a lot... rebuilt several times.
When I went to put the velocity stacks on, they didn't tighten down enough. The plate was a tiny bit loose. The bottoms of the stacks were warped and it had a BMC filter in there which seemed a but thicker than normal, maybe its stretched the plastic mounts. Regardless, I shoved in another gasket under the filter plate to make it work.
If any of you encounter a similar issue, let me know. While I think its an isolated problem, I can't say for sure. All the filter plates up till yesterday fit nice and tight... I can rush out a filler gaskets and include them with subsequent kits if this is a problem.
I haven't had it apart again since our tuning day, and I'm confident our creative gasketing is holding up well, but I may order new stacks and have them on hand for the jetting swap at the Rendezvous.
In conclusion, I'm a huge fan of Sporting Wood's filter dealio. The factory airbox is a nightmare and a PITA. This arrangement simplifies things dramatically, and there's no doubt the performance gains.
Thanks again, mang. I feel like I've got my bike back!