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performance intake mod

mmattockx said:
My 1100E came to me with a big single K&N filter on the front half of the airbox and the rear half removed. You can see the filter with the side panel removed, below:

XbIvRNA.jpg



Mark
Click to expand...

sweet! cant wait until mine is ready and tuned well!
 
What were the performance gains like? Seems like it might run smoother than a aftermarket filter being it was designed for a large inline 4 motor
 
No measured performance comparison between running standard verses panel filter.
Mainly did it because i could and I wanted to eliminate any restrictions.
Running EFI mans I do not have to worry about air flow balance e.g. CV carbys.
I am at 1260 cc which is all well and good but it's performance is limited with standard valves/ 36mm throttle body/ standard (degreed) cams/ standard (cleaned up) intake exhaust ports.
it is my commuter/ project bike so outright performance was not a priority.
 
I would hate to be a glass 1/2 full guy and I wish you all the success with your project but I bet you'll have to sacrifice something in the power band. Idle, mid range, top end.....something wont be just right.
 
zed1015 said:
As for using pods on CV carbs.
It's not the increased air that causes the problems but the separate intake pulses causing fluctuations on each individual diaphragm .
CV's prefer a still air supply so creating a singular higher flowing smooth air supply from a modified airbox that acts evenly across the carb bank is the way to go..
Click to expand...

Interesting. I had read somewhere where it was theorized that with C/V and pods, the intake pulse bounces off the the metal endcap of the typical pod and causes similar issues to what you mentioned. Very unscientific, but I removed the pods from my 1150, stuck the rubber trumpets from the original airbox on and went for a ride. It did seem smoother and more responsive, but I didn't get that into detail, plus it was a nice and cool night.
Of the three GS's I've owned, the best and smoothest runner was the 85 1150e with a 4 into 1 exhaust and stock intake with a K&N drop in original type replacement filter. I have been toying with the idea of going back to an airbox, but currently only have the front half on the shelf so this thread has been of interest.
 
dorkburger said:
Interesting. I had read somewhere where it was theorized that with C/V and pods, the intake pulse bounces off the the metal endcap of the typical pod and causes similar issues to what you mentioned..
Click to expand...
Yes! That's correct but not just with CV's but any carbs.
The solid caps cause pressure waves that can affect fueling/lean spots at particular rpm's depending on the engine tune and a million other factors.
It's not something you would probably ever notice or cause issues on the road.
The foam UniFilter types with are the ones to use for best results especially for racing.
 
bonanzadave said:
I would hate to be a glass 1/2 full guy and I wish you all the success with your project but I bet you'll have to sacrifice something in the power band. Idle, mid range, top end.....something wont be just right.
Click to expand...

Well the good thing is we will get to find out lol, if anything I can just go back to the stock airbox since no hacking has been done and then possibly draw up another gameplan from there.

something that kinda sucks is one of the previous owners (I have a strong feeling it's the one on YouTube) had to cut open the airbox to fit the master cylinder on the bike and there's a hole in it now so I wrapped that area of the airbox in duct tape but I have a feeling it still might not perform aswell as an unmolested one
 
getting closer to the rebuild being done and well i think its a better idea to use the stock airbox instead of modifying and tuning an aftermarket intake from a brand new engine, and it came with a question that hopefully actually helps my bike run better, after having an aftermarket exhaust installed my bike would have a really bad low end and also a idle that wasnt that stable, well with the stock pilot jets and turning the mixture screws as much as you can to affect the mixture, it still would have issues in the low end to about 2500 and i would tend to ride the clutch to prevent a rough takeoff, when i would go the next size up on pilots and do the minimum turns out on the pilots it would run too rich and have even less power and foul the plugs, well with me increasing the size of my engine i was wondering if it could possibly be enough increase in air to go up a size on the pilot jets from stock and maybe get a better mix.
 
Are you open for opinions?? I've not heard of pilots having near that much affect on a bike. I never owned a GS"650", but on other Gs's I've always went up one size on pilots, even with stock exhaust & air box, or with bigger pistons, cams, 4 into 1 exhaust, as the GS's always seemed cold natured, Up one size makes them easier to start in cold weather & slightly quicker to be able to turn choke off. NEVER seen one size up pilots foul any plugs. or affect the running of the bike. If you've lost low end power, adjust your cam timing & make a restrictor for your exhaust. V&H in the past, shipped some of their pipes with restrictors that slid in the collector for exactly that reason... Like said, just my opinion.
 
Yes I'm open for opinions lol I couldn't be on here if I wasnt, do you think it could be something else causing the bike to act up? would leaky valves do something like that? My exhaust valves were very built up with carbon behind the valve seat.

Is it a common thing to adjust stock cams timing? Will it affect other parts of the powerband?

​​​​​​I have the stock exhaust and I could run it but the baffles were taken out by the PO so Im not sure if it's gonna be better than the 4:1

Going back to how it would act, with pilot size up it was very slow and bogged until it went to the next set of jets, it was a pretty dramatic difference, and with the stock jets max turns out it would idle well for the most part and rev up well with no load but under load without riding clutch it could act up pretty bad with the bike running and feeling rough and also being choppy, would be worse if I gave the bike more throttle, could die out if I wack it to full throttle. If it sounds like something other than the pilot jets or exhaust are behind this let me know what to check
 
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Just a thought, May try lowering the needles a little, they may be too high (rich) & letting in too much gas in just off idle, thus the stumbling & fouled plugs. How much larger than stock are the mains???? With stock air box you should have plenty of vacuum to pull plenty of fuel through a reasonable ( couple of sizes maybe above stock) jets. BIG jets are needed for opener (less vacuum) intakes. I'm not an eng. tuner so beware.
 
Mains are stock but I have 110 I can put in there, plugs looked lean last time it ran and it has stock pilots in there right now aswell, I'll have to learn how to check and adjust needle height.
 
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