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Discussion Starter #1
Well I eventually fitted the Cobra Speedster pipes which came free with the bike today.
I'll be taking them off again tomorrow! They're far too loud, and cause the bike to misfire and have a flatspot (at about 40mph) where the bike runs on only one cylinder, requiring a big handful of throttle to pick up again, horrible. AND the fuel injection light comes on to cap it all.
Spanners out tomorrow morning and the standard pipes will be going back on. It's a shame because they look great and probably save 5 or 6kgs..:frown2:
 

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FI is for Fault Indicator light.
You can check the codes to see what it is.

The popping on decel is not uncommon when you remove the backpressure. It is easily stopped by blocking the large hose from the air intake to the Air Injection System. (AIS) A lot of the loudness will go away too.(on decel, anyway)

How did you conclude you were running on one cylinder?

(I have the cobras fitted too.)

EDIT: Is your bike fitted with Oxygen sensors over there?
 

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Discussion Starter #3
Snap, crackle and pop.

Thanks for the reply Westcoastkevin.
Yes, I'm running the Oxygen sensors. I was told on a another forum that when fitting the Speedsters the ECU would adjust itself after riding for a while. It didn't do that and heres how it ran: Small throttle openings and light acceleration a few pops and bangs until up to 40 mph when it would go onto one pot until a big handful of throttle was taken, then it would run fine. If I closed the throttle quickly then it would decelerate with no pops or bangs, until about 40 mph or lower when it would start the one cylinder running accompanied by more pops and bangs until the throtte was reapplied.
It's running very weak at intermediate revs due to lower back pressure with the Cobra pipes. The info. from the O2 sensors is obviously confusing the ECU.
Even if I was to get the fueling right with a Power Commander, etc. it would still be way too loud for me, I was actually embarassed riding the bike through local villages and towns.
Getting my spanners ready now to take them off. I'll put them on ebay.
 

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I’m not sure if the ecu will auto adjust or not but when the cobra pipes got put on my bike it had to be tuned. The pipes sound great and ya once and awhile I get a small pop but nothing you have described.
 

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Discussion Starter #5 (Edited)
I'm a quiet type of biker

Thanks Mike. I've also got the oxygen sensor eliminators which I could have tried but the pipes will still be too loud. My standard pipes are back on and the bike's running as it usually does, although I must admit it it is one of the worst fueled bikes I've ever owned.
It sometimes stalls or pops when the engines cold and sometimes when it's warm if I shut off quickly. I think it's the US spec. emissions friendly settings which cause it. There's a sharp downhill left handed turn-off where I have to take extra care in case the bike stalls (as the road goes back up hill again)
Generally I'm guilty of setting off before the bike warms up fully, and I think this is the cause of the stalling. When i wait a bit longer it's generally ok. It does run weak though, as the plugs show (white electrode)
I wouldn't mind experimenting with a Power Commander or somesuch to richen it up, or an Ivans ECU tune up mentioned elsewhere on this site.
Problem is they're both a bit expensive! (and Ivans UK agent has just died). Has anyone any experience with the Power Commander type fueling aids?
 

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When I had my 900 I put Cobra Dragsters on it, with a K&N air filter and a Cobra FI2000 tuner. It ran great. I did have some decel popping, but nothing too bad. As far as the sound, I loved it. It was good and loud. I used to put it in a strain going through tunnels just to hear it roar.
 

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Thanks Mike. I've also got the oxygen sensor eliminators which I could have tried but the pipes will still be too loud. My standard pipes are back on and the bike's running as it usually does, although I must admit it it is one of the worst fueled bikes I've ever owned.
It sometimes stalls or pops when the engines cold and sometimes when it's warm if I shut off quickly. I think it's the US spec. emissions friendly settings which cause it. There's a sharp downhill left handed turn-off where I have to take extra care in case the bike stalls (as the road goes back up hill again)
Generally I'm guilty of setting off before the bike warms up fully, and I think this is the cause of the stalling. When i wait a bit longer it's generally ok. It does run weak though, as the plugs show (white electrode)
I wouldn't mind experimenting with a Power Commander or somesuch to richen it up, or an Ivans ECU tune up mentioned elsewhere on this site.
Problem is they're both a bit expensive! (and Ivans UK agent has just died). Has anyone any experience with the Power Commander type fueling aids?
I know you have already taken them off but as a side note they do make quiet baffles for the cobra pipes. Just Incase you like the styling of the cobra vs oem.
 

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Discussion Starter #9
Baffles

Thanks MIke.
That's something to think about. I do like the styling of the Cobras and the bike seems to be noticeably lighter with them on (gets a bit hot on my right leg though!) It's also a lot easier to remove the rear wheel, brake caliper etc. with them on so it's a possibility. I'll have a look on the Cobra site and check it out. Cheers.
 

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And besure to check your air filter. I had horrible gas mileage when I first bought it until I pulled the cover off and realized a mouse was living in there lol. So much for trusting the previous owner. He’s luckily the bike looked so clean lol. After I bought K&N cleaning kit and reoiled the filter the bike instantly saw better mileage. Today I rode 150 miles and only used half a tank. So that’s about 250-300 before I refill.
 

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Discussion Starter #12
Mouse free zone

Mike I think all of the 900's are fuel injected, only the earlier 800s are carbed, if I'm not mistaken. No mice either, the bikes been looked after by the look of things. If it was carbed I would have already jetted it up with one of the sigma6 jet up kits I used previously on my 1100 Shadow. (US product)
I'm getting between 55 and 62 mpg (UK) so I think it's running as it should. As I've said previously they're made in Japan for the larger US market, a good deal of which is for California, and the fueling has to suit the stricter emission laws. Legislators don't care if our bikes run weak or not! :serious:
 

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Mike I think all of the 900's are fuel injected, only the earlier 800s are carbed, if I'm not mistaken. No mice either, the bikes been looked after by the look of things. If it was carbed I would have already jetted it up with one of the sigma6 jet up kits I used previously on my 1100 Shadow. (US product)
I'm getting between 55 and 62 mpg (UK) so I think it's running as it should. As I've said previously they're made in Japan for the larger US market, a good deal of which is for California, and the fueling has to suit the stricter emission laws. Legislators don't care if our bikes run weak or not! :serious:
That's why you send your ECU to Ivan and get all the emissions BS taken out. My buddy talked to Ivan and he said that the 900s are starved for air. He said an aftermarket intake makes a world of difference.
 

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Discussion Starter #14
Weak and watery set up

Yes, I have thought of an Ivans tweak. I would need to get another ECU though, to send, since the VN900's my only transport beside my bicycle.
It's pathetic really isn't it. To get the bike running right you have to spend £300+, to get it comfortable (according to other posters) you have to spend $500 on an aftermarket seat, 300 for a decent windscreen, a motorcycle tyre costs 4 times that of a car, etc. etc
Sometimes I think we bike riders are being taken for a ride! :smile2:
 

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When I had my 900 I put Cobra Dragsters on it, with a K&N air filter and a Cobra FI2000 tuner. It ran great. I did have some decel popping, but nothing too bad. As far as the sound, I loved it. It was good and loud. I used to put it in a strain going through tunnels just to hear it roar.
I have the same config, and had some loud popping on decel. I did an update on my valve adjustment and the popping went away.
 
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