Pointy de-snorkeled - why such large improvements?

[Nutsinatin]

Well my SV had started running a little rough the last few weeks so after my little adventure cleaning the air filter (hitting it off a bin the get half a tree out of it) I figured why not remove the snorkel as I've heard good things about this. So out it came and I went for a gentle ride to check all was well. First thing the rough running was gone, she was running beautifully, secondly I could sit at 2000rpm before the bike started to bog down (it used to bog down below 4500rpm), thirdly there was much less vibration than before. Pretty good I thought.

Well as all seemed to be okay I thought I would go for a quick 10 mile sprint to see if the performance had changed at all, so I twisted the throttle as normal and nearly ripped my arms off! She was flying through the revs, used to slow down by 80mph but was still rocketing at 91mph when I decided to back off a bit. She was so rev happy and I found myself sitting at 5500rpm at 80mph instead of the previous 6000rpm.

So now I'm pretty concerned, there is now way that these sort of improvements should have come from this right - or if they do what is the big catch? It's not been long enough for me to see the effect on MPG but if I'm sitting lower in the rev range to do the same speeds then I can only guess it will improve (it had dipped a bit coinciding with the rough running). I was expecting a loss in top end power but it has just increased across the range, especially the bottom end.

I'm guessing water in the airbox could be an issue as it's an all weather bike, so I could put an SV1000 snorkel in with some mesh to stop all the bits of tree getting in if I leave it like this. So basically was there something wrong with my bike before hand to cause these gains, are there likely to be many downsides to this, or did I just get lucky?

Just as a last though I sometimes thought I could faintly smell fuel when I got off the bike but couldn't notice any today - related or not? Thanks!

Another thought, the throttle response was much quicker, it was fairly slow to build up power when I twisted before, but now it's a near instantaneous response and much smoother, although it feels like there's a bit less engine braking when I wind off.

Originally Posted by Nutsinatin

Well my SV had started running a little rough the last few weeks so after my little adventure cleaning the air filter (hitting it off a bin the get half a tree out of it) I figured why not remove the snorkel as I've heard good things about this. So out it came and I went for a gentle ride to check all was well. First thing the rough running was gone, she was running beautifully, secondly I could sit at 2000rpm before the bike started to bog down (it used to bog down below 4500rpm), thirdly there was much less vibration than before. Pretty good I thought.

Well as all seemed to be okay I thought I would go for a quick 10 mile sprint to see if the performance had changed at all, so I twisted the throttle as normal and nearly ripped my arms off! She was flying through the revs, used to slow down by 80mph but was still rocketing at 91mph when I decided to back off a bit. She was so rev happy and I found myself sitting at 5500rpm at 80mph instead of the previous 6000rpm.

So now I'm pretty concerned, there is now way that these sort of improvements should have come from this right - or if they do what is the big catch? It's not been long enough for me to see the effect on MPG but if I'm sitting lower in the rev range to do the same speeds then I can only guess it will improve (it had dipped a bit coinciding with the rough running). I was expecting a loss in top end power but it has just increased across the range, especially the bottom end.

I'm guessing water in the airbox could be an issue as it's an all weather bike, so I could put an SV1000 snorkel in with some mesh to stop all the bits of tree getting in if I leave it like this. So basically was there something wrong with my bike before hand to cause these gains, are there likely to be many downsides to this, or did I just get lucky?

Just as a last though I sometimes thought I could faintly smell fuel when I got off the bike but couldn't notice any today - related or not? Thanks!

I suspect there's an awful lot of the old placebo effect. You've changed something and you expect an improvement but really a lot of it's in your head.

I dare say it will allow the engine to breathe better in some ways but they're generally pretty well set up from the factory usually. If there's some form of restriction built in then it'll more than likely be to cover an emissions based regulation.

As for it being faster for the same amount of revs, that's impossible unless you've changed the gearing or tyres or something else which would otherwise affect the drive speed from the engine to the rear wheel.


I presume your 33bhp is the ECU? If it's such a vast improvement then maybe you've somehow affected that too and you'd want to get it checked out in order to remain legal.

[Nutsinatin]

Originally Posted by Phil 1

I suspect there's an awful lot of the old placebo effect. You've changed something and you expect an improvement but really a lot of it's in your head.

I dare say it will allow the engine to breathe better in some ways but they're generally pretty well set up from the factory usually. If there's some form of restriction built in then it'll more than likely be to cover an emissions based regulation.

As for it being faster for the same amount of revs, that's impossible unless you've changed the gearing or tyres or something else which would otherwise affect the drive speed from the engine to the rear wheel.


I presume your 33bhp is the ECU? If it's such a vast improvement then maybe you've somehow affected that too and you'd want to get it checked out in order to remain legal.

It's not placebo as I was skeptical of any noticeable improvement and I ran it on my test route, there is a definite change, especially smoother running at low rpm.

As for better breathing I've opened the airbox up again and it's cooler than before (when I took it out) so a thermometer is going to have to go in there to see if there is a big temperature difference with or without the snorkel. (Maybe the ECU is very different from the factory setup)

As for speed vs rpm I'll have to watch that over the next week and see what numbers it throws up with and without - I probably got over excited earlier and misread it going so much faster than I normally do.

And it is ECU restricted, which has always been slower than my friends restricted bike both in acceleration and top speed (his was recorded at 32.5bhp) but I'll run it against his to get an idea if I see him before I get a quick dyno run in, as I am concerned this might push it over the limit, I hope not as it feels like a totally new machine!

[Tomor]

Well, you have cleaned the air filter, allowing more air through, and you have opened the air channel, so I would expect it to run a little better, but not the sort of things you are saying. Have you just done a full service (plugs oil etc?)

[Nutsinatin]

Originally Posted by Tomor

Well, you have cleaned the air filter, allowing more air through, and you have opened the air channel, so I would expect it to run a little better, but not the sort of things you are saying. Have you just done a full service (plugs oil etc?)

Plugs are 5000 miles old and oil is 1500 miles old, it's due for it's 15K service in a few weeks.

I put the snorkel back in now and it's running rough again and the faint smell of fuel is back. So I'm guessing it's an airflow issue (filter looked okay but might try a new one and see what that does - it'll need one eventually so no waste there) or it's the restricted ECU causing issues (doubtful as it was okay before - but I can put the original one in and see if there's any difference).

[Sid Squid]

The filter was full of crud, much of which you have removed - but taking the intake silencer off is what you ascribe the improvement to.

I've found that removing said silencer made no measurable difference at all.

[Nutsinatin]

Originally Posted by Sid Squid

The filter was full of crud, much of which you have removed - but taking the intake silencer off is what you ascribe the improvement

I thought that but I put the snorkel back in and it started running rough as before :/

[MJC-DEV]

Maybe bit of tree still in the snorkel? - I removed mine and it made not the slightest bit of difference to performance, just made a loud, very annoying induction roar. Was glad to put it back on.

[Nutsinatin]

Snorkle is clear, I'm thinking it must have something to do with the restricted ECU, it's like a new bike, at no point have I ever been able to sit so low in the revs. I'll give it a week out while I order a new filter, stick that in with the snorkel see what happens. If it's still better with the snorkel out I'll send a test pilot out with the full ECU and see if that's the culprit.

[Nutsinatin]

Well I put a new air filter in today along with the snorkel back in, and it's no different to snorkel out, so the problem was with my air filter (which looked fine). Still it sounded cool with the snorkel out for a bit! After a few weeks the problem reared its head again, tested full vs 33 ECU and there's the problem - snorkel out doesn't affect total power but does significantly change where the power is usable!