Sweet Mother of Mary!
04-06-2009, 02:32 PM
#1
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Sweet Mother of Mary!
For the FIRST time since I have owned this bike, I have full rpm range and full throttle, and christ is it awesome. I ended up taking off the top of the airbox, and it made everything perfect. I can probably even jet it a little bigger... The intake was blocked up with wiring and crap... Do people ever remove the top of the airbox? I am most definitely leaving mine off. I just need to secure that filter down somehow... I am so freaking stoked. 
Full throttle, it's a good thing.
Full throttle, it's a good thing.
04-06-2009, 02:43 PM
#2
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You sure that the intake boot wasn't plugged up?
Everyone says that removing it is a bad thing.
There was a post about someone that cut off the top of the box leaving just the ridge of the edge on to hold down the filter. You could try that.
Everyone says that removing it is a bad thing.
There was a post about someone that cut off the top of the box leaving just the ridge of the edge on to hold down the filter. You could try that.
04-06-2009, 03:03 PM
#3
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Intake boot? You mean the boot holding the carb on? If so, yes I'm sure. I've had the carbs off and apart about a dozen times or so. I'm not sure why they would think it would be a bad thing... all the air is still being filtered... I would understand if the airflow made the bike perform worse, but if it helps, why not?
04-06-2009, 03:42 PM
#6
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If your intake was blocked I think you're better off simply clearing it than removing or chopping the air box lid.
https://www.superhawkforum.com/forum...02&postcount=6
https://www.superhawkforum.com/forum...ght=airbox+mod
https://www.superhawkforum.com/forum...02&postcount=6
https://www.superhawkforum.com/forum...ght=airbox+mod
04-06-2009, 06:25 PM
#7
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Cutting the lid and just leaving enough to hold the filter was a failed experiment. The guy did plenty of dyno runs to try and get it right and in the end gave up.
I have done my own experiments with the VTR intake, and came across some interesting discoveries. You can make some nice increases in power across the whole rev range, BUT you can get flat spots to go with it. Awesome for a track bike but annoying on the road.
In my case by doing a few mods I ended up with a lot more airflow, and jetting to suit, which was 50 pilots and 205 mains. Man it hauled........
But I had a flat spot at about 5000rpm at constant throttle, which I could not get rid of. At larger throttle openings it was great. The answer was to use a K&N filter which is much smaller than what I had in there, re-jet to suit and the problem was fixed. Better for road use.
In the end I decided that the carb slides could not operate well with any intake changes. Changing needles and slide holes did not fix the problem. Perhaps changing spring rates MAY have been an option, but I decided not to persist with the experiments as I had run out of patience. Perhaps the CV carb can be made to work with more airflow, but there is no certainty.
In my opinion, if anyone wants to start modifying the intake you should factor in changing to flatslide carbs such as the Keihin FCR, or EFI. Changing carbs will be much easier than EFI, and much cheaper. I am working on an EFI set-up now, but the cost would be too high, and too much work for most people.
I have done my own experiments with the VTR intake, and came across some interesting discoveries. You can make some nice increases in power across the whole rev range, BUT you can get flat spots to go with it. Awesome for a track bike but annoying on the road.
In my case by doing a few mods I ended up with a lot more airflow, and jetting to suit, which was 50 pilots and 205 mains. Man it hauled........
But I had a flat spot at about 5000rpm at constant throttle, which I could not get rid of. At larger throttle openings it was great. The answer was to use a K&N filter which is much smaller than what I had in there, re-jet to suit and the problem was fixed. Better for road use.
In the end I decided that the carb slides could not operate well with any intake changes. Changing needles and slide holes did not fix the problem. Perhaps changing spring rates MAY have been an option, but I decided not to persist with the experiments as I had run out of patience. Perhaps the CV carb can be made to work with more airflow, but there is no certainty.
In my opinion, if anyone wants to start modifying the intake you should factor in changing to flatslide carbs such as the Keihin FCR, or EFI. Changing carbs will be much easier than EFI, and much cheaper. I am working on an EFI set-up now, but the cost would be too high, and too much work for most people.
04-06-2009, 09:53 PM
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FYI here is the original source: http://www.ablett.jp/bikes/vtr/air_box_lid.htm
It sounded better, and he thought it was better till he got it on a Dyno and found he was ~5 HP below stock across the board.
Your bike may be different though..
It sounded better, and he thought it was better till he got it on a Dyno and found he was ~5 HP below stock across the board.
Your bike may be different though..
04-06-2009, 10:12 PM
#10
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Good source. I can't even compare how it feels to stock though... because this is the first time I've had it running well since I got it. And even if the bike is 5hp below stock (which i doubt) It's still probably 25hp higher than the pos I have been riding. It never could get over 7 grand without dying. And no matter what rpm I was at, full throttle would kill it too. I've shimmed the needles to every position, changed the main jets 4 times, and tried I a thousand different pilot jet settings and everything I did did nothing for my lack of top end. This completely fixed it. So I would be an idiot to put it back on because some guy did it and it didn't work for him. It worked for me. In a big way.
04-06-2009, 10:37 PM
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maverick;
Nice that your bike is running better and now you know what the problem was- It wasn't getting enough air. But why wasn't it? Was the air box snorkel getting blocked, squished, is something stuck in it? Don't see what else it could be.
In the meantime at least think about securing down the air filter tight somehow otherwise you'll be sucking unfiltered air around the edges and into the engine. You could try putting the lid on without the front snorkel and see how it runs. That way the lid will cinch down the air filter.
EDIT;
Just read an older thread where you mentioned you don't have a snorkel and you modded a K&N to fit from another vehicle (car?).
Don't know, but maybe that filter doesn't flow enough air and bike runs better without air box lid 'cause now the air is getting in under the filter, assuming you've still got the filter there.
Nice that your bike is running better and now you know what the problem was- It wasn't getting enough air. But why wasn't it? Was the air box snorkel getting blocked, squished, is something stuck in it? Don't see what else it could be.
In the meantime at least think about securing down the air filter tight somehow otherwise you'll be sucking unfiltered air around the edges and into the engine. You could try putting the lid on without the front snorkel and see how it runs. That way the lid will cinch down the air filter.
EDIT;
Just read an older thread where you mentioned you don't have a snorkel and you modded a K&N to fit from another vehicle (car?).
Don't know, but maybe that filter doesn't flow enough air and bike runs better without air box lid 'cause now the air is getting in under the filter, assuming you've still got the filter there.
Last edited by RK1; 04-06-2009 at 10:59 PM.
04-06-2009, 11:19 PM
#13
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Well I inherited this problem... and I did the k&n myself. He has a lot of the wiring very close to the air intake, and I suppose that was it. I don't really see an easy way of getting rid of that wiring though... So for now I'm just going to ditch the top. And thanks I'm also happy its running well 
04-06-2009, 11:46 PM
#14
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Yeah after reading the earlier thread I see where your at. Short of getting that wiring out the way and buying a snorkel, sounds like your better off without the air box lid. If the plastic frame of the air filter fits the air box pretty well you could seal that with five cents worth of duct tape.
03-13-2017, 09:41 AM
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A stroke best one ever. Some days when I'm draining my coolant I think two things hmm can this stuff really pass as koolaid? Will I want to drink it so bad if she has the first glass?
Wrong thread!!!! Jeeslus! Sorry guys no coolantaid for me. This was a post about motherinlaws for nvt. .. I just gotta say I hate the way you brows on the phone because its too easy to post in the wrong thread and you all be like Huh !? Anyways sorry guys it was 2am and I went to bed soon after.
Wrong thread!!!! Jeeslus! Sorry guys no coolantaid for me. This was a post about motherinlaws for nvt. .. I just gotta say I hate the way you brows on the phone because its too easy to post in the wrong thread and you all be like Huh !? Anyways sorry guys it was 2am and I went to bed soon after.
Last edited by RedStormJ; 03-13-2017 at 05:06 PM. Reason: wrong thread!!!
03-13-2017, 11:43 AM
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03-21-2017, 11:44 AM
#18
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Back in the day the shop that did my performance work cut the top of the airbox off and ran a K&N. Dyno proven tuning and results, and the bike was a monster (for a Superhawk anyway...) Not saying it's the right solution for everyone but if it's jetted right it works brilliantly.
03-21-2017, 02:20 PM
#19
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Is it possible that you have a broken choke cable guide? This would constantly be slightly choking the bike so that would explain your results.
Especially if you have messed with the carbs a few times, they break really easily.
So in effect you may be choking the bike then opening the airbox. This could sorta work temporarily but may foul things in cold weather or long term.
You should at least check those elbows in the choke lines located where they meet the carbs. I will bet a waffle breakfast they are busted or not seated.
(Note: Bet will not be honored if lost)
Especially if you have messed with the carbs a few times, they break really easily.
So in effect you may be choking the bike then opening the airbox. This could sorta work temporarily but may foul things in cold weather or long term.
You should at least check those elbows in the choke lines located where they meet the carbs. I will bet a waffle breakfast they are busted or not seated.
(Note: Bet will not be honored if lost)
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