MC, was the "Burnie Morgan" mod (http://www.burniemorgan.com/firestorm/airfilter.html) done on it or is it totally stock (as in with the filter lip intact and upper deflector still screwed into the cover)?

thanks again

 

Cutting the top off the air box may not be necessary for the STG1 build, but I want to try it just to see if we can tune it. I'll have a full lid nearby in case it's needed cuz I don't want to cause my dyno guy to start drinking. At least not before 5pm

RCVTR, I'm using the K&N set up like stock, so no preceived torque hole (at least not from the butt dyno), but she studders more than usual at less than 4K RPMs, which I attribute to needing rejetted for the K&N on the slow side.

Also, I have no doubt once we cut the lid that we could end up with a run that looks like Rob described, but at least I can get dyno runs printed to put this one to rest...

 

I tried that mod with a K&N, but the bike ran like it was cold I went back and cut the lip off the old filter and installed it on the K&N and she runs good now, so I attributed the problem to inner airbox turbulence...

 

That's just what I believe the air dam is for.

the way I see it, the air dam causes the air to flow up along the top of the box. The filter is drawing air downward and since the air enters at the top, it creates streamlines that vector downward and enter the filter at ~90 degrees.

Remove the dam, and the air goes everywhere.

Just a thought...
I have no data to verify.

 

That's exactly what I experienced, so for all those folks that made that mod work, I'm scratching my head how???

 

The Burnie mod wasn't done. That part looks stock.

 

cheers

 

I think MCs bike made 135-140 HP when it was fresh, on race gas.

 

Pretty impressive numbers!!!!!

Further to this discussion (and my recent dyno numbers), I have decided to put the airbox and filter completely back to OEM. I'm done experimenting with this stuff. If the likes of Bob H and Roger D weren't able to improve on the stock design, who am I to think I can. The airbox lab is now closed, lol

 

I'm running that mod on a stock filter and it works there... I did try it on a K&N and it made the gaping hole even worse... I can't back it up with dyno sheets, but the *** dyno says it makes fueling a bit more even (could be interpreted as equally bad though?!)

And my own DIY tuning dyno says the same... No fancy electronics, just A/F and a basic calculated power to compare my own results to each other... I use it for tuning and comparing setups, and then if I want a dyno sheet I'd go to the local shop... Haven't bothered yet though...

 

I kinda came to the same conclusion a while ago... I'm on the fence on the burnie mod (wich I'm running) but gave up on the K&N as it just pissed me off... Last one I owned was saturated in gasoline and set on fire to calm my nerves...

 

My experiments showed that needle profile wasn't the problem. It was the airflow change affecting the slides, as has been suggested slesewhere in this thread. I tried all needle settings, including some HRC needles which are waaaay richer than anything else, and it made no differnce.

I have increased compression (10:1) and billet velocity stacks, and my modified airbox and bigger airfilter would not work. Good luck with it Flo. Here is my tip. It is about the slides I think. You will need to find out a way to keep them working smoothly. Perhaps spring rates are the answer, unless you are going to flat slides.

 

At 100% VE, 111 hp@9500 RPM, 130 hp@11000 RPM, 140 hp@12000 RPM
This is assuming perfect breathing, matched cams, ports, compression, separate exhausts...
So, can the stock crank handle such a beating, it seem to be way over it's design, are they making billet or forged cranks ??
Or using Al or Ti rods with mini skirts pistons, someone could crank up some revs, but it's a lot of money for a street bike, specially Al rods that need to be changed as regular maintenance...
Two 4340 Carrillo rods with ultralight pistons could do the trick, no overbore (this is often argued but I'm stiff on this), stiffer valve springs, Cams, compression, exhaust, velocity stacks and timing need to be optimized for the last 500-1000 RPM to bump the curve.
Fuel injection would be a must

 

I could see that, when we dynoed the bike it was way lean already... we figured with jetting changes and good race gas we could find 5 more HP. Add to that the motor is not so young any anymore, 140hp would not be to hard to see.

What would be hard is riding it. The last thing that bike needs is more power. The suspension is about 90% sorted, the cosmetics are almost done. I just need to change a few more little things and she will be all set. But it's a hard bike to ride fast. I just wish it felt better on the brakes and the front wheel would stay put.

 

My memory tells me that about 140hp was the limit for the stock crank, and after that they broke. Moriwaki made a billet crank for them, but it cost a fortune and they were hard to get. If they were still available then Revolution Racing in the UK would be the first place to ask I reckon. They will know for sure.

If you are aiming for this type of power, then I really think you should consider whether the engine will just overpower the chassis. The VTR is just not designed for it in my opinion. I think you would need to factor in some serious mods to frame and suspension, and then you may just be better off buying another bike, such as an SP2 or a Ducati.

 

I think also the reason for the bracing on the swingarm and added mountings for the pivot bolt comes into play at about 130 hp... That's about what the stock pivot will handle... Above that you might get into trouble...

 

Bob was able to make ~140 HP reliably. Stage 3 cams were available, but would break the stock crank, even after substantial lightening, Carillo rods, etc. He was advised of this by Mr. Moriwaki. To my knowledge, he never broke a crank. He did have a brittle wrist pin that shattered and the case was about sawn in half by the time he got it shut down.

Even with substantial bracing, the chassis was overpowered. He has described laying up on the tank and just letting the ***-end shake until it was done shaking when hard on the gas. People behind him wondered how he rode it.

 

Im 6'4 265lbs (no Gear) and I cant hold my SH down in 1st gear to save my life and Im still way lean. Roll-on 1st and 2nd gear wheelies are very impressive to onlookers though LoL