98 VFR800 motor upgrade question

I just read this whole thread......(bit of a waste of my time and brain power)
I have come to the conclusion that I want to find any person alive who can state and PROVE that THEY HAVE BEAT A BUSA of any kind on a VFR800. I am not a porfessional driver but I am a great rider and I ride with CBR1000's and Busa 1300's every weekend. When they get on it I hold my own, but once we hit 130 plus I am left behind until they slow down and I play catch up(via turns and my skills). I Know for a fact that the VFR800 will hit 140MPH (I Just did it on Saturday playing with a CBR1000RR) but after that they leave me behind and they continue on to 160+. I would love to keep up and or beat a 1000RR or a BUSA1300. Until I buy a VFR1200 or a bigger Sports bike I will continue to dream and pray the day comes when I get 80K+ to put into my VFR and make it a race bike......

If I am wrong prove it.......
Until then like the old saying goes........
I am From Missouri......SHOW ME

 

I'm sure toe cutter would love to show you

 

Well take a look here at parts 24-26, I'll fix the dyno link in a minute.

http://vfrworld.com/forums/5th-generation-1998-2001/39430-vfr800-10-year-refresh-part-d-ux.html

FACT the VFR800 engine uses the same cases & heads as the RC45. The 10hp ECU thing is for the RC45 NOT the VFR800, which uses a wholly different ECU & Injector system.

That said I have done more research than anyone else I have communicated with or found & here are some details. The RC45 was modified as follows to become the VFR800 RC46 engine. They added a molding to the rear crankcase to support the swingarm & changed the crank to 180 degree, plus new smaller (36mm-V- 45mm) throttle bodies. The 45's throttle bodies had to be that big to comply with WSBK rules, they are one of the things they were NOT allowed to replace. The standard RC45 had these retricted to 40mm intake trumpets. Larry tried making bigger ones & lost power on his bike as it was NOT race kitted ! Note that the Bandit 1200 & CB1300 use 36mm throttle bodies & draw approx 50% more air at max rpm compared to VFR so 36mm is more than big enough for 130hp.

FACT - RC45 racers can't get new cases anymore, so they use VFR ones & grind the extension off !
FACT - They can't get new cylinder heads either so they use VFR800 ones & block the pair drillings (they did not exist on the 45) & use the 45's Magnesium cam/engine covers.
FACT - They transplant the 45's 360 degree crank & most of the other internals into the 800's cases !

The RC45 had a rev limit of 12,500rpm, the 800's is set at 11,750rpm & the rev limiter kicks in above 12,000rpm. The 45's RACE ECU allowed it to rev to 14,500rpm.
The reason the 800's limit was reduced was two fold. The 800 uses STEEL conrods & the crak was modified to provide 2mm Longer stroke, hence the 781cc rather than the 45's 749cc. This longer stroke allowed for the HIGHER compression ratio & more torque for a road biased engine.

So having bought a spare engine to measure & consulted with many RC45 owners & got hold of technical measurements, I decided to have some cams reground to STANDARD RC45 profiles with a little tweak of my own. The standard 800 puts out approximately 95rwhp (110 at crank claimed by Honda) & 53lb/ft torque, verses a standard RC45 with a free flowing exhaust (NO RACE KIT) making approx 108rwhp. So with my new cams, a free flowing exhaust & PC3 plus custom map, my 800 now puts out 107rwhp & 57lb/ft torque, that's a 12% increase in power & more torque than a 45 EVERYWHERE !

The bioblade makes 124rwhp on pump gas, I contacted the journalist that made it to get details. It used reworked cams & a bit of porting, as per HRC guidance for the RC45 race motors (it's in public domain try here Honda HRC RVF750 RC45 & VFR750R RC30 V4 ). It uses standard 36mm 800 throttle bodies + Airbox & Pipercross AirFilter due to the No Budget Cup race rules stating they have to keep the airbox & filter.
He did not confirm it, but I'm certain in uses shorter velocity stacks which is what I intend to do next to mine, this has the effect of moving peak torque higher in the rpm & as HP is a calculation of peak torque x rpm then you will get a bigger HP figure, which also means the bike revs on better at higher velocities, meaning a higher top speed.

Example-1;- 53lb/ft @ 8250rpm (53x8250/5252) = 87hp * 1.15 (Dynojet fudge factor) = 95rwhp (Dynojet reading) Standard VFR.

Example-2;- 53lb/ft @ 9500rpm (53x9500/5252) = 95hp * 1.15 (Dynojet fudge factor) = 110rwhp (Dynojet reading) Higher Peak Torque VFR.

Example-3;- 57lb/ft @ 10000rpm (53x10000/5252) = 108hp * 1.15 (Dynojet fudge factor) = 124rwhp (Dynojet reading) My Planned Peak Torque.

Just remember that all Dynojets have the 1.15 fudge factor built in, so the figure is relative if NOT real HP. So you can see in example-3 if I can push my peak torque up to 10k/rpm without losing much torque then I should be able to match the BioBlades output.

The reason the VFR never really got any off the shelf tuning was due to the gear cams stopping people skimming heads for more compression, a quick fix for most bikes.
Plus the engines unit construction means to access the pistons you have to completely strip the engine & that would normally entail a full gasket set cost plus many hours labour etc. Not the same as a quick head & barrels job for a big bore or head skim/tune, with slotted cam chain wheels !

But you could use .25mm thiner head gaskets to pop compression up to 12.2/1. Or buy a set of RC45 race pistons to put it up to the 13.x/1 levels, but would need race fuel etc.
If you want to increase compression, you could strip the motor & use 74mm CBR929 pistons, I have a set to compare with my spare motor parts this Christmas That would make an 825cc motor & with the current state of tune should pop power up to approx 120rwhp & if the intake mods work, then that would see another 5-10hp.
You could advance the ignition & run higher octane fuel, that would require some experimentation.

If you are happy doing all your own mechanicing & a full engine strip then 130rwhp should be possible with a bit of work !

Hope that settles some earlier assumptions by some folk ! :chaingun:

Mohawk.

 

I just wanted to say thanks a lot for taking the time to research and share all of that with us. Just a heads up, I have found that with minimal trimming, the 01-02 r6 velocity stacks are an almost perfect replacement for ours. They are staggered just like ours and a little shorter/wider over all. They seem to make the bike pull a lot harder everywhere over 5000, but it runs pretty rough below it(which I hope auto tune will fix).

One question though. Have you found anyway to advance the ignition timing yet? As the. Ignition module is not offered for our bike from dyno jet. Thanks for all your help again.

 

why not cut an advancer plate like every other bike on the planet has had done to it?
heck even the red headed step-child has one available.
Honda VTR1000 Targa Ignition Advance Kit - 11-109 by Targa

compression ratios up to around 13:1 are now safe in the U.S. on premium pump gas due to all the ethanol and other agents (water) in todays fuel.

porting and polishing generally are not needed until you get DRASTICALLY outside the original engine design.

my turbo 4-cylinder 2.4 litre car has less air space in the throttle body then what the VFR does. and should make 400HP if i ever get it put together.

wiseco will do custom pistons for a 4-cyl for about 500$. get a stock crank stroked about 2 mil and custom pistons cut, bump the CR to atleast 12:1 do not PORT the head but maybe get a cam done, and custom cut an ignition advancer plate for the flywheel. there is no reason someone does not have a 150hp N/A vfr800.

 

i can think of 3 off the top of my head. cost, practicality, and reliability

 

reliability will not change much, wisecos are forged, honda cranks are not week. head and valves would be un-altered, and we are not trying to turn 16,000rpm. its not needed.

cost? less then a dang supercharger, less then a lot of you people have spent on 'cosmetics' and a heck of a lot less then most of you have spent on suspension. the crank MIGHT run 1000$ depending on how far out you want to go and if it needs the journals turned or polished. the last stroker crank i had set up cost me 300$. it was for an I-4 though. and the custom cut pistons, 500$ no ifs ands or buts, 4 custom cut pistons from wiseco = 500$

the rest of it would be the persons time, and its been pointed out that the vast majority of us on here are garage mechanics.

PRACTICALITY?!? YOUR ON A VFR, THAT WORD HAS NO REASON TO BE USED IN THIS FORUM.


honestly total cost would not be much more then what a lot of you have spent on a dang slip-on that netted you .05 hp gain.

 

i want to reply to your whole answer so i will respond to each section in red.

again people need to celebrate what the vfr is and not spen more than another bike to try to make it something its not...

just for fun a bike that would still beat your mythical vfr and the whole bike costs less than the engine build and has much better suspension out of the box

Honda : CBR in Honda | eBay Motorcycles

 

even better example... this is actually making me want to sell the rc51...

Honda : CBR in Honda | eBay Motorcycles

 

Got a bud who is a wrench. Works on Ferraris and the like. I was gonna do all kinds of shit to a Yamaha thumper I have since he built a couple of Racebike with the SR/XR engines. The question he posed was do you want to be the fastest guy for one lap until your engine blows or maybe settle for less than that? A DNF is a DNF no matter the cause.

Oh yes, I forgot to mention, my riding ability is God like.. The fast guys tremble at my very presence.. LOL

 

Looks like my roughness under 5000 rpms was a side effect of a bad 30 amp fuse holder. After replacing the fuse holder and reinstalling the vfrness it seems to have smoothed out.

Also I would like to add that I think port/polish/milling the heads is key to big numbers and to dismiss this mod is incorrect. Anyone that has seen our heads in person can see that the valves are heavily shrouded and could benefit majorly from a good porting, and milling will easily raise compression as opposed to piston replacement. Bore and stroking, I do not see as Being very cost effective though.

 

I did this mod on my CB1. Really woke the bike up in the upper RPMs.
In my thread whoring it seems no one made a trigger wheel for the VFR as it was thought there wouldn't be enough of a benefit.

 

Theoretically there should be more of a benifit as the vfrs are tuned more conservatively from the factory than cbrs are. So there should be more room to advance the timing. And thus more possible gains.

 

Well a few crazy ideas running around here, I guess a few people missed the TOTAL ENGINE STRIP required to change the pistons !

As I mentioned the compression can be upped with a set of RC45 pistons, that is the simplest way to do it, but is expensive because of the cost of the pistons about the same as custom set & a full engine strip.

The head does NOT require any work up to approx 130 hp, it is very similar to the CBR1000RR in valve & intakes & they make over 160 !

No one made an ignition advancer, as there was no perceived market as no one was tuning VFR800's when they came out . Plus the cam drive makes any alteration to stroke a real problem. Remember you can't move the cam gears further way from each other & as Honda already added a 2mm stroke to the 750 crank, there is NO room for more in the standard cases !

One of my jobs this Christmas is to strip some of the spare engine including the ignition rotor to see if I can make one that firers earlier. I don't have the info to hand, but the RC45 race ignition has a massive advance of the 800's standard setting which is very close to the standard RC45.

But all good stuff keep it coming

 

Yeah bro let me just throw on a 10 year old electrical part on a bike that already has awful electrical problems. You think the pc2 will connect to a 6th gen anyways?

 

Welllll....... anyone who would go deep into engine re-design should have no problem implementing a microsquirt or the full sized megasquirt. That will do ANYTHING you can possibly dream up.

V3 MicroSquirt® Introduction

I built up a megasquirt V2 (with megastim) that I was going to use for a custom CB750F project. If anyone wants to take that off my hands I could be talked out of it. :smile:

Jose