837cc Big Bore Kit

[Guest Nailer45]

from across the pond though..

http://www.tts-performance.com/catalog/pro...products_id=472

VFR800 98-01 837cc Big Bore Kit

£400.00

H0839

JE Pistons supply the highest quality forged pistons on the market. Most of our kits come complete with Pistons, Pins, Circlips and Rings. Standard bore piston kits do not come with piston rings. At TTS we can bore your cylinders, fit sleeves if required, bore and replate plated barrels. We also provide ride in, ride out services. Just bring your bike to us, we will remove the engine, do the work required, refit the engine and setup on the Dyno. Call us on the number at the bottom of this page for a competitive quote.

Honda VFR800 837cc Big Bore Kit

74mm Bore, 12.5:1 Compression Ratio

4mm Overbore Size

Barrels require bore and hone

[fallzboater]

The aforementioned "Torocharger" for the VFR800Fi (in development and chronicled on this site) does seem like it would give you all you could possibly need in terms of VFR horsepower, but I can't help wondering what supercharging combined with a substantial displacement increase might be like...

One problem might be finding larger pistons that don't also give higher compression. If anything, you want to drop the compression ratio with forced induction, especially if you're not fitting an intercooler and you want to run pump gas. You might be able to do something with machining the piston tops or a thicker head gasket (not with gear-driven cams) or something.

[Andy Griff]

Hi Andy,

Did you modify the RC30 airbox ?

On the dyno my results were much better after making extra holes in the airbox. (I also have a 837cc)

The result with the (bigger) RC36 airbox was better than with the RC30.

But at the moment I have the Durbahn -www.durbahn.de- carbon (RC30) which is even more bigger than the RC36.

Did you already try different cabs ?

Let me know your results on the dyno !

HI VFROEM... I've seen your contributions on the PB VFR tuning thread also... good man !

The primary reason for fitting the RC30 airbox was because I have an RC30 fuel tank on my VFR, the standard VFR airbox is too tall to fit under the 30 tank.

The RC30 airbox sorts this issue and is almost a direct bolt on to the standard VFR carb plate -

I had to file a couple of area's out and seal some small gaps with silicone sealer. I also had to drill some 5 mm holes for a couple of the retaining screws too - but nothing difficult.

I didn't drill extra holes in the RC30 airbox as this would have let in unfiltered air due to the design...

Air enters via a short duct or 'snorkel' at the front of the airbox housing, before passing through a flat cone style K&N filter within the housing.

I agree that there might be some more power to be gained in using the larger VFR airbox, but space dictates this not possible as I want to use the RC30 tank.

I would like to build a new airbox with a cold air intake, possibly using a VFR airbox, whereby cold air is taken via a duct from above the radiator (I might have to lower the rad a couple of cm to do this) and then passed into a larger airbox through a large flat panel filter. It would be my intention to use the under side of the fuel tank as an airbox lid.

I am running a set of standard '97 VFR CV carbs at present with a Dynojet kit, but also I have a set of the earlier RC36 carbs which have a 1 mm larger in diameter.

Ultimately, I would like a set of RC30 carbs.

No dyno figures at present, as i do not live on the UK mainland (I live in the Channel Islands) and we have no dyno here.

Tell us all about your Durbahn airbox !

Andy.

[Guest]

HI VFROEM... I've seen your contributions on the PB VFR tuning thread also... good man !

The primary reason for fitting the RC30 airbox was because I have an RC30 fuel tank on my VFR, the standard VFR airbox is too tall to fit under the 30 tank.

The RC30 airbox sorts this issue and is almost a direct bolt on to the standard VFR carb plate -

R> yes, I agree. I bought the RC30 tank to fit the Durbahn airbox.... (and RC30 is alu, not steel like the RC36)

\I had to file a couple of area's out and seal some small gaps with silicone sealer. I also had to drill some 5 mm holes for a couple of the retaining screws too - but nothing difficult.

I didn't drill extra holes in the RC30 airbox as this would have let in unfiltered air due to the design...

Air enters via a short duct or 'snorkel' at the front of the airbox housing, before passing through a flat cone style K&N filter within the housing.

I agree that there might be some more power to be gained in using the larger VFR airbox, but space dictates this not possible as I want to use the RC30 tank.

I would like to build a new airbox with a cold air intake, possibly using a VFR airbox, whereby cold air is taken via a duct from above the radiator (I might have to lower the rad a couple of cm to do this) and then passed into a larger airbox through a large flat panel filter. It would be my intention to use the under side of the fuel tank as an airbox lid.

I am running a set of standard '97 VFR CV carbs at present with a Dynojet kit, but also I have a set of the earlier RC36 carbs which have a 1 mm larger in diameter.

R> the 837 really needs more air and fuel. RC36-I (36mm) will give some extra ponies.

Ultimately, I would like a set of RC30 carbs.

R> sometimes at Ebay.de there is a set (somehow not all german ebay products show up at ebay.co.uk searching international).

See my dyno in my gallery: RC30 carbs are absolutely worth the money ! (and RC30 parts prices only increase, no costs when you ever sell them)

No dyno figures at present, as i do not live on the UK mainland (I live in the Channel Islands) and we have no dyno here.

Tell us all about your Durbahn airbox !

R> Had to wait 2 years before I could bring my bike to his 'workplace' :fing02: :fing02:

Did not fit, had to modify it. Can send you pics and dimensions if you want.

Andy.

[The Phantom]

sometimes at Ebay.de there is a set (somehow not all german ebay products show up at ebay.co.uk searching international)

I found the same thing when searching on ebay.com.au with International tagged - not all stuff on ebay US would come up (so I search there directly).

Did you know that on a phone keypad, VFR750 translates as 837-750? It's a sign :fing02:

[Andy Griff]

That's a sexy looking carbon airbox Vfroem !

Does it encase the whole carb assy and is the bottom part sandwiched between the carb intake rubbers and the cylinder head ?