[RumrunnerRacing]

I'm new to the VFR800's but I'm thinking of using an Interceptor engine for a project bike I have in mind.

What I need to know before I decide whether or not to use this engine are what engine performance upgrades are available for this bike?

Exhaust. . .are full systems available. . .I don't care about the canister, I would like to know if there is an quality aftermarket header pipe available?

Big bore kits?

Upgraded engine internals. . .rods, adjustable cam shaft gears, valves and valve springs, cams, pistons, con-rods, heavy duty clutch plates & springs, etc.

I'm sure that DynoJet has a PCIII for the EFI, but I haven't checked that out yet either.

I figure rather than was a bunch of my time trying to find info about a bike I know very little about technically it would be better to ask the people who actually own and ride the bike and I would greatly appreciate all your help.

What about weaknesses in the engine area. . .does it have any areas prone to failure? Does it cool adequatedly? Can the clutch handle any power upgrades?

Thanks for your help guys.

[Darth Bling]

My answers are below in blue.

Originally Posted by RumrunnerRacing

I'm new to the VFR800's but I'm thinking of using an Interceptor engine for a project bike I have in mind.

What I need to know before I decide whether or not to use this engine are what engine performance upgrades are available for this bike?

The short answer: No.

The long answer: Depends on how much money you have. Somebody on VFRD actually installed a supercharger on their 5th gen. He plans on making kits for the 6th gen after he finishes designing a kit for the 5th gen. He was able to get about 150 hp out of the engine with minimum boost. He also had to completely upgrade the FI system to pump out more fuel and he used an aftermarket FI controller as well.

Exhaust. . .are full systems available. . .I don't care about the canister, I would like to know if there is an quality aftermarket header pipe available?

You've got three options:

Motad Headers. Pretty pricey, but nice. These headers are 45mm in diameter I believe

98/99 VFR headers. Cheaper than the Motad system if you can find a used set in good condition. You'll want to consider getting it cermaicly coated or powercoated or whatever. They're steel and will rust (unlike the Motad or 6th gen headers). Lots of 6th Gen owners snatch these up, so good luck find them. Like the Motad, these headers eliminate the catalitic convertor.

Cut your current exhaust open an remove the cut. Weld in back up. Cheapest option by far. Your stock headers are 2mm smaller in diameter than the 98/99 headers (43mm vs 45mm, I think)

Big bore kits?

A company called Dynohum (sp?) used to make them in Canada, but they’re out of business now. I think the only place that I’ve seen them recently is TTS Performance in the UK. Here’s their website: VFR800 98-01 837cc Big Bore Kit Honda VFR800 837cc Big Bore

Unfortunately, nobody makes a kit specifically for the 6th gen VFR. But, the 5th gen kit “should” work. It’s a 4mm overbore, so you go from 781cc to 837cc. I’ve taken a 6th gen motor apart, and removing 2mm of the cylinder wall doesn’t really leave you much. Plus, from everything I’ve heard, the big bore kit doesn’t really get you much. You have more torque down low, but it’s no more powerful higher up in the RPM range.

Upgraded engine internals. . .rods, adjustable cam shaft gears, valves and valve springs, cams, pistons, con-rods, heavy duty clutch plates & springs, etc.

Good luck finding anything. This would all be custom work. Nobody makes a kit. You might be able to find a power-up kit for the RC45 that might work, but you’re talking so much money it make my mind hurt. I’ve also heard somewhere that CBR900 cylinders are the same size as VFR800 cylinders.

I'm sure that DynoJet has a PCIII for the EFI, but I haven't checked that out yet either.

Yes, they have one. You’ll also need to get O2 sensor eliminators as well.

I figure rather than was a bunch of my time trying to find info about a bike I know very little about technically it would be better to ask the people who actually own and ride the bike and I would greatly appreciate all your help.

What about weaknesses in the engine area. . .does it have any areas prone to failure? Does it cool adequatedly? Can the clutch handle any power upgrades?

The t-stat likes to get stuck open, which can cause the engine to run too cold and thus hurt your fuel mileage and power. Sometimes the CCT (cam chain tensioner) will die and needs to be replaced. You’re more likely to have R/R and electrical problems than mechanical.

Yes the clutch will handle power upgrades. The guy with the supercharge 5th gen didn't have to upgrade the clutch with stiffer springs or anything. He did add a bigger oil cooler to the bike though to deal with the heat better.

On the topic of cooling. Honda designed a really retarded system on the 5th and 6th gens (Goldwings too). Basically, the radiator fan is designed to suck cool air from the side of the bike and draw it in past the radiator. When riding around town at low speeds, the air will naturally want to get travel out though the radiators. If the fan is running, it cancels out the air movement on the left radiator and the bike heats up. It probably won't overheat unless it's extremely hot out, but keep an eye on it. The popular mod nowadays is to replace the fan with one from the VTR1000. It spins the same direction, but the fan blades are angled the other way, so it pushes air out.

Thanks for your help guys.