Mohawk

Seems like people don't understand how the O2 sensor works. It has 2 circuits, #1 is a 12v supply to heat the sensor. #2 is the Narrow band Lambda circuit which flips from rich to lean. The 02 eliminator only puts a resistance over the 12v heating circuit which the ECU uses to determine if it should see Lambda circuit outputs. If there is no load on the 12v circuit the ECU throws an error code & illuminates the Fi fault light. It also throws a code for no Lambda change but does NOT illuminate the Fi light. Because it has a default fuel map for just this situation, its a rich map as it can't see Lambda so rich is safer than lean conditions. You only need one O2 sensor circuit to have a resistance to keep the Fi light off. So you really need to get a proper fuel tune & make sure your starter valves are balanced. The snatching is caused by the Fi shutting off fuel delivery completely when you shut the throttle on the overrun. So get used to not fully closing the throttle or opening it with more care when transitioning from closed to initial opening. The Rapid Bike Racing module has a setting to keep fuelling on the over run, I've not had a snatch since, as it acts more like carbs now. 👍

Plus you need throttle wide open when doing compression test ! Sounds like cam chain or tappet noise to me, but if you replaced the chains & tensioners not likely to be that. Have you checked the Vtec valve clearance ?

Not sure where you are in the world Jim, but you can have wheels straightened. But may be cheaper to replace with a straight 2nd hand wheel.

Theres much more past 9k if you open up its breathing. Intake and exhaust are both restrictive beyond 9K/rpm. A good exhaust & K&N+ deflap & PowerCommander is good for circa 112hp, thats plus 15hp 👍 Will make power all the way to 10,500rpm then. Needs more work to push the peak to max RPM.

As you are in the UK get an Electrex World one. I put one on mine 12 years ago, mosfet & been perfect since. Unfortunately they like everything have got more expensive in last 12 years, now £114 ☹️ https://www.electrexworld.co.uk/cgi-bin/sh000001.pl?WD=vfr800fi&PN=RR881-Regulator-Rectifier-CBR600-VFR800-CB900F-CBR900RR.html#SID=439

You will be hard pressed to improve the stock rebound on 5w oil. 7.5w as a minimum would be best. When you say 1.0 weight spring I assume that is Kg/mm. IIRC the stock spring is about .75Kg/mm so the damping as stock is set for that weight spring & usually to soft. So you will need heavier oil or a far stiffer shim stack.

He says he picked it up for £750 (approx $935). I had a crashed one I picked up for £350. Good engine, lots of other good bits but damaged frame & scrapped panels as side hit by a car damaged both sides. The sale of parts came to nearly £900, so was a good job. 👍

Its one of the things I want to do once I retire. Just to keep my hands busy. Oil Cooler+line kit, FPR kit. +/- Injectors etc. Unfortunately I'm in the UK so, shipping would be a killer, for US guys, which is mostly where the market would be. But we really could do with a VFR store listing all the custom options we can get & who from.

You will need to increase the fuel rail pressure for any injectors other than stock. VFR800FI runs 2.5bar Pressure, anything newer runs 3 or 4 bar pressures. 929 is 3bar. I ran mine originally on 2.5bar but had to add loads of fuel using my RBR module. I tried 4bar but even on zero map it delivered way to much fuel. So switched to 3bar & its been great with better mpg to boot. One of the benefits of multi-hole injectors is that they produce finer fuel droplets which means better fuel air mix, which allows less fuel to be injected because it burns more completely. Hence the evolution from single pintle through 4-hole to 12, now 16-hole injectors. The greater the hole count, the smaller the holes the finer the fuel mist produced. Smaller holes require more pressure to deliver similar volumes of fuel in the same time frame. The stock pintle injector shoots the fuel out in a cone shape & relies on deflection off the intake walls to complete atomisation of the fuel. The 4-hole produces a V shaped finer spray directly into the inlet track either side of the intake bridge between the intake valves. This avoids wasted fuel being sprayed on to the bridge & sticking to the intake walls. There are many car videos on U-tube showing good gains from 4-hole compared to 1-hole. either way if you swap out the injectors you will need to correct the AFR with a combination of PC/RBR &/or fuel pressure regulator. There will be a market for an adaptor to use standard automotive FPR's as VFR ones are NLA & are not a standard fit. I had to make mine form a couple of adaptors. 1998 throttle bodies before And after I had to use the 90 degree to drop it below the airbox. There is only just enough room for this.

Any coolant suitable for alloy engines will do. Unless you expose your bike to sub -10 C temps, you can use 75% distilled water & 25% antifreeze. This helps the cooling too 👍

All of the add on inline fuel controllers work on a percentage basis. PC3, PC5, RBE, RBR etc. So if ECU commands X-duty cycle, say 50% then you add 10% via the fuel controller, its sends 55% to the injector as a timed signal. So at the same RPM's you can directly transfer any map to any other. They may need a little fine tuning once transferred, but should be pretty close.

Hey Skids I hope you appreciate my advice was tongue in cheek 👍😂

Black round ones are the best, preferably less than 10yrs old depending on storage & just scrubbed in. Pick ones that match your budget & performance expectations, but be realistic in your assessment of your intended use. In which case most modern tyres from any reputable brand will out perform you EVERY day. Don't confuse your intensions with your ability, or you will be wasting money on tyres you don't need. As always YMMV

The crank sensor rubber gasket leaks on all 800's I've seen up close. Its on the top of the right side engine cover at the base of the V with a cable coming out. If your oil level is to high it will leak. But this usually only causes damp oil stain along top of gasket line then down right front of the crankcases.

Traxxion Dynamics Cartridges for the win 👍