6th Gen VFR800 Valve clearance

I need to inspect and adjust the valves on my VFR. What tools do I need, and what parts will I need. Any tips would be helpful.

 

Patience, and lots of it! You can check the standard valve clearance without disturbing the cams or tensioner, but to check the VTEC calves requires the cams out (so the tensioner backed out and locked and the chain off the sprockets), the stopper pins get fitted into the slide mechanism under the buckets, then you have to reassemble the chain, sprocket, tensioner, cam saddles. And THEN you can get your feel gauge to work. If the clearances are fine, you still have to disassemble all to recover the stopper pins...The VTEC valves can't be re-shimmed so you need to replace a bucket if the clearance is out of spec. The standard valves use 7.48mm diameter shims.

Tools needed:
Just basic hand tools to disassemble parts, and definitely a torque wrench for reassembly of critical fasteners
Feeler gauges, of course
You do need a cam tensioner lock tool, but that is easy to make, I used a spare feeler gauge and a grinder, dimensions are in the service manual
You will need the 4 x slide stopper pins for the VTEC valves, I used a cut down 6mm bolt into 2.5mm thick slices but anything could be used as all the pins do is hold the VTEC slide stopper in the latched position against quite light spring tension; even plastic rod or aluminium.
Gasket sealer, for the half moons on the cam covers

Feel free to ask questions. None of this s very complicated, just a bit long-winded

 

Okayy, thank you. So if the non VTEC valves are out of spec, they can be re-shimmed? Where would I find shims for the non-VTEC valves and the buckets for the VTEC valves?
I picked up my bike for cheap but with high mileage. ~97k km. I'm not sure if the previous owner has ever checked the valves. The engine runs fine but before VTEC kicks in, I can hear a faint valve tick I'm pretty sure, and the VTEC transition isn't too smooth, so I'm sure I'd have to adjust the clearances on most valves. I want to get any work on it done through the winter. Because its at a higher mileage, is there anything else I should check/look out for?

 

I bought a Hotcams shim kit many years ago, and have topped this up as needed. I bought some spares from Aliexpress recently and these checked just fine with a micrometer. You don't need a VFR-specific kit, they use a standard 7.48mm shim, same as many other bikes/brands. From my records, the stock shims were in the 1.58 - 1.92mm range (at similar mileage to yours).

For the VTEC valves, your only option is OEM buckets. The best price I found was Webike in Japan at USD25 each (and I needed 6!). All but one VTEC valve was out of spec, and I was able to re-use just one of the removed buckets in a different location. The worst intake valve only had 0.05mm clearance (minimum spec is 0.12mm).

All of my non-VTEC valves were in spec for clearance, which I think indicates that these had been reshimmed by a PO, while the VTECs were ignored because of the cost/complexity.

What else could you do while you are in there? New sparkplugs are easy (you'll have the old ones out anyways), and you could swap out the camchain tensioners but unless they were noisy I don't know why.

You will have ample opportunity to inspect the cam lobes and journals but (unless maintenance was poor) there's no reason they should be worn.

 

Thank you for your help. Its much appreciated. I also read on another forum about the PAIR valve mod, Flapper mod, and airbox mod. If you've done these, are they easy to do? and what significant differences are there from doing them.

 

I have done the PAIR but not the flapper or snorkel.
P
AIR involves blanking the ports that inject air into the exhaust to help burn off residual hydrocarbons; I think the system introduces another variable that can cause the O2 sensor to adjust the fuelling which make the midrange feel a little off sometimes. I think the throttle response is better with the system disabled, plus you get to dump quite bit of excess hoses. The ECM doesn't know you've done this so no faults are thrown.

The flapper is super easy to experiment with; by default the flapper is held closed below 5500rpm and opened above that point; Honda say it is to enhance low rpm smoothness but cynical me thinks it is also noise related. You can unplug the hose to the flapper diaphragm on the air box and bung that so no air leaks back into the hose; that leaves the flapper permanently open. Try it and see if you like it, I couldn't tell a difference aside from noise.

The last mod is removing the snorkel that feeds air into to the airbox; I'm not a believer in messing with that one. The geometry of inlets/airboxes/trumpets is a science which I trust Honda to get right.

 

This YouTube video should be helpful.

 

It was for me.