Mohawk

I much prefer this site for bike specs https://www.motorcyclespecs.co.za/model/Honda/honda_vf400f 83.htm Enjoy

OK the fact that it comes and goes is harmonics. If the engine is allowed to idle with clutch in rolling at speed & this is still happening then it’s likely the drive chain & sprockets causing the harmonics &/or the wheels. The stock 17/43 gearing means the front sprocket rotates 2.3 times for every one of the rear. Plus as chains wear they create slack areas. You said this has persisted over tyre changes & before latest chain & sprockets. Then it’s likely to be wheels balance &/or worn bearings combining in a harmonic frequency. Just because tyres are X years/miles old & were balanced when new does not mean they stay that way or the tech that did them did a good job. Check all bearings & then remove both wheels & have them re balanced. While the wheels are off have your head bearings checked & regressed, when were they last done !?

Aha yes that can be a problem, but my 16T front was symmetrical and a little thinner on the shaft, so I had to use a spacer to get it in the right place for the chain run 👍😎 The current 520 front is from an R1.

Try gearing commander to see the benefits of different gearing & how it affects rpm etc.

I forgot to add that I run a 520 chain now too. I did run 525 for about 8 years, but there are a larger choice of sprockets for my QD hub in 520 so last year I changed to 520 chain. There is no real difference in strength to the 5xx chains, as the side plates determine the strength & a short pin by any measure is always stronger than a long one of the same diameter. If race teams can run 1000cc 200hp machines flat out on 520, then your average VFR will not strain them ! Here’s a useful video explaining it. A standard 520 is lower strength due to thinner side plates as they are normally fitted to smaller capacity bikes, with less weight & power. So make sure you get one of the high tensile strength ones. But saving over 0.5Kg of weight from the rotating parts is an easy win 🙂 As always YMMV depending on chain maintenance.

They are so worth it, lower final drive ratio makes the bike so much more responsive on the throttle regardless of gear or revs. Lowering the gearing makes the most of the torque available to us. I run 16/45 or 16/44 most of the time on my 5th gen.

I know I'm repeating myself, but an old courier trick was to turn the front round after 5k mikes, then replace it at 10k miles then flip #2 at 15k miles, expecting a 20k life. So buy new chain + rear sprocket plus two front sprockets.

Gone already, that was quick. Garage clear out turned up these seals which I bought but never used. I did open the packets before rebuilding the callipers, but then decided to replace the brakes with 4-pots. Free to good home in the UK. Ping me an address to post them too. I think they are all there NOT oem but good quality aftermarket ones. Front left & Front right caliper piston seals, see pics.

Check at car tyre shop if bike shop won’t do it. The repair is the same.

When you say rhythmic vibration, do you mean harmonic vibration ? This is when slightly out of balance parts vibrate in harmony with other parts thus producing a rhythmic pulsing effect, sometimes enhancing the effect & when out of sync suppressing it. I would check both wheels are balanced correctly, then check your head race bearings, front wheel & rear hub bearings to ensure there is no play there. Also check your front spindle & swingarm spindle/bearings. Check your wheels spin freely at both ends with no brake drag. If you have brake drag then check out your callipers first. Last but not least check your wheel alignment.

^^^^^. What he said. You can’t just go from two valve cross swirl to 4 valve without disrupting the induction pulses. Most Dyno charts show that dip in power at Vtec transition point.

So it looks to me that something caused the pads to wear to the metal, this looks like they got thin enough for at least the piston side pad to escape the calliper, which left the pistons acting on the brake disc with the other pad. Until the heat caused the seals to melt or deform enough to leak all the fluid. I’ve never looked to now at the 1200’s CBS, but it appears not to activate the rear brake when the front is used, but does activate front when rear pedal is pressed. Are you sure the rear pedal releases cleanly & that you did not inadvertently keep the rear pressed at any time ? Either way the only way those pistons could get like that would be in direct contact with the disc. You say the pads pads were nearly new, doe that imply that someone changed them recently ? I’d have a word with them ! If you are lucky (& U appear to be, making it out of that corner) and the calliper is not damaged, then a new set of seals, pistons & pads, with bleed would see it sorted. I had a blocked master cylinder return passage on a bike many moons ago, it kept brake pressure in the calliper, but you would definitely feel that drag. This looks like a mechanics clock up or the wrong pads were fitted !

You could always do this 👍😎 Works a treat. Same both sides oem fan is long gone these are IP67 rated fans & the combined FPM is 50% more than the OEM fan & both suck air outwards through the rads. I have 90C thermal switch which resets at 80C. Works great. Plus if one fan dies there are 3 others still working. Just needs a little sculpting of the outlet vents where they cross the fan frames. This is not visible from outside. Have fun.

Doh, sorry I never looked past the plastic & exhaust, I’ll blame it on target fixation ! So same applies to 6th gen then. But being a long production model, then no worries, just buy a spare bit of plastic & be happy 😉

^^^ What he said. They are performance headers NOT OEM replacements, there may be minor clearance issues. I’ve never looked closely at an 8th gen fairing lower V, but I’m stunned by your picture & how big those holes are, Honda must have no faith in their own exhaust manufacturing now, if you compare those with the pipe cooling holes on 5/6th gens ! What’s a little melted plastic when you get such benefits !? YCMV. ( your clearance may vary !)