HRC VF400RK TT F3 Replica.

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marcus57
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Re: HRC VF400RK TT F3 Replica.

Post by marcus57 » Sun Jul 17, 2016 9:43 pm

Interesting looking build , no doubt it will be difficult at times but looks very interesting

Will be following

colinf
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Re: HRC VF400RK TT F3 Replica.

Post by colinf » Sun Jul 24, 2016 7:54 pm

Picked up about 75% of another VF400 off ebay last week.Actually bid on it because it had the fairing,fuse holder cover and instrument surround that the stock bike needs but it's pretty much only missing the tank,seat,some of the exhaust and the swingarm, so £71.99 well spent as it gives me a spare engine for the racer project.The wiring harness will be useful too as the stock bike's has been butchered so now i can de-construct one to modify for the racer and donate the other to the stock bikes parts pile. I'm toying with the idea of one standard engine with just the carb and exhaust mods and maybe try a more highly modified one with the other engine.They are pretty cheap to pick up and you can get genuine Honda oversize pistons for £12.50! the rings and gudgeon pin are about the same so thats new pistons for £100!! During my ebay searches i came across one of the Japanese magazines on F3 race bikes which did include a picture of a couple of VF400s .I didn't bid as it's in Japanese text and only had the two small pics but it appears to show one bike with a different (not HRC) Honda style paint job but still on its original wheels and the only colour,but even smaller, pic of the HRC race kitted bike i've seen.
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Tim400GB
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Re: HRC VF400RK TT F3 Replica.

Post by Tim400GB » Thu Jul 28, 2016 2:53 pm

following :up:

colinf
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Re: HRC VF400RK TT F3 Replica.

Post by colinf » Sun Jul 31, 2016 9:14 pm

Although there's going to be quite alot of small modifications and mountings etc to fabricate the main areas for modifications are the fairing/seat unit,cooling system,exhaust system,wheels/brakes and forks.Once the frame was de-lugged it seemed like the front end would be a good place to start.The wheels on the HRC bike and the Honeybee one are the same style as the ones on the NS400R ( and VF1000R,RS850,NS500 etc in various rim sizes) but,according to the on-line translation,they are CBR400F wheels.The front is 2.50x16 and the rear 3.00x18.I should think CBR400F's with these wheels are a bit thin on the ground but the front is the same size as the NS400R and available.Given that the wheel is the same size and that the racer and NS both have TRAC anti-dive forks and what look like the same calipers i thought the NS front end might be the answer but the mudguard mounting is different.The mudguard was the clue and it dawned on me that the front end is VF500 37mm forks ( obviously!).The forks i got came complete with yokes and stem and fitted okay although the threaded part of the stem is slightly different.I had a bit of a rumage and found an NC21 top yoke that fitted nicely and also looks cleaner than the VF one with the Ignition barrel mounting on it (the ignition will be hidden away somewhere).These forks will be stripped and seals etc replaced before being painted black later.Will make sure all the pieces fit before anything gets rebuilt properly.You can see the forks are wider than the stock VF400.
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colinf
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Re: HRC VF400RK TT F3 Replica.

Post by colinf » Tue Aug 09, 2016 8:19 pm

Got hold of a good NS400R front wheel to see how it would fit the VF500 forks.Took the old tyre off the VF400 wheel and stuck it on the NS one so the height is right and to check for clearance issues ( just in case anyone enlarges the image i know the tyre's on the wrong way round! ).Seems to fit okay although it hasn't got a speedo drive on it,will obviously need spacers sorting and will probably go for electronic speedo.The front discs for the VF500 and NS400R are only 1mm different in diameter, 255mm and 256mm respectively so i'm hoping it will just be a case of aligning the calipers.The front mudguard on the VF400 & VF500 look the same but the fork are wider on the 500.As the mounting is riveted onto the mudguards they dont come up on their own so despite having a 400 mudguard i had to get a 500 one.This has now been cut down to match the Honeybee racer's version but i think the HRC race kitted bike must be similar as it has an extra radiator mounted behind the wheel as opposed to the Honeybee bike which has a thicker radiator with deep extensions either side of the front cylinder.
VF400RKa.jpg
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colinf
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Re: HRC VF400RK TT F3 Replica.

Post by colinf » Tue Aug 09, 2016 8:44 pm

Forgot to mention,while i was on the subject, that the NS wheel is actually 0.9kg HEAVIER than the VF one despite it's massive hub!!!......very disappointing! The HRC ones have magnesium hubs though ( not sure about the rims? ) Twice as many discs and calipers as well, it's supposed to be getting lighter not heavier!

colinf
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Re: HRC VF400RK TT F3 Replica.

Post by colinf » Tue Aug 16, 2016 8:14 pm

The shed's been a bit full with "visiting" bikes recently so the bench with the VF on it has been stuck some of the time so i started going through some of the parts i do have that need modifying.The wiring loom needs some of the redundant circuits removed,the rear mudguard (under-seat section) and the sprocket cover both need surgery to match the Honeybee racer's.I'll cover the wiring and the mudguard later as they're sort of connected in that it involves re-positioning some of the electrical components.This is the standard sprocket cover [img]
VF400RKa.jpg
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and the cut down version [img]
VF400RKb.jpg
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There will be a bit of a compromise when it comes to the electrics as the racer has no starter motor! I will need to find space for the related components like reg/rec and starter relay etc without spoiling the stripped down look under the bodywork.I think i will relocate the battery to the seat hump so everything isnt crammed in around the rear shock like the road bike.I know you don't really want extra weight that high or far back but i've found a supplier in Classic Racer magazine who sells Lithium/ion batteries.Their equivalent battery for the VF400 is 5mm narrower,27mm shorter and 3.1kg lighter! There is no acid or gel and no breather tube so it can be mounted any way up. ( i've saved the weight i lost on the wheel again !).
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colinf
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Re: HRC VF400RK TT F3 Replica.

Post by colinf » Sun Aug 28, 2016 9:24 pm

Found another set of VF500 forks on ebay that still had the spindle clamps and the caliper mounts ( which move to operate the TRAC anti-dive system ) which are missing on the pair i have. No other bidders so i got them for the £29.99 start price! I doubt i could have bought the bottom clamps and mountings inividually for that so it's like getting a spare set of forks for free. The same vendor had the pair of calipers off the same bike complete with the reservoir and all the hoses still connected so i bid on these as well,that way i'd have all the mounting bolts which you probably wouldn't get buying the calipers on their own.A bit more interest in these so had to bid £38 for them.The vendor very kindly arranged postage for the whole lot for £10! They turned up as a sealed system complete with pads still in them! Will probably be using a different master cylinder depending on the anle of the clip-ons, certainly wont be using the pads but i've left them in to get a better idea of the alignment. There aren't any discs on the front wheel yet but i bolted up the calipers and it looked promising.As there are no spacers on the spindle yet it's possible to move the wheel from side to side slightly.The right hand mount could be moved easily by removing a bit of material or adding thin spacers to achieve the required alignment but the moving one on the left is more difficult as the casting touches the part of the fork leg it pivots on both sides. I noticed that by moving the wheel so the fixed one is in line that the other side is out by about 2 or 3mm.This got me thinking so i measured the distances between the rim and the forks on two other Hondas that were in the shed.A 1981 Superdream and a 1987 VFR750F.....neither were dead centre and were 2-3mm different each side( the VFR shares the TRAC type forks too ).I will check the wheel is in line with the centre of the headstock and probably just remove the 2-3mm from the part of the mount that the disc passes through.It doesn't look like the extra 1mm diameter of the NS400 discs will matter either so no major dramas.
VF400RKh.jpg
VF400RKg.jpg
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colinf
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Re: HRC VF400RK TT F3 Replica.

Post by colinf » Wed Sep 07, 2016 8:32 pm

Made a start on stripping down the wiring loom (how sticky is 33yr old insulation tape when you unwind it!) to remove the wiring for redundant components like indicators and relevant switches/relays,instrument lights,rear brake light switch etc.Will leave just enough of the lighting circuit for addition of front brake operated brake light and power for a "hidden" but removeable head light/riding light which i hope to mount under the fairing.In order to see where everything was going to go i've cut down the underseat part of the rear mudguard to match the Honeybee racer's.This isn't the finished article so consider it as the prototype ( or Mk 1!).The spark units have been repositioned as per one of the photos of the H'bee bike.I'm tempted to put the starter relay next to the battery in the seat hump which would just leave the Reg/Rec to mount somewhere under the seat.Once i've finalised the mounting positions i'll fit new connector blocks and reduce or extend the wiring as required to keep things neat.
VF400RKa.jpg
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colinf
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Re: HRC VF400RK TT F3 Replica.

Post by colinf » Sun Sep 11, 2016 8:22 pm

Before getting clip-ons and buying or fabricating rear sets i thought i'd better get an idea of exactly where they need to go first.Bearing in mind i'm 6ft tall and the Japanese racers probably weren't ! One factor that complicates this ( but does allow me to increase leg room) is the fact that the seat unit has to be made too.The only bike in the shed that had a sporty riding position was a friends Aprilia Falco ( not as extreme as RSV Mille etc ) which happens to be a comfortable riding position for me.With the aid of a straight edge and a spirit level i made a note of the relative positions of parallel lines at the bars,seat and footrest height and the distances between them through imaginary verticle lines at bars,front and rear of seat and the footrests.Because the aprilia looks and feels quite big i was expecting to have to compromise quite alot somewhere transferring these to a compact 400.I fabricated some clip-ons ( for mock up only ) and cut some 5mm mild steel plate to bolt on the frame with enough holes to try various footrest positions.Also made a crude seat from alloy sheet and MDF.These were all set up to replicate the Aprilias riding position.The VF is up on a bench and the back end is on a paddock stand (minus rear wheel) so i had to get on using steps! First impression is that it felt too far forward but i think that is just because it has no fairing or instruments on it ( my head was towards the front of the tank as it was on the Falco).The other thing was it felt a bit cramped at the knee.Tried moving the position of the footrest and it felt better when i moved it a inch backwards rather than down anymore. My arms would be fairly straight when sitting up and elbows and knees dont touch when crouched down .At least i've got a starting point to work from, more adjustments can be done later.The rearsets are about the same height as the Honeybee racers still but about 1.5inches back.The clip-ons are below the top yoke but could go above if i didn't feel comfortable.[*]
VF400RKd.jpg
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