HRC VF400RK TT F3 Replica.

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royster81
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Re: HRC VF400RK TT F3 Replica.

Post by royster81 » Thu Mar 30, 2017 10:33 am

https://www.instagram.com/nagtics_naga/

Colin is this guy relevant to your cause?
It's not having what you want but wanting what you've got....Loud ,Proud and Modified ....

colinf
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Re: HRC VF400RK TT F3 Replica.

Post by colinf » Thu Mar 30, 2017 6:04 pm

I have seen pictures of the bike before and i think there are some build pics online of the same bike.The problem i find ,and it's probably an age thing!, is that instagram etc usually have no details at all .The pics are a useful reference but it's nice to find bikes on forums so that you can actually ask the owner questions.Keep putting anything up you think is relevant, i appreciate it.Thanks too for Ligurts second find on the Japanese auction sites.Although VF400F is on the listing again i'm not sure it would fit.Someone on here could probably identify it as one of the other models listed? I will update the build when i get back to it, i'm having to move a garage and build an extension to the bike shed so time is a bit limited at the moment.

duke748bp
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Re: HRC VF400RK TT F3 Replica.

Post by duke748bp » Tue May 30, 2017 1:20 am

Any updates? Was watching this with much interest.

colinf
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Re: HRC VF400RK TT F3 Replica.

Post by colinf » Wed May 31, 2017 6:35 pm

Sorry it's been a bit quiet.I did get back to doing some work on it last weekend and will post details and pics this weekend if i'm happy with the finished article.Been looking into getting parts from the Japanese auction sites too including looking for CBR400F back wheel , they are available but the only 18"Comstar wheels i could find have a 6 bolt disc set up not the 3 bolt type the racer has ( later CBRs with cast wheels do have the 3 bolt type ! ). Also came across a useful pic of the radiator set up.Not sure if this is genuine HRC kit but the manual would suggest it is.The style of mounting is very similar the the type on the RS750 racer from the same period.
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rad.jpg
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colinf
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Re: HRC VF400RK TT F3 Replica.

Post by colinf » Mon Jun 12, 2017 8:53 pm

Actually got around to doing a bit more to the bike.As i've said before i'm keen to keep it looking as authentic as possible ( one of the reasons i'm still undecided on rear wheel options !) so i was looking at the engine to see what details needed sorting to match the pictures of the Honeybee bike.One of the most obvious is the clutch cover, the translated text says it's an SPL item? and has the oil level "window" removed and a dipstick instead.Presumably this was considered a potential weak point on a bike competing in 4hour races
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HBcover.jpg
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I'd looked at this before and had checked the profile of the cover/dipstick on on my brother-in-law's VFR750.it seemed feasable at least to graft in the dipstick housing to the stock NC13 cover.Once i thought i'd try it i found an NC21 cover on ebay,as you all know, the later VFR400's share the basic engine architecture with the NC13 so when it arrived i put it on the motor to check the dipstick cleared the clutch,which it did.The key thing would be to keep the dipstick in the same position so i decided to cut out that section including one of the mounting bolt holes
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I took an ally plate and drilled holes corresponding to the cover mounting ones so the "donor" piece could be bolted in the correct position while keeping the gasket surface flat too.
It was a case of cutting the minimum off the NC13 cover and then slowly cutting and filing it until the donor piece fitted.The only hitch is that the profile of the NC21 cover doesn't taper quite as much and is a bit deeper than the NC13
one.So there was a slight void and a need to blend the profiles somehow.The bottom pic is what we're aiming for.....
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colinf
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Re: HRC VF400RK TT F3 Replica.

Post by colinf » Mon Jun 12, 2017 9:13 pm

Although i have oxy-acetylene gear here i'm not really skilled enough to weld Ally with it.I don't know if any of you have used or heard of the Lumi-weld cold fusion method of joining Ally but i've used it successfully to repair a damaged crankcase on my Bultaco Sherpa before and used correctly it's a very strong joint and can be used a bit like bronze welding where you can use the rod to fill.There are other types on the market that use the same technique.Because the joint is much harder than the Ally around it i did the join on the inside of the cover after putting "v" sections along the joint edges.I also removed the sight window and put a blanking piece behind it using the same technique.The raised section around the window was then carefully ground back, the remaining void of about 4-5mm on the outside of the blanking plate was filled using chemical metal.
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NC13cover2.jpg
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The area around the dipstick took quite a while to gradually file and fill in odrer to blend in the profile
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NC13cover1.jpg
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You can see the difference in the profiles.I had to make a mild steel jig/brace to bolt to the plate so that the void could be filled using the rod while making sure both edges stay at the correct temperature to make the joint.
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colinf
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Re: HRC VF400RK TT F3 Replica.

Post by colinf » Mon Jun 12, 2017 9:26 pm

I wasn't going to finish the cover in a final coat of paint but after careful filing/filling/sanding etc and in primer it was hard to see any high or low spots even outside in natural light.So i dug out a tin of satin black and managed to get one coat on it with what was left in the tin.Black shows up imperfections better than any other colour.There is a small area in front of and above the area the oil level glass area that needs a little more work.The dipstick section was put in prior to blanking the oil window so i was able to compare the dipstick levels to the marks cast on the cover.If the dipstick isn't screwed home they are almost perfect but because of the different depth and shape of the clutch part of the cover i will put a punch mark on the dipstick once the engine has the specified oil quantity in it.
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NC13cover5.jpg
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The sad thing is unless you're a TT F3 "nerd" or an expert on VF/VFR400's nobody with ever notice!
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duke748bp
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Re: HRC VF400RK TT F3 Replica.

Post by duke748bp » Tue Jun 13, 2017 3:32 pm

Seriously nice work. We'll worth it.

Sent from my SAMSUNG-SM-G870A using Tapatalk

colinf
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Re: HRC VF400RK TT F3 Replica.

Post by colinf » Tue Jun 13, 2017 6:32 pm

Thanks.My nephew came round on Sunday,as his trials bikes live here ,so i showed him the modified cover and his only conclusion was that he thought i had too much time on my hands!
If anyone has cracks or small chunks missing from Aluminium casings i'd recommend they try using Lumi-weld or Dura-fix type rods to try and repair them, you only need a good blow-torch with mapp gas or similar to get it hot enough and once it gets up to temperature it doesn't take much to keep it there.Doesn't take much practice to get tidy looking repairs.

colinf
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Re: HRC VF400RK TT F3 Replica.

Post by colinf » Sun Jun 25, 2017 9:46 pm

As i've said before i'd like to keep the "road" equipment needed as discreet as possible to the extent that the ignition switch will be hidden away somewhere and i was going to mount the choke lever away from the bars too.My original idea was to get something like an NC24 style lever but mounted under the right-hand top frame-rail just under the tank, this would look cleaner and would only need a very short cable.I was looking at the carbs last weekend when it occured to me that even that was more sophisticated than it needed to be.If the mountings for the two levers operating the front two chokes were the same ( located the same way and the same length from the pivot to the operating end ) then they could be swapped around so the short one takes the place of the one the cable pulls on and ,once modified, the long one could go on the outside carb.This one could be modified buy removing one half of the retainer for the cable barrel/nipple and then putting a 90 degree twist in it once heated.It now forms a very simple finger operated lever mounted directly on the carb and does away with the cable ,the little retainer for the outer cable and of course a separate lever ( another few grams saved ! ).It seems to work okay but might need a little more resistance added to compensate for the loss in the cable/lever assembly.
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