Dr Honda Velocity Stacks Copy

[VTRDark]

Over the last couple of weeks I have been making a copy of the Dr Honda Velocity Stacks. I was kindly lent some genuine ones to use as a guide. I decided the easiest way to go about this was to use fibreglass and bodyfiller.

First off I wrapped the original stacks in clin-film to protect them and use these these to make my template mould.


I then used fibreglass resin sheets to wrap around the inside and around the curvature to get my basic shape and proportions and then pulled the mould out from inside the originals which have come out pretty accurate.




Now I have the moulds I once again wrapped them in clin-film, only this time on the outside of the mould which brings the diameter and curvature out to the same as the originals.




I then got the body filler out and started building up the layers and smoothing out the shape. Then trimmed the bottom so they are the same height as the originals. I then marked a line around the base from where it tapers off to sit in the top of the carbs and sanded down.






Once this was complete it was time to make the ring that mounts the stacks to the airbox. To do this I used some carboard which I slid over the originals and drew the outline and then cut out. This was then used as a guide to make my fibreglass outline. Then filled and smoothed to shape and size.


I now have the main stacks and the mounts complete.


I then put the originals and copies side by side and using a spirit level marked a line around the circumference at the exact height for attaching the mounts. I tapered the bottom inside of the mounts so filler could be used to attach to the main body and be sanded down smooth.






I happy with the shape and accuracy so coated in primer.




Then a applied a couple of top coats using a heat resistant Aluminium spray that contains 99.5% Pure Aluminium, so gives a nice finish.






I still need to give them a final wet n dry to smooth off more to get rid of the little niggly bits (should have used a putty primer) and give a light coat over the top. I am happy with the way they have turned out and I have got the size and inside taper pretty much spot on. I weighed the originals which weigh in at 154gm and my copies weigh in at 126gm. They fit the bike airbox nicely and I have drilled the holes for mounting bolts. As far as accuracy compared to the originals, they are not 100% but they are dam close and looking good.

When they are complete I shall take some comparison pics of them side by side with the originals and shall post pics of them when mounted to the bike.

(:-})

[grumpyfrog]

That's some mighty fine work there sir. Hope all the work is worthwhile.

[AMCQ46]

Carl, they look great, almost like the real thing when painted silver.

BUT the most important thing is to be sure that they wont fall apart under vibration or Oil / Petrol contamination and get sucked into the carb.

I dont want to hear that you couldnt close the throttle because you had a lump of inlet trumpet stuck in the buterfly

[Kev L]

Nice work Carl, but I would share Al's concerns. Good luck.

[VTRDark]

Fibreglass apparently is as strong as steel how true that is I don't know but the stacks are pretty solid. I will just keep an eye on them for any stress fractures. Maybe I should stick a bit of innertube under the mounting plate. I would be more concerned about a bit shooting down inside the inlet tract rather than getting caught in the butterfly. A stuck butterfly I can deal with by shutting the engine down. Anyway I don't see it as being any different from removing the return cable on the throttle as one of the reasons for that is a safety thing in case the butterfly gets stuck.

(:-})

[AMCQ46]

just need to make sure the filler is not going to delaminate

[Wicky]

or paint flakes/flecks entering the carburettor

[AMCQ46]

Carl,
if you ever had a throttle jam when you shut the throttle going into a corner you might be surprised how scary it is.......same as finding your brake lever comes back to the bar!.......and I have had both of those happen when I was racing.

problem is
1) you feel like the bike is accelerating as your brain had already mapped out that you should be slowing, so staying at the same speed feels like acceleration!
2) your brain takes time to work out WTF happened and then has to initiate a solution that is not mapped into your riding instinct and this takes significant time during which you have traveled a signficant distance. even pulling in the clutch will not be your first instinct, and hitting the kill switch is bloody dificult when you are hanging on for dear life!

2nd time it happens is much easier as you have already had a practice, but 1st time is never good

and I can also tell you that coming into a hairpin a full chat is never a good place to finds out that the tankslapper that you had when exiting the previous corner has flexed the forks so much the disc has pushed the pads back in the caliper and it will take 3 pumps of the lever to get them back into contact

[VTRDark]

Point taken. I guess I will just have to be a test pilot then. I will most likely get around to buying some billets at some stage anyway. Unless I can get some Mori ones to clone. Seriously though I will just have to keep an eye on them for any stress fractures. I don't think the vibrations inside the airbox would be that severe from the engine as the whole thing is sort of sitting on suspension as the carb rubbers have flex in them. The airbox has a certain amount of wobble in it. The air and pressure on the other hand may be a bit different.

(:-})

[agentpineapple]

nice work carl.........
deffo keep an eye on them, will you be doing a dyno run with them on this weekend?
i did say at the time about the vibrations, you did a top job tho. not sure how the paint finish will hold up, will you be laquering them?
i get some discolouration on mine, i suppose thats airbox farts for you.......
can't believe you nicked my primer.......
pray tell who was the kind soul that leant you the originals..........

[VTRDark]

Some really strange bloke just lent them to me out of the kindness of his heart. I could whack a sheet of real Carbon around the outside of them. Probably not much different from fibreglass except it's carbon. but if I'm going to do that, I may as well buy some billets with the price of Carbon.

(:-})

[agentpineapple]

and theres me thinking that stranger didn't have a heart...........
well are you going to dyno them or not??????????

[VTRDark]

Not this weekend, but in the near future once I have tweaked the carbs. There's no point in going for a run first as I can't use my other one for a true comparison. If I wanted a comparison with and without them I would have to do two runs on the day. Maybe I should do that out of curiosity but I would like to get a custom madrel made first for the left link pipe. I know they richen up the mains So I may have to drop a size or two, but I could do with being a tad richer on top anyway going from my last dyno. I have also blocked a hole in each slide, so they need to go in my carbs as well, also I need to put the standard emulsion tube back in the front and I want to put the BMC filter back in.

(:-})

[agentpineapple]

Not this weekend, but in the near future once I have tweaked the carbs. There's no point in going for a run first as I can't use my other one for a true comparison. If I wanted a comparison with and without them I would have to do two runs on the day. Maybe I should do that out of curiosity but I would like to get a custom madrel made first for the left link pipe. I know they richen up the mains So I may have to drop a size or two, but I could do with being a tad richer on top anyway going from my last dyno. I have also blocked a hole in each slide, so they need to go in my carbs as well, also I need to put the standard emulsion tube back in the front and I want to put the BMC filter back in.

(:-})

i'll get the bike mot'd, taxed and insured tomorrow afternoon, how about we take a ride to flowtech on wednesday...

[VTRDark]

Defo sounds good to me.

(:-})