The RD400 drag bike

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AMCQ46
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The RD400 drag bike

Post by AMCQ46 »

A new thread to chronicle the work on the retro RD restoration.


Collecting from John who built it 30 yrs ago.
Image

Image

John used to run it in the SuperBike mag Ultimate Street Bike drag races when it was a pure road bike, then he got carried away and created this longer and lower version with a full Harry Barlow tuned motor.

It’s never been run in this version, but was speced to produce 70 bhp.

It has air shifter
Lock up clutch
Aprillia rs125. Front end
Tz swingarm with lengthend chain adjuster
Firestorm Subframe
6 petal reed blocks and carbs off modern 250 MX bikes
Vapor clocks
Femsa ignition with custom made Cdi box
custom bodywork
Yoshimura rearsets
Harry Barlow pipes (no silencers)


But when he finished the build and dynoed it 20 yrs ago, it was running very lean and although he had put some 500 main jests in (as a guess) it has never been run since.

after spending a lot of time sitting in a shed he had the crank seals replaced 3 yrs ago and vapour blasted the carbs with the plan of decommissioning it, but then the project stalled again and hence he has tasked with getting it running and to run it down the 1/4 mile the best it can do.

as it stands, there is no wiring harness, almost everything is corroded (the roof blew off the shed at some point), there Are bits missing and seized, and there are no instructions!.

so my plan is
1) to get the wiring sorted and get it running
2) sort the brakes and Clutch so they work
3) then take it to a dyne to make sure it is jetted safe.
4) clean up and paint various parts
5) take it to a drag strip and see what it does in anger
6) based on the drag tests, then I will start looking at how to improve it (remove weight, programmable ignition etc)


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neil
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Re: The RD400 drag bike

Post by neil »

See you at Elvington nr. York sometime soon then? Also Melbourne nearby has been upgraded recently. See "Staightliners" events
redvtr
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AMCQ46
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Re: The RD400 drag bike

Post by AMCQ46 »

Thanks for the tip on straightliners
AMcQ
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Kev L
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Re: The RD400 drag bike

Post by Kev L »

That looks a lot of fun mate, enjoy 👍
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Duffy1964
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Re: The RD400 drag bike

Post by Duffy1964 »

Will look forward to seeing your progress Al, hope it will run on Castrol R


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Duffy1964
Yellow 1997 Storm R.I.P. Orange 2000 Streetfighter (Rufus), Red & Silver 1968 Triumph Trophy 650, Blue 2003 Storm Project, Red 2007 Montesa Cota Trials 250 & 1959 BSA D7 175cc Bantam Trials Project
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lloydie
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Re: The RD400 drag bike

Post by lloydie »

Better project than planting an allotment al 👍.
Look forward to seeing it run 😁
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sirch345
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Re: The RD400 drag bike

Post by sirch345 »

Great stuff Al 8)
Look forward to hearing how things progress :D

Chris.
A closed mouth gathers no foot. :thumbup:
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fabiostar
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Re: The RD400 drag bike

Post by fabiostar »

Top class project. thats gona be fun to ride..........

bin the femsa :eek2 i spent 20 years using them and they are sh1te, good in the day but age inst good to them :thumbup:
the older i get,the faster i was :lol:
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AMCQ46
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Re: The RD400 drag bike

Post by AMCQ46 »

fabiostar wrote:Top class project. thats gona be fun to ride..........

bin the femsa :eek2 i spent 20 years using them and they are sh1te, good in the day but age inst good to them :thumbup:
Good info on the ignition Robert , what did you replace them with?


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ItsaKeeper
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Re: The RD400 drag bike

Post by ItsaKeeper »

Al - my ignition was dodgy on my RD350LC and I got it replaced with a Vape kit. Not sure if that kind of kit is what you are looking for but it's my tuppence worth :plainsmile

https://www.vape.eu/en/yamaha-air-cooli ... t-ignition
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ItsaKeeper
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Re: The RD400 drag bike

Post by ItsaKeeper »

Forgot to add that the RD runs perfectly now, I got it supplied & fitted by Dave Whatham in his Wetherby workshop and he is a great source of knowledge for RDs, I know there are many others but he is my go to person :thumbup:

https://www.muttsnuts2strokes.co.uk/about-mutts-nuts/
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AMCQ46
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Re: The RD400 drag bike

Post by AMCQ46 »

So I had half a day to start fettling the RD.
1st was to get the basics of the rolling chassis working and safe.

Staring to realise it has never been fully assembled in this guise as I am finding all kinds of glaring problems.

Rear spindle wouldn’t fit through the brake side swing arm slots as the powder coating was too thick. Cleaned all the powder coat off the slot and it is a nice engineered fit now.

Front spindle didn’t want to go through the wheel bearings as there was rust on the bearing, so took the bearings out and whoever painted the wheels didn’t bother to mask the brg pockets or the disc mounting face, so that had all to be scraped back to aluminium.
Then new 6004 brgs fitted, I have used shielded bearings as the have less friction than sealed and I won’t be riding in rain and salt.


Then I had a look at the front calliper. Do see anything wrong here? !!!!

Image

And once I split the callipers the dust seals were hanging off and lots of corrosion.
Image


I have cleaned and rebuilt them
Without dust seals. Same reason as above.

Then I had a look at the carbs as I had noticed the choke plungers were seized as it had been put together dry.
Image

Got them out with penetrating oil and gentle heat.

Rear master cyl is also seized, again from being left dry when assembled. I will likely put another master on it rather than rebuild this one.

But I now know that I need to go through everything. . Especially after seeing that brake pad error!


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lloydie
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Re: The RD400 drag bike

Post by lloydie »

Looks like it’s going to be a fun journey building that .
Keep up the good work al
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Duffy1964
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Re: The RD400 drag bike

Post by Duffy1964 »

Great work Al, like you say best to check everything and start from scratch.


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Yellow 1997 Storm R.I.P. Orange 2000 Streetfighter (Rufus), Red & Silver 1968 Triumph Trophy 650, Blue 2003 Storm Project, Red 2007 Montesa Cota Trials 250 & 1959 BSA D7 175cc Bantam Trials Project
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fabiostar
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Re: The RD400 drag bike

Post by fabiostar »

AMCQ46 wrote: Thu May 12, 2022 6:08 am
fabiostar wrote:Top class project. thats gona be fun to ride..........

bin the femsa :eek2 i spent 20 years using them and they are sh1te, good in the day but age inst good to them :thumbup:
Good info on the ignition Robert , what did you replace them with?


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from memory Al i think it was a Hitachi ignition me and the brother started using, much better tho now a days im sure more modern units can be bought, id check on some of the RD forums and see what guys are using these days. RD LC crazy forum has some great brains on it :thumbup: :thumbup:
the older i get,the faster i was :lol:
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