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1971 R5/RD Hoyt-Clagwell vintage race kit street racer

Started by irk_miller, January 21, 2023, 07:25:27 PM

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I have a vintage race fairing i acquired amongst all the RD stuff that became the liquid 75 I finished last year.  This kit raced in the early 80s by privateers from Mid-Ohio area.  They matched it with an RD400 glass tank and 60s Honda glass race seat.  Both are on the LC RD.  The radiator kept the kit off that bike, so I set out to find another frame to build around this fairing with.  Last weekend, I headed to Brunswick, GA to pick up the R5 frame.  Pretty neat deal with this frame is it shows a 7/71 manufacture date.  My birthday is also July 71, so now I have my first birth day bike.  Expect something in the way of the RD 350/400 tank and TZ twin shock seat Airtech makes. 

I have most of what I need to piece together an engine, but I need to double check if it's RD250 bottom end.  I definitely have a 350 crank and a complete 350 transmission in addition to that bottom end.  This will stay air cooled, but pistons and bore are tbd.  I have stock LC pistons left from when I robbed the LC top end, but that's all.

I would love to be as close to era specific on this build, as far as can be done with a stock frame and lights.  I've seen Teazer post about using FZ400r forks, but they're hen's teeth in the US best I can figure.  Only other front ends I have are EX500 and Katana traditional fork front ends.  I do not have an RD front end, so if I go that route having to buy a set would factor into the price of making them as modern as possible.

m in sc

fzr600 lowers and fj? 600 uppers are what are on my hybrid. but, tbh, stock forks with emulator valves work really well. .02


41mm conventional Katana forks are suitable if a bit heavy and look right.  I have a pile of forks and weighed a bunch of them a while ago which is why I became a big fan of the FZR400 forks. They are very thin wall and much lighter than any other conventional sets I could find including RD and TZ forks.

With RD/TZ forks, there's not a lot of difference.  Damper rod designs are better on a TZ but I have seen sets modified to work more like an RD and with modified foot valves and so on.  The set of TZ forks I have was revalved by 4&6 racing years ago and what they did was to braze fill the damper rod holes and re-drill them.  Rinse and repeat until felt right.

Later RD forks are 35mm and are a slightly better design than earlier designs but a set of Mike's XS cartridge emulators is all you need to make them work. 

For that bike, I'd keep it period as far as looks and use conventional forks. preferably not to chunky though. XS650 or TX750 forks will also work.

m in sc

fwiw, the 35mm fork emulators from mikes fit right in the 34mm rd forks. :toot:


I like to use RaceTech adapters with seals to provide a better fit and to allow for oil flow around the adjuster lock nut.

That's good to know that for an RD they are a well priced alternative to Racetech or YSS.


Quote from: teazer on January 27, 2023, 02:25:31 PM

For that bike, I'd keep it period as far as looks and use conventional forks. preferably not to chunky though. XS650 or TX750 forks will also work.

I have what I'm pretty sure is a 77 XS650 front end on a DT frame in my barn. The wheel in the pic is an RD wheel, so I would just need to figure out the axle, caliper and rotor to run it.