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1975 Yamaha RD350 fork swap

Started by 4schizzle, December 02, 2021, 10:53:15 AM

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irk_miller

Quote from: 85RZwade on December 26, 2021, 08:56:19 PM
Pictures, man, push-leez! Was the Radian 'arm a direct fit?

Full disclosure:  It hasn't been off the bench yet, so no idea how the extra length will play, but I always felt the RD was short.  As wild as this bike is ported, I wanted a longer wheelbase.  It's a direct swap, as far as frame fit.  I adds angle to the shocks, so you have to go longer and compensate for extra angle on spring rate.  I'm running CB700SC shocks.


85RZwade

#31
Lovely! Those rims look super-wide and I like it  :thumbs: What are those footpeg/pipe hanger brackets from? Sorry 4Schizzle  :jacked:
I post waayyy too much

m in sc

this is my bikes long lost brother, i swear. all very similar.  :olaf:

85RZwade

I post waayyy too much

4schizzle

Quote from: irk_miller on January 02, 2022, 01:58:51 PM
Quote from: 85RZwade on December 26, 2021, 08:56:19 PM
Pictures, man, push-leez! Was the Radian 'arm a direct fit?

Full disclosure:  It hasn't been off the bench yet, so no idea how the extra length will play, but I always felt the RD was short.  As wild as this bike is ported, I wanted a longer wheelbase.  It's a direct swap, as far as frame fit.  I adds angle to the shocks, so you have to go longer and compensate for extra angle on spring rate.  I'm running CB700SC shocks.



That bike looks good.  I am going to try to do a xs 400 swingarm on my RD.  Its about 2 inches longer as i need it to fit a 19 inch rear wheel. 

TPR5


4schizzle

Update on fork install.


4schizzle

Update

teazer


4schizzle


irk_miller


Vintagetz

For a period performance upgrade the 1979 and 1980 RD400 35mm forks are the easiest to improve internally.  The RZ350 emulators are a direct fit, the only other modification is to drill out the existing compression holes to .312 or 8mm and add one more set.   If anyone wants details feel free to contact me.  I ran a TZ front end with RD400 inner tubes and damper rods, and race tech emulators.  I can offer advice on spring rates, in the race bike I run straight wound that might be a little harsh on the street.

teazer

That's basically what I did on a TZ350E IIRC.  I had a late model A/C 250 or 400 back in Australia that i grabbed the parts from.

I also had a set of TZ forks re-valved years ago and it took the suspension guys for ever to get them within the ballpark of what might be considered OK by modern standards. 

That set will go on the Spencer replica with Champion frame, but if I were to build a street RD again, I think I'd fit a set of FZR400 forks.  They are so light compared to almost anything else out there.

m in sc

the 35mm valve from mikes xs or racetech will drop right into a set of 34mm forks as well, just fyi.  :twocents:

manicmecanic

Hi M in SC

are these the parts you mentioned ?

https://www.mikesxs.net/yamaha-xs650-damper-valve-pr-front-forks-77-84-oem-1t3-23170-00-00.html

If so,would they fit also in a fork of the first RD 400 which had the same diameter/34 mm as the first RD models ?
Asking because I'm told that these 400 forks were different inside from those pre 1976

               
                    greets    Richard