Good Morning all!
New to the forum. Have been looking at old posts but can seem to find exactly what I'm looking for to help with my new addition.
I recently bought a 75 RD350 without a front end. I am looking to build a dirt track racer and was wondering what fork swap would be the easiest/best to do on an RD. I want to run a 19" spoked front wheel and have been searching the forum.
I don't need a front brake.
From what i have learned from the forum and others.
R6 pre inverted is a common swap.
97-00 GSXR600 will also work.
I was on all balls racing fork conversion website:
https://www.allballsracing.com/forkconversion/
And determined that both the RD and GSXR have:
TOP bearing : ID 25 OD 48 WIDTH 13
BOTTEM bearing: ID 30 OD 48 WIDTH 12
I also know that the GSXR has a 25mm front axle which would allow me to use the front wheel i was looking at using.
Was wonder what fork swaps have been done and what work is required to complete the swap.
Thanks again,
I can tell you that I am putting a '97 GSX-R600 front end on my '75 RD350 and bought those bearings from All Balls. The bearing kit came with two spacers and a dust seal; it's too early to say for sure, but it appears to be plug-n-play. Steering stops will need to be modified, but everything else appears to be falling into place.
Thanks 85RZwade. I read your post on here. I was also talking to a guy that has an RD250 dirt tracker. He has 2006/2007 GSXR 600 upside down front forks on his RD and he also said that the conversation was basically bolt on. He stated that he did have to make some spacers for the top as the stem is longer. I want to go with the 1997 due to the 25mm axle.
When I put USD forks on my 73 I just used 2 RD bottom stem bearings and made 2 spacers out of the old bearings that came with the new stem.I make new steering stops, but Cognito Moto makes a sweet adjustable set. new ignition switch and instrument brackets and add a magnetic pickup for my digital speedo as there is no cable drive in my setup.
Why do you want to run a 19"front?
rodneya,
They only sell dirt track racing tires in 19 inch. However you could go with an 18 and run a dunlop k180, but i like the look of 19's front and rear. What USD forks did you use?
i used an fzr600 one, same stem as an r6. i also used spacers on mien to make it work way years ago though. have you considered ktm forks? some if the indian guys have used them i think.
Quote from: 4schizzle on December 02, 2021, 10:40:02 PM
rodneya,
They only sell dirt track racing tires in 19 inch. However you could go with an 18 and run a dunlop k180, but i like the look of 19's front and rear. What USD forks did you use?
07 GSXR 600 / 750 forks with a spoked hub from Cognito Moto. Currently 18", but probably going to switch to 17" next year when my other project is finished.
Quote from: m in sc on December 02, 2021, 10:42:26 PM
i used an fzr600 one, same stem as an r6. i also used spacers on mien to make it work way years ago though. have you considered ktm forks? some if the indian guys have used them i think.
m in sc. Are you talking about the current indian twins using ktm forks? which ktm fork are they using in the indian? off a dirt bike or one of their street models?
Just another question. The rd 400 swingarm is longer correct? Does anyone know how much longer than a 350 swingarm?
Or are there any good swingarm swaps?
I am also planning on running a 19 on the rear and from talking to another guy the 350 swingarm needs to be extended at least an inch.
400 swingarm is an inch longer.
the ktm forks ive seen used are 390/200/125 duke forks on the indian rd's(radjoot). I had a 390, the forks would be great for an 'offroad' version of an rd. I man, anything can be made to work just depends on the fabrication ability.
Quote from: m in sc on December 03, 2021, 10:10:41 AM
400 swingarm is an inch longer.
the ktm forks ive seen used are 390/200/125 duke forks on the indian rd's(radjoot). I had a 390, the forks would be great for an 'offroad' version of an rd. I man, anything can be made to work just depends on the fabrication ability.
That makes sense now. I was thinking the new Indian twins. I'm an offroad 2 stroke guy but new to the street bike 2smokes. What you said is true, you can make anything work if you have the ability.
That really helps knowing the 400 is an inch longer. Thanks
Well i got the 97 GSXR fork off a friend and the bearings are ordered so we can see how this goes.
I read on economy cycle that when you switch the steering head from conical to tapered rollers the outer races are a little higher.
Thanks again for all the help.
Quote from: rodneya on December 02, 2021, 11:52:11 PM
Quote from: 4schizzle on December 02, 2021, 10:40:02 PM
rodneya,
They only sell dirt track racing tires in 19 inch. However you could go with an 18 and run a dunlop k180, but i like the look of 19's front and rear. What USD forks did you use?
07 GSXR 600 / 750 forks with a spoked hub from Cognito Moto. Currently 18", but probably going to switch to 17" next year when my other project is finished.
rodneya,
I see that both 07 and 97 GSXR steering head bearing are the same size. upper: 30-48-12 lower: 30-48-12. So you used the RD conical bearings on the top and bottom. I am going to check out Cognito Moto. Thanks again.
Next i need to split the cases and get it running. Do i need a tool to split the cases. I have the tool for a yz 125/250. Do i need to make a new post for this?
Thanks again all!
Top and bottom split cases, so no special tools necessary. Just patience cause they can sometimes be stuck together pretty well.
make sure you pull the bearing retainer plate off behind the clutch basket before you split the cases. .02
oh gawd Mark no kidding, one good pry and you'd need case halves.... gives me the heeby jeebies.
I alway's link to this for the first time motor rebuilds, cause it really helped me.
https://www.aircooledrdclub.com/smf/index.php?topic=25398.0
Quote from: Striker1423 on December 05, 2021, 11:02:32 AM
oh gawd Mark no kidding, one good pry and you'd need case halves.... gives me the heeby jeebies.
I alway's link to this for the first time motor rebuilds, cause it really helped me.
https://www.aircooledrdclub.com/smf/index.php?topic=25398.0
Thanks for a the info. I'm sure when I split the cases i will need some more help. The bike has been stored inside for the past 45 years. It turns over and has compression. The skirt of one of the pistons has some scratches that you can grab with your fingernail. Need to pull the cylinders off and take a look.
Thanks for the link to the motor rebuild.
You will want to split anyway to replace the old crank seals.
Quote from: RDFL on December 06, 2021, 02:45:53 PM
You will want to split anyway to replace the old crank seals.
yup. do it now or regret it later.
Quote from: RDFL on December 06, 2021, 02:45:53 PM
You will want to split anyway to replace the old crank seals.
That's what i was thinking as it has been sitting for years and I'm sure they are hard and leaking.
Any good rebuild kits out there for the RD's? Or what brands of parts to buy. I see that Yamaha still sells a lot of the parts.
Thanks
Seals and gaskets? Yamaha if possible. Economy Cycle sells them and can hook you up with all you will need.
:stupid-1:... I mean, :agree:! Definitely Yamaha for seals and head gaskets, but I'd feel OK about other gaskets from reputable aftermarket suppliers.
Quote from: 85RZwade on December 02, 2021, 03:52:14 PM
I can tell you that I am putting a '97 GSX-R600 front end on my '75 RD350 and bought those bearings from All Balls. The bearing kit came with two spacers and a dust seal; it's too early to say for sure, but it appears to be plug-n-play. Steering stops will need to be modified, but everything else appears to be falling into place.
85RZwade got mine mounted. Looks to close to plug and play. You were right
Quote from: 85RZwade on December 02, 2021, 03:52:14 PM
I can tell you that I am putting a '97 GSX-R600 front end on my '75 RD350 and bought those bearings from All Balls. The bearing kit came with two spacers and a dust seal; it's too early to say for sure, but it appears to be plug-n-play. Steering stops will need to be modified, but everything else appears to be falling into place.
Top shelf! It seems you've passed me around the outside; I'm still playing around with wheel spacers.
What hub is that?
What's your plan for the steering stop(s)? I think I'll weld an extension onto the frame stop.
Love to see your progress :thumbs:
Quote from: 85RZwade on December 19, 2021, 10:08:44 AM
Top shelf! It seems you've passed me around the outside; I'm still playing around with wheel spacers.
What hub is that?
What's your plan for the steering stop(s)? I think I'll weld an extension onto the frame stop.
Love to see your progress :thumbs:
2008 and up or sportster or dyna. They have a 25mm axle. I don't need a front brake to flat track. I know that Harley is a bad word here, but I built a ironhead sportster to flat track and knew the axle sizes. When i seen in your post about the 99 gsxr had a 25mm axle i knew that wheel i was using.
With the sportster/dyna hub you have 21/19 options. Or probably more.
I am just going to weld an extenstion on the fork stop. Need to get a tank first.
I also ordered a top triple clamp from cognito moto with bar mount for 1 1/8 bars. I will mount and post pic.
What are the best reeds and intakes for my rd350?
Thanks
:omg: you might as well have asked about religion, politics or the dreaded two stroke oil! Brace for impact. I went with OEM Yamaha YZ85 cages and TDR reeds; cages are cheap and plentiful on eBay and require very little modification to the cylinders to fit.
Late to the convo, but I'm running CB900f forks with progressive springs, emulators and nitrogen charge, plus a Radian swing arm on my RD350.
Pictures, man, push-leez! Was the Radian 'arm a direct fit?
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.
(https://www.dotheton.com/index.php?attachments/6abba3df-e130-4587-a2b7-d82650dac76c-jpeg.235018/)
Lovely! Those rims look super-wide and I like it :thumbs: What are those footpeg/pipe hanger brackets from? Sorry 4Schizzle :jacked:
this is my bikes long lost brother, i swear. all very similar. :olaf:
I suggest a family reunion!
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.
(https://www.dotheton.com/index.php?attachments/6abba3df-e130-4587-a2b7-d82650dac76c-jpeg.235018/)
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.
Iam liking it !
Update on fork install.
Update
What are those forks from?
Looks the part, no doubt.
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.
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.
the 35mm valve from mikes xs or racetech will drop right into a set of 34mm forks as well, just fyi. :twocents:
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
yup :gentleman:
thx
good to know
I'm almost reaching the start of the reactivation of my poor old caferacer based on a RD 350 model 351.I put in a fork of the first RD 400 after my last heavy crash with it.The rest of it are common mods of those old times.Tomaselli clipons and lampholders,R5 tank,Raask rearsets and a selfmade one piece seat/backcover.Engine almost stock.
I parked it many years ago after a piston gave up.At those times it was difficult to get parts at all and I started parallel to work as professionell mecanic for motorcycles.
So I did turn a lot of screws combined with the daily test flights which are a must over here for the mec who did the job on the bike.
So my RD got sort of forgotten.
If I make it I will let you guys here have a look at the reactivation job
do it!
:whoop: