Yamaha rd350 Road Racer Liquid Cooled!!

sav0r

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Re: Yamaha rd350 road racer

Make sure you put your old steel rims on scale to compare to those shouldered set. Some shouldered rims can be damned heavy and those old steel units aren't as heavy as you might think. Tires of course make up the major rotating mass there, but every little bit helps.
 

Hurco550

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Re: Yamaha rd350 road racer

Sav0r said:
Make sure you put your old steel rims on scale to compare to those shouldered set. Some shouldered rims can be damned heavy and those old steel units aren't as heavy as you might think. Tires of course make up the major rotating mass there, but every little bit helps.
I'll look into that when I get them un laced, they were heavier than I expected when I picked them up. Bad thing is the steel hoops are in pretty shabby condition.

Thanks!
 

Hurco550

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Re: Yamaha rd350 road racer

Not a huge update, but I made up an arbor to do my squish machining when that time comes. I have yet to put an indicator on it to see if the plug holes are centered, as I've read that sometimes they aren't. I also still have to take a light mill cut off of the spark plug surface to make sure that it is true with the gasket surface before doing any machining.

I used a buddy's lathe to make the arbor. He is tooled up a bit better than I am at the moment, plus his lathe has a dro, which makes everything easier.







I'll use my South Bend 9 when the time comes.


Didn't think about clearance of the bed, but I have a half inch, which is about a mile in machinist terms, so it's all good.
 

teazer

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Re: Yamaha rd350 road racer

That is looking very professional. I need to get my machinist to make an arbor for our nexyt project to do exactly what you are doing there.
 

Hurco550

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Re: Yamaha rd350 road racer

THANKS! I used a stud drilled and tapped into the arbor instead of single point threading. Luckily my buddy is a mechanic and had a 14mmx1.25 tap on his service truck and a harmonic balancer bolt of the same size and thread pitch to rob for the threaded lug.
 

Hurco550

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Re: Yamaha rd350 road racer

Again, not a ton to update, but I did get the tapered neck bearings fitted.



Xs650 forks mocked up. They are about 2 inches longer than the Rd units, so they have to go up through the top tree a bit. I thought about flipping the top tree upside down, but that looks pretty goofy.


What's you guys advice on the steering damper? Worth keeping? Not worth keeping? Does it even make a difference?
 

irk miller

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Re: Yamaha rd350 road racer

Put that damper on your camera :eek: whooooooaaaahhhhh :-[
 

Hurco550

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Re: Yamaha rd350 road racer

Question on top triple design. Planning on making my own as I don't feel like dropping $235 on this one. I've seen a few like this with the steering stem pinch bolt deleted. How crucial is it to performance/ fork flex ect to keep it intact?
 

irk miller

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Re: Yamaha rd350 road racer

Doesn't matter a whole lot. Matter of fact, you can overtighten the top nut and adversely affect the bearings. The nut below it, plus the fork tube bolts are doing all the work. A top nut over it is all that's necessary. The bottom triple is more important. The stock R100 top triple I removed was nothing more than 4mm thick piece of plate cut into the shape of a triple.
 

Hurco550

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Re: Yamaha rd350 road racer

Ha, I just put them on like the stock Rd was. Oops.


Chances are I'll use the Rd lowers anyways. I'm only using a single rotor. That should be more than enough stop.
 

jpmobius

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Re: Yamaha rd350 road racer

As far as I remember, 1975 and earlier had the calipers mounted in front, and later years had them behind. Behind is much better - especially if running dual discs. Those iron calipers are heavy! I don't think there are any issues to swapping the assembly around, the wheel and spacers and speedo drive need to be kept as they are so the speedo will work - just the axle will have to be flipped with the forks. Not important of course if you won't be using the speedo.
 

Hurco550

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Re: Yamaha rd350 road racer

deviant said:
Doesn't matter a whole lot. Matter of fact, you can overtighten the top nut and adversely affect the bearings. The nut below it, plus the fork tube bolts are doing all the work. A top nut over it is all that's necessary. The bottom triple is more important. The stock R100 top triple I removed was nothing more than 4mm thick piece of plate cut into the shape of a triple.
That's kinda what I figured, the only thing that worried me was the fact that in most cases Yamaha wouldn't put a useless piece of mechanical hardware on if they didn't have to. I remember my buddies top triple on his beamer was just flat plate with bolts as you described as well.

Thanks
 

Hurco550

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Re: Yamaha rd350 road racer

jpmobius said:
As far as I remember, 1975 and earlier had the calipers mounted in front, and later years had them behind. Behind is much better - especially if running dual discs. Those iron calipers are heavy! I don't think there are any issues to swapping the assembly around, the wheel and spacers and speedo drive need to be kept as they are so the speedo will work - just the axle will have to be flipped with the forks. Not important of course if you won't be using the speedo.
Good to know! Planning on running a single fzr rotor with some kind of modern 2 piston caliper. Should be plenty for as light as I'm hoping this bike will end up. I was contemplating running the caliper behind anyhow. I don't know, but the extra stopping ability makes me nervous as far as pulling on the mount tabs.seems like pushing would be better, but on the same coin I've never seen any brake off. May be over thinking it, but I don't know if there is any benefit performance wise to shifting the weight of the caliper back vs. Front?

Still undecided on a speedo as well. Kinda planning on a tach only with a cell phone mount if I'm curious about my speed =p
 

irk miller

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Hurco550

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Re: Yamaha rd350 road racer

deviant said:
These are what I like to use for double pot adaptations. I've used them on four bikes so far. They're cheap, easy to adapt, and plentiful. There's always a bunch on eBay without hardly a nick. Suzuki used them on a bunch of their motorcycles...

here http://www.ebay.com/itm/2003-03-Suzuki-gsx600f-front-left-brake-caliper-oem-98-06-katana-2-piston-tokiko-/302033064893?hash=item465292d3bd:g:XN4AAOSwdj9XT7zZ&vxp=mtr

Cool thanks! Link is invalid though, is that katana?
 

jpmobius

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Re: Yamaha rd350 road racer

hurco550 said:
Question on top triple design. Planning on making my own as I don't feel like dropping $235 on this one. I've seen a few like this with the steering stem pinch bolt deleted. How crucial is it to performance/ fork flex ect to keep it intact?
It does have some value, though I can't say how much. Clamping the top tree to the steering stem to lock it to the lower tree unquestionably stiffens up the assembly - imagine assembling just the upper and lower together and twisting the two trees against each other. Much more rigid than just clamping down with the upper crown nut. Most old bikes can have the whole front end twist pretty easily. Loosen the triple tree pinch bolts and stand astride the front wheel and clamp the wheel between you knees and twist the handlebars. Big difference when the pinch bolts are tight of course.
 
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