These appear to be the internals of an RD350 1974, taken from another forum. Should be the same as mine ('75).
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Adapting '72 XS2 or '73 TX650 Fork Tubes to the '73-'75 RD350
- Thread starter YamadudeXS650C
- Start date
....and the sequence for the RD350:
And the sequence for the XS2, thanks to Skull.
That ring-ding is looking sharp Dude!!
So, it would seem important to have the dimensions from your nice dial caliper of the two largest (outside) diameter parts of the damper tube, which I put an "X" on in the picture, which I imagine have the same diameter.
Plus, the length and outside diameter of part #7 , if you have it, as seen in the diagram I pictured in post #23.
.
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......and as I see it, the overall length of the damping rod is 21mm, yes?
BTW, Txxs, thanks for sticking with this effort.
txxs
XS650 Addict
some more dimensions:
The piston (Item 7) is the same for both 73 TX650 and 73 RD350.
Actually I haven't used these callipers since 1984 I think.
txxs
XS650 Addict
The crown for the RD350 is a "clamp" style similar to the TX650 (whereas the XS2 is not).
Just guessing I think the easiest thing to do would be let the inner tubes rise above the RD350 crown and use TX650 caps.
You could modify the length of the spacer above the spring.
Just guessing I think the easiest thing to do would be let the inner tubes rise above the RD350 crown and use TX650 caps.
You could modify the length of the spacer above the spring.
Now we are really getting somewhere !
Thanks for cross referencing the piston; that is good news.
So, you haven't used your calipers, much; do you trust the accuracy of the instrument?
.
The caps for the RD, TX and XS2 all have the same last seven numbers [ xxx-23111-60 ]. Can we assume that all three of these models use the same caps?
txxs
XS650 Addict
Although there might be some subtle diffferences, there are a number of fork caps being sold on EBay which are noted as (basically) fitting a number of models, although the RD350 is not one of them. This suggests that I would be up against buying new or used ones.
Notes Year Make Model Submodel
1972 Yamaha DS7 250
1970 Yamaha R5 350
1971 Yamaha R5B 350
1972 Yamaha R5C 350
1974 Yamaha TX650 Twin
1973 Yamaha TX650 Twin
1971 Yamaha XS1 Twin 650
1970 Yamaha XS1 Twin 650
1972 Yamaha XS2 Street Twin 650
Notes Year Make Model Submodel
1972 Yamaha DS7 250
1970 Yamaha R5 350
1971 Yamaha R5B 350
1972 Yamaha R5C 350
1974 Yamaha TX650 Twin
1973 Yamaha TX650 Twin
1971 Yamaha XS1 Twin 650
1970 Yamaha XS1 Twin 650
1972 Yamaha XS2 Street Twin 650
One key difference I see in the pistons is that one of them has 8 holes and the other has 12 holes.
That could have a significant effect on the damping provided by the forks - depending on the other characteristics of the oil passages in the forks.
Pete.
That could have a significant effect on the damping provided by the forks - depending on the other characteristics of the oil passages in the forks.
Pete.
damping rod mods are popular at the RD sites. There are threads detailing drilling more holes, as well as welding some shut, as well as adding emulators (adjustable valves).
Again, I'd have to see the parts up close to tell for sure, but my instincts are that:
Pete
- more/larger holes = weaker damping force and,
- fewer/smaller holes = stronger damping force.
Pete
txxs
XS650 Addict
I wouldn't believe half the stuff on eBay.
The fork caps are different because the crown is different.
The tube can slide through the steering crown with the 73 TX650 and RD350.
The tube can't slide through the steering crown with the 72 so you can't use the 73 TX650 cap with a 72 steering crown.
The RD has a similar style crown to the TX650 where the tubes can slide through.
If your fork tubes extend above the crown you can use any type of cap you like so long as the thread is correct.
I only suggest the TX650 cap as it will look better as it is designed for that type of arrangement.
As to the re-chroming option, not knowing of that service before seeing Mr. Bultaco's link either, I inquired with the folks at United Surface Finishing about the inners for my XS1B project. For stripping, prep, hard chrome and polishing their quote was $300 w/15-20 day turn around.
Factor in shipping both ways and you're right back in the same neighborhood of Frank's $350+shipping for new tubes.
Factor in shipping both ways and you're right back in the same neighborhood of Frank's $350+shipping for new tubes.
