My R5 project has RD350 crank cases and transmission, with R5 stator/ignition timing.
My question is how do I tell the difference between an RD and R5 cranks?
i think the r5 crank is slightly heavier on the flywheels (that's hearsay, i never measured), but they are interchangeable.
So there is no telltale sign? Bummer.
No difference between R5 and Rd cranks 250 or 350.
Quote from: m in sc on November 02, 2019, 08:58:12 AM
i think the r5 crank is slightly heavier on the flywheels (that's hearsay, i never measured), but they are interchangeable.
Correct.
Thicker and heavier.
I have a special press plate I made to do R5 cranks.
C
Quote from: Brad-Man on November 02, 2019, 10:53:33 AM
No difference between R5 and Rd cranks 250 or 350.
Incorrect.
See above...
I'll find one and post measurements of the flywheel thicknesses.
Chuck
I'm trying to get some parts together to ship to you Chuck.
Do you have the thickness of either flywheel?
I'm trying to decide if I should send you my crank.
Here's what was inside my bike.
After texting back and forth we have detremend Bill has a RD350 bottom end and not a purebred R5 engine.
So he has a RD crank not a R5 crank.
I've tried to find a R5 crank at my shop, but can't fine one to measure.
Chuck
I think I have a R5 crank in my crankshaft spares box. I'll check later today and if so, will post the info.
Lyn Garland
From a practical point of view are there any real differences or reasons to prefer one rather than the other?
I couldn't see any differences between the R5C parts book and RD350B list. Maybe earlier R5s or later RDs had different parts.
You guys (Supertune & Yamaha 179)helped me through this way back when on the old site! I had the same question!
The R5 cranks are heavier with thicker webs. Critical dimensions are the same - thus they are interchangeable.
The "connecting rod gap" - don't know the formal term- is smaller on the r5 crank (thicker webs) by about 1mm.
The r5 webs are about .5mm thicker. I have 1 of each. The r5 measures 21.4mm (roughly) and the rd is around 21.05 (roughly)
As has been concluded - it appears you have an RD crank.
I guess it comes down to what is the benefit of spinning a lighter crank?
Unfortunately the cranks exceed the limit of my small scale so I can't get a weight difference.
Pics on my phone are too large to upload....
Very interested in this - if the heavier R5/DS7 crank makes a difference in performance. I just bought my next project bike (a DS7) and the crank is likely bad from sitting without plugs in the top end. If I go replacing it...
Chuck (SUPERTUNE) has my core crank. Hit him up.