Yamaha RD350 meanderings.

I could probably mill out a few
More bits but they’re light enough already. Moving on, I’ll either start some of the jig fixtures or cut and weld the arms.

Small coda. Considering that aside from the holes, I didn't have to take more than a few MM from any axis, the mess is quite astonishing. My shop vac seems to have shuffled off this mortal coil and it took me at least 20 minutes to do a bad job of sweeping up. If anyone is considering a small mill for projects in the house.....don't! Little fucker is like a glitter factory.

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Little more progress. I cut notches for the bends in the arms. They turned out to be so slender I had to use a die grinder and fine tipped carbide bit to take out material. Seemed to work OK though. They’re just tacked at the moment. After that I put a stop on the mill and cut the holes for the swingarm pivot tube. One more brace to cut and then I probably need to start on the jig.

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I’ve also managed to bag a complete second bottom end, so now the plan is to build a second motor, rather than mess with the current one. Picking it up from a friend in the Bay Area end of Feb when I’m up there.

Aside from the porting / head work I think I’m also going to swap to straight cut primaries because I like the noise and they are easier on the main bearings. Looks like I can use a old YZ250 clutch basket and all I need to do is machine the existing RD centre a bit for clearance.

Again it's all looking so neat. Only realised how much people love these Yamaha RD and LCs recently, they're before my time but seems they have a massive following.

Yeah, I’m probably about the last generation that grew up on two strokes. Even back in the middle 90s I though the aircooled RDs were a bit old fashioned but they were so much more fun that the other four stroke dreck that was around at affordable prices. Cheap speed. The noise, smell and two stroke power definitely stick with you.

Yeah they're well before my time too, doesn't explain the want I've had for an RGV250 for the longest time...

I've been pretty tickled with the idea of a TDR250 lately too...

TDRs are cool! I had a Gen 1 TZR250 for a little bit, which had the same motor. Exceptional power plant, smooth and tractable and it held together well too.

Sold it to a mate, who promptly fell off right in front of me and launched it the wrong way down an M25 off ramp. Fortunately very little damage….

Yeesh. My mate has a TZR250SPR that resides in his spare bedroom. I'm deeply envious. It's not helping my RGV desires in the least bit.

RGVs are excellent - more focused than my TZR and quicker too. So annoying they never made it to the US. They pop up from time to time but at absolutely insane money.

Jiggery pokery….as suspected, trying to square the box section, was boring, messy and time consuming. It’s where you want a massive 5000lb, 5hp horizontal mill, to just go Buuuuuuuuurp once across each side and be done. The central spar is too long to do on my machine, so I will probably shim it to get the ends square. More fixtures to make now to hold the pieces.

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Oof, the near biblical rainstorm has brought any progress to a sharp halt. All my concreting wasn't enough to hold off 12" of rain in 24hrs. The whole back and side wall have opened up again and are pissing water in. Nothing I can do about it except hope that the bloody building doesn't collapse. I'll get some fans going in there to help with the standing water once it stops. Would be nice not to live in such a tumbledown, old shit hole. Still another two months of potential storms after this one though...it's not looking good.

Shit dude, knew you were experiencing Irish levels of rain but fuck didn’t realise you were near getting washed away.

Hope it sits strong and stays the duration

Also because of you the algorithms of instagram keep on showing me lairy 80/90’s 2 strokes.

Not that it’s a bad thing

They are the best kind...

It finally stopped this morning. Not been down to assess yet, even if it hasn't collapsed, it'll be pissing water for days as it's down the hill from the flat and has earth on 2 sides. Depressing.

Loving this thread, subscribed.

Well it hasn't fallen down. Still water pissing through the wall though. I've parked a fan on the worst of it and locked up again. Lathe and mill are slathered in way oil so the extra moisturizing shouldn't be an issue. Fingers crossed we have time for the water to drain before the next storm. Sunny Los Angeles, eh?

https://www.instagram.com/reel/C1bXz_fJh8r/?igsh=MTJ3Ym5mejhvN2dkdQ==

Like this for example

Very bling!

Achingly slow progress on the jig and now another downpour….ho-hum. Need to drill the cross braces for the standoffs and make a couple more inserts on the lathe.

Truly torrential rain again today, forecast to stick around until Wednesday. So much for winter being the project season!

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All bolted in, and squared up, though in a truly DOH! moment, the arms sit 1/8th of an inch too low to weld in the cross brace in front of the pivot. I'll have to machine up some spacers. Whoops.
I fired up the torch and did a couple of test passes for destructive testing. Both held fine, with just a small crack in one after some serious hammer time. Hopefully should go a bit quicker from here.

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Looking a bit more swingarm shaped.

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Nearly there - a small amount of cold setting required. Welding could have been easier, I’m nearly out of O2, so there was a lot of starting and stopping. Now I need to trim the pivot end to dimension, make the bearing carriers and the shock / torque arm mounts. Hopefully the hard work is done.

At the weigh in, it’s currently 2.5lbs lighter than the stocker. Which given it’s an inch and a half longer and considerably stiffer, seems a good result.

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This is a cool project, and your lathe is lovely!

Cheers! It’s a nice old lathe (logan 11”.) I’m not sure if I mentioned it but it started life at JPL. Slumming it with me….