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Another One.. 2Cyl 2-Stroke Content
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Author:  95naSTA [ Tue Sep 20, 2016 12:10 am ]
Post subject:  Another One.. 2Cyl 2-Stroke Content

Lately I've been into the idea of having a 2-stroke street bike with the whole café thing going on.. Early Yammie RD350s specifically. But, I think I would feel bad about messing with one of those and not doing a resto to it..

Cruising Craigslist I found the RD250's predecessor a '72 DS7 nearly complete but with a seized engine for $350.. It was about an hour and a half away but right near where a couple of my buddies were headed (with truck) last weekend anyway. I didn't even have to go.. lol. My buddy talked the guy down to $250 since the inner fork tubes were pitted and a carb was missing and now it's in his backyard because I literally have no place to put it. But at that price, I'll figure it out later.

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It's definitely out of a barn, a bit rough, but should fit the bill.

The short term plan is to swap in a 75 RD250 engine/trans (6 speed!) setup I purchased below, strip down unnecessary parts -turns/crash car etc., chain/gears, tires, battery, and everything necessary to just get it going safely.

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Long term plan is to swap on a 350 top end, clubmans, paint, seat, suspension, etc.

I like the idea of starting with this barn find, sold for parts only, then just doing whatever I want to it knowing it's better than it's previous fate.

For point of reference a RD250 will get up close to 100mph, a 350 over it, and they're mid and low 14 sec bikes respectively. Not rocketships but awesome for early 70s and that displacement.

Registering won't be an issue since I'll do the same thing I did with my DT. And I'll probably let the DT go if I find someone willing to buy it for a decent price.

Author:  Sirius [ Tue Sep 20, 2016 10:14 am ]
Post subject:  Re: Another One.. 2Cyl 2-Stroke Content

Because you can never have enough projects. :lol:

I'll be watching to see what you do about the pitted stanchion tubes on the forks - seals aren't fond of defects in the plating.

Author:  95naSTA [ Tue Sep 20, 2016 11:22 am ]
Post subject:  Re: Another One.. 2Cyl 2-Stroke Content

The right number of bikes is always n+1 right?

At first glance I'm having a tough time finding replacement inner fork tubes or DS7 forks.. I'm still not sure if I should just hold out until I find a 350 front end and have a front disc brake as a result.

Author:  Sirius [ Tue Sep 20, 2016 4:44 pm ]
Post subject:  Re: Another One.. 2Cyl 2-Stroke Content

Indeed.

Pitting from rust on the fork stanchion tubes is rather common on the old 70's bikes. I don't know if there's a vintage supplier out there that could source new/reconditioned tubes for that particular machine or not. I wonder if there's a way to clean them up, fill in the pits, and have them replated? Sounds like a job for...the internet.

Author:  95naSTA [ Fri Oct 21, 2016 6:47 pm ]
Post subject:  Re: Another One.. 2Cyl 2-Stroke Content

The forks actually turned out to be seized. I guess I needed new ones either way though.

I spend a few hours breaking the bike down to a roller today and degreasing/assessing the frame. There's some light surface rust here and there so next on the hit list is to sand then paint the frame and swing arm.

No barn find would be complete without some squirrel's stash:
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Engine out
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Degreased
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Tank and seat back on for S&G
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I think I'm going to stick with all the stock yellow painted pieces and focus on everything else. Seat, bars, shocks, forks, will all get replaced another with the other necessary wear items.

Author:  Sirius [ Mon Oct 24, 2016 10:50 am ]
Post subject:  Re: Another One.. 2Cyl 2-Stroke Content

That should keep you busy for a while.

Author:  96 SSEi [ Mon Oct 24, 2016 4:41 pm ]
Post subject:  Re: Another One.. 2Cyl 2-Stroke Content

cool find!!

Author:  95naSTA [ Mon Oct 24, 2016 6:59 pm ]
Post subject:  Re: Another One.. 2Cyl 2-Stroke Content

Thanks! Ive got some parts ordered. Going CDI, no battery, detabbing the frame and hiding the 2 stroke oil tank.

Might as well right?

Author:  95naSTA [ Thu Nov 10, 2016 8:57 pm ]
Post subject:  Re: Another One.. 2Cyl 2-Stroke Content

Here's a little more progress.

I installed the '75 engine and Powerdynamo so I can start mocking stuff up. I found that I have enough room to mount that new coil and reg/rec in place of the old coils. This will give me plenty of room for an oil tank under the tank and seat.

The coil is mounted good with stand off spacers i made from bar stock. The reg/rec need a revisit.

I roughed up a pan that I'll likely integrate an oil tank into and also started detabbing.

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Once everything is mocked up and I'm happy with it, I'll strip it back down to have the frame and rear swing blasted.

Author:  95naSTA [ Tue Jun 27, 2017 9:43 pm ]
Post subject:  Re: Another One.. 2Cyl 2-Stroke Content

Mini update on this guy.

I was going to finish de-tabbing the frame then completely disassemble it for powercoat. I decided instead to get it together and running before the end of the summer. I'll get it running as a 250 then do the 350 swap when I take it all back apart.

I spent a couple hours this past weekend messing around with it, installing clubmans.. which will get cut down, new throttle and clutch cables and trying to assess what else I need.

About a month and a half ago I ordered Jim Loma's expansion chambers. See 1st pic below. They should be shipping from the UK this week.

Andd I finally mailed the VT registration, same as my DT175. There was some talk of that avenue not working anymore but I guess I'll find out.

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Author:  Sirius [ Wed Jun 28, 2017 9:13 am ]
Post subject:  Re: Another One.. 2Cyl 2-Stroke Content

When I saw the black bike above I thought "Holy crap, what a transformation!". Then I scrolled down to see there's still a little more work to do. :) The potential is there, though.

Two forever stamps? Trying to get it there twice as fast? :poke:

Author:  95naSTA [ Wed Jun 28, 2017 8:39 pm ]
Post subject:  Re: Another One.. 2Cyl 2-Stroke Content

Sirius wrote:
When I saw the black bike above I thought "Holy crap, what a transformation!". Then I scrolled down to see there's still a little more work to do. :) The potential is there, though.

Two forever stamps? Trying to get it there twice as fast? :poke:


Haha. I thought it might throw someone. That bike is a beaut.

With 3 pages, 3 4x6" pictures and a check it was just over an oz. Going by the 1 forever/oz rule I decided to play it safe.

Author:  95naSTA [ Sat Jul 08, 2017 11:14 pm ]
Post subject:  Re: Another One.. 2Cyl 2-Stroke Content

Pipes came in. Works of art as far as I'm concerned. I had to cut the center stand mount off to fit and I'll need to mess with the kick stand as well. Not too big of a deal. What sucks is I have nice rear sets coming that take the place of the rear foot peg brackets that are currently holding up the exhaust in the rear. I'll probably just design a new bracket and have it water jetted.

Pod filters, and some other stock bits went back on too.

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Author:  Sirius [ Mon Jul 10, 2017 9:40 am ]
Post subject:  Re: Another One.. 2Cyl 2-Stroke Content

Good thing the suspension doesn't have any more travel than it does...and I'd avoid any speed bumps! :lol: Those expansion chambers are cool, though. I'm guessing they're designed to improve high RPM performance? They've got some long stingers when you add the mufflers in...

Author:  95naSTA [ Mon Jul 10, 2017 9:58 pm ]
Post subject:  Re: Another One.. 2Cyl 2-Stroke Content

On the suspension.. RD250/350 rear shocks are 320mm. I'm guessing my DS7 is similar or less due to age. A lot of people go to the RD400 shock length of 340mm and I'll probably follow suit. The forks are likely an inch lower than they should be too. I took the one cap off and didn't put a spacer back in. I have forks with nice stanchions already.. I just need to get them on there.

So, I'll likely have about an inch more on something not wanting to compress as easy. But, either way I completely agree it'll take some caution not to dink these up.

From what I've seen the powerband is from like 8-11k. So it's up there. And honestly they're for the RD350 not my current 250 engine. So the powerband will likely be even more of a light switch. I plan on doing the 350 swap when it comes back apart.

Author:  95naSTA [ Fri Jul 14, 2017 11:00 pm ]
Post subject:  Re: Another One.. 2Cyl 2-Stroke Content

Good news - this thing is registered and plated through Vermont now.

My rear sets came in. As mentioned before I'm planning on having new brackets water jetted with ears for the Jim Lomas pipes to bolt up. I drafted the current brackets, printed 1:1 and made sure they match up. Next is measuring and testing for the exhaust ear.
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Author:  95naSTA [ Sat Jul 15, 2017 10:04 pm ]
Post subject:  Re: Another One.. 2Cyl 2-Stroke Content

I transposed the stock rear foot peg bracket (black line) over the new (red line), combined in CAD and printed to check. It's good to go. The file is emailed out and I'll be getting new brackets soon. :)

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Author:  95naSTA [ Sat Jul 22, 2017 8:27 pm ]
Post subject:  Re: Another One.. 2Cyl 2-Stroke Content

New rearset brackets will come next week.

I had to heat and bend the crap out of the kickstand and relocate the spring tab to get it to fit with the expansion chambers. I preheated the kickstand before welding since it's cast.. It makes the bike lean a good bit but it should be ok. I can always through something under the stand. I have to do that on asphalt with my Ducati anyway.

https://youtu.be/EXDpzEJBWDQ
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Author:  95naSTA [ Sun Jul 23, 2017 7:00 pm ]
Post subject:  Re: Another One.. 2Cyl 2-Stroke Content

Well, today I did the following:
Chain and gears
Set the timing on the new magneto setup, hooked up the wiring and verified spark
Tried to put gas through the gross tank for S&G. Too clogged..
Unclogged the petcock
Anddd

I got it kick over. woooot.


https://youtu.be/JQhAXP-nKDI

Among other things the carbs need to be rebuilt and rejetted and it looks like my clutch is fried.

Author:  Sirius [ Mon Jul 24, 2017 9:41 am ]
Post subject:  Re: Another One.. 2Cyl 2-Stroke Content

Sweet. Most 2 strokes take 2-3 kicks to start up...one kick is awesome.

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