Topic: 1973 RD350

[Scott S]

 I just acquired this 1973 RD350. It's my first ever two stroke and I'm clueless.



 It's nice, but not so nice that I can't do some minor mods. It runs great (man...that kick in the pants when you get it past 5K RPM!), but will run even better when I get rid of the old gas and clean the carbs.
 I know you can get as wild as you want with mods on these things. I'm not going there....at least not yet. I'm kinda thinking about a somewhat period bike, like, what would it have been like in '74?
 I have some vintage Magura bars and want some cool pipes.
 
 I'll forgo the $700-1,000+ hydroformed chambers, but are the cheapo DG pipes any good at all? I don't plan on any porting or anything like that. It has a K&N filter in the stock air box and I know I'll probably have to rejet a little bit. That's it....that's fine by me.
 I would LOVE to keep the center stand (weight savings be damned), so that limits my choices. I would also prefer to NOT have to run rear sets at this time.

 Can you guys walk a total RD/2-stroke newbie through this?

[Stev-o]

Nice bike!   I have your twin and prefer to keep it stock.  It is a lot of fun to ride!
I used it as a pit bike at COTA....

[ekpent]

  May run better with the stock pipes. A major old two stroke guru and race tuner I know says expansion chambers are pretty much worthless on these without doing the port work.
   Welcome to two stroke world !!

[jas67]

Nice!    I had one just like it!

+1 on the chambers comment, you'll need port work to make it worth it.

I'd keep it stock!

[scottly]

  May run better with the stock pipes. A major old two stroke guru and race tuner I know says expansion chambers are pretty much worthless on these without doing the port work.

I don't agree with that. The first stage of hopping up a 2-stroke was chambers; it was the equivalent of a big-bore kit on a 750 as far as the increase in power.
Scott, got any pics of the DG pipes?

[MoMo]

Keep it stock, that looks like a beautiful survivor...Larry

[grcamna2]

Keep it stock, that looks like a beautiful survivor...Larry

+1
I had one just like it in 1975' when i was 17 and I put a Lot of miles on that bike.I was friends w/ the service manager Bill who owned an RD that he was always working-on/improving,etc. at the local Yam. dealer and had him do a simple performance improvement to the stock pistons(and came to his house a lot to visit & get lessons) which really woke-up the engine,powerband then pulled strongly past 9200 rpm w/ stock mufflers plus great midrange.The K&N filter in the box is also the hot set-up for great mid-high rpms;expansion chambers aren't what you want(unless you can find a pr. of 'Torque Engineering' chambers  )because they will limit you to just top rpms and the RD is peaky as it is plus the oil pump isn't too reliable when you keep it above 9500rpm steadily.

[Scott S]

 I'm probably going to leave it as-is. I ordered a set of mirrors for it and spent a little time detailing it. Also have replacement tires on the way - Avon M26 RoadRiders in the stock skinny sizes; 90/90-18 and 100/90-18.

 I contemplated pulling the carbs, only because the RH one will pee from the overflow sometime. It seems to be getting better the more I ride it, though. I drained out the smelly old gas and put in some fresh non-ethanol. I'll see if the float gets better with some heat cycles and good gas. If not, I'll do the carbs.

[grcamna2]

I'm probably going to leave it as-is. I ordered a set of mirrors for it and spent a little time detailing it. Also have replacement tires on the way - Avon M26 RoadRiders in the stock skinny sizes; 90/90-18 and 100/90-18.

 I contemplated pulling the carbs, only because the RH one will pee from the overflow sometime. It seems to be getting better the more I ride it, though. I drained out the smelly old gas and put in some fresh non-ethanol. I'll see if the float gets better with some heat cycles and good gas. If not, I'll do the carbs.

I think flushing the tank w/ some BB's inside will help,probably some sediment in the tank/petcock.

[Scott S]

 The tank is spotless and lined properly with a POR-15 kit.
 I did replace a couple of fuel lines between the tank and the carbs. This Yamaha now has genuine Honda 5.5mm fuel line on it now!

 The weepy carb is something recent  according to the guy I got it from. And like I said, it  doing it less and less. Some fresh non ethanol gas with a splash of Marvel Mystery Oil in it and some heat cycles and I'll see what happens.

 To be honest  I'm a little scared of pulling the injector  nozzles on the carbs. They're not available if I break one.

[bwaller]

The RD's were giant killers (and the best wheelie machines), great lightweight simple motorcycle. Your's looks great, have fun with it. There were 1000's roadraced since it was a cheap way to get started, myself included.

[grcamna2]

The tank is spotless and lined properly with a POR-15 kit.
 I did replace a couple of fuel lines between the tank and the carbs. This Yamaha now has genuine Honda 5.5mm fuel line on it now!

 The weepy carb is something recent  according to the guy I got it from. And like I said, it  doing it less and less. Some fresh non ethanol gas with a splash of Marvel Mystery Oil in it and some heat cycles and I'll see what happens.

 To be honest  I'm a little scared of pulling the injector  nozzles on the carbs. They're not available if I break one.

The oil injector nozzles on each carb. w/ the oil line attached are a tapered fit into the carb. and you can carefully & slowly twist them back and forth between the pair of locating tabs w/ a decent pr. of gentle pliers;you install them by pushing/twisting them in slowly side-side until they're tight and seated.

[becken]

Lots of good information here: http://www.2strokeworld.com/forum/index.php
Also a good source of parts is https://www.economycycle.com/
They are a great little bike. Weak coils was a problem causing a lot of plug fouling. The new coils available should be better. Hondaman's ignition will help a lot.

[ekpent]

  I 'found' this one some time ago, a low mile 1974, by sitting next to a stranger at a bar one night for a reasonable price. Pays to ride your motorcycle to places like that and carry in your helmet     I have only ridden it a couple times, felt like it needed carbs cleaned etc back then from sitting so long. Another project this year on the list if I can keep some motivation.  I like your color scheme much better.

[grcamna2]

  I 'found' this one some time ago, a low mile 1974, by sitting next to a stranger at a bar one night for a reasonable price. Pays to ride your motorcycle to places like that and carry in your helmet     I have only ridden it a couple times, felt like it needed carbs cleaned etc back then from sitting so long. Another project this year on the list if I can keep some motivation.  I like your color scheme much better.

You did 'Score' on that bike  , I've always liked the original Maroon factory paint on the 74' model.

[ken65]

Nice bike. Take your time , do your homework and get to know it. They're fairly simple machines and they can be a bit moody at times. 

Set it up and ride it like you stole it..  Modern oil now is very good with little smoke .
Make sure the oil pump is delivering enough oil. A little extra won't hurt.. Ps. Keep some extra plugs near by.

[grcamna2]

+1 on taking a spare pr. of B8HS plugs with you and keep them in your tool kit.I think the Yamaha repro coils sold by MikesXS(same style/size coils used on the XS650's) are a very good deal for a pr. w/ decent(china) 3 ohm quality,please change out those original coils 

[Scott S]

 It has new coils and plug caps on it, too. Done not long before I got it.

 Call me crazy, but I kinda want a luggage rack for it so I can ride it to work!
 I'm also in need of a tool kit if anyone has one.

[MoMo]

It has new coils and plug caps on it, too. Done not long before I got it.

 Call me crazy, but I kinda want a luggage rack for it so I can ride it to work!
 I'm also in need of a tool kit if anyone has one.

Not crazy at all on that thought-I had the earlier R5 with a luggage rach and rode it everywhere sans problems.  Carried a spare set of plugs but never fouled one.  The secret is a heavy throttle hand

[Powderman]

Why does your title say 1973 RD350 if it's a 74?

[Scott S]

Why does your title say 1973 RD350 if it's a 74?

 Because it's a '73??

[grcamna2]

That's a true 73',first year they made them;the maroon color one that ekpent posted is a 74'.

[Powderman]

Sorry, I mistook ekpents post about his 74 for yours.

[ken65]

this is the son of your 73.  my 81 LC

[grcamna2]

Nice RD350LC Ken;are you in Canada?