RD400 'Motopaika'...Yeah I'm back.


Coast to Coast
I don't really need a build thread until the winter for this thing, but I'll be doing some small stuff over the summer as I ride it so I figured I'd post here. Got out on the RD for the first ride of the season. It was great weather and plenty warm enough by mid day. What a fun bike. It runs perfectly and turns heads. My buddy and I got back to the speed lab and started getting rid of some of the chrome by way of black powdercoat. I think it looks a hell of a lot better. I also replaced the front brake master with the one off my FZR. It fits much better as the stock one covered half the tach. I have some signals, brake light, and clubmans on the way to help update the look a bit more.










Re: RD400, not really a build

Oh wow. That's incredibly clean! Ya know, I've never been one to say "leave it stock", but I don't know, that thing is NICE!
Re: RD400, not really a build

Great bike Squad. I've been wanting an RD for a while- heck I even offered to trade my CL175 for Go's bike. Sadly, she declined......
Re: RD400, not really a build

Wow, that bike looks fresh from the box. Even the exhaust looks great. That is a hard bike to cut up. That said, it is yours. Looking forward to seeing what you do with it.
Re: RD400, not really a build

It's not getting cut up, don't worry ;D Anything done will be bolt-ons, as the bike needs very little. All I'll be doing is adding chambers, bolt-on FFTP rear sets, and probably a seat similar to this that uses a stock seat pan. Like lots of vintage bikes it's just 2 pins holding the seat on:

Re: RD400, Chambers Fitted

RD400 recieved some lovely DG chambers. I don't care what anyone says, how can you top these for $250? I put the pipes on the other night after work and after running it and doing a plug chop it's definitely running too lean. I ordered $100 worth of jets so we'll have at it tomorrow and see if I can get the mixture where it needs to be. Also I put on new sprockets front and rear and a new chain. The ones on there were completely shagged.






Re: RD400, DG Pipes Fitted

Very nice pipes. Like the way there are tucked neatly in.
Remember the 400's back in the day, properly set up pipes combined with fancy reeds were stupid powerful.
Re: RD400, DG Pipes Fitted

Looks great.

Glad to see you're happy with the DG setup as well. Im going to have to pick up a set for the R5 when the time comes, and found so many oddball reviews online.
Re: RD400, DG Pipes Fitted

VonYinzer said:
Looks great.

Glad to see you're happy with the DG setup as well. Im going to have to pick up a set for the R5 when the time comes, and found so many oddball reviews online.

Yeah man the reviews are all over the map. They fit right up, are pretty lightweight, and sound wicked. For 1000 bucks I'm sure you could get better, but who cares at $250?

Went from 115 main jets to 160's. Plugs look decent and it's running great.
crappy cell phone pic:

Re: RD400, DG Pipes Fitted

Sweet! I love those bikes, and that looks like a great example.

Glad to hear you got the mixture moving in the right direction. That's going to be a pantload of fun.
Re: RD400, DG Pipes Fitted

Well something broke about 40 miles from home yesterday. It's running on 1 cylinder and billowing smoke out the right chamber. Probably time for new pistons, rings, seals, etc. It does have 15K miles on it and it's still on the factory engine. Whatever, it's a 2 stroke, nothing to it ;D


Re: RD400, DG Pipes Fitted

Resurrecting this thread to start my winter build with. I have quite a few ideas and some parts have started coming in. The inspiration for the build will be this Seely:


Plated frame, British Racing Green colors, fabbed up oil tank, etc. Comfort is going out the window on this one as I don't really plan on riding it all that often, I've got my FZR for daily driver duty and will be just taking this out to look cool on ::) I'll be making a seat similar to that as I think it will fit the RD tank pretty well. It will not be sporting a full fairing but have more of a classic cafe look.

I've been slowly taking bits off of it now that I have a garage. Now that I'm fully moved in to the house progress should flow as money allows. This home ownership thing is expensive....

Where she sits now:

Re: RD400 Winter Build kicks off on Page 2

Got some clip-ons yesterday so I took the headlight and gauges off and mounted those up. I will be doing a different dash setup, along with a roccity headlight bucket and motolanna headlight mounts. All of which are in route. Also popped the tank back on so I could start mocking up the seat.

RD400 by TMK84, on Flickr

RD400 by TMK84, on Flickr

RD400 by TMK84, on Flickr

The seat will look similar to the seat on the Seeley posted above, however I will add some lines that follow the lines on the RD tank. I plan on having a plug machined out on a CNC and then making a proper mold from that, followed by a finished part. Carbon sounds appealing as I'd love to make this thing a featherweight. After pulling all the stock stuff off it's amazing how much weight has been shaved...

Here's the first concept for the seat:

RD400 Seat Concept 2 by TMK84, on Flickr
Re: RD400 Winter Build kicks off on Page 2

So what model is that? Most of it looks like a C, but it's a much later "Daytona" head. Interesting. We used DG pipes on an F model with electronic ignition and it flew.

hardest thing to get right was part throttle fueling and we ended up with LEDAR nozzles and something like 240 mains.

What did the dead cylinder turn out to be?
Re: RD400 Winter Build kicks off on Page 2

It is a C with a Daytona head. Good eye man. I honestly have no idea what the dead cylinder is due to. The piston looks great and the bore is immaculate, same with the combustion chambers. I was getting spark in that cylinder, but maybe the timing is off or something with the points. I'm going to upgrade to electronic ignition when I refresh the motor, along with a better electrical system so I can run some decent lighting. But nothing glaring was wrong so Maybe something else will come up as the motor comes apart more?

Piston from the dead cylinder:

RD400 Piston by TMK84, on Flickr
Re: RD400 Winter Build kicks off on Page 2

Sounds like it lost spark on that side. Piston has a lot of blowby but nothing terminal. It's usually the left side that goes as it sucks air in through a dry crank seal. We had a yard ful of RDs and spare motors at one time and the left pot was usually several sizes larger than the right

I'd be tempted to put the top end back on and do a leakdown test (the 2 stroke low pressure variety). Just remember that RDs have a lab seal in the crank and that allows pressure leakage from one side to the other, so they both have to be sealed off.

This was the inspiration for an E model I was converting.


It's Chris "Jez" Kelsall's bike and the exhaust are Swarbrick. I liked the miniature 2 stroke Superbike look
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