78 RD400E revival

Last year I went to go look at this bike to buy as a restoration project, the seller's ad listed two '78 RD's. I originally intended to only buy one, but when he offered me a price on both bikes and everything RD related in his possession, I jumped on it. One was mostly original and prepped for storage, ie. fuel and brake fluid was all drained, and nice chrome pieces were removed and wrapped up. The other was already restored and modded, and running but not jetted properly. In addition to a ton of yambits packages and spare parts from another bike he had previously parted out, a set of FPP expansion chambers were included as well. My plan was to get the runner jetted and sell it as-is, and to do a showroom style restore on the original.



Mostly original bike



Restored modified bike

Well I got the restored runner jetted a little better (still not dialed in perfectly) and went ahead and listed it on craigslist. I know price and value is a hot topic on these vintage bikes, and actually my listing was used in a Jalopnik blog specifically about vehicle asking prices... Its an interesting read. For full disclosure I didn't even know about the article for several months after I sold the bike, and I *did* get my asking price when I sold it, by the way. At a nearly 50-50 split on the poll I don't feel like my price was all that bad, and the buyer drove 3 hours and kept telling me how hard of a time he was having finding a runner for a decent price.

http://jalopnik.com/for-3-250-give-this-1978-yamaha-rd400-a-stroke-or-two-1738651582

Next post - update on the keeper bike!


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I started in on my keeper bike by pulling apart and cleaning the carbs, checking the timing and compression and firing it up! It sounded good with the spare set of open pipes I had. A little noisy on the top end but with the mileage it had(25,800) I fully expected it to be at least a little worn out. With the engine running, I started in on the brakes and quickly realized it would be a little more difficult than putting pads and brake fluid and go, as the pistons were seized in the calipers and there was a little gunk evident in the front m/c. I rebuilt the calipers and flushed out the front cylinder, and it bled pretty easily, but after the same treatment and a few hours of bleeding, the rear still won't build pressure. I guess I'm gonna have to rebuild the rear m/c after all

With a functioning front brake I wanted to see how the bike ran and handled, so I took it for a short ride down my driveway and to the corner. I'm happy with it so far, now I just need to fix the rear brake and get it running for the road. My plans have changed a bit since I got it, now I'm planning to build a reliable good looking rider, instead of a showroom restoration that I don't want to ride. I'll get it running reliably and put a new top end in it (I have a spare set of original bore cylinders) and then tear it down for paint!

Thanks for looking!


Some aftermarket coils I don't recognize. Seems strong though!


It lives!


After my first ride on it.


Last inspection happened the year I was born!

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On that mileage the engine should be fine in regards to wear, but could have age related problems like rusty bores or rings, but if it runs good it should be fine.
Not sure what the top speed of an RD400E is, I had a C and a D which would do about 105 mph, E should be faster as it has different porting and ignition to the early bikes - but worse brakes.

Replace crank seals asap. Nearly 30k miles is a good bit for an RD if everything is original. If the bike sat for any period of time the crank seals are shot. A full "rebuild" on this motor is pretty simple and if the mechanical bits are all reusable, it's cheap insurance.

Good lot ya got there. Interested to see this one, RDs have been on my radar for a while now.

Would love to have one of these one day!

Oh yeah, crank seals are definitely on the short list. A set of new ones still in the package was included with the bike, but I have this mindset that until the bike is inspected and registered for the street I can't focus on anything else really. So legal nonsense first, then once I have a plate for it, crank seals will probably be the first item taken care of.

It doesn't have any warning signs of bad seals, it smokes about the same on both cylinders and they both seem to run about the same but I definitely want to change them just for peace of mind.

Fenders, tail light and mirror installed!

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Bad crank seals will destroy an engine. Not, oh boy... That stinks. More like, HOLY FUCK WHY IS MY CONNECTING ROD STICKING OUT OF MY CRANKCASE AND WERE THE HELL DID THAT CYLINDER GO!?!?!?!

For real. I've seen the carnage first hand.

Dude... chill. Thy will be done.

I might be new to the site but I'm not new to vintage bikes, two strokes, or engine failures. I know the warning signs and I've seen the aftermath. I appreciate the concern though.

In other news, the rear brake master has been rebuilt and bled, an intermittent brake light issue was traced to a faulty ground wire and fixed. I'm waiting on a package from yambits with the damper for the rear brake light so it doesn't vibrate the bulbs out while riding ;D

Not much to update on the bike front lately, I've pretty much just been enjoying the weather and awesome roads by my house!

https://www.youtube.com/watch?v=_9aj76_n0zs

Planning to do the full tear down over the winter.