pidjones' bicentenial build - a '76 RD400

pidjones

Over 1,000 Posts
"Back in the day" I traded a too-small-for-me RD250 in on a brandy new '76 RD400 with the cool new cast wheels, front and rear disks, and promised broad power band. I got the Geneva green with Honda CB400F bars. Loved the machine (I had a 24 year-old body then, too) and rode it a lot on off-crews, even from Charleston, SC to Monticello, KY and back one weekend. Early in '79 I knew that my discharge was due that summer, and was mature enough to realize that I was not mature enough to have that bike on the Eastern KY/TN roads where I planned to move. So, I sold it to a shipmate. Life happened and I didn't have another bike until '04. Since then it has been primarily GoldWings for me. I like the big, curvy girls. But I've always had a wandering eye for another little RD filly. So, when I saw one in Marketplace in need of a loving daddy to straighten her out and keep her like she deserves (while she willingly serves his desires), she was made mine.

The Chappy red paint will have to go, and Geneva green replace it. Engine internals are yet to be explored, yet a hand-push on the kicker gives a satisfying feel and sound. Carbs and 98% of engine are there, including down pipes, but no mufflers (I plan for stock). Clocks are trashed, but replacements on the way. Also both front and rear calipers. Notice the non-stock disks? Never been touch by a pad! Rear fender, tail light, "stay" (hoop) and signals are needed plus seat cover. Patience and ebay will provide.
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Rider52

Over 1,000 Posts
A good find! Most around ATL are frames with junk motor pieces. The seat and tank are big pluses!
 

pidjones

Over 1,000 Posts
Been busy working on kitchen change over from electric drop-in to gas slide-in to ~3" taller than stock cabinets. Everything had to be adjusted, it seemed. Finally ready fro the gas company to come hook it up. Went out to the shed and tested the coils - 2 Ohm primarys and ~7k Ohm scondarys. Stuck my compression tester on the Right cylinder and gave it five easy kicks - 90 psi. Same for the Left. Not stellar, but at least there are pistons without holes in it.
 

pidjones

Over 1,000 Posts
A good find! Most around ATL are frames with junk motor pieces. The seat and tank are big pluses!
The seat may not be such a plus. I've read this is common - the pan is barely there. Enquiring from the ebay seller of Vietnamese seats to see if they will sell judt the pan. Got keys in yestderday - I'll be able to check in the tank today.
 

teazer

Over 1,000 Posts
DTT BOTM WINNER
that compression is very low. It may be rusty bores and stuck rings, but the crank seals are probably shot. You could do a leakdown test, but I'd suggest a complete rebuild. Fortunately the motor can be stripped and rebuilt in an evening if you have the parts on hand.

use genuine Yamaha oil seals which are reasonably priced and Pro-X pistons which are good balance between performance and cost. After you build the motor, do a leakdown test. It's not unusual to find minor leaks around the reed boxes/intake manifolds and it's best to find out sooner rather than later.

And for spare parts Economy Cycles in Texas is a great source. John is an RD expert and all round good guy.
 

Rider52

Over 1,000 Posts
Shame on the seat pan. I ordered one of the Vietnam seat for the CL360 and I'm waiting on shipment.
 

pidjones

Over 1,000 Posts
Shame on the seat pan. I ordered one of the Vietnam seat for the CL360 and I'm waiting on shipment.
If their stockish seat is very close to the original, wuld be a good deal compared to finding a pan, moving the foam to it, and then buying and fixng it up with a new cover. Ebay seller hasn't responded yet, so I'll ping him again.
 

pidjones

Over 1,000 Posts
Set of clocks came in with ignition switch, seat lock (with helmet lock) and key. Found a rear "clip" - stay, fender, tail light , signals, mounts on ebay and snapped them up. Moved one bike to the other side of the basement. Might swap one out to the shed next week to get the RD in the garage and start on it.
 

pidjones

Over 1,000 Posts
Started digging through the bin of parts tonight. Pulled out the carbs and took them off of the throttle cable. The cable is seriouslt freyed to the pump, so will all need replaced. Rear master totally dry and full of evaporated brake fluid, but no corrosion evident (yet). Brake light switch and feed adapter off. I'll pull it apart and check for corrosion in a few days along with the front master that held dark DOT3 syrup. The front has a mirror stud broken off in it, so that is soaking in penetrant. The front brake lever is broken also (probably the same incident that dented the tank, distorted the headlight bucket and mounts, and smashed the speedo and indicators). All that I've done so far with the carbs was to place them in separate plastic boxes marked R and L.

Feels good to be starting on this, but would feel better if someone bought my '78 GoldWing to give me more room to work.
 

pacomotorstuff

Coast to Coast
Look at doing an ignition coil upgrade using automotive coils, condensers and ballast resistors (Oregon Motorcycle Parts has a kit for this, if you don't wish to source the parts yourself). I did this with my 350 Yamaha, set the spark plug gap at .035" instead of the factory-specified .028 and 8,000 miles later, pulled the plugs just to check them - the bike was running fine. The electrodes were a nice light tan brown the full length; looked like they came from a 4 stroke motor. Prior to the coil conversion, the best I ever got was 1,000 miles on a set of plugs. Presently, I'm doing a similar conversion on another 2 stroke but this time, using a high performance Accel coil and going to start the plug gap at .040 and close it up a bit if I get a misfire. I also stuck with the points ignition in both cases and never really had any issues with them.
Good start for a nice restoration.
Pat
 

pidjones

Over 1,000 Posts
I'll start out with the stock Yamaha ignition as long as the parts are Ok. May need new points and condensers, but might use generic automotive condensers if they fit. I've had poor luck with motorcycle condensers. Did a leak-down test today, and the right-hand crank seal is leaking between the seal and the case, so it all has to come apart. Folks on the RD forums say I should take it apart anyway just to check it all. Orders in for seals and gaskets. Will do part of the disassembly in-frame, then take the rest out so the frame can be stripped and repainted. Master cylinders are rebuilt (although with the original parts - sure looked nicer than the GoldWings) and new repop calipers from 4into1 fitted, but they have to come off and have their mount pads milled a couple mm to center the disks. Or, maybe I should buy some NOS disks? Maybe the aftermarket disks on it aren't right.
 

pidjones

Over 1,000 Posts
Did the compression check with just a dribble of oil down the plug holes and into the intakes to hopefully prevent piston/ring/bearing damage. Both were 110.
 

teazer

Over 1,000 Posts
DTT BOTM WINNER
Still low, but nothing that fresh crank seals and rebore won't fix. That must have been with pipes and carbs off, so we can't blame them. It's possible that the pistons and bore are OK and that it just needs rings, but expect the worst and hope for the best.

Stock ignition is barely enough, but should be a good place to start. Coils are not too expensive and Vintage Smoke makes a nice Dyna (points replacement) ignition. How bad is your seat base? They can often be welded up and powder coated to work if you don't mind tin bashing.
 

pidjones

Over 1,000 Posts
Still low, but nothing that fresh crank seals and rebore won't fix. That must have been with pipes and carbs off, so we can't blame them. It's possible that the pistons and bore are OK and that it just needs rings, but expect the worst and hope for the best.

Stock ignition is barely enough, but should be a good place to start. Coils are not too expensive and Vintage Smoke makes a nice Dyna (points replacement) ignition. How bad is your seat base? They can often be welded up and powder coated to work if you don't mind tin bashing.
Pretty much of the lip on the seat is rotten. Might be repairable, but I would almost try making a fiberglass copy with this one as the mold. I have one that I bought on ebay on my Hunley build, and it is great. There is also the options to a) buy a repop from Texavina that isn't as thick as the original b)buy a repop sest pan from Texavina that is thinner material than original c)wait five or six months for Texavina's team in Vietnam to produce a stamped steel pan like the original.

Seals and gaskets are on order. Waiting until she is apart to decide on pustons and rings since I don't know what is in it.

Meanwhile, clean the other carb, pull the lump and begin frame cleanup. I'll probably leave the electrics stock with refreshed connectors. They functioned well when new, and I'll replace anything that shows weakness.
 

pidjones

Over 1,000 Posts
Shazbot. Pulled the left head. Piston and head spotless. Cylinders? I think they must have installed new pistons without honing or something. Never seen them with zero cross hatch and piston this clean. Guess I'll know more tomorrow when I pull the jug and see the rings and piston sides/measure the cylinders. Of course, the brown at the top is oil mixed with rust running down, still down by the ports. But then, I'm just learning two strokes. At least both carbs are clean now!
left cylinder.jpgleft head.jpgtop left piston.jpg
 

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