Yamaha RD350 is my first motorcycle, a 350cc, twin cylinder, 2 stroke engine from the year 1988. The full name is Yamaha RD350 YPVS F2 -88, 1WT engine. I have had it since 2015.
Super fun bike to drive. It’s very lightweight and power wheelies on first gears.
- Before and after
- Restoration summary
- Front forks
- Rear swingarm
- Engine and transmission
- Tank and fuel lines
- Fairings and paint
- 350cc twin cylinder 2 stroke, 1WT engine
- Jolly moto exhaust
- V-Force reed valves
- 2x 28mm Mikuni flat slide carburetors
- Zeeltronic PCDI-10VT programmable ignition and exhaust valve controller
- Iridium spark plugs
- ~63HP on rear wheel
- Dry weight ~110 - 120kg ( This is an estimate, original dry weight is 141kg)
The after state is still missing rear fairings + rims and front fender should be painted. Also the bike has not been cleaned in a while.
The bike also looked like this for a couple of years, but the rear fairing’s fasterners kept breaking up from all the vibration, so I didn’t want to keep fixing them. Also It’s nice to change the look of the bike every now and then.
The bike was undriveable when I got it and required a lot of work to fix it. It had countless problems, but the main issues that the bike had were here:
- Gas tank was covered in rust inside
- Gas lines and carburetors were covered in rust because of the gas tank.
- Carburetor settings were way off, engine didn’t rev or run idle.
- Didn’t rev or idle at all, also oil mixture was so bad that you couldn’t see through the smoke from the exhaust.
- Didn’t know the condition of the crank or the gearbox so engine overhaul was needed.
- Steering head bearing was completely done so that the handlebar couldn’t be properly moved.
- Front fork oil seals were leaking.
- Bad battery
- Fairings had bad paint and looked like crap so new fairings and seat were needed and a paint job.
- A lot of weird “fixes” that the old owner had done which needed to be fixed again.
The bike had been sitting in a garage for the past 5+ years before I bought it so a complete engine rebuild and overhauling pretty much every part of the bike was necessary.
Can’t remember all the details from the rebuild since I’m writing this 5 years after these photos. I’m just going through my old photos, adding some of them here and write what I can remember.
Old top yoke steering bearing. The bike didn’t handle very well because the steering bearing had some damage done to it. The steering would get a little bit stuck everytime when the handle bar was straight.
Rear swingarm, linkage and shocks looked like they had seen alot so I took them apart, bought new spacers + other parts and added new lubrication.
The engine didn’t run very well and it was crazy to even run the engine without knowing the condition of it. The engine had been sitting still for 5 years so it had to be taken apart and refurbish it.
Outer crank bearings were making noise so the crank had to be sent to the machine shop with the cylinders. Crank was also measured properly in the machine shop to make sure it wasn’t bent.
Transmission oil, coolant liquid and 2 stroke oil. Carburetors, cooling system, YPVS and so on had to be assembled at this point also, didn’t take pictures though, not that interesting. At the background there is one of the carburetors diving in diesel to clean it, more on this in the tank and fuel lines section.
Got to have some performance exhaust on two strokers. More lightweight, more power, better sounds. I didn’t find any recordings of my own of jolly moto pipes on RD, but here are some youtube clips:
- https://www.youtube.com/watch?v=f0G3IVtEQms ( Dyno clip, I have pretty much same specs as this bike )
- https://www.youtube.com/watch?v=iK_on_AbUfI ( Driving clip, bigger carburetors though )
Most annoying part of this whole project was trying figure out how to remove the rust from the gas tank. The rust would immediately clog the fuel filters and the jets in the carburetors. I battled with this problem for weeks and tried several different methods.
Method number 1. I bought a liter of this expensive rust removal chemical from the local hardware store.
Placing the tank in different positions didn’t really help because the spot where the chemical removed the rust would start to just rust almost immediately after removing the chemical.
So I had to give up with this one and come up with something better.
Method number 2. I went to a local agri market and bought 4 kilos of citric acid. This can be mixxed up with water so that it covers the whole tank.
Method number 3. I found this tank rust removal and zincing kit online for about 60€ and decided to try it. Can’t remember the name of the kit sadly, it was the method that finally worked.
It had 3 parts, some rust removal chemical, some sort of anti rust chemical and finally a zinc paint.
The rust removal chemical would need to be added to the tank and shake it properly so that every part of the tank is covered. Then drain out the rust removal chemical and add the anti rust chemical, again proper shaking required. Drain out the anti rust chemical and finally add the zinc paint to the tank and make sure the zinc covers every part of the tank.
I checked the insides of the tank last year ( 2019 ) and the zinc has stayed in there with zero rust. I added the zinc in the tank in 2015.
I think the bike looked like crap when I bought it so it had to be painted. Also the last owner build the rear fairing using wood and what not so it weighted a ton. Had to buy new fairings because of it.
I hunted for this little piece for a month from the internet and this cost something like 75€! It belongs to the back of the seat, to the rear fairings connecting the right and left side.
Didn’t know anyone with a 3d printer at the time, it would have been a lot cheaper and faster to just print one.
I was too lazy to sand the front fender because it is more a complex shaped piece so I didn’t paint it. I thought I would paint it later but at least haven’t yet painted it 5 years later.
With the zeeltronic programmer, I can adjust the ignition timings and at which rpm area will the exhaust valve start to open and close.
I have been writing this post quite some time now, mainly because finding good pictures from the old albums is time consuming, I think it’s best to end the post here.
These pictures include the main things I did during the restoration, but I have countless of pictures from after the restoration because 30 year old bikes tend to break alot. Especially 2 stroke engines with a driving style like mine and when the total amount driven with this is somewhere around 80 000km.
To be honest the bike has been like this for the past 2 yers. Though I drove something like 12 000km with it before this state. Also I had to open the engine at least once during those 12 000 kilometers. The engine has been in the back of my garage since the head gasket blew up.
Didn’t find motivation to rebuild the engine yet since one of the cylinder head bolts has bigger threads than what can fit through the head gasket, which is 3 layered metal gasket so it’s not easy to drill it bigger without having the edges of the bolt holes thickening.
I have had all the required parts to fix it for a while now. Maybe during the next winter I’ll finally fix it, not that big of a deal especially after this sort of restoration.